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To reduce costs associated with nest building, some birds steal (kleptoparasitize) nest material. While this behavior is rarely reported in solitary nesting birds, it has been previously documented in 2 species of white-eyes, the Japanese White-eye (Zosterops japonicas) and the Indian White-eye (Z palpebrosus). During surveys for Tinian Monarchs (Monarcha takatsukasae) on Tinian Island in the Northern Mariana Islands, we documented nest material kleptoparasitism by the Bridled White-eye (Z conspicillatus). Through camera-trap footage and real-time observation, we observed Bridled White-eyes stealing material from 2 other forest bird species: the Micronesian Rufous Fantail (Rhipidura versicolor,; n = 1 observation) and Tinian Monarch (n = 7). We documented nest material piracy during multiple nesting phases including building, incubation, and post-fledge, and from abandoned and depredated nests. This behavior was previously undocumented in the Bridled White-eye, and nest material kleptoparasitism is not documented in any other forest birds in the Mariana Islands. Kleptoparasitism of nest material has been known to cause destruction or abandonment of the host's nest. Given the potential implications of nest material kleptoparasitism on host nesting behavior and success, and that the Bridled White-eye is estimated to be the most abundant forest bird on Tinian, our observations warrant inquiry into how this behavior could be affecting the broader ecology of forest birds in the Manana Islands. Received 13 July 2023. Accepted 17 June 2024. Key words: heterospecific, Mariana Islands, nest material kleptoparasite, nesting, songbird, theft. (Chamorro)--Guaha' paluma ni ma a'amot materiat guien otm na chonchon pat gi otru n finihu', ma kleptoparasitize i materiat (kleptoparasitize--betbu/kleptoparasitism--na'an: esti na palabra kumekeilelek-ria i chinile' yan i usun materiat ni esta mana'setbe gi otru na chonchon) para u ma na'libianu mama'chonchon ya para u na'ribaha lokkue' i tiempo para u ma e'materiat. Achokka' hassan esti na bida masusedi gi ayu na klasen paluma ni manmama'chonchon na maisa, malili'e' esti na aktibidat gi dos na espisis nosa', i nosa' Hapon (Zosterops japonicus), yan i nosa' India (Z palpebrosus). In dokumenta i kleptoparasitism gi nosa' (Z conspicillatus) annai m chechegue' inaligaon i chichirikan Tini'an (Monarcha takatsukasae) gi iya Tini'an gi i Sankattan na Islas Marianas. In li'e' i nosa' manmananakki materiat ginen i chenchon dos na espsis paluma: patitkulamenti i na'abak (Gu/Lu/Ti/Sa)/burike' ande'(Lu)/chichirika(Gu/ri/ Sa) (Micronesian Rufous Fantail/Rhipidura rufifons; n 1 kuentas m mali'e'), yan i chichirikan Tini'an (n = 6). In dokumenta I kleptoparasitism gi i tiempon manada' enteramente, achokka' mama'chonchon i paluma, kumuleleka i paluma, despues di ma dingu i chenchon i pechon, yan lokkue' gi eyu na chonchon ni esta maabandona. Ti dinekumenta esti na aktibidat gi i nosa' antes di in li'e', yan lokkue' ti madokumenta i kleptoparasitism gi otru na espesis paluman halomtano' guini gi i islas Marianas, Matungo' ha' na i kleptoparasitism siria' ha distrosa i chenchon ni ma chuchule' i materiat, pat o sino ha ma abandona i pal urna ni chenchon-niha. Debi di maestudiayi taimanu inafefekta i lina'la' paluman halomtano' ni kleptoparasitism guini gi i islas Marianas sa' siria' i kleptoparasitism ginen i nosa' (matataha na guiya i mas abundansia na paluman halomtano' guini giya Tini'an) u mas ha na'chatsaga' i tiempon mariada' asta i uttimo-tia. Palabra na manglo: i ga'ga' ni ma sasakki materiat chonchon, Islas Marianas, i tiempun manada', Nosa', manakki, paluman halumtanu', ti parehu na espisis., For most birds, nest construction is a prerequisite for breeding. Given that it is a time-consuming and potentially dangerous process, selective forces may favor behaviors that reduce costs associated with [...]

