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Stopover sites are essential to bird migration between wintering and breeding grounds, but annual variation in use and habitat conditions make it difficult to determine which sites are most critical for conservation. By studying physiological factors that may influence a bird's behavior when choosing and using a stopover site, researchers can target certain species or locations and more efficiently invest in conservation efforts. In spring 2013 and 2014, we studied stopover refueling performance in a common northeastern spring migrant, the White-throated Sparrow (Zonotrichia albicollis), at 2 locations near the south shore of Lake Ontario. We used morphological measurements and physiological techniques that assessed the concentration of the blood metabolite plasma triglyceride as a measure of fat deposition and feeding efficiency. We found that birds captured at an inland location had a significantly higher body condition score than birds captured at a coastal stopover site within 0.5 km of the shore; a trend toward higher triglyceride concentrations was also noted at the inland location. We found no significant differences in triglyceride concentrations between White-throated Sparrow color morphs, in contrast to previous studies performed during fall migration. Our results suggest that spring migrants arriving in the area in good energetic condition may begin their cross-lake journey directly from the inland site, while birds in poorer condition may 'pile up' at the lakeshore and then compete with other migrants for available resources, slowing their fat deposition rate. Our results also reinforce the importance of protecting high-quality stopover habitat where birds congregate near geographic barriers but suggest that inland habitat patches are important stopover sites that may allow some migrants to bypass nearshore areas of intense competition. Received 5 June 2017. Accepted 15 July 2018.Key words: condition, migration, refueling, stopover, White-throated Sparrow, Zonotrichia albicollis.Les sites d'escale sont essentiels a la migration des oiseaux entre les aires d'hivernage et de reproduction, mais il est difficile pour determiner des sites les plus critiques pour la conservation a cause des variation annuelles de l'utilisation et des conditions de l'habitat. En etudiant les facteurs physiologiques qui pourraient influencer le comportement d'un oiseau migrateur lors du choix et de l'utilisation d'un site d'escale, les chercheurs peuvent viser certaines especes ou endroits et investir plus efficacement dans les efforts de conservation. Au printemps 2013 et 2014, nous etudiames le ravitaillement chez un oiseau migrateur qui est commun du Nord-Est (au Canada), le Bruant a Gorge Blanche (Zonotrichia albicollis), a deux sites d'escales pres de la rive sud du lac Ontario. Nous utilisames les mesures biometriques et les techniques physiologiques pour evaluer la concentration plasmatique en triglycerides (dans le sang) comme mesure du depot de graisses et de l'efficacite de ravitaillement. Nous constatames que les oiseaux captures a un site d'escale a l'interieur des terres avaient un indice d'etat corporel significativement plus eleve que les oiseaux captures a un site d'escale cotier dans un rayon de 0,5 km de la rive ; il y avait aussi une tendance positive entre les concentrations de triglycerides et le site d'escale a l'interieur des terres. Nous ne trouvames aucune difference significative dans les concentrations de triglycerides entre les deux morphorypes du Bruant a Gorge Blanche (blanc et chamois), contrairement aux etudes anterieures effectuees pendant la migration automnale. Nos resultats suggerent que les oiseaux migrateurs qui arrivent en bon etat a ces sites d'escale au printemps pourraient commencer directement leur voyage au-dessus du lac depuis le site interieur, tandis que les oiseaux en moins bon etat peuvent << s'accumuler >> a la rive du lac et rivaliser avec les autres oiseaux migrateurs pour les ressources disponibles, par consequent ralentir leur taux de depot de graisses. Nos resultats renforcent egalement l'importance de proteger les sites d'escale de haute qualite ou les oiseaux migrateurs se rassemblent pres des barrieres geographiques, mais suggerent aussi que les parcelles d'habitat interieur sont des sites d'escale importantes qui pourraient permettre aux certains oiseaux migrateurs de contourner les zones littorales de competition intense.Mots-cles: Bruant a Gorge Blanche, condition, migration, ravitaillement, site d'escale, Zonotrichia albicollis., Migrant birds move seasonally to take advantage of plentiful resources on their summer breeding grounds while avoiding the harshest winter weather. Despite these advantages, migration may be the most dangerous [...]

