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A long-standing mystery in paleontology is why we have discovered thousands of eggs from some types of dinosaurs, such as the duck-billed hadrosaurs, but none at all from other types [...]

Some wood duck hens lay eggs in nests that aren't theirs, while others stay at home. The behavior isn't simply cooperative or a con job. It's complicated in the duck [...]

The Mexican Woodnymph (Eupherusa ridgwayi) is endemic to west-central Mexico with a narrow distribution range and relatively small population size. The species nest, nesting activities and nestling's characteristics were unknown until now. We generated a map of this species using data from BirdLife International, the Global Biodiversity Information Fund database, e-Bird, and the Naturalista. We used the Mexican Woodnymph records in Jalisco and projected them on a vegetation map. We documented a female constructing a nest, later nesting, until the nestlings flew out of the nest in the cloud forest in central-western Mexico: Jalisco state. The nest site was characterized and the materials used for the nest construction were determined. In addition, we documented several observations made on territorial and foraging behavior., INTRODUCTION Eupherusa is the monophyletic genus of tropical hummingbirds in the family Trochilidae (Schuchmann, 1999). It comprises five recognized species, namely, Eupherusa poliocerca (White-tailed Hummingbird), Eupherusa cyanophtys (Blue-capped Hummingbird), Eupherusa [...]

Exurban development (i.e., low-density residential housing) comprises at least 25% of the contiguous United States and disturbs the natural landscape, typically impairing habitat for forest interior songbirds and creating habitat for urban-adapted species. However, it is poorly known how exurban development affects shrubland birds, which require disturbance to create habitat (i.e., early successional vegetation). Therefore, our objective was to explore landscape patterns associated with shrubland bird occupancy in a forested region undergoing extensive exurban development. To address this objective, we conducted point counts across a natural-exurban gradient in Macon County, North Carolina, USA, and measured 8 land-cover covariates within 200 m and 1,000 m of survey sites. The covariates were percent canopy cover (CANOPY), contagion (CONTAG), percent of the landscape (PLAND) that was developed (DEV), elevation (ELEV), PLAND forest (FOREST), forest edge density (EDDF), Simpson's landscape diversity index (SIDI), and PLAND shrub (SHRUB). We modeled occupancy for 12 shrubland species using a hierarchical occupancy model that accounts for false-positive detections. We fit a global model that incorporated all non-collinear covariates and used stochastic search variable selection to determine which covariates showed a relationship with occupancy. The most frequently selected covariate was CANOPY (8 species), followed by ELEV (5 species), DEV (4 species), SIDI (3 species), and CONTAG (2 species). CANOPY and DEV were negatively associated with occupancy. SIDI and CONTAG are both metrics of landscape heterogeneity; heterogeneity was positively associated with occupancy. Additionally, of the study species, generalists showed the highest occupancy rates, while specialists showed the lowest occupancy rates. We suggest that the associations between occupancy and canopy cover and landscape heterogeneity are logical because natural disturbance, in addition to creating early successional habitat, decreases canopy cover and increases landscape heterogeneity. Furthermore, we suggest that exurban development can drive these patterns, but, given the negative (or neutral) relationship between DEV and shrubland bird occupancy, we hypothesize that exurban development as a form of disturbance does not generate early successional habitat. We conclude that exurban development will benefit only a small subset of urban-adapted shrubland species without creating habitat for most shrubland birds, despite exerting considerable disturbance to forested landscapes. Received 9 February 2018. Accepted 15 December 2018. Key words: Bayesian, disturbance, habitat selection, landscape, occupancy model, southern Appalachian, urbanization El desarrollo exurbano (i.e., desarrollo residencial dc baja densidad) se extiende por al mcnos en el 25% dc los estados eontiguos de los Estados Unidos. Perturba el paisaje natural, tipicamente impidiendo el habitat de aves de interior de bosque y creando habitat para cspecies adaptadas al ambiente urbano. Sin embargo, se sabe poeo sobre eomo el desarrollo exurbano afecta a las aves de matorral que requieren de perturbacion para erear su habitat (i.e., vegetacion sucesional temprana). Nucstro objetivo fuc cxplorar los patroncs del paisaje asociados con la ocupacion en una region de bosque que sc encuentra en un proccso extensivo de desarrollo exurbano. Para atender este objetivo, llevamos a cabo conteos por puntos a lo largo de un gradiente natural-exurbano en el condado dc Macon, North Carolina, EUA, e hicimos mediciones de ocho covariables de cobcrtura del suclo dentro de 200 y 1000 m dc los sitios visitados. Las covariables fueron el porcentaje de cobertura del dosel (CANOPY), contagio (CONTAG), porcentaje del paisaje (PLAND) que ha sido desarrollado (DEV), elcvacion (ELEV), PLAND de bosque (FOREST), densidad del horde del bosque (EDDF). el indice de diversidad del paisaje dc Simpson (SIDI) y PLAND de matorral (SHRUB). Modelamos la ocupacion de 12 especics de matorral usando un modelo jerarquico de ocupacion que cuantifica dctcccioncs dc falsos positivos. Los ajustamos a un modelo global que incorpora todas las covariables no-colincarcs y usamos la busqueda estocastica dc seleccion dc variables para detenuinar que covariables mostraban una rclacion con la ocupacion. La variable mas frecucntemcnte scleccionada fuc CANOPY (ocho espceies), seguida por ELEV (cinco especics), DEV (cuatro especies), SIDI (ties espeeics) y CONTAG (dos especies). CANOPY y DEV fueron negativamente asociadas con la ocupacion. Ambas, SIDI y CONTAG, son metricas de heterogeneidad del paisaje. La heterogeneidad estuvo positivamente asociada eon la ocupacion. Ad!cionalmentc, entre las espceies cstudiadas las gcncralistas mostraron las tasas de ocupacion mas altas, mientras que los cspccialistas mostraron las tasas de ocupacion mas bajas. Sugcrimos que las asociaciones entre la ocupacion, y la cobertura del dosel y la heterogeneidad del paisaje son logicas debido a la perturbacion natural, ademas dc erear habitat sucesional tcmprano. disminuyen la cobertura del dosel e incremental! la heterogeneidad del paisaje. Ademas. sugerimos que el desarrollo exurbano pucde ser el responsable de esos patroncs, pero, dada la rclacion negativa (o neutral) entre DEV y la ocupacion dc aves dc matorral, nuestra hipotcsis es que el desarrollo exurbano como forma dc perturbacion no genera habitat sucesional tcmprano. Concluimos que, si bien el desar[tau]ollo exurbano ejerce una perturbacion considerable en paisajes boscosos, este bencficiara solamentc a un pcquefio subconjunto de espceies dc matorral adaptadas a habitat urbano sin erear habitat para la mayoria de las cspecies. Palabras clave: Apalaches del sur, bayesiano. modelo dc ocupacion, paisaje. perturbacion, seleccion de habitat, urbanizacion, Humans affect birds profoundly via habitat loss and degradation from land use change (Vitousek et al. 1997, Devictor et al. 2008). Urbanization--a form of land use change--is expanding as cities [...]

Cooperatively nesting birds are vulnerable to social parasites that lay their eggs in host nests but provide no parental care.sup.1-4. Most previous research has focused on the co-evolutionary arms race between host defences and the parasites that attempt to circumvent them.sup.5-9, but it remains unclear why females sometimes cooperate and sometimes parasitize, and how parasitic tactics arise in cooperative systems.sup.10-12. Here we show that cooperative and parasitic reproductive strategies result in approximately equal fitness pay-offs in the greater ani (Crotophaga major), a long-lived tropical cuckoo, using an 11-year dataset and comprehensive genetic data that enable comparisons of the life-histories of individual females. We found that most females in the population nested cooperatively at the beginning of the breeding season; however, of those birds that had their first nests destroyed, a minority subsequently acted as reproductive parasites. The tendency to parasitize was highly repeatable, which indicates individual specialization. Across years, the fitness pay-offs of the two strategies were approximately equal: females who never parasitized (a 'pure cooperative' strategy) laid larger clutches and fledged more young from their own nests than did birds that both nested and parasitized (a 'mixed' strategy). Our results suggest that the success of parasites is constrained by reproductive trade-offs as well as by host defences, and illustrate how cooperative and parasitic tactics can coexist stably in the same population. Mixed-effects logistic regression modelling of a dataset of individual reproductive behaviours shows fitness pay-offs of cooperative versus mixed cooperative and parasitic reproductive strategies are approximately equal in female greater anis (Crotophaga major)., Author(s): Christina Riehl [sup.1] , Meghan J. Strong [sup.1] Author Affiliations: (1) Department of Ecology and Evolutionary Biology, Princeton University, Princeton, USA Main Conspecific brood parasitism--in which a female lays [...]

