Migratory organisms face many challenges as they travel to take advantage of changing resources, ... more Migratory organisms face many challenges as they travel to take advantage of changing resources, exhibiting a variety of strategies to successfully move between locations. Birds are a model taxa for understanding migratory systems, relying on a multitude of cues and showing diverse behaviours, one of which is their propensity to give calls during migratory flight. However, this behaviour is understudied and may have implications in orientation, navigation and migration monitoring. Because a variety of migratory behaviours differ among and within species as a function of age, sex and body condition, we evaluated whether flight-calling behaviour was related to any of these variables. We studied flightcalling behaviour in four species of passage migrant warblers in captivity during autumn migration at Powdermill Avian Research Center (Rector, PA, U.S.A.) and Braddock Bay Bird Observatory (Greece, NY, U.S.A.). Our results demonstrate extensive variation in flight-calling behaviour by migrant warblers. When all species were combined, young birds were more likely to call and call at a higher rate than adults. All species-specific models were consistent in suggesting a higher propensity and rate of calling by young birds, although the black-throated blue warbler, Setophaga caerulescens, was the only speciesspecific model with significant age-related differences. When all species were combined, sex did not have a significant effect on either propensity or rate of calling. The effect of sex was inconsistent across species, and only magnolia warbler, Setophaga magnolia, males were significantly more likely to respond to calls than females. Surprisingly, body condition did not significantly affect the propensity or rate of calling. While our results reflect the complexity of flight-calling behaviour, our finding that young migrants consistently gave more calls has broad utility, particularly in quantitative migration monitoring. These results demonstrate the need for additional study to determine the selective forces influencing flight-calling behaviour.
Stopover-site quality has often been assessed using changes in the body mass of migrants estimate... more Stopover-site quality has often been assessed using changes in the body mass of migrants estimated from individuals recaptured on subsequent days or using regression methods. We compared estimates of mass change using these two techniques to estimates of mass change determined from birds recaptured on the same day. Using spring and fall banding data collected on Appledore Island, Maine, from 1990-2007, we examined body mass changes of the five most common species. Over this period, 18,954 individuals of these five species were captured and banded, with 11.6% of birds recaptured at least 1 d after initial capture and 3.1% recaptured on the same day. Using both regression and same-day recapture methods, all five species had positive hourly mass gains during fall migration; results were mixed for the subsequent-day analysis method. Trends were less consistent during spring migration. Using all three methods of estimating mass change, Red-eyed Vireos (Vireo olivaceus) lost mass, American Redstarts (Setophaga ruticilla) and Northern Waterthrushes (Parkesia noveboracensis) gained mass, and results for Yellow-bellied Flycatchers (Empidonax flaviventris), and Black-and-white Warblers (Mniotilta varia) varied with method. We found similar trends in mass change using the same-day recapture and regression methods. However, we found lower mean mass gain for most species using the same-day recapture method, suggesting that there may be a short-term capture and handling effect. Our results provide additional support for the use of regression models to compare changes in mass of migrating songbirds at stopover sites. RESUMEN. Estimando el cambio de masa en aves canoras migratorias en una parada: comparación de tres métodos diferentes La calidad de los lugares de parada muchas veces ha sido determinada utilizando cambios en la masa corporal de migratorios, siendo determinada con recapturas en días subsiguientes o mediante métodos de regresión. Comparamos estimados en cambios de masa utilizando estas dos técnicas para determinar el cambio en masa de aves recapturadas el mismo día. Utilizando datos de anillamiento durante la primavera y el otoño tomados desde el 1990-2007, en la isla Appledore, Maine, examinamos el cambio en masa corporal de las cinco especies más comunes. Durante el periodo indicado, 18,954 individuos, de las cinco especies, fueron capturados y anillados, con un 11.6% de las aves recapturadas al menos un día después de la captura inicial y de 3.1% de individuos recapturados el mismo día. Utilizando ambas regresiones, y el método de captura el mismo día, las cinco especies mostraron aumentos positivos en peso por hora, durante la migración otoñal; aunque los resultados fueron mixtos para el método de análisis del día subsiguiente. Las tendencias fueron menos consistentes durante la migración primaveral. Utilizando los tres métodos para estimar el cambio en masa corporal encontramos que Vireo olivaceus perdió masa, Setophaga ruticilla y Parkesia noveboracensis, ganaron masa, mientras que en Empidonax flavoventris y Mniotilta varia, los resultados variaron con el método utilizado. Encontramos tendencias similares, en cambio en masa, utilizando el método de recaptura el mismo día y con el método de regresión. Sin embargo, encontramos una ganancia menor de masa para la mayoría de las especies, utilizando el método de recaptura el mismo día, lo que sugiere que pudiera haber un efecto por la recaptura y la manipulación. Nuestros resultados proveen apoyo adicional para el uso de modelos de regresión en aras de comparar cambios en masa en migratorias canoras en lugares de parada.