Understanding full annual cycle movements of long-distance migrants is essential for delineating populations, assessing connectivity, evaluating crossover effects between life stages, and informing management strategies for vulnerable or declining species. We used implanted satellite transmitters to track up to 2 years of annual cycle movements of 52 adult female Whitewinged Scoters (Melanitta fusca (Linnaeus, 1758)) captured in the eastern United States and Canada. We used these data to document annual cycle phenology; delineate migration routes; identify primary areas used during winter, stopover, breeding, and molt; and assess the strength of migratory connectivity and spatial population structure. Most Whitewinged Scoters wintered along the Atlantic coast from Nova Scotia to southern New England, with some on Lake Ontario. Whitewinged Scoters followed four migration routes to breeding areas from Quebec to the Northwest Territories. Principal postbreeding molting areas were in James Bay and the St. Lawrence River estuary. Migration phenology was synchronous regardless of winter or breeding origin. Cluster analyses delineated two primary breeding areas: one molting area and one wintering area. Whitewinged Scoters demonstrated overall weak to moderate connectivity among life stages, with molting to wintering connectivity the strongest. Thus, Whitewinged Scoters that winter in eastern North America appear to constitute a single continuous population.Key words: Whitewinged Scoter, Melanitta fusca, population delineation, migratory connectivity, annual cycle, satellite telemetry, phenology.La comprehension des deplacements sur un cycle annuel complet d'especes qui migrent sur de longues distances est fondamentale pour delimiter les populations, evaluer la connectivite et les effets de chevauchement de differentes etapes du cycle biologique et elaborer de strategies de gestion pour les especes vulnerables ou en declin. Nous avons utilise des emetteurs satellitaires implantes pour suivre le cycle de deplacement annuel pendant jusqu'a deux ans de 52 macreuses a ailes blanches (Melanitta fusca (Linnaeus, 1758)) femelles adultes capturees dans l'est des Etats-Unis et du Canada. Nous avons utilise ces donnees pour documenter la phenologie du cycle annuel, delimiter les routes de migration, cerner les principales aires d'hivernage, de sejour, de reproduction et de mue et evaluer la force de la connectivite migratoire et la structure spatiale de la population. La plupart des macreuses a ailes blanches hivernaient le long de la cote atlantique, de la Nouvelle-Ecosse au sud de la Nouvelle-Angleterre, certaines passant plutot l'hiver sur le lac Ontario. Les macreuses a ailes blanches suivaient quatre routes de migration vers des aires de reproduction allant du Quebec aux Territoires-du-Nord-Ouest. Les principales aires de mue apres la reproduction etaient dans la baie James et l'estuaire du fleuve Saint-Laurent. La phenologie de la migration etait synchrone, quelles que soient les aires d'hivernage ou de reproduction d'origine. Des analyses typologiques ont delimite deux principales aires de reproduction, une aire de mue et une aire d'hivernage. Les macreuses a ailes blanches presentaient globalement une connectivite faible a moderee entre les etapes du cycle biologique, la connectivite entre la mue et l'hivernage etant la plus forte. Ainsi, les macreuses a ailes blanches qui hivernent dans l'est de l'Amerique du Nord semblent constituer une seule population continue. [Traduit par la Redaction]Mots-cles : macreuse a ailes blanches, Melanitta fusca, delimitation des populations, connectivite migratoire, cycle annuel, telemetrie satellitaire, phenologie., IntroductionMonitoring movement patterns of long-distance migratory animals over space and time provides insights into key aspects of their ecology (Trierweiler et al. 2014; Hallworth et al. 2015; Stanley et al. [...]