We examined relationships between nest success and attributes of brood crevices in rock outcrops used by green salamanders (Aneides aeneus) on the Blue Ridge Escarpment from 2010 to 2015. We used data from a long-term monitoring program by the North Carolina Wildlife Resources Commission and defined nest success as evidence of at least one egg hatching in a clutch. We georeferenced all rock outcrops with nesting green salamanders and calculated straight-line distances to closest outcrops with nesting green salamanders using ArcGlS. A total of 2578 rock outcrops during six nesting seasons were surveyed to determine nest success for 168 nests in 88 crevices from 74 outcrops. Where all crevices could be thoroughly surveyed, attributes of brood crevices (N = 29) and corresponding random crevices at 29 rock outcrops were quantified. Nest success during the 6 y period ranged from 73-92% and was not related to year or any crevice attribute. There was a negative relationship between nest success and straight-line distance to outcrop with nesting green salamanders, and crevices that contained one successful nest were more likely to have a successful nest in another year. Females selected brood crevices that were higher above the ground and shorter in length than those randomly available on the outcrop. These resulLs suggest that the odds of a green salamander having a successful nest decrease as the distance to the closest rock outcrop with other nesting individuals increases. Female green salamanders select brood crevices with attributes that likely minimize direct competition and nest predation from other species of salamanders as well as other predators in general., INTRODUCTIONThe green salamander (Aneides aeneus) is a rare species associated with rock outcrop habitats of the Appalachian Plateau and Blue Ridge Province (Petranka, 1998). As a result of its close [...]

Despite Hispaniola's high rates of avian endemism and its importance to supporting global biodiversity, relatively little information is available on the basic biology and ecology of its resident birds, particularly the 31 species endemic to the island. Here we describe the nesting ecology and nesting success (n = 643 nests) of species of resident and endemic birds occurring in southwestern Dominican Republic, spanning 4 major habitat types over an elevational gradient from sea level to ~1,750 m: desert thorn scrub, dry broadleaf forest, pine forest, and montane cloud forest. We quantify nesting success in terms of daily nest survival and cumulative survival probabilities for 14 resident species (3 endemic) and describe life history metrics for these species, including clutch size and length of incubation and brooding. We compare nest success among habitats and highlight the large impact of introduced mammalian predators in all habitats studied. Nesting success was generally lower than in temperate areas, but comparable to other studies of nesting success in the Neotropics, with a mean cumulative survival probability for all open-cup nesting species of 33.6%. Nest failure due to predation varied by species but was overall notably high, ranging from 73% to 100% of all failed nests. Predation was primarily attributable to nonnative mammals introduced via European colonization. Received 12 May 2017. Accepted 22 December 2017.Key words: Dominican Republic, Hispaniola, introduced predators, nest success, program MARK, tropical birds.A pesar de las altas tasas de endemismo de aves de la Espanola y su importancia para apoyar la biodiversidad mundial, se dispone de relativamente poca informacion sobre la biologia basica y la ecologia de sus aves residentes, particularmente las 31 especies endemicas de la isla. Aqui describimos la ecologia de anidacion y el exito de anidacion (N = 643 nidos) de especies de aves residentes y endemicas en el suroeste de la Republica Dominicana. abarcando cuatro tipos principales de habitats en un gradiente altitudinal desde el nivel del mar a ~1750 m: matorral espinoso del desierto, bosque seco latifoliado, bosque de pino. y bosque nuboso montano. Cuantificamos el exito de anidacion en terminos de la supervivencia diaria del nido y las probabilidades de supervivencia acumulada para 14 especies residentes (3 endemicas), y describimos las metricas del ciclo de vida de estas especies, incluido el tamano de la puesta de huevos y la duracion de incubacion y crianza. Comparamos el exito de los nidos entre los habitats y destacamos el gran impacto de los depredadores mamiferos introducidos en todos los habitats estudiados. El exito de anidacion fue generalmente menor que en las zonas templadas. pero comparable a otros estudios del exito de anidacion en el Neotropico, con una probabilidad acumulada de supervivencia para todas las especies de anidacion de copa abierta del 33.6%. El perdido del nido debido a la depredacion vario segun la especie, pero en general fue muy alta, variando del 73% al 100% de todos los nidos perdidos. La depredacion fue principalmente atribuible a mamiferos introducidos a traves de la colonization europea.Palabras clave: aves tropicales, depredadores introducidos, exito del nido, La Espanola, Programa MARK. Republica Dominicana., Knowledge of the basic biology of Hispaniola's resident and endemic bird species has expanded substantially in the last 15 years (Latta et al. 2003, Rimmer et al. 2008, Townsend et [...]

Midwestern savannas and woodlands were once dominant transitional communities but are now considered endangered. Savanna and woodland habitat is being restored and managed throughout the central and east-central portions of the United States, bin few studies have investigated the effects of management on songbird nest survival. We monitored songbird nesls in managed savanna and woodland siles in southern Missouri from 2009 to 2011 to estimate nest survival and to predict the relationships between nest survival and temporal, vegetation structure, and nest site variables. Daily nest survival was generally higher for the four canopy-nesting species, Acadian flycatcher (Empidonax virescens), blue-gray gnatcatcher (Polioptila caerulea), Eastern wood-pewee (Contopus virens), and summer tanager (Piranga rubra) (0.96-0.98), than the four shrub-nesting species, field sparrow (Spizella pusilla), indigo bunting (Passerina cyanea), prairie warbler (Setophaga discolor), and yellow-breasted chat (Icteria virens) (0.92-0.95), for which we estimated survival rates. In general vegetation structure around the nest had little influence on nest survival, except for canopy cover, which occurred in the top model set for four species. Nest survival of yellow-breasted chats was much higher in areas of lower canopy cover, whereas nest survival of Eastern wood-pewees was moderately lower and indigo buntings and summer tanagers peaked at low and intermediate levels of canopy cover, respectively. Therefore, savanna and woodland management, which tends to open the tree canopy, may benefit some bird species in this forested landscape, particularly those associated with low to intermediate canopy cover., INTRODUCTION Oak savannas and woodlands were dominant natural communities in the Midwestern United States prior to European settlement but are now considered endangered (Nuzzo, 1986; Noss et al., 1995). These [...]