Understanding a species' distribution is vital for making sound conservation and management decisions. Secretive behaviors and complicated seasonal movement patterns have made range delimitation surprisingly elusive for some North American birds, including the Northern Saw-whet Owl (Aegolius acadicus). Despite bei3.ng among the most common of North American forest owls, only the species' breeding range is well demarcated. This has resulted in the species historically being considered a 'northern' bird, with eastern migratory and nonbreeding ranges extending only as far south as central Missouri and eastern Tennessee. Recent banding efforts have shown that saw-whet owls arc fall migrants much farther south. We extend this work by investigating stopover duration and nonbreeding habitat selection during 2 winters at the edge of the species' southern distribution in the Ozark Highlands of northwest Arkansas. We used radio telemetry to track 27 owls, with 17 individuals detected at least once post-release (n = 54 surveys and 131 total detections). Length of stay in the study area was most influenced by year- - birds remained an average of 3.6 weeks longer during an irruption year--and our data suggest that the species uses the Ozark Highlands for both nonbreeding residency and brief stopover periods. During the 2 year study, 37% of marked owls were winter residents, 26% remained in the area temporarily, and 37% were not rcdetectcd. Winter habitat preferences of saw-whet owls in the southeast are consistent with what is known about the species in its more northemly range, with birds selecting conifers on south-facing slopes in areas with an open understory. Overall, our results suggest that saw-whet owls are not rare fall migrants and winter residents in Arkansas as was previously assumed, and more generally, are likely underappreciated winter predators in southern pine ecosystems. Received 24 August 2023. Accepted 28 June 2024 Key words: habitat use, nonbreeding range, owl, radio tracking, raptor, roosting, species distribution. (Spanish)--Entender la distribucion de una especie es vital para hacer decisiones de conservacion y manejo acertadas. Comportamientos reservados y patrones de movimiento estacionales complicados han hecho que las delimitaciones de rango sean sorpresivamente elusivas para algunas aves de Norteamerica, incluyendo para el mochuelo Aegolius acadicus. A pesar de ser uno de los mochuelos de bosque mas comunes de Norteamerica, solo se ha demarcado correctamente su rango reproductivo. Esto ha resultado en que el ave sea considerada historicamente como 'nortena', con migraciones orientales y rangos no reproductivos que se extienden hacia el sur solo hasta el centro de Missouri y el este de Tennessee. Esfuerzos de anillado reciente han mostrado que estos mochuelos migran en otono mucho mas al sur. Realizamos este trabajo investigando duracion de paradas y seleccion de habitat no reproductivo durante 2 inviernos en el borde sur de la distribucion mas surena en Ozark Highlands en el noroeste de Arkansas. Usamos radio telemetria para monitorear a 27 mochuelos, con 17 individuos detectados al menos una vez despues de su liberacion (n=54 busquedas y 131 detecciones totales). La longitud de parada en el area de estudio fue mas influenciada por el ano--las aves permanecieron en promedio 3.6 semanas mas en un ano de interrupcion--y nuestros datos sugieren que la especie utiliza Ozark Highlands tanto para sitio de residencia no reproductiva como para sitios de paradas migratorias breves. Durante el estudio de 2 anos, 37% de los mochuelos marcados eran residentes de invierno, 26% permanecieron temporalmente en el area y el 37% no volvieron a ser detectados. Las preferencias de habitat invernales de los mochuelos Aegolius acadicus en el sudeste son consistentes con lo que se conoce de la especie en su rango mas norteno, con aves seleccionando coniferas en pendientes con orientacion sur en areas con un sotobosque abierto. En general, nuestros resultados sugieren que los mochuelos Aegolius acadicus no son migratorios de otono raros y residentes invernales en Arkansas, como era asumido previamente, y mas generalmente, son posiblemente depredadores invernales poco apreciados en ecosistemas de pino surenos. Palabras clave: descanso, distribucion de especies, lechuza, monitoreo por radio, rango no reproductivo, rapaz, uso de habitat., The Northern Saw-whet Owl (Aegolius acadicus), hereinafter saw-whet owl, is a small migratory owl restricted to forest habitats in North America (Weidensaul 2015). Despite being a common forest owl, surprisingly [...]

Byline: B. Yilmaz Dikmen Keywords: Ostrich (Struthio camelus), climate-change, behavior, animal welfare. INTRODUCTION Ostriches are commercially raised in many countries around the world for their main products, meat, skin, feathers [...]