The awe-inspiring seasonal migrations of birds between breeding and wintering grounds has long at... more The awe-inspiring seasonal migrations of birds between breeding and wintering grounds has long attracted the interest of casual naturalists and professional ornithologists alike. Although new technologies improve our ability to follow individual migrants throughout their annual cycle, the scale and detail provided by banding records remain incredibly valuable. The focus of avian migration studies is often the most physiologically challenging migratory feats that sometimes leaves certain species or seasons relatively understudied. The Blackpoll Warbler (Setophaga striata) is well-known for its transoceanic migratory flight during fall migration, the season in which it is best studied, yet the details of its spring migration are not well known, at least not at a continental scale. Here we use spring migration banding data on over 15,000 Blackpoll Warblers from 28 banding sites across North America to describe the details of the spring migration patterns in this species. Our data, which spans almost 60 years, indicates that Blackpoll Warblers are migrating earlier at a rate of 0.5 days per decade. We also demonstrate an expected protandrous migratory pattern and an unexpected sex-dependent difference in migration speed with females migrating more quickly than males. Our analyses of longitudinal timing patterns reveal that passage through sites west of 85° occurs prior to passage at sites east of 85° and that this difference increases throughout the migratory period, indicating that birds using western sites are migrating faster. Additionally, we provide evidence vis-à-vis analyses of wing length that birds from eastern and western breeding locations mix at lower-latitude migratory sites but their migratory paths diverge as birds proceed north. These results indicate that birds migrating to western breeding sites differ in their migration speed and route thus compensating for the longer migratory distances traveled by western populations of Blackpoll Warblers compared to those breeding in eastern North America. Migration printanière de la Paruline rayée en Amérique du Nord RÉSUMÉ. Les migrations saisonnières combien admirables des oiseaux entre leurs aires de nidification et d'hivernage ont depuis longtemps attiré l'attention des naturalistes occasionnels tout comme des ornithologues professionnels. Même si de nouvelles technologies ont permis d'améliorer notre capacité à suivre individuellement les oiseaux migrateurs tout au long de leur cycle annuel, l'échelle et les détails fournis par les retours de bagues ont toujours une très grande valeur. Les études sur les migrations aviaires portent souvent sur l'incroyable défi physiologique qu'elles représentent, ce qui entraine parfois un relatif sous-examen de certaines espèces ou saisons. La Paruline rayée (Setophaga striata) est bien connue pour sa migration transocéanique durant l'automne, saison à laquelle elle est le plus étudiée, mais les détails de sa migration printanière sont peu connus, du moins à l'échelle continentale. Nous avons utilisé les données de baguage réalisé en migration printanière de plus de 15 000 Parulines rayées à 28 sites de baguage en Amérique du Nord pour décrire les tendances de la migration printanière de cette espèce. Nos données, qui s'étendaient sur presque 60 ans, ont indiqué que les Parulines rayées migrent plus tôt au rythme de 0,5 jour par décennie. Nous avons aussi observé un profil de migration protandre, auquel nous nous attendions, et une différence dépendante du sexe inattendue sur le plan de la vitesse de migration, les femelles migrant plus rapidement que les mâles. Nos analyses de la tendance de chronologie longitudinale ont révélé que le passage dans les sites à l'ouest du 85° se produisait avant le passage aux sites à l'est du 85°, et que cette différence augmentait durant la période de migration, indiquant que les oiseaux utilisant les sites dans l'ouest migrent plus rapidement que ceux dans l'est. De plus, nous avons obtenu des indices à partir d'analyses de longueur d'ailes indiquant que les oiseaux provenant des sites de nidification dans l'est et l'ouest se côtoient sur les sites migratoires à des latitudes plus faibles, mais que leur corridors de migration se séparent à mesure qu'ils progressent vers le nord. Ces résultats montrent que les oiseaux qui migrent vers des sites de nidification dans l'ouest ont des vitesses et des trajectoires de migration différentes qui compensent pour les distances de migration plus longues des populations de l'ouest de Parulines rayées comparativement aux oiseaux qui nichent dans l'est de l'Amérique du Nord.