Black-capped Vireos (Vireo atricapilla) and White-eyed Vireos (Vireo griseus) are closely related and ecologically similar. Despite these similarities, the White-eyed Vireo is widely distributed and common, whereas the Black-capped Vireo has a restricted breeding range and is currently federally endangered in the United States and Mexico. Here we address this apparent paradox with a comparative ecological study of co-occurring Black-capped and White-eyed vireos. We studied vireos in shrublands and woodlands in central Texas, USA, in 2013 and 2014. We used point count surveys (n = 256) and nest monitoring (n = 144) to determine arrival dates, settlement patterns, nest site selection, and nest survival relative to temporal and habitat factors. Additionally, we conducted reciprocal playback trials (n = 16) to test for the presence of interspecific aggression. White-eyed Vireos arrived first and established territories in both habitats with equal probability. Black-capped Vireos arrived after White-eyed Vireos and settled in greater numbers in shrubland habitat. White-eyed Vireos initiated nests earlier than Black-capped Vireos and selected nest sites surrounded by taller, more mature, and more densely wooded vegetation. For both species, nest survival declined as the season progressed and was greatest in tall, mature vegetation. Lower nest success in Black-capped Vireos (27% vs. 40%), although equivocal, supports earlier findings and suggests that the flexibility demonstrated by White-eyed Vireos confers a reproductive advantage. Playback trials failed to detect evidence of interspecific aggression, suggesting that competition with White-eyed Vireos is not limiting the Black-capped Vireo. Received 21 December 2016. Accepted 8 February 2018. Key words: comparative reproductive ecology, habitat use, interspecific competition, nest survival. Vireo atricapilla y Vireo griseus son especies estrechamente relacionadas y ecológicamente similares. A pesar de estas similitudes, Vireo griseus es una especie comun y ampliamente distribuida, mientras que Vireo atricapilla, tiene un tango de reproducción restringido y se encuentra en peligro de extinción en Estados Unidos y México. Hemos abordado esta aparente paradoja con un estudio ecológico comparativo de la concurrencia de Vireo atricapilla y Vireo griseus. En este trabajo, estudiamos poblaciones de ambos vireos en bosques y matorrales del centro de Texas, EUA, en 2013 y 2014. Utilizamos puntos de conteo (n = 256) y seguimiento de nidos (n = 144) para determinar fechas de Ilegada, patrones de asentamiento, selection de sitios de nidificación y supervivencia relativa de cada nido a factores temporales y de hábitat. De forma paralela, realizamos experimentos de playback reciproco (n = 16) para evaluar la existencia de agresión interespecifica. Vireo griseus Ilegó primero y estableció territorios en ambos hábitats (bosques y arbustos) con la misma probabilidad. Vireo atricapilla Ilegó más tarde que Vireo griseus y se estableció preferentemente en matorrales. Vireo griseus inició nidos antes que Vireo atricapilla y nidificó en zonas de vegetación más alta, más madura y mvs densamente arbolada. Para ambas especies, la supervivencia de los nidos disminuyó a medida que avanzaba la temporada y fue mayor en la vegetación alta y madura. El menor éxito de nidos de Vireo atricapilla (27% vs. 40%), respalda los hallazgos anteriores sugiriendo que la flexibilidad demostrada por Vireo griseus confiere una ventaja reproductiva. Los experimentos de reproducción no detectaron evidencia de agresión interespecifica, lo que sugiere que la competencia con Vireo griseus no resulta limitante para Vireo atricapilla. Palabras clave: competencia interespecifica, ecologia reproductive comparative, sobrevivencia de nidos, use de hábitat., Comparisons of common, wide-ranging species with restricted or rare congeners have historically been used to address ecological, evolutionary, and genetic questions within a wide range of taxa (e.g., Shine 1986, [...]

On the Missouri River, the federally endangered interior population of Least Terns (Sternula antillarum) historically nested on sandbars created by sediment deposited during high flows. The Missouri River has been dammed and regulated, however, resulting in decreased flooding and sediment deposition and thus decreased sandbar habitat. In 2011, unusually high water releases created extensive sandbar habitat on the Gavins Point Reach of the Missouri River, and from 2012 to 2014 we examined the post-flood demography of Least Terns. We monitored 382 nests, uniquely marked 672 chicks, and attempted to recapture chicks every 3-4 d until fledging (~18 d). Daily nest survival was high (0.99 [SE 0.002]), resulting in high mean nest success (0.87 [0.03]). Nest success was highest in 2012 and declined slightly each year. Daily chick survival was 0.96 (0.01), resulting in a mean survival to fledge of 0.44 (0.08). Daily chick survival did not vary by year or by age of chicks but was negatively correlated to hatch date. Similar to another sandbar nesting species, the federally threatened Piping Plover (Charadrius melodus), Least Terns were highly productive on sandbars created by flooding on the Gavins Point Reach of the Missouri River. Least Terns may have taken advantage of newly created sandbars with similarly high reproductive output to boost and maintain population levels. Received 20 November 2016. Accepted 13 May 2017. Key words: chick survival, habitat, Least Tern, nest success, Sternula antillarum. La poblacieón del interior del charran Sternula antillarum, federalmente enlistada como en peligro, anidaba históricamente en playas arenosas creadas por sedimentos depositados durante las crecidas del río Misuri,. Ahora, este río tiene represas y ha sido regulado, lo que ha resultado en un decremento en las inundaciones y la deposición de sedimentos con una disminución de hábitat de playas arenosas. En 2011, la liberación del agua por crecidas inusuales creó grandes extensiones de hábitat de playas arenosas en el Gavins Point Reach del río Misuri. De 2012 a 2014 examinamos la demografia de S. antillarum después de la inundación. Seguimos 382 nidos, colocamos marcadores únicos a 672 polluelos e intentamos recapturar los polluelos cada 3-4 dias hasta que se emanciparan (~18 d). La sobrevivencia diaria del nido fue alta (0.99 [EE 0.002]), que resulta en una media de éxito del nido que es alta (0.87 [0.03]). El éxito del nido más alto fue en 2012 y declinó levemente cada año. La sobrevivencia diaria de los polluelos fue 0.96 (0.01) y resulta en una sobrevivencia media de emancipación de 0.44 (0.08). La sobrevivencia diaria de los polluelos no varió según año o la edad de los polluelos, sino que estaba negativamente correlacionada con la fecha de eclosión. De manera similar a otra especie que anida en playas arenosas, el playero Charadiurs melodus, federalmente enlistado como amenazado, S. antillarum the altamente productiva en las playas arenosas creadas por la inundación del Gavins Point Reach del río Misuri. Estos charranes podrian sacar provecho de las playas arenosas recientemente creadas, con un alta productividad reproductiva para levantar y mantener sus niveles poblacionales. Palabras clave: Éxito del nido, hábitat, sobrevivencia de los polluelos, Sternula antillarum., Riparian species are generally adapted to the dynamism of riverine environments. The natural variations of high and low flows in rivers drive ecological processes and rejuvenate these ecosystems (Poll et [...]

It is often assumed that passerine birds conceal nests to reduce predation because nest predation is usually the primary cause of reproductive failure. We hypothesized that nesting success would be higher in nest cavities with more concealed entrances and therefore more likely chosen over less concealed cavities. We set 200 nest boxes in ~100 territories of White-rumped Shamas (Copsychus malabaricus), territorial cavity nesters, in a seasonal evergreen forest in northeastern Thailand. Shamas were provided two boxes per territory, one with high and the other with low vegetation cover in front of the box entrance. Boxes were reset in new locations after a nest fledged or failed, providing 170 'choice' trials. We also compared vegetation characteristics of natural nest cavities with available natural nest cavities. Contrary to predictions, shamas placed nest material in the less concealed boxes significantly more often (89 boxes vs. 48), were significantly more likely to lay eggs in less concealed boxes (66 vs. 27), and eggs were significantly more likely to hatch in the low concealment treatment (38 vs. 8). Nest survival in the low concealment treatment was approximately twice that of the highly concealed boxes 36% ([+ or -] 0.035) vs. 18% ([+ or -] 0.042). Vegetation around natural nests (n = 26) was not significantly different from available randomly selected cavities (n = 52). Both used and available cavities had low levels of concealment. Cavity-nesting species may prefer less concealed sites because it is easier for an incubating/brooding female to detect approaching predators, allowing additional time for escaping and/or for mounting a defense. Received 17 August 2016. Accepted 18 March 2017. Key words: cavity-nesting, concealment, nest boxes, nest-site selection, nest survival, White-rumped Shama., Nest predation is the primary source of reproductive failure for birds and can greatly influence avian populations and habitat preferences (LaManna et al. 2015). Nest-site selection by forest birds is [...]

We studied the relationship between song repertoire size, territorial behavior, and nesting success in Pied Bush Chat (Saxicola caprata) in Haridwar (Himalayan foothills), India for three consecutive years (2013-2015). Our findings indicate song repertoire size is correlated with nesting success, but pre-nesting territory size, average territory size, and territorial conflicts are independent of song repertoire size. It may be inferred that larger territories are not necessarily better territories. The findings suggest that larger territory size is more susceptible to increased territorial conflict. Significant differences were apparent between territory size and territorial conflicts in the different stages of the nesting cycle. The findings suggest that larger territory size is more susceptible to increased territorial conflict. We propose that even if territorial conflicts are independent of song repertoire size, the amount of territorial conflict may be constrained by the stage of nesting cycle or size of the territory. Depending upon breeding requirements, male Pied Bush Chats tailor their territory sizes and territorial conflicts during the course of the breeding season. Received 30 July 2016. Accepted 20 December 2016. Key words: nesting success, Pied Bush Chat, Saxicola caprata, song repertoire size, territorial conflicts, tropical songbirds., Song repertoire size (a set of distinct song/phrase types used by one individual/species) and territoriality of male songbirds during the breeding season is believed to play an important role in [...]