West Nile virus (WNV) is a mosquitoborne virus that can cause severe and even fatal disease in humans. After WNV introduction into New York, NY, USA, its geographic range expanded [...]

Numerous organisms exhibit carry-over effects, in which previous environmental conditions impact current performance. For example, reproductive output for many migratory birds can be impacted by events during the preceding migration. Lesser Scaup (Aythya affinis (Eyton, 1838); hereafter scaup) declined dramatically during 1970s-2000s, and there is evidence linking reduced reproductive output to reduced body condition during spring migration. In addition to food availability and quality, haemosporidian parasites (Plasmodium spp., Haemoproteus spp.) may be associated with condition of spring-migrating birds. We examined whether haemosporidian parasite infection status was linked to measures of size (mass, wing length, tarsus length, and keel length) and condition (body fat, size-corrected mass, wing-loading) in female spring-migrating scaup. Infection prevalence varied by year (21.7% in 2014; 47.1% in 2015) and percent body fat was negatively associated with the probability of infection. Body fat levels declined from 2014 to 2015, but at a similar rate for infected and uninfected birds. This pattern suggests that the increased prevalence in 2015 may have been related to the greater proportion of poor-condition birds being more susceptible to infection or recrudescence of latent infections. In light of forecasted range shifts and expansions of avian malaria vectors, the impact of haemosporidian parasites on migratory waterfowl condition warrants further investigation. Key words: avian malaria, Aythya affinis, blood parasite, body fat, Lesser Scaup, migration, spring condition hypothesis, waterfowl. De nombreux organismes présentent des effets résiduels, selon lesquels des conditions environnementales passées ont une incidence sur la performance présente. L'efficacité de la reproduction pour de nombreux oiseaux migrateurs peut par exemple être influencée par des évènements s'étant produits durant la migration précédente. Les petits fuligules (Aythya affinis (Eyton, 1838); appelés fuligules ci-dessous) ont connu un déclin drastique des années 1970 aux années 2000, et des indices relient une baisse de l'efficacité de la reproduction à une baisse de l'embonpoint durant la migration printanière. Outre la disponibilité et la qualité de la nourriture, des hémosporidies parasites (Plasmodium spp., Haemoproteus spp.) pourraient être associées à l'embonpoint d'oiseaux à migration printanière. Nous avons vérifié si le statut d'infection aux hémosporidies était relié à des mesures de la taille (masse, longueur des ailes, longueur du tarse et longueur du bréchet) et de l'embonpoint (graisse corporelle, masse corrigée pour la taille, charge alaire) chez des fuligules femelles à migration printanière. La prévalence d'infection varie selon l'année (21,7 % en 2014; 47,1 % en 2015) et le pourcentage de graisse corporelle présente une association négative avec la probabilité d'infection. Les pourcentages de graisse corporelle ont baissé de 2014 à 2015, mais à un rythme semblable pour les oiseaux infectés et non infectés. Ce motif donne à penser que la prévalence accrue en 2015 pourrait être reliée à la plus grande proportion d'oiseaux de faible embonpoint plus vulnérables à l'infection ou à une recrudescence d'infections latentes. À la lumière des modifications et expansions projetées des aires de répartition de vecteurs de paludisme aviaire, l'impact des hémosporidies parasites sur l'embonpoint d'espèces migratrices de sauvagine nécessite des études plus poussées. [Traduit par la Rédaction] Mots-clés : paludisme aviaire, Aythya affinis, hémoparasite, graisse corporelle, petit fuligule, migration, hypothèse de l'embonpoint printanier, sauvagine., Introduction An organism's performance at any given time is influenced by current environmental conditions, as well as previous environmental conditions that resulted in persisting changes to the organism's somatic or [...]

ABSTRACT.--Wanning temperatures have been linked to advancing spring migration dates of birds, although most studies have been conducted at individual sites. Problems may arise ecologically if birds arrive or depart [...]