The availability of detailed information that encompasses the geographic range of a species, span... more The availability of detailed information that encompasses the geographic range of a species, spans a long-term temporal range, and yields individual information (e.g., age and sex), is a principle challenge in ecology. To this end, the North American Bird Banding Laboratory maintains a unique and underutilized dataset that can be used to address core questions of phenological change in migratory birds. We used records from 1966 to 2015 to quantify how the timing of migration has shifted in a long-distance migrant, the Black-throated Blue Warbler (Setophaga caerulescens). Additionally, we examined age and sex differences in the timing of migratory movements. We observed that early spring migrants passed through sites ~1.1 days earlier per decade and the peak of spring migration also occurred earlier over the 50 yr of this study. Additionally, phenological change was more rapid with increasing latitude during peak spring migratory periods. During fall, the peak of migration stayed con...
The timing of avian migration has evolved to exploit critical seasonal resources, yet plasticity ... more The timing of avian migration has evolved to exploit critical seasonal resources, yet plasticity within phenological responses may allow adjustments to interannual resource phenology. The diversity of migratory species and changes in underlying resources in response to climate change make it challenging to generalize these relationships. We use bird banding records during spring and fall migration from across North America to examine macroscale phenological responses to interannual fluctuations in temperature and long‐term annual trends in phenology. In total, we examine 19 species of North American wood warblers (family Parulidae), summarizing migration timing from 2,826,588 banded birds from 1961 to 2018 across 46 sites during spring and 124 sites during fall. During spring, warmer spring temperatures at banding locations translated to earlier median passage dates for 16 of 19 species, with an average 0.65‐day advancement in median passage for every 1°C increase in temperature, ra...
AяѠѡџюѐѡ.-Capture-mark-recapture models require estimation of parameters that may be either const... more AяѠѡџюѐѡ.-Capture-mark-recapture models require estimation of parameters that may be either constant or time-dependent. Open-population models have been adapted for use in estimating stopover duration of migratory songbirds. However, with data collected over an extended period or with relatively few recaptures, small sample sizes may preclude use of fully time-dependent models. Pooling is commonly used to reduce the number of parameters estimated in time-dependent models. In pooling, all captures and recaptures during a specifi ed interval are treated as a single capture event, which results in a loss of information about recaptures within the interval. Additionally, pooling of banding data of migratory songbirds appears to bias stopover-length estimates upwards. An alternative to pooling is use of multiple-dayconstancy models. Advantages of this approach include maintenance of all recapture data, simultaneous Akaike's Information Criterion-based comparison of models using diff erent constancy intervals, and unbiased stopover estimates.