Q My 8-year-old neutered male Cairn Terrier, Toby, lives with three family members (ages 82, 82, and 55). Over the past several years, Toby has had a number of aggressive [...]

Animal communication carries the risk of signal exploitation by predators, and thus many prey species will adjust their signals into riiore discreet messages to conspecifics, or conspicuous antipredator cues. Although rails (Family Rallidae) use the visual display of tail flicking as a warning of vigilance toward predators, how these birds alter their vocal behavior based on perceived predation risk remains little studied. The calls of owls, predatory birds that consume a variety of rallid species and can home in on acoustic cues of their prey, can reduce singing in numerous bird species. We applied remotely activated broadcasts and autonomous recording units to study whether rails in the wetlands of the Lake Calumet region near Chicago, Illinois, would decrease their vocal activity rate following the broadcast of a rallid predator, the Great Horned Owl (Bubo virginianus). Contrary to predictions, Soras (Porzana Carolina) significantly increased vocal activity when exposed to owl vocalizations and decreased vocal activity when exposed to a harmless control. Our results indicate that rails appear to increase their vocal activity as a potential alarm mechanism, likely to reduce predation risk by warning conspecifics. Received 3 June 2020. Accepted 4 March 2021. Key words: acoustic interactions, alarm calls, playback, predators. Rallidae, Sora. La comunicacion animal conlleva el riesgo de que su serial sea explotada por depredadores y por ello muchas especies ajustan sus senates a mensajes mas discretos a sus conespecificos o con senas antidepredador conspicuas. Aunque los rascones (Familia Rallidae) usan el despliegue visual de alzar la cola como una serial de vigilancia antidepredador, la forma en la que estas aves alteran su comportamiento vocal basado en el riesgo percibido de depredacion sigue siendo poco estudiado. Los llamados de biihos, aves depredadoras que consumen una variedad de especies de ralidos y pueden encontrar presas basandose en senales acusticas de sus presas, pueden reducir los cantos en numerosas especies. Usamos grabaciones remotamentc activadas y unidades de grabacion autonomas para estudiar si los rascones en los humedales de la region de Lake Calumet cerca de Chichago, Illinois, rcducirian su tasa de actividad vocal despues de escuchar a un depredador de ralidos. el biiho Bubo virginianus. Contrario a nuestras predicciones, Porzana Carolina incremento significativamente su actividad vocal cuando fue expuesta a vocalizaciones de b[degrees]hos y redujeron su actividad vocal cuando fueron expuestas a un control inofensivo. Nuestros resultados indican que los rascones parecen incrementar su actividad vocal como un potencial mecanismo de alarma. posiblemente para reducir el riesgo de depredacion avisando a sus conespecificos. Palabras clave: depredadores, grabaciones, interacciones acusticas, llamados de alarma, Porzana Carolina, Rallidae., Communicating animals run a near-constant risk of their signals attracting eavesdroppers such as predators. Many species are aware of this danger, as both senders and receivers of a variety of [...]