ABSTRACT.--The Brown Dipper (Cinclus pallasi) was discovered to be a regular winter resident in the mountains of Verkhoyansk Range in Northeastern Siberia. This area is one of the coldest in [...]

ABSTRACT.--Global change can affect several aspects of bird biology, including population size and migration timing. We used count data collected during 25 years (1990-2014) at Hawk Mountain Sanctuary, a raptor [...]

ABSTRACT.--Throughout North America, organized groups of citizens and scientists have collected climate and bird phenology records since the 1880s. Most studies utilizing these data sets have compared mean first arrival [...]

Floodplain forest of the Upper Mississippi River is important for songbirds during spring migration. However, the altered hydrology of this system and spread of reed canary grass (Phalaris arundinacea) and emerald ash borer (Agrilus planipennis) threaten tree diversity and long-term sustainability of this forest. We estimated tree preferences of songbirds during spring migration 2010-2013 to help guide management decisions that promote tree diversity and forest sustainability and to evaluate yearly variation in tree selection. We used the point center-quarter method to assess relative availability of tree species and tallied bird foraging observations on tree species as well as recording the phenophase of used trees on five 40 ha plots of contiguous floodplain forest between La Crosse, Wisconsin and New Albin, Iowa, from 15 April through 1 June. We quantified bird preferences by comparing proportional use of tree species by each bird species to estimates of tree species availability for all 4 y and for each year separately. Species that breed locally preferred silver maple (Acer saccharinum), which is dominant in this forest. The common transient migrant species and the suite of 17 transient wood warbler species preferred hackberry (Celtis occidentalis) and oaks (Quercus spp.), which are limited to higher elevations on the floodplain. We observed earlier leaf development the warm springs of 2010 and 2012 and later leaf development the cold springs of 2011 and 2013. Yellow-rumped Warbler (Setophaga coronata), American Redstart (S. ruticilla), Warbling Vireo (Vireo gilvus) and Baltimore Oriole (Icterus galbula), and the suite of transient migrant wood warblers spread their foraging efforts among tree species in colder springs and were more selective in warmer springs. All three of the important tree species are not regenerating well on the UMR and widespread die-off of silver maple is possible in 50 y without large scale management., INTRODUCTION Migration poses many challenges for songbirds because most avian mortality may occur during migration (Stillett and Holmes, 2002), and birds en route necessarily forage and rest in unfamiliar locations [...]

ABSTRACT. During migration, Common and King Eiders (Somateria mollissima and S. spectabilis) cross the Beaufort and Chukchi Seas of Arctic Alaska. Because they may become attracted to lights, eiders are [...]

Research of and surveillance for influenza A viruses in wild birds inhabiting western Alaska have consistently provided support for the exchange of viruses between East Asia and North America via [...]

Since the first bird observatory was established over a century ago, hundreds have been established around the world. Classic observatories share a focus on capture and study of birds in the hand, particularly migrants. Many professionals were first inspired by working at a bird observatory, and researchers have long been using observatory data and facilities in collaborative studies. Results from observatories have made major contributions to knowledge of migration: timing, routes and destinations, body condition and local movement during stopover; as well as tracking long-term population change. Nonetheless, observatories are an underutilized resource for researchers, and this paper highlights the benefits they offer and opportunities for further cooperation. Received 26 November 2015. Accepted 13 May 2016. Key words: bird observatories, cooperative studies, migration timing, routes, energetics, strategies., THE BIRD OBSERVATORY RESOURCE The term 'bird observatory' came from the English translation of 'Vogelwarte,' part of the original title of a book describing 50 years of bird study on [...]