Blackpoll Warblers (Setophaga striata) breed across Canada and the northern United States and fly... more Blackpoll Warblers (Setophaga striata) breed across Canada and the northern United States and fly across the Atlantic Ocean to South America in fall. Studies of fall migration in this species have centered on the extensive overwater flights but have ignored other aspects of this migration, including potential geographic variation. We used Blackpoll Warbler banding records from 3 coastal (Atlantic seaboard) sites and 9 inland sites to study the fall migration. The sites covered a wide range of the species' geographic distribution during breeding and fall migration in North America. The data spanned the years 1967-2013, though the particular years sampled varied considerably among the stations. We found that the Blackpoll Warbler's fall migration is occurring later by~1 day decade À1. Young birds generally moved through western sites before adults, whereas at eastern sites the reverse was generally true, which suggests that young birds are taking longer on migration. We also found that young birds were in poorer condition than adults, which may lead to an overall decreased rate of migration due to shorter flights and/or longer stops. Wing chords differed between western birds (longer wings) and eastern birds (shorter wings), and wing chords from the 2 more southerly coastal sites may reflect mixing of these groups. Birds were captured at coastal sites .10 days later than at inland sites, even when at similar latitudes. The heaviest individuals and those with the most fat were found at the 2 more southerly coastal sites from late September to mid-October. These results suggest that Blackpoll Warblers from the west move toward the east, where they develop the energy stores needed for their extensive overwater flights.
General and comparative endocrinology, Jan 24, 2015
Preparation for breeding may overlap extensively with vernal migration in long-distance migratory... more Preparation for breeding may overlap extensively with vernal migration in long-distance migratory songbirds. Testosterone plays a central role in mediating this transition into breeding condition by facilitating changes to physiology and behavior. While changes in testosterone levels are well studied in captive migrants, these changes are less well known in free-living birds. We examined testosterone levels in free-living Nearctic-Neotropical migrants of three species during their vernal migration. Testosterone levels increased during the migratory period in males of all three species but significantly so in only two. Testosterone levels in females remained the same throughout their migration. Our results support the extensive overlap between vernal migration and breeding preparation in male songbirds. The pattern of testosterone changes during vernal migration is far from clear in females.
About the National Wind Coordinating Committee A U.S. consensus-based collaborative formed in 199... more About the National Wind Coordinating Committee A U.S. consensus-based collaborative formed in 1994, the National Wind Coordinating Committee (NWCC) identifies issues that affect the use of wind power, establishes dialogue among key stakeholders, and catalyzes activities to support the development of an environmentally, economically, and politically sustainable commercial market for wind power. NWCC members include representatives from electric utilities and support organizations, wind developers and equipment suppliers and support organizations, environmental organizations, state legislatures, state utility commissions, consumer advocacy offices, green power marketers, and local, state, tribal, and federal agencies, and agriculture and economic development orga nizations. RESOLVE, a non-profit environmental dispute resolution organization, provides a full range of facilitation services to create opportunities for NWCC members and other wind stakeholders to build long-term relationships, and to develop a number of landmark products resulting from significant negotiation and reflecting consensus of the Committee. Over 2,500 individuals from diverse sectors and wind resource areas across the country have participated in the NWCC's collaborative efforts.
Geometric morphometric methods of capturing information about curves or outlines of organismal st... more Geometric morphometric methods of capturing information about curves or outlines of organismal structures may be used in conjunction with canonical variates analysis (CVA) to assign specimens to groups or populations based on their shapes. This methodological paper examines approaches to optimizing the classification of specimens based on their outlines. This study examines the performance of four approaches to the mathematical representation of outlines and two different approaches to curve measurement as applied to a collection of feather outlines. A new approach to the dimension reduction necessary to carry out a CVA on this type of outline data with modest sample sizes is also presented, and its performance is compared to two other approaches to dimension reduction. Two semi-landmark-based methods, bending energy alignment and perpendicular projection, are shown to produce roughly equal rates of classification, as do elliptical Fourier methods and the extended eigenshape method ...