Nomadism is a type of movement lacking fixed spatiotemporal patterns, evident in species inhabiting variable environments. The irregular movement characterizing nomadic species often acts as a challenging barrier for scientists investigating their ecology. We provide an insight on the movement of a nomadic desert bird, the Spotted Sandgrouse (Pterocles senegallus), within and between different activity seasons. The data were obtained from I individual fitted with a satellite transmitter, which was tracked for -2.5 years. Three main activity seasons were detected during which the bird stayed in a specific area: prebreeding, breeding, and winter. Nomadic behavior was evident during the pre-breeding and breeding seasons, whereas site fidelity was observed during winter (i.e., seasonal nomadism). Local scale fidelity with respect to roosting behavior was also evident among and within the 3 winters of tracking. Field observations carried out during the first breeding season enabled us to link the movement patterns of the bird with its behavior at different phases of the breeding season. Within and between activity seasons. the bird was engaged in short- and long-distance scouting forays. The long-distance ones occurred only during the prebreeding season. In some of the scouting forays, the bird arrived at sites it had previously utilized, suggesting the existence of spatial memory and navigation capability. This fine-scale description of movement can uncover key features, which allow the survival and reproduction of nomadic birds inhabiting arid areas where the distribution of resources is largely unpredictable. Received 6 October 2019. Accepted 23 February 2021. Key words: Argos satellite tracking, irregular movement, roosting site, seasonal dynamics. El nomadismo es un tipo de movimiento que carcee de patrones espaciotemporales fijos. evidente en ambientes variables. Los movimientos irregulares que caracterizan a las especies nomadas frecuentemente actuan como un reto dificil de franquear para los cientifieos que investigan su ecologia. Aqui proveemos una mirada a los movimientos intra- e inter-estacionales de una especie nomada del desierto. la ganga Pterocles senegalhts. Los datos fueron obtcnidos de I individuo a quien se le coloco un transmisor de satelite y el cual fue seguido por -2.5 afios. Detectamos 3 temporadas principales de actividad. durante las cuales esta ave estuvo en un area especifica: prerreproductiva, reproductiva e invierno. El comportamicnto nomada fue evidente durante las temporadas prerreproductiva y reproductiva, mientras que su fidelidad a sitio fue obscrvada durante e! inviemo (i.e., nomadismo estacional). La fidelidad a escala local, en lo que respecta al comportamiento de dormideros. tambien fue evidente intra- e interestacionalmente en los 3 inviernos de este seguimiento. Las observaciones de campo que se Uevaron a cabo durante la primera estacion reproductiva nos permitieron vincular los patrones de movimiento de esta ave con su comportamiento en diferentes fases de dicha temporada. Intra- e inter-estacionalmente, esta ave se dedico a movimientos cxploratorios de cortas y largas distancias. Aquellos de largas distancias tuvieron lugar unicamente durante la temporada prerreproductiva. En algunas de sus exploraciones. esta ave llego a sitios que previamente habia utilizado. los cual sugiere la existencia de capacidades de memoria espacial y navegacion. Esta descripcion de movimientos puede develar caracteristicas clave que permiten la sobrevivencia y reproduccion de aves nomadas que habitan areas aridas dondc la distribucion de recursos es en su mayoria impredecible. Palabras clave: dinamica estacional, dormideros, movimientos irregulares. seguimiento satelital Argos., Large-scale movements performed by birds could be divided into 2 major categories, regular and irregular movement (Cottee-Jones et al. 2016). Regular movement involves fixed spatial and temporal components (e.g., seasonal [...]

Interactions between hummingbirds and potentially dangerous or aggressive insects at shared food sources may result in interference competition and risk-avoidance behaviors. To examine the potential interplay between perceived risk and interference competition, we observed the vigilance behaviors of Ruby-throated Hummingbirds (Archilochus colubris) foraging at artificial feeders with and without visual obstruction in the presence and absence of 3 species of wasp (Hymenoptera: Vespidae: Vespinae). Hummingbirds withdrew their bills from the visually obstructed feeder more rapidly than when feeding with a clear view of the surroundings. Wasps caused hummingbirds to spend a greater proportion of their visit vigilant, an effect positively correlated with the number of wasps at the feeding station. Aggressive competitive interactions at feeders were asymmetric. Hummingbirds avoided feeders with wasps and switched between available feeders more often and were never observed pursuing wasps away from the feeder. Instead, hummingbirds were chased by wasps or avoided foraging from feeders when wasps were present. Changes in hummingbird vigilance patterns in response to wasp aggression match those of other avian species whose antipredator vigilance patterns have been thoroughly examined. Thus, although interference competition inevitably occurs, vigilance patterns suggest that hummingbirds do perceive wasps as a potential threat and not solely as competitors. Received 25 February 2019. Accepted 8 September 2020. Key words: foraging, interference competition, risk, tradeoff, Vespidae, visual obstruction. Las interacciones entre colibries c insectos potencialmente peligrosos o agresivos cn los sitios donde compartcn recursos alimcnticios pueden resultar en competencia por interferencia y comportamicntos dc evasion de ricsgo. Para cxaminar la posible relacion entre el riesgo percibido y la competencia por interferencia, observamos los componamientos dc