Theory predicts prey should flee to safety when the fitness benefits of flight meet or exceed the costs. Empirical work has shown the importance of predation risk (e.g., predator behavior, distance to refuge) to prey flight behavior. However, less is known about the influence of flight costs. We monitored nesting Painted Turtles (Chrysemys picta (Schneider, 1783)) to examine their response to a human observer (potential predator) depending on the distance between a turtle and an observer, distance between a turtle and water (i.e., refuge), and nesting stage at the time of the encounter (i.e., searching for a nest site vs. constructing a nest). We found no evidence that the distance to an observer influenced flight decisions. However, turtles were less likely to flee as the distance to water increased, and turtles already constructing nests were more likely to continue nesting than those still searching for nest sites. Turtles that traveled farther from water and that were constructing nests may have continued nesting because they had invested considerable energy and were close to completing oviposition. Thus, the fitness benefits of being closer to successful oviposition may outweigh the costs of increased vulnerability to predators during this important and vulnerable period of reproduction. Key words: risk assessment, flight initiation distance, fitness trade-off, aquatic turtles, Chrysemys picta, painted turtle, escape, defense., Resume : En theorie, les proies devraient s'enfuir vers des lieux surs quand les avantages de la fuite sur le plan de l'aptitude sont egaux ou superieurs aux couts. Des [...]

ABSTRACT.--The behaviors of animals can be highly variable across individuals and environments; however, recent studies have demonstrated that the behaviors of individuals in response to similar environmental stimuli are often [...]

ABSTRACT.--Nest tenacity, defined as the persistence of an individual to continue nesting during and or following a disturbance, can be an important behavior to influence reproductive potential of individuals and [...]

Nest reuse is a common phenomenon in many passerine and non-passerine birds species. Although interspecific nest reuse has been reported in many African species, it is rare in passerines that nest in open, cup-shaped nests. Here, I report on interspecific nest reuse in larks (Alaudidae), specifically of a pair of Chestnut-backed Sparrow-larks Eremopterix leucotis using a nest previously occupied by Pink-billed Larks Spizocorys conirostris. It is possible that the Chestnut-backed Sparrow-larks selected a nest site in an area where predation seemed low as there were other successful nests or nests with nestlings in the near vicinity. The interspecific nest reuse reported here suggests opportunistic occupation of a previously used nest while at the same time saving the pair some energy during a period of peak activity and high energetic demands. Received 27 September 2015. Accepted 14 February 2016. Key words: Alaudidae, breeding, Eremopterix leucotis, nest reuse, Spizocorys conirostris., Reusing nests is common in many species and families of birds. Many large non-passerines (e.g., eagles, vultures, storks, egrets, herons) put forth a lot of time and effort to construct [...]

Parental investment is a unique balance between optimizing reproductive success and survival, yet how individuals vary their effort with respect to age and the contributions of their partner remains poorly studied. Here, we examine the provisioning of nestlings by Wood Thrushes (Hylocichla mustelina) at 38 nests in southern Indiana during the breeding season of 2013 to address the influence of adult age and sex on reproductive investment. We used video cameras to quantify an adjusted provisioning rate (provisioning rate = adult visits/hr/nestling X mean prey size X mean number of prey/visit) by individuals in both age-assortative (same age) and disassortative (different age) pairs (n = 33 pairs), hereafter referred to as pair type. Disassortative pairs delivered less prey than expected given nestling age, and sexes differed in their respective provisioning effort. In contrast, age-assortative pairs consistently provisioned more, and provisioning effort was comparable between the sexes regardless of parental age. These findings are contrary to studies where older breeders had a greater foraging efficiency and provided young with more prey. Our results indicate that adult age is not an accurate predictor of provisioning in Wood Thrushes and highlight the previously overlooked importance of age-assortative mating on parental investment in this system. Received 20 October 2015. Accepted 51 January 2016. Key words: age-assortative mating, age-specific variation, Hylocichla mustelina, nestling provisioning., Avian life history theory predicts that parental investment, which includes both nest attendance and provisioning, creates allocation trade-offs between reproductive success and survival (Ricklefs 1977, Clutton-Brock 1991). Specifically, the provisioning [...]

The genus Chlorospingus is distributed from central Mexico to northern Argentina. Despite its wide distribution, natural history information is sparse. We present the first detailed breeding biology information for C. flavigularis, plus descriptions of the nest, eggs, and other natural history information for C. parvirostris and C. flavopectus based on 26 nests monitored (22 from C. flavigularis, two from C. parvirostris, and two from C. flavopectus) in the buffer zone of Manu National Park, Cusco, Peru. Nests of C. flavigularis were bulky open-cups placed on a variety of substrates (e.g., ferns, moss). The clutch size of C. flavigularis varied between two to three eggs, but clutch size for C. flavopectus and C. parvirostris was consistently two eggs. The eggs of all three species were white with small light-brown speckles. Incubation and nestling period for C. flavigularis was 17 and 14 days, respectively, and daytime nest attentiveness was 60%. Nest architecture, clutch size, and eggs encountered for these species were consistent with previous reports for the genus Chlorospingus. More nesting behavior studies are needed to fill the knowledge gap regarding all species of Chlorospingus to help us understand nesting requirements for this cloud forest genus. Received 27 August 2015. Accepted 14 February 2016. Key words: Andean mountains, breeding biology, eggs, incubation behavior, nestling period., The knowledge of breeding biology of tropical birds is central to examining geographic variation in reproductive and life history traits and variation in avian life history strategies (Martin 1996, Marini [...]

Fraser Darling suggested that reproductive synchrony enhances reproductive success of colonial seabirds as a result of predator satiation. However, the cost of yearly reproductive synchrony is high for colonial species for which intraspecific predation is the primary cause of egg and chick loss. A few studies indicate that egg-laying synchrony on a daily time scale within the annual breeding pulse may be an adaptive response to intraspecific predation. Here, we report everyother-day clutch-initiation synchrony in densely nesting cohorts of Ring-billed Gulls (Larus delawarensis). This is the second known case of clutch-initiation synchrony on a daily time scale in larids, the first being for Glaucous-winged Gulls (L. glaucescens). In both Ring-billed Gulls and Glaucous-winged Gulls, the degree of clutch-initiation synchrony is inversely related to nearest neighbor distance. Further studies are needed to test whether clutch-initiation synchrony in Ring-billed Gulls is adaptive in the presence of cannibalism, or if it is simply a neutral byproduct of colonial nesting. Received 10 July 2015. Accepted 7 January 2016. Key words: clutch initiation, egg laying, Fraser Darling effect, Larus delawarensis, Ring-billed Gull, synchrony., Fraser Darling (1938) famously argued that if an individual synchronizes its reproductive efforts in time and space with others of the same species, its offspring will be more likely to [...]

ABSTRACT. The Kittlitz's Murrelet (Brachyramphus brevirostris) is a broadly distributed but uncommon seabird species endemic to coastal Alaska and eastern Russia. Although northern Alaska constitutes a large portion of this [...]

We present the first detailed nesting biology information for the highland Andean hummingbird Gould's Inca (Coeligena torquata omissa) at 2,200-3,000 m in Manu National Park, SE Peru. We found nine mossy cup-shaped nests lined with red fern scales containing nestlings or 1-2 synchronously hatching eggs. We obtained 17 days of internal nest temperatures from one nest, which exhibited wide circadian variation (range = 14.9-36.2 °C). We show that C. t. omissa meets the challenges of life and incubation at high altitudes by undertaking numerous (20.3 ± 0.4 trips/morning, range = 1427) and short morning off-bouts (5.2 ± 0.2 min, range = 1-24 min). In the morning, the focal bird warmed the nest 1.7 times faster than in the afternoon where incubation bouts are long (17.8 [+ or -] 0.6 min, range = 4-56) and less frequent (10.2 ± 0.3 trips/afternoon). Incubation off-bout frequency and durations were not influenced by external temperature, suggesting strong nest insulation. On-bout durations increased with external temperature most strongly in the cold mornings. Short off-bouts and long on-bouts yielded high attentiveness (70.2%). One nestling fledged after 23 days. The eggs measured 15.2 ± 0.4 mm by 9.3 ± 0.3 mm and weighed 0.75 ± 0.03 g (n = 12). The small mossy cup nest was 81.9 ± 5.9 mm by 75.8 ± 4.4 mm wide and 73.1 ± 6.7 mm high. The inner cup was 45.7 ± 3.0 mm long by 45.6 ± 4.1 mm wide and 30.9 ± 2.5 mm deep (n = 8). Compared to C. t. torquata, we found a smaller egg width, higher nest placement and different nest substrate, but confirmed similarities in many aspects of nesting strategies. Received 6 March 2015. Accepted 17 September 2015. Key words: Andes, Coeligena inca, Collared Inca, incubation rhythm, nesting biology, nestling growth., The genus Coeligena (family: Trochilidae) is exclusively distributed throughout the Andean mountains from Venezuela to Bolivia and encompasses up to 12 species (Zuchner 1999, Parra et al. 2009, Parra 2010). [...]