As a small nocturnal migrant, the Northern Saw-whet Owl (Aegolius acadicus) is hypothesized to reduce predation risk by avoiding migration during the full moon. However, small-scale studies have given mixed results on whether there is a relationship between capture rate of Northern Saw-whet Owls and the lunar cycle during fall migration. We used 50 years of data from the U.S. Bird Banding Laboratory to examine capture rates of Northern Saw-whet Owls throughout North America in relation to lunar illumination. A logistic regression of 156,794 fall captures compared to random dates in the fall showed that captures are significantly less likely as lunar illumination increases. Captures at high illumination were 22% less likely than captures on moonless nights during the waning half of the lunar cycle and 41 % less likely during the waxing half of the lunar cycle. Modification of the lunar illumination index to correct for the duration of the night that the moon is in the sky gave similar results. Owls were also most likely to be captured on a Sunday or Monday, perhaps reflecting higher weekend capture effort. The relationship of captures to lunar illumination and wax/wane phase is consistent with an ultimate explanation of predator risk avoidance, but a proximate mechanism of altered owl movement is not demonstrated and alternative explanations such as variable human capture effort and changes in owls' ability to detect and avoid nets may also be responsible. Neither of our logistic models had much power, probably because local habitat and weather are strong modifiers of the lunar cycle effect on capture probability of Northern Saw-whet Owls. The average reductions calculated here may still underestimate the decrease in owl captures under local conditions of bright moonlight. Received 5 June 2015. Accepted 10 December 2015. Key words: Northern Saw-whet Owl, Aegolius acadicus, fall migration, lunar illumination, moon phase, predation risk avoidance., Most studies on moonlight and animal activity suggest that lunar cycles influence predation risks for prey and opportunities for predators (Kronfeld-Schor et al. 2013). Under normal foraging conditions, many prey [...]

While a common species throughout most of the United States, little is known on the migration habits of Red-tailed Hawks (Buteo jamaicensis). From 1999-2002, we tracked 16 adult Red-tailed Hawks from their breeding grounds in northwest Wyoming using Argos PTT transmitters. Our objectives were to identify dates and duration of migratory movements, stopover sites, and identify migration routes and wintering areas. We found the mean migration initiation date from the breeding area was 13 October, mean fall migration duration including stopovers was 23.3 days, mean distance of fall migration was 2489.6 km, and mean end date of fall migration was 5 November. Wintering locations were in Mexico and ranged from the southern Mexican state of Chiapas north to Sonora and Chihuahua. The mean number of days spent on the wintering grounds by tracked hawks was 133.1. The mean departure date from wintering grounds to breeding areas was 17 March, mean spring migration duration including stopovers was 22.1 days, mean end date of spring migration was 8 April, and mean distance of spring migration was 2 490.3 km. Most birds made stopovers during both fall and spring migration which varied in location and duration. Using satellite telemetry, we identified wintering locations of Red-tailed Hawks breeding in northwest Wyoming and confirmed a leapfrog migration pattern with no concentrated migration routes from the breeding area to non-breeding areas. Received 6 February 2015. Accepted 23 July 2015. Key words: Buteo jamaicensis, migration, migratory patterns, Red-tailed Hawk, Wyoming., The Red-tailed Hawk (Buteo jamaicensis) is a common species throughout North America (Preston and Beane 2009). Yet, our knowledge on the migratory habits of this raptor is limited. Migration count [...]

Early successional habitats are declining in eastern North America while at the same time remaining habitats are being invaded by a suite of nonnative shrub species. While the significance of these transidonal habitats to breeding birds is well known, increasing evidence suggests they are important during the postfledging/premigratory and migratory periods, not only for shrub-nesting species but also for many species that breed in latesuccessional habitats. Additionally a number of studies suggest exotic species have the potential to alter habitat quality, in turn affecting the fitness of migratory landbirds. The purpose of this study was to evaluate fitness correlates associated with migrant use of shrubland habitat dominated by nonnative honeysuckle (Lonicera spp.) in order to gauge habitat quality for spring migrants using an inland stopover site in northeastern Pennsylvania. We used estimates of mass change as our fitness indicator, with positive mass change indicating quality habitat. Our results suggest most birds gain mass while using honeysuckle-dominated habitat and many species, including species that characteristically breed in forested habitats, accrue fitness advantages from using shrubland habitat during spring stopover in northeastern Pennsylvania. However, we emphasize the need to examine the cumulative effects of exotic vegetation through multiple stages of the avian annual cycle to better understand the fitness consequences of nonnative vegetation on migratory landbirds., INTRODUCTION Transitional, early successional habitats in eastern North America are declining (Askins, 2000; Oehler, 2003; Rich et al., 2004). To date most of the concern about this loss has focused [...]