vigilancia de los colibries Archilochus colubris forrajeando en comedcros artificiales con y sin obstruccion visual en presencia y ausencia de 3 especies de avispas (Hymenoptera: Vespidae: Vespinae). Los colibries retiraron sus picos del comedcro visualmentc obstruido mas rapido que cuando se alimentaban cn condiciones de visibilidad dc los alrededores sin obstrucciones. Las avispas provocaron que los colibries pasaran una mayor proporcion de sus visitas siendo vigilantes, un cfecto positivamente correlacionado con el numero de avispas cn la estacion de alimentacion. Las interacciones competitivas agresivas fueron asimetricas. Los colibries evitaron los comedcros con avispas y cambiaron entre comcderos disponibles mas frccucntemente y nunca fueron observados ahuyentando avispas lejos del comedero. En cambio, los colibries fueron perseguidos por avispas o evitaron forrajear en comederos cuando habia avispas presentes. Los cambios en patrones de vigilancia de colibries en respuesta a la agresion de avispas coinciden con aquellos de otras especies de aves cuyos patrones de vigilancia antidepredadores han sido detalladamente cstudiados. Por ello. si bien la competencia por interferencia inevitablemcnte ocurrc. los patrones de vigilancia sugieren que los colibries perciben a las avispas como una amcnaza potencial y no solamcnte como compctidorcs. Palabras clave: competencia por interferencia. costo-bcncficio, forrajco, obstruccion visual, ricsgo. Vespidae., Due to a hummingbird's small size, competitive interactions with aggressive, potentially venomous insects (e.g., wasps) may be hazardous. Interactions between hummingbirds and aggressive insects are certainly more common in a [...]

Of the more than 150 ctenophore species, the oceanic ctenophore Eurhamphaea vexilligera is notable for its bright orange-yellow ink, secreted from numerous small vesicles that line its substomodeal comb rows. To date, in situ observations by scuba divers have proved the most fruitful method of observing these animals' natural behavior. We present the results of one such contemporary scuba-based observation of K vexilligera, conducted in the Gulf Stream waters off the coast of Florida, using high-resolution photography and video. Utilizing underwater camera systems purpose built for filming gelatinous zoo-plankton, we observed E. vexilligera ink release and swimming behavior in situ. From these data, we describe the timeline and mechanics of E. vexilligera ink release in detail, as well as the animal's different swimming behaviors and resulting ink dispersal patterns. We also describe a rolling swimming behavior, accompanied and possibly facilitated by a characteristic change in overall body shape. These observations provide further insight into the behavioral ecology of this distinctive ctenophore and may serve as the foundation for future kinematic studies., Introduction Even among the morphologically diverse ctenophores, the lobate Eurhamphaea vexilligera Gegenbaur, 1856 is distinct. Dozens of bright-red vesicles line the comb rows on either side of its body, following [...]

Behavioral plasticity can drive feeding innovations, a frequent trait of urban exploiter species. The House Sparrow (Passer domesticus) is a widespread and abundant urban dweller whose success has often been related to its dietary breadth. Although both formal and informal sources (e.g., internet videos, news, and blogs) have shown meat scavenging behaviors of this sparrow, it has been overlooked in the literature. While it is recognized that this sparrow has a diverse diet in urban settings, quantitative sources report only 3 types of foods (i.e., seeds, plant origin, and invertebrates). Our field observation of a female House Sparrow feeding on a chicken 'drumstick' (presumably fibula/tibia) leftover at a greenspace of Manhattan (i.e., High Line), USA, adds to the available formal and informal information regarding the opportunistic scavenging of dressed and cooked meat by these sparrows when available. Thus, our observation adds to the feeding plasticity knowledge of this urban-related invasive bird and suggests the importance of the role of pedestrians in molding House Sparrow diet. Received 6 May 2019. Accepted 4 December 2019. Key words: meat, novel food resources, scavenger, urban ecology, urban exploiter species La plasticidad conductual es un factor que puede impulsar las innovaciones alimenticias, un rasgo frecuente de las especies explotadoras urbanas. El gorrión doméstico (Passer domesticas) es una especie muy prolifera en zonas urbanas, cuyo éxito se ha relacionado con su amplitud de dieta. Aunque existe evidencia formal e informal (e.g., videos, noticias y blogs) que muestra el comportamiento carroñero de este gorrión, ésta información se ha pasado por alto en la literatura. Si bien se reconoce que éste gorrión tiene una dieta amplia en entornos urbanos, la información cuantitativa sobre su alimentación únicamente incluye 3 tipos de alimentos (i.e., semillas, origen vegetal e invertebrados). En esta nota reportamos a una hembra de gorrión doméstico que se alimentaba de un sobrante de 'pierna' de pollo (presumiblemente peroné / tibia) en un área verde de Manhattan (i.e., High Line), EE. UU. Nuestra observación se suma a la información formal e informal disponible sobre el comportamiento carroñero por parte de estos gorriones cuando esta disponible. Por lo tanto, nuestra observación contribuye al conocimiento sobre la plasticidad alimentaria de esta ave invasora relacionada con la urbanización y sugiere la importancia del papel de los peatones en la dieta del gorrión doméstico. Palabras clave: carne, recursos alimenticios novedosos, carroñero, ecología urbana, especies explotadoras urbanas, Global assessments of urban avifaunas have identified several widespread generalist species that tend to have large urban populations, of which the following head the list: Rock Pigeon (Columba livid), House [...]