The Lanceolated Monklet (Micromonacha lanceolata) is a puftbird (Bucconidae) generally considered rare throughout its range. This species is little-studied and its reproductive behavior is largely unknown. Here, we provide the first detailed account of its nesting biology. All 17 nests consisted of round tunnels in earthen banks terminating in widened brood chambers. Tunnels averaged 405.41 ± 59.52 mm in length (n = 14) and 68.64 ± 13.12 by 57.89 ± 12.20 mm (n = 16) in diameter at the entrances. The clutch size was two. The unmarked, white eggs averaged 22.53 ± 1.04 by 18.29 ± 0.71 mm (n = 22) and weighed 3.84 ± 0.39 g (n = 19). The incubation period, determined from one nest was 25 days. The number of trips made from three nests averaged 3.42 ± 1.12 per day (n = 33), with each absence lasting an average of 70.54 ± 89.98 mins (n = 113). Nest attentiveness steadily increased from 11.55 to 71.73% and on-bouts from these three nests averaged 166.28 ± 96.58 mins (n = 79). During the nestling period, which we determined from one nest to span 22-23 days, food deliveries consisted of large insects and larvae; averaged over four nests, attendants made 1.72 ± 0.78 (n = 28 days) deliveries per hour. Received 1 July 2015. Accepted 22 November 2015. Key words: breeding behavior, Bucconidae, incubation, life history, Micromonacha lanceolata, nest, nestlings., The Lanceolated Monklet (Micromonacha lanceolata) is a distinctive, monotypic species of puffbird (family: Bucconidae) patchily distributed from the Caribbean slope of Costa Rica to central Bolivia, with an elevational distribution [...]

The Red-winged Blackbird (Agelaius phoeniceus', redwing) is a commonly used accepter host species that incubates eggs and cares for nestlings and fledglings of the obligate brood parasitic Brown-headed Cowbird (Molothrus ater; cowbird). This host species, however, may reduce the risk of parasitism with a frontloaded antiparasite strategy in which it attacks parasites that approach active host nests. To test this ffontloaded parasite-defense hypothesis (FPDH), we presented taxidermic models of a female Northern Cardinal (Cardinalis cardinalis), which represents no threat to redwings, a male cowbird, which cannot lay a parasitic egg, and a female cowbird, together with species- and sex-specific vocalization playbacks for 5 min. We conducted these presentations at 25 active redwing nests at Newark Road Prairie in south-central Rock County, Wisconsin, USA, where 18% of redwing nests were parasitized by cowbirds in 2015. As predicted by the FPDH, the female cowbird mount elicited the most aggressive responses and the female cardinal mount the least aggressive, as measured by number of times more than one male redwing responded and number of times the male host attacked the mount, and by Principal Component Analyses yielding the highest redwing aggressive behavior and intimidation scores. Contrary to the predictions of FPDH regarding the success of nest defense behaviors, male redwings responding at naturally parasitized nests were significantly more likely to attack the mount than males with nests that were not parasitized, although our sample size was small. We also compared our results with those of a study using the same methods in New York State where cowbird parasitism was rare. Redwings in Wisconsin were more aggressive toward the female cowbird mount than redwings in New York. Red-winged Blackbirds appear to frontload their antiparasite defenses, but the success of those defenses depends on individual and population-level experience with parasites. Received 20 October 2015. Accepted 21 January 2016. Key words: Agelaius phoeniceus, antiparasite behavior, brood parasitism, Brown-headed Cowbird, Molothrus ater, Redwinged Blackbird., About 1 % of bird species are obligate brood exclusively on host species to build nests, incubate parasites, whose reproductive strategy depends eggs, and care for nestlings and fledglings (Davies [...]

Abstract: Timing of breeding varies among waterfowl species and individuals, with strong effects on reproductive success, and may be related to habitat quality. Here, we analyse the start, span, and [...]

Abstract: Individual variation in nest defense behaviour is common in altricial birds, but despite clear predictions about why such variation exists, there is no consensus on its causes. We tested [...]

The use of video to monitor nests has increased in frequency over the past 25 years and new research using this technology has shed light on many aspects of the interactions between predators and nesting birds. We used video cameras to describe the timing of nest predation events for Acadian Flycatchers (Empidonax virescens), Indigo Buntings (Passerina cyanea), and other forest-dwelling songbird species. Seventy-four percent (111 of 151) of nest predation events occurred during diurnal hours for both focal species. Although some of our observations were unexpected (e.g., Barred Owls [Strix varia] were primarily diurnal nest predators), many of the predator-specific temporal patterns we observed were consistent with prior knowledge. Understanding diel patterns of nest predation in conjunction with identification of the suite of predators that contribute to overall predation rates will improve our understanding of how birds recognize and respond to the risk of nest predation across ecological and evolutionary time scales. Received 27 February 2015. Accepted 25 July 2015. Key words: nest predation, nest predator ecology, nest visitation, songbird ecology, video surveillance., Predation is the primary source of nest failure for many species of songbirds (Ricklefs 1969, Martin 1992) and has received much attention from ecologists and evolutionary biologists. Until recently, however, [...]

We present descriptions of nest architecture, clutch size, nestling growth and nestling attendance for the Fire-eyed Diucon (Xolmis pyrope), based on nests found at the Fray Jorge National Park, Chile, at the northernmost part of its distribution. Nests were cup-shaped structures averaging 283.5 ± 26.6 mm in width and 123.1 ± 6.8 mm in height (n = 5), found in matorral steppe habitat and Olivillo humid forest relicts. Nests contained 2-3 eggs. Nestling growth in Fray Jorge's nests was nearly two times slower than in populations from central Chile, as suggested by our calculations of the constant rate (K = 0.277) and the [T.sup.10-90] period (12.9). During 20 hrs of video recording, the breeding adults spent a total of 3.4 hrs at the nest. Both parents attended the nest, and the rates of visits, nestling provisioning and fecal sac removal increased with nestling development. We observed that adults can still care for the young at least 2 weeks after fledging, covering an area of 2.3 ha while searching for food. This information could be valuable for further studies on geographic variation in the species' behavioral ecology. Received 6 April 2015. Accepted 17 September 2015. Key words: egg size, incubation period, nesting ecology, nestling growth, parental care, population variation., The Fire-eyed Diucon (Xotmis pyrope) is a medium-size tyrannid that breeds from northcentral Chile (Coquimbo Region, 30° S) and west-Argentina (Neuquen Province, 38° S) to Tierra del Fuego and Isla [...]