?seq=1&cid=pdf-reference#references_tab_contents You may need to log in to JSTOR to access the li... more ?seq=1&cid=pdf-reference#references_tab_contents You may need to log in to JSTOR to access the linked references. JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact
Key words: mark-recapture, migratory passerines, pooling, stopover length. ... Introduction Stopo... more Key words: mark-recapture, migratory passerines, pooling, stopover length. ... Introduction Stopover sites may provide places for migrants to rest, avoid predators, and feed to build or rebuild fat stores that fuel migration. Adequate stopover sites may be critical for the successful ...
Stopover-site quality has often been assessed using changes in the body mass of migrants estimate... more Stopover-site quality has often been assessed using changes in the body mass of migrants estimated from individuals recaptured on subsequent days or using regression methods. We compared estimates of mass change using these two techniques to estimates of mass change determined from birds recaptured on the same day. Using spring and fall banding data collected on Appledore Island, Maine, from 1990-2007, we examined body mass changes of the five most common species. Over this period, 18,954 individuals of these five species were captured and banded, with 11.6% of birds recaptured at least 1 d after initial capture and 3.1% recaptured on the same day. Using both regression and same-day recapture methods, all five species had positive hourly mass gains during fall migration; results were mixed for the subsequent-day analysis method. Trends were less consistent during spring migration. Using all three methods of estimating mass change, Red-eyed Vireos (Vireo olivaceus) lost mass, American Redstarts (Setophaga ruticilla) and Northern Waterthrushes (Parkesia noveboracensis) gained mass, and results for Yellow-bellied Flycatchers (Empidonax flaviventris), and Black-and-white Warblers (Mniotilta varia) varied with method. We found similar trends in mass change using the same-day recapture and regression methods. However, we found lower mean mass gain for most species using the same-day recapture method, suggesting that there may be a short-term capture and handling effect. Our results provide additional support for the use of regression models to compare changes in mass of migrating songbirds at stopover sites. RESUMEN. Estimando el cambio de masa en aves canoras migratorias en una parada: comparación de tres métodos diferentes La calidad de los lugares de parada muchas veces ha sido determinada utilizando cambios en la masa corporal de migratorios, siendo determinada con recapturas en días subsiguientes o mediante métodos de regresión. Comparamos estimados en cambios de masa utilizando estas dos técnicas para determinar el cambio en masa de aves recapturadas el mismo día. Utilizando datos de anillamiento durante la primavera y el otoño tomados desde el 1990-2007, en la isla Appledore, Maine, examinamos el cambio en masa corporal de las cinco especies más comunes. Durante el periodo indicado, 18,954 individuos, de las cinco especies, fueron capturados y anillados, con un 11.6% de las aves recapturadas al menos un día después de la captura inicial y de 3.1% de individuos recapturados el mismo día. Utilizando ambas regresiones, y el método de captura el mismo día, las cinco especies mostraron aumentos positivos en peso por hora, durante la migración otoñal; aunque los resultados fueron mixtos para el método de análisis del día subsiguiente. Las tendencias fueron menos consistentes durante la migración primaveral. Utilizando los tres métodos para estimar el cambio en masa corporal encontramos que Vireo olivaceus perdió masa, Setophaga ruticilla y Parkesia noveboracensis, ganaron masa, mientras que en Empidonax flavoventris y Mniotilta varia, los resultados variaron con el método utilizado. Encontramos tendencias similares, en cambio en masa, utilizando el método de recaptura el mismo día y con el método de regresión. Sin embargo, encontramos una ganancia menor de masa para la mayoría de las especies, utilizando el método de recaptura el mismo día, lo que sugiere que pudiera haber un efecto por la recaptura y la manipulación. Nuestros resultados proveen apoyo adicional para el uso de modelos de regresión en aras de comparar cambios en masa en migratorias canoras en lugares de parada.