Winter flounder (Pseudopleuronectes americanus) have declined to less than 11% of their historical abundance in offshore areas and have experienced severe declines and inbreeding in coastal subpopulations. Understanding metapopulation structure and disparate migratory behavior is vital to understanding the species' dynamics. We used acoustic telemetry to evaluate migratory types, homing behavior, and spawning behavior in adult winter flounder (n = 72) in Mattituck Creek, New York. Telemetry results showed that 17% of the tagged individuals displayed resident behavior and remained in the creek year- round despite mean summer temperatures reaching 28[degrees]C. Alternatively, the migratory group (~83%) started to leave the system when the mean water temperature reached 12[degrees]C. A dominant driver of migration was not indicated; instead, migration out of or into the creek appeared complex and related to date, temperature, lunar cycle, photoperiod, and year. Approximate spawning was estimated to occur as early as November and continued through April based on aggregative behaviors of adults and backcalculations of dates using young-of-the-year otoliths. Our results support the emerging view that winter flounder's dynamics reflect local life history and population diversity, which are currently unaccounted for in management. L'abondance des plies rouges (Pseudopleuronectes americanus) a chute a moins de 11 % de sa valeur historique dans les zones extracotieres et l'espece a subi des baisses et une endogamie importantes dans les sous-populations cotieres. La comprehension de la structure de la metapopulation et des comportements migratoires disparates est d'importance vitale pour la comprehension de la dynamique de l'espece dans la region. Nous avons utilise la telemetrie acoustique pour evaluer les types migratoires, le retour et le comportement de frai chez des plies rouges (n = 72)adultes dans lacrique Mattituck (Etatde New York). Les resultats de telemetrie montrent que 17 % des specimens etiquetes presentaient un comportement resident et demeuraient dans la crique toute l'annee malgre des temperatures estivales moyennes atteignant 28[degrees]C. En comparaison, le groupe migrateur (~83 %) commenqait a quitter le reseau quand la temperature moyenne de l'eau atteignait 12[degrees]C. Un moteur dominant de la migration n'est pas ressorti; la migration hors de la crique ou vers celle-ci semble complexe et reliee a la date, la temperature, le cycle lunaire, la photoperiode et l'annee. Il est estime que le frai commence des novembre pour se poursuivre jusqu'a avril, a la lumiere de comportements de regroupement d'adultes et du retrocalcul des dates base sur les otolites. Nos resultats appuient l'opinion emergente selon laquelle la dynamique des plies rouges reflete la diversite locale des cycles biologiques et de la population, un aspect dont la gestion actuelle ne tient pas compte. [Traduit par la Redaction], Introduction Large-scale movements by individuals occur across almost all taxa (Dingle and Drake 2007). The prevalence of migration across taxa indicates that it is a key life history component, particularly [...]