Predation is the major cause of avian nest failure, and an important source of natural selection on life history traits and reproductive behavior. However, little is known about the identity of nest predators in much of the world, including the Neotropics. To identify some of the nest predators exerting selection pressure on birds of the subtropical Atlantic forest, we present observations of animals depredating bird nests in Argentina and Paraguay. We recorded depredations (destruction or removal of eggs or nestlings) at 33 nests of 25 species of birds, confirming as predators ten species of birds (Squirrel Cuckoo Piaya cay ana, White-eared Puffbird Nystalus chacuru, Toco Toucan Ramphastos toco, Red-breasted Toucan Ramphastos dicolorus, Saffron Toucanet Pteroglossus baillonii, Chestnut-eared Aracari Pteroglossus castanotis, Planalto Woodcreeper Dendrocolaptes platyrostris, White-throated Woodcreeper Xiphocolaptes albicollis, Buff-browed Foliage-gleaner Syndactyla rufosuperciliata, and Plush-crested Jay Cyanocorax chrysops) and two species of medium-sized mammals (White-eared Opossum Didelphis albiventris and Crab-eating Fox Cerdocyon thous), and inferring two additional mammal species (Black Capuchin Monkey Sapajus nigritus and Southern Tigrina Leopardus guttulus). Fifty-five percent of these nests were depredated by toucans or aracaris (Ramphastidae), which destroyed eggs and nestlings at cup-, closed- and cavity-nests. Red-breasted Toucans destroyed nests 1.6-22 m high, in habitats ranging from primary forest to a backyard. Mammals and jays depredated nests from ground-level to midstory, whereas woodcreepers and aracaris depredated nests from the midstory to canopy. We did not record snakes at any bird nests, in strong contrast to studies from other Neotropical forests. Further studies should examine trade-offs among nest concealment, physical protection, and parental defense behavior as means of reducing nest predation, and use camera traps to quantify nest predation rates by predator species. Received 8 January 2015. Accepted 30 May 2015. Key words: Atlantic forest, Neotropical, nest fate, nest predator, nest site, nest usurpation, toucan., Predation is the major cause of nest failure among birds (Ricklefs 1969). As such, it is an important source of natural selection on life history traits and reproductive behaviors such [...]

The factors affecting the timing of nesting in tropical birds remain poorly understood. We investigated the phenology of White-throated Magpie-Jay (Calocitta formosa) nesting in the dry forest of northwest Costa Rica, a region characterized by a severe 5-month dry season followed by a very rainy wet season. We examined whether nesting was associated with climate, diet, risk of parasite infection to nestlings, risk of nest predation, and opportunity to re-nest. Groups of White-throated Magpie-Jays nested repeatedly, initiating nests over a 7-month period that spanned the transition from the dry to early wet season. The diet of adults and the composition of food fed to broods varied seasonally in parallel with changes in vegetation condition and climate associated with the transition from dry to wet season. Fledgling transition to nutritional independence occurred exclusively in the wet season when caterpillars and other arthropods were a large component of the diet. The timing of groups' last nests was associated with an increase in nestling infections by Philornis botflies. We argue that progress at understanding tropical birds' nesting seasons will be made by looking beyond diet and climate at the time of nesting, to additional factors such as the conditions during the post-fledging period of offspring development, temporal patterns of risk of parasite and pathogen infection to nestlings, and temporal patterns of nest or fledgling predation risk. Received 2 July 2014. Accepted 29 July 2015. Key words: breeding biology, Calocitta fonnosa, Corvidae, omnivory, Philomis parasitism, seasonality, tropical ecology., Few birds breed continuously throughout the year, and the timing and length of the 'breeding season' strongly affect the likelihood of successful reproduction and the number of offspring produced. The [...]

ABSTRACT. Outside of northern Quebec, there is little evidence to confirm reports of nesting by Canada Geese in Arctic habitats of North America, but they nest regularly in the Arctic [...]

ABSTRACT. This study documents observations of breeding behavior at two Osprey Pandion haliaetus carolinensis nest sites discovered at Fort Wainwright, Alaska. We developed Osprey location criteria and behavior and activity [...]

American Oystercatchers (Haematopus palliatus) and Reddish Egrets (Egretta rufescens) are coastal species of conservation concern known to nest along most of the Gulf of Mexico's coastline. However, there is a distributional gap in breeding records for both species between southeastern Louisiana and eastern Texas. Herein, we report on the first breeding records for each species from southwestern Louisiana at Rabbit Island (Cameron Parish, Louisiana), a small, marsh island in Calcasieu Lake. Suitable nesting habitat for American Oystercatchers (1 nesting pair) was present on the island via shell rake and for Reddish Egrets (6-12 pairs, min) in clumps of Juncus roemerianus; this is the first report of Reddish Egrets utilizing this plant species for nesting. A large scale island restoration project is slated for Rabbit Island and therefore, we provide restoration recommendations for conservation planners to improve habitat suitability for multiple bird guilds at this and other potential dredge spoil island projects. Received 7 July 2014. Accepted 9 December 2014. Key words: American Oystercatcher, breeding distri bution, island restoration, nesting, Reddish Egret, southwestern Louisiana., The Chenier Plain of southwestern Louisiana is most widely known for providing valuable wintering habitat for waterbirds (e.g., waterfowl, shorebirds; Bellrose 1980, Bettinger 1984, Michot 1996), as well as critical [...]

Here, we describe nests, eggs, and nestlings of the monotypic Star-throated Antwren, Rhopias gularis (formerly Myrmotherula gularis), found at Carlos Botelho State Park, in Atlantic Forest in the state of Sao Paulo, Brazil. Nests were pensile cups of dark rootlets and black fungal hyphae, found near forest streams, 34-70 cm high, over ground or water. A leaf appeared to form a roof over two nests. Clutch size was always two eggs, white with reddish and dark brown spots and blotches. Hatchlings were naked with pinkish skin. Nest architecture, eggs, and nestlings were similar to other Myrmotherula and Epinecrophylla, suggesting that nesting characteristics may not be informative to reconstruct recent DNA-based phytogenies that resolved the monotypic genus of this Brazilian Atlantic Forest endemic species. Received 3 July 2014. Accepted 12 December 2014. Key words; Atlantic Forest, breeding, Myrmotherula, nesting behavior, reproduction., Myrmotherula antwrens are small, short-tailed, antbirds (Family Thamnophilidae) of Neotropical forests, most often near water. The genus formerly comprised at least 32 species, with the greatest diversity in the Amazon [...]

Birds are considered excellent bioindicators in urban areas. Some of the ecological processes behind bird ecological patterns in urban areas have been related to birds' capacities to shift their behaviors. In this brief communication, we report a nest of Azure-crowned Hummingbird (Amazilia cyanocephala) built on a metallic structure that connects telephone wires, surrounded by other electricity and cable wires. After visiting the nest for 19 days, we did not have any evidence of predation, and because of the size and behavior of the chicks during the last two visits, we assume that the nest was successful. Previous studies have suggested that urban systems lay open to colonization by species that can reach them, use their resources, and survive their hazards. We recorded a nest of Azure-crowned Hummingbirds that was built on an open sky telephone. Our observation was a notable example of the degree of venture that some individual birds can exhibit in response to urbanization, suggesting a certain degree of ecological plasticity. Thus, future detailed studies are needed to untangle the advantages and disadvantages of nesting on open sky urban wires, to assess if it is profitable to nest on such structures. Received 28 May 2014. Accepted 16 November 2014. Key words: Amazilia cyanocephala, Azure-crowned Hummingbird, ecological plasticity, Mexico, Neotropics, urban ecology., Urban areas are complex human-modified systems that have been related to a broad array of long-term ecological consequences at different temporal and spatial scales, directly affecting the ecological patterns that [...]

Studies on breeding biology in Neotropical birds are crucial for understanding different aspects of their life histories and also for their conservation. We describe the nesting biology of the Red-crested Cardinal (Paroaria coronata) in central Argentina, a common suboscine that inhabits south temperate forests. We monitored 367 nests from October to February 2005-2008. Nest initiation followed a unimodal distribution with a peak in November. Within the forest, no nests were built on exotic tree species. Mean clutch size was 3.05 [+ or -] 0.05 eggs and decreased with time within the breeding season; egg size did not vary across the breeding season. Nesting cycles lasted, on average, 25.8 [+ or -] 0.1 days (nest construction: 6.1 [+ or -] 0.4 days; incubation period; 11.9 [+ or -] 0.1 days; nestling period: 13.8 [+ or -] 0.1 days). At least one young fledged in 26% of nests, 62% were depredated, and 11% were abandoned. Egg survival rate was 0.95 [+ or -] 0.02, hatching success rate was 0.84 [+ or -] 0.02, and nestling survival rate was 0.81 [+ or -] 0.03. Partial nestling losses were detected in 45% of the nests, of which 52% were because of brood reduction. Each breeding pair had on average 4.4 [+ or -] 0.2 nesting attempts over the breeding season. Our results support the prediction that small clutch sizes are associated with extensive breeding seasons and several nesting attempts within a season. Except for the short incubation period, all other breeding features reported in this study differ from those of most north temperate birds and are consistent with the life history traits of Neotropical birds. Received 23 June 2014. Accepted 17 November 2014. Key words: breeding success, Buenos Aires province, nesting habitat, reproductive biology, reproductive parameters, south temperate birds., Studies on the breeding biology of birds are crucial for understanding different aspects of their life histories. During the last decades, many studies on avian breeding biology have focused on [...]