Studies of the effects of climate change on migratory bird behavior have established that many species are shifting the average day of year of their arrival at nesting sites earlier. If migrating birds are adapted to arrive at the optimum stage in the growth season to maximize the availability of resources, then migration phenology shifts may result in arrival at nesting sites at selectively disadvantageous points in seasonal development of the nesting ecosystem. First arrival dates (FAD) are changing for many species, but we know little about shifts in the corresponding accumulated growing degree units (AGDU) of arrival date in association with increasing global temperatures. By transcribing field notes for migrant arrival times during the years of 1910-1950 in the region around Fargo, ND, we obtained a detailed and robust description of historical phenological patterns. Comparison of the arrival times of 83 of the same species in the same location over the past 10 years indicate that the majority of bird species studied are arriving earlier than they did historically. The accumulated growing degree units at the time of arrival deviated from past values by as much as 4-5% higher or lower depending on the species. In general, short-distance migrants have advanced their arrival times and reduced the AGDU at the time of arrival relative to long-distance migrants. These results indicate that changing climate is influencing bird migration patterns and leading to arrival of migrants at different points in the progress of the growing season relative to the past. The impacts of this divergence on fitness and selection are expected to influence the nature of future bird communities. Received 7 March 2014. Accepted 4 September 2014. Key words: bird migration, climate change, Great Plains, growing degree units, phenology., The ability of migratory birds to maximize reproductive success in a temperate nesting environment with a finite growing season depends on their ability to mate, nest, produce offspring, and rear [...]

Breeding has a high energetic cost and, in central place foragers, also restricts the ability of parents for self-foraging, with affecting on their body and immunological conditions. In migratory species, breeding overlaps the period of recovery of body conditions before the following outbound migration. Those factors may reduce the breeding success and even lead parents to abandon their offspring if parental body condition cannot guarantee the success of the next migration. We studied the body and immunological conditions of a low breeding success population of Brown Skuas (Stercorarius antarcticus lonnbergi) throughout their breeding season. We evaluated changes in their body mass, blood parameters and heterophil:lymphocyte ratios (H:L), at three stages of their breeding period: Incubation, Early rearing and Late rearing. The body mass of female Brown skuas decreased during the initial stages of the breeding period and recovered towards the end. The changes in metabolites suggest a use of protein body reserves but not of lipid reserves. The H:L ratio did not indicate changes in the immune condition of the birds. Our results suggest that this low breeding success population begins its breeding period with a poor body condition that it continues to decline throughout the season. Those poor body conditions added to the need for recovery for the next migration may be the cause of the abandonment of almost totally feathered chicks. Our evidence highlights the importance of food availability, in either the breeding or wintering sites, or both, on the health of the populations of migratory top predators., Author(s): Maricel Graña Grilli [sup.1] , Marcela Pari [sup.2] , Andrés Ibañez [sup.3] Author Affiliations: (Aff1) 0000 0001 1945 2152, grid.423606.5, Grupo de Investigaciones en Biología de la Conservación, Laboratorio [...]

Bird migration is influenced by weather, making it hard to predict when birds will pass through a particular place on their route. A model that forecasts bird migrations has been developed using radar data and weather information.The development of a system to predict bird-migration movements., Author(s): Mary AbrahamAuthor Affiliations:Bird forecasting by radar Credit: P. Choui/Getty [see PDF for image]A male Baltimore Oriole flaps his wings as he takes flight from a branchRelated [...]