We present observations of breeding behaviors exhibited by a bilateral gynandromorph Eastern Towhee (Pipilo erythrophthalmus) in Rhode Island during June and July 2017. The individual had the black plumage of a male towhee on the left side of its body and brownish plumage of a typical female towhee on the right side of its body. We observed this individual moving with, interacting with, and feeding fledged young. We also recorded the bird singing in similar locations over a 35 day observation period. This is one of the first observations of a free-living gynandromorph bird exhibiting certain breeding behaviors such as associating with another adult, singing, and feeding young. Received 13 December 2018. Accepted 9 February 2019. Key words: bilateral gynandromorphy, breeding behavior, Eastern Towhee Presentamos observaciones de comportamientos reproductivos mostrados por un ginandromorfo bilateral del rascador Pipilo erythrophthalmus en Rhode Island durante junio y julio 2017. El individuo tenia el plumaje de un rascador macho en el lado izquierdo de su cuerpo y plumaje pardo de una hembra tipica en el lado derecho del cuerpo. Observamos a este individuo en movimientos, interacruando y alimentando polluelos emancipados. Tambien registramos este pajaro cantando en localidades similares a lo largo de un periodo de 35 dias. Este es una de las primeras observaciones de un ginandromorfo en libertad exhibiendo ciertos comportamientos reproductivos como su asociacion con otro adulto. cantando y alimentando polluelos. Palabras clave: comportamiento reproductivo, ginandromorfo bilateral, Bilateral gynandromorphy is a rare state in which a bird's plumage shows a demarcation along the midline with one lateral side exhibiting female characteristics and the other side male characteristics [...]

Territories provide important breeding and nonbreeding resources for many bird species. Most songbird territory research has been conducted in temperate regions during the breeding season, a situation in which primarily males appear to defend territories and for only a few months. In the tropics, however, both females and males of many species may defend territories year-round and for multiple years, yet few studies have verified this with marked or radio-tagged birds. To assess territory stability in both sexes between seasons and years, we examined similarity in territory size, location, and overlap with neighbors between the breeding and nonbreeding seasons and 2 subsequent breeding seasons in a tropical resident songbird, the Troupial (Icterus icterus). Mated females and males maintained similar-sized, tightly overlapping territories that had considerably less overlap with neighbors than each other. Both sexes maintained similar-sized territories in the breeding and nonbreeding seasons and between years. The location of territory centers and extent of overlap with neighbors was also similar between seasons and years. Divorce and/or territory switching appeared to be uncommon, but upon disappearance of a mate, both sexes often replaced the mate to maintain the territory. Our work quantitatively verifies for both sexes the year-round territorial behavior expected for this and many tropical species. Such territory similarity and stability likely plays a role in song, plumage, and sex role similarities also seen in female and male Troupials. Received 13 August 2018. Accepted 28 January 2019. Key words: female territoriality, Icterus icterus, nonbreeding season, tropical songbird, year-round territoriality Los territorios proveen recursos reproductivos y no-reproductivos para muchas especies. La mayoria de la investigacion sobre el territorio de las aves canoras se ha llevado a cabo en regiones tempiadas durante la temporada reproductiva, situacion en la que los machos parecen defender territorios solo por algunos meses. En los tropicos, sin embargo, machos y heinbras de muchas especies pueden defender territorios durante todo el ano por multiples anos, si bien son pocos los estudios que han verificado este hecho por medio de aves marcadas o con radiotransmisorcs. Para determinar la estabilidad de territorios en ambos sexos entre estaciones y anos en un ave tropical residente, el turpial Icterus icterus, examinamos la similitud en tamano del territorio, localidad y traslape con aquel de sus vecinos entre las temporadas reproductiva y no-reproductiva en dos estaciones reproductivas subsecuentes. Parejas de hembra y macho mantuvieron territorios de tamano similar que se traslapan entre si de manera cstrecha y que mantienen un traslape considerablemente menor con el de sus vecinos. Ambos sexos mantienen territorios de tamanos similares en las temporadas reproductiva y no-reproductiva, asi como entre anos. Asimismo, la localizacion del centra de los territorios y la extension del traslape con sus vecinos tambien fue similar entre temporadas y anos. El divorcio y/o el intercambio de territorios parecen ser poco comunes, aunque con la desaparicion de su pareja, ambos sexos frecuentemente encontraron un reemplazo para mantener el territorio. Nuestro trabajo verifica, de forma cuantitativa, y para ambos sexos, el comportamiento territorial durante todo el ano que es esperado para esta y muchas especies tropicales. Dicha similitud y estabilidad de territorios juega un papel en las similitudes en el canto, plumaje y papel de los sexos que pueden observarse en turpiales hembras y machos. Palabras clave: aves canoras tropicales, temporada no-reproductiva, territorialidad de hembras, territorialidad todo el ano, Most studies on territorial behavior of songbirds have been conducted at temperate latitudes. At those latitudes, males generally defend breeding territories that exist only a few months of the year [...]