In the past two decades, stable isotope analysis (SIA) has been increasingly used to infer dietary ecology and habitat use in sea turtles. Tissue samples for SIA are often collected from adult females during a nesting event because turtles are easily accessible then. However, this sampling opportunity can be easily missed, or the female may be disturbed during the nesting event and abandon nest construction. The current research assessed the relationships of carbon and nitrogen stable isotope values between mothers, and their eggs and hatchlings of loggerhead turtles Caretta caretta to evaluate the accuracy of using eggs or hatchlings in inferring the mothers' stable isotope values. Whole blood and epidermis from mothers (n = 5), yolk, albumen and shell in their eggs (n = 5 per female) and epidermis, whole blood, liver, muscle and residual yolks in their hatchlings (n = 5 for 3 females) were collected from loggerhead turtles in the 2012/2013 nesting season at Mon Repos sea turtle rookery (24°47'46'S; 152°26'26'E), in South East Queensland, Australia. The effect of lipid extraction on isotopic values in sampled tissues was also evaluated. Lipid extraction had a significant effect on [delta].sup.13C values for egg yolk, residual yolk and liver, but also altered [delta].sup.15N values for these tissues. Significant correlations were found between adult tissues and both their egg-yolk and hatchling tissues. Isotopic values of fresh egg yolk sampled straight after oviposition and residual yolk internalized by hatchlings at hatching were similar, implying that the stable isotope values of yolk remains unchanged throughout embryonic development. Stable isotope values were distinct between different tissues sampled from the same hatchling. With the caution that our results are based on a small sample size (n = 3), they support the method of sampling hatchlings, or eggs, rather than nesting females, to infer information about the feeding habits and migratory patterns of nesting turtle populations., Author(s): Alice S. Carpentier[sup.1] , David T. Booth[sup.1] , Karen E. Arthur[sup.2] , Colin J. Limpus[sup.3] Author Affiliations: (1) School of Biological Sciences, The University of Queensland, 4072, Brisbane, Queensland, [...]

Understanding the breeding ecology of grassland birds is vital for understanding the mechanisms underlying their widespread population declines. We describe the breeding biology of Spragues Pipit (Anthus spragueii), Vesper Sparrow (Pooecetes gramineus), Savannah Sparrow (Passerculus sundwichensis), Bairds Sparrow (Ammodramus buirdii), and Western Meadowlark (Stumella neglecta) and quantify the effects of nest predation, brood parasitism, and weather on the nest survival of these species in southeastern Alberta. Nest predation was the primary cause of nest failure, accounting for 75% of all nest losses. Daily survival rates were higher during incubation than the nestling stage for the three sparrow species, and nest survival of Bairds Sparrows was highest at intermediate temperatures. For all five species, clutch size, hatching success, and fledging success were within the range of values previously reported for these species in other parts of their range. Brown-headed Cowbirds parasitized nests of all species except Spragues Pipit, with 4-11% of nests containing cowbird eggs. Savannah Sparrow experienced the highest frequency of brood parasitism and was the only species to successfully fledge cowbird young. Parasitized nests of Savannah Sparrows had reduced clutch size and hatching success, and fledged fewer young compared to non-parasitized nests. The overall cost of parasitism to Savannah Sparrows was at least 1.7 young per successful nest. Received 21 October 2013. Accepted 16 June 2014. Key words: Alberta, clutch size, cowbird parasitism, logistic exposure, mixed-grass prairie, nest survival, reproductive success., Native grasslands have been reduced to ~20% of their historic area and represent the most drastically altered biome in North America (Samson and Knopf 1994). Historically, much of the loss [...]

Understanding geospatial linkages is critical to the development of appropriate management and conservation strategies for migratory species. Stable isotope analysis is a powerful tool that is performed routinely across taxa to unravel migratory connectivity. Marine turtles are a highly migratory and widely distributed taxon, but are largely studied at breeding areas. Isotopic values of several slow turnover rate tissues have been used to identify often distant foraging areas. However, as more isotopic data from various tissues become available, the relationships between tissues need to be calculated to permit meta-analyses to elucidate isotopic patterns across broader spatiotemporal scales. We used several commonly collected tissues (blood, skin, fresh eggs and unhatched eggs) collected simultaneously from loggerhead turtles (Caretta caretta) to develop a common currency for stable isotope analysis studies conducted on the nesting beach. We found highly significant relationships between the tissue signatures ([r.sup.2] ranged from 0.83 to 0.96) and developed equations to convert isotopic values from one tissue to another. We examined inter- and intra-clutch isotopic variability and found that a single sampling event over the 4-month nesting season adequately defined the loggerhead female foraging area. Consequently, we propose using unhatched eggs as a common currency in stable isotope studies of nesting loggerheads. Unhatched eggs represent a noninvasive and nondestructive method that enables more extensive (both numerically and spatially) sampling. Given similar physiologies, analogous relationships might be derived in other sea turtle species., Introduction Studying animal migration is challenging as migratory species often traverse vast distances and are often elusive. Nonetheless, identifying linkages between habitats used by migratory species during their lifecycle is [...]

Recent research suggests that male birds could use eggshell color as a signal of the quality of their offspring to decide how much parental care to provide. Previous studies have found support for this hypothesis in bird species that lay blue eggs, but it has not been as thoroughly tested in species that lay brown eggs, such as House Wrens (Troglodytes aedon). In this species, brighter eggs are associated with greater female investment. We tested whether males responded to this potential cue. We experimentally manipulated clutch brightness by randomly adding a white or brown plastic egg to nests during incubation and then compared the male provisioning rates between those two treatment groups. Male House Wrens whose nests had received a white egg provisioned their nestlings at significantly higher rates than males whose nests had received a brown egg. These results suggest that male House Wrens pay attention to female investment when deciding how much energy to spend on nestling provisioning. This study supports the generality of the hypothesis of egg color as a sexually selected signal by experimentally demonstrating that males of a species that lays brown eggs also can respond to egg color. Received 18 December 2013. Accepted 18 April 2014. Key words: egg color. House Wren, protoporphyrin, provisioning, sexual selection., A variety of factors, such as crypsis or brood parasitism, likely influenced the evolution of the current diversity of eggshell colors from the ancestral white shell (Kilner 2006), and a [...]

Laughing Falcons (Herpetotheres cachinnans) are common, medium-sized falconids that occur throughout the Neotropical region and marginally in the Nearctic American continent. There is little data on their breeding biology with the only information available based on scattered records. Here, we report data on 11 nests of H. cachinnans from the Pantanal, Brazil, including four in nest-boxes, between 2007-2008. The breeding season occurred between July-December, which is in accordance with the few records for this region. Records of two eggs or nestlings were found in 28% (n = 3) of nests, while the remaining 72% (n = 8) had one egg or nestling. The eggs were rounded and buff with brown markings or dark brown or purplish brown with darker markings. The hatchlings, even when a few days old, are pale buff overall in plumage with the distinctive black mask, typical of the adults. An undescribed vocalization of the nestling was recorded, which is similar to an uncommon vocal type emitted by the adults when disturbed. The study reveals novel data on the use of nest-boxes and on the breeding biology of the species, and reinforces the importance of such studies on its conservation. Received 26 July 2013. Accepted 30 November 2013. Key words: breeding biology, cavity, Falconidae, Herpetotheres, nest-box, nesting., Laughing Falcons (Herpetotheres cachinnans) are widespread falconids that occur in the Neotropical region and marginally in the Nearctic American continent. In Brazil they are encountered throughout the country, with a [...]

We conducted field work during May-July 2005 in the Mexican states of Nuevo Leon, Tamaulipas and San Luis Potosi. We observed breeding activity of Black-capped Vireos and found active nests in northwestern Nuevo Leon and southwestern Tamaulipas. These findings represent the first documented nests for those states, and for the latter state, the first records of Black-capped Vireos nesting below the Tropic of Cancer. Our findings suggest that the breeding range of Black-capped Vireos should be extended approximately 520 km to the southeast of the previous known nesting area near Ocampo, Coahuila. Received 25 June 2013. Accepted 6 September 2013. Key words: Black-capped Vireo, breeding, Mexico, nests., The Black-capped Vireo (Vireo atricapilla) is classified as a vulnerable species internationally (BirdLife International 2013), and as Endangered by the U.S. Fish and Wildlife Service (Ratzlaff 1987), Texas Parks and [...]

Despite being widespread and abundant, little is known about the breeding ecology and natural history of the Eastern Wood-Pewee (Contopus virens), in part because nests are often high in the canopy, difficult to view, and adults are monomorphic. We monitored nests of Eastern Wood-Pewees and recorded the feeding rate of nestlings by adults as part of a larger study on breeding demography of Eastern Wood-Pewees across a gradient of savanna, woodland, and forest in the Missouri Ozarks in 2010-2011. We monitored 287 nests between 26 May and 22 August and conducted feeding rate observations for 54 nests with nestlings. There was an 88-day nesting season with peaks of nest activity on 24 June and 22 July. We recorded 19 cases of double brooding and nine cases of within-season nest reuse. Seasonal fecundity was 2.2 fledglings per territory. The frequency of parental feeding visits increased with nestling age. These are additional observations of nest reuse, nesting cycle lengths, and breeding season length for Eastern Wood-Pewees; future demographical research of marked individuals will continue to fill in gaps in breeding ecology for this common and widespread flycatcher. Received 12 July 2013. Accepted 5 November 2013. Key words: breeding ecology, double brooding, East ern Wood-Pewee, feeding rate, Missouri Ozarks, nest reuse, seasonal fecundity., Eastern Wood-Pewees (Contopus virens; hereafter 'pewee') are vocal and abundant Neotropical migrant songbirds that breed in a variety of wooded habitats across the eastern United States north into the southern [...]

Scytalopus, the largest genus of tapaculos (Family: Rhinocryptidae) typically build mossy globular nests within bank or tree cavities. Only 23 of the 40 recognized species' nests have been described, and of these only one has incubation patterns described. We provide the first description of the nest architecture, eggs, incubation behavior, and nestlings of the Trilling Tapaculo (Scytalopus parvirostris). The globular nest was mostly built of dark rootlets, and was lined with fern scales, hyphae, and feathers placed within the cavity of a rotting tree 1.5 m off the ground. The nest contained two white eggs. Nest attentiveness averaged 91 ± 0.5% per day, with an average of 12.6 ± 0.3 trips per day. Incubation bouts on the nest averaged 54.6 ± 2.9 mins and foraging trips averaged 8.8 ± 0.7 mins. Combined daily nestling growth rates averaged 18 ± 2% weight, 9 ± 2% tarsus, and 16 ± 3% wing (n = 4 days). Received 1 April 2013. Accepted 2 November 2013. Key words: eggs, incubation pattern, nest, nestlings, Scytalopus parvirostris., Tapaculos (Rhinocryptidae) are small understory suboscines, found in South and Central America (Krabbe and Schulenberg 2003). Similarities in plumage among species and their cryptic behavior in dense understory have made [...]

Interspecific nest usurpation was observed when a Eurasian Collared-Dove (Streptopelia decaocto) took over the nest of an American Robin (Turdus migratorius) in Plainview, Hale County, Texas in April 2014. The nest was constructed and occupied by an American Robin, briefly shared by a Eurasian Collared-Dove over a period of 3 days, and then aggressively taken over by the collared-dove. The collared-dove pair fledged two young in May 2014. This represents a first record of interspecific nest usurpation by Eurasian Collared-Dove. Interspecific nest piracy by this invasive species has implications for songbird conservation if the behavior proves to be frequent. Received 19 January 2015. Accepted 9 July 2015. Key words: American Robin, Eurasian Collared-Dove, nest usurpation, songbirds., Eurasian Collared-Doves (Streptopelia decaocto, hereafter referred to as 'collared-dove') have become a widespread invasive species throughout North America (Romagosa and McEneaney 1999, Romagosa 2012) since they were first documented in [...]

The use and potential consequence of alien plant parts in the construction of open-cup leaf nests by Nearctic-breeding forest songbirds has not been investigated. We dissected 19 leaf nests constructed by Veeries (Catharus fuscescens) over two breeding seasons in a temperate broadleaf forest infested with alien plants. Our objectives were: (1) confirm the architectural approach used by Veeries to construct nests, (2) determine if Veeries used alien plant parts in nest construction, (3) determine if nest success was related to the use of alien material, (4) determine the use of alien plants relative to native plants, and (5) test for an association of alien plant mass with the progression of the nesting season. Our results showed that Veeries constructed three separate nest layers: (1) a platform for support, (2) an inner cup, and (3) nest lining. Veeries incorporated parts from six alien plant species in their nests representing 22% of the 27 species used. All nests contained alien plant parts but use differed among the three layers. In particular the use of stems of Alliaria petiolata and Rosa multiflora, two alien species, appeared to provide important structural support in the nest's outer layers. Although our sample size was small, we found no relationship between the use of alien plant parts and nest failure suggesting use of alien plant material does not have negative effects on productivity. We caution that sudden large-scale restoration efforts, which remove the alien forest plant species used in nest construction prior to the recovery of comparable native species, may result in the temporary reduction of materials available to birds for nest construction., INTRODUCTION The effect of alien plant invasions on the ecology of North American forest songbirds has received widespread attention (Borgman and Rodewald, 2004; Heckscher, 2004; McCusker et al., 2010; Gleditsch [...]

We present the first nesting information for the Black Bushbird (Neoctantes niger), an enigmatic and poorly known member of the family Thamnophilidae. A hanging bulky cup nest was found in September 2011, in the buffer zone of Manu National Park, Peru. The nest contained a single white egg with scattered dark maroon spots and light streaks and was being attended by a male. The general shape of the nest resembled the deep pouch-shaped nests of other ant-birds (e.g., Hypocnemis, Myrmotherula) but with clear differences in overall dimensions, thickness and amount of nesting material. More information is needed on nest architecture and breeding behavior for the Black Bushbird and all of its possible close relatives. Received 24 April 2013. Accepted 23 August 2013. Key words: Black Bushbird, egg, Neoctantes niger, nest, nesting biology, tropical., The Black Bushbird (Neoctantes niger) is an enigmatic and poorly known member of the antbird family (Thamnophilidae). One of its most distinctive morphological traits is the bill shape with an [...]

Because Sharp-shinned Hawks (Accipiter striatus) are among the most secretive of North America's forest-breeding raptors, little is known about their breeding biology, including the characteristics of their nesting habitat. In 2009 and 2010, we searched forest stands in Kentucky and located 11 nests, all in pines (Pinus spp.). Nests were at a mean height of 18.6 [+ or -] 1.4 m in trees with a mean height of 23.7 m. Comparison of the characteristics of nest sites and randomly selected unused sites revealed significant differences (P = 0.021). Discriminant analysis revealed that six variables (foliage cover, mean tree height, basal area, percent deciduous canopy cover, distance from edge, and distance from road) permitted the best discrimination between used and random sites. Sharp-shinned Hawks nested in areas closer to edges and in areas with denser stands of taller conifers and denser understory. All nests were in stands of young (~25-50 years), even-aged conifers about 18-25 m in height. Nest sites were also closer to edges where stands of dense pines transitioned into areas with more, shorter deciduous trees and less foliage cover than nest sites. These adjacent areas may provide better foraging habitat for nesting Sharp-shinned Hawks because small birds, their primary prey, are more abundant in mixed stands than in dense stands of conifers where they nested. Received 19 January 2013. Accepted 22 June 2013. Key words: Accipiter striatus, canopy cover, even-aged stands, foliage cover, foraging habitat, nest success., Populations of Sharp-shinned Hawks (Accipiter striatus) in North America are thought to be relatively stable (Sauer et al. 2008), but little is known about their population status in specific portions [...]