The role of migratory birds in the dispersal of Ixodes scapularis ticks in the northeastern U.S. ... more The role of migratory birds in the dispersal of Ixodes scapularis ticks in the northeastern U.S. is well established and is presumed to be a major factor in the expansion of the geographic risk for Lyme disease. Population genetic studies of B. burgdorferi sensu stricto, the agent of Lyme disease in this region, consistently reveal the local presence of as many as 15 distinct strain types as designated by major groups of the ospC surface lipoprotein. Recent evidence suggests such strain diversity is adaptive to the diverse vertebrate hosts that maintain enzootic infection. How this strain diversity is established in emergent areas is unknown. To determine whether similar strain diversity is present in ticks imported by birds, we examined B. burgdorferi strains in I. scapularis ticks removed from migrants at an isolated island site. Tick midguts were cultured and isolates underwent DNA amplification with primers targeting ospC. Amplicons were separated by gel electrophoresis and sequenced. One hundred thirty-seven nymphal ticks obtained from 68 birds resulted in 24 isolates of B. burgdorferi representing eight ospC major groups. Bird-derived ticks contain diverse strain types of B. burgdorferi, including strain types associated with invasive Lyme disease. Birds and the ticks that feed on them may introduce a diversity of strains of the agent of Lyme disease to emergent areas.
In seasonally migratory species, the overlap between the migratory and breeding life history stag... more In seasonally migratory species, the overlap between the migratory and breeding life history stages is a balance between the physiological and behavioral requirements of each stage. Previous studies investigating the degree to which songbirds prepare for breeding during spring migration have focused on either circulating hormone levels or direct measures of gonadal recrudescence. In this study, we evaluated the phenology of breeding preparation in a long-distance migratory songbird, the Swainson's Thrush (Catharus ustulatus), by assessing hypothalamic-pituitary-gonadal (HPG) axis sensitivity with gonadotropin-releasing hormone (GnRH) bioassays throughout the migratory period. During spring migration both males and females had a significant response to GnRH injections as reflected in elevated testosterone levels. The magnitude of response to GnRH injections, R, in females stayed consistent throughout spring migration; however, R in males increased as the migratory season progress...
Migratory organisms face many challenges as they travel to take advantage of changing resources, ... more Migratory organisms face many challenges as they travel to take advantage of changing resources, exhibiting a variety of strategies to successfully move between locations. Birds are a model taxa for understanding migratory systems, relying on a multitude of cues and showing diverse behaviours, one of which is their propensity to give calls during migratory flight. However, this behaviour is understudied and may have implications in orientation, navigation and migration monitoring. Because a variety of migratory behaviours differ among and within species as a function of age, sex and body condition, we evaluated whether flight-calling behaviour was related to any of these variables. We studied flightcalling behaviour in four species of passage migrant warblers in captivity during autumn migration at Powdermill Avian Research Center (Rector, PA, U.S.A.) and Braddock Bay Bird Observatory (Greece, NY, U.S.A.). Our results demonstrate extensive variation in flight-calling behaviour by migrant warblers. When all species were combined, young birds were more likely to call and call at a higher rate than adults. All species-specific models were consistent in suggesting a higher propensity and rate of calling by young birds, although the black-throated blue warbler, Setophaga caerulescens, was the only speciesspecific model with significant age-related differences. When all species were combined, sex did not have a significant effect on either propensity or rate of calling. The effect of sex was inconsistent across species, and only magnolia warbler, Setophaga magnolia, males were significantly more likely to respond to calls than females. Surprisingly, body condition did not significantly affect the propensity or rate of calling. While our results reflect the complexity of flight-calling behaviour, our finding that young migrants consistently gave more calls has broad utility, particularly in quantitative migration monitoring. These results demonstrate the need for additional study to determine the selective forces influencing flight-calling behaviour.
Stopover-site quality has often been assessed using changes in the body mass of migrants estimate... more Stopover-site quality has often been assessed using changes in the body mass of migrants estimated from individuals recaptured on subsequent days or using regression methods. We compared estimates of mass change using these two techniques to estimates of mass change determined from birds recaptured on the same day. Using spring and fall banding data collected on Appledore Island, Maine, from 1990-2007, we examined body mass changes of the five most common species. Over this period, 18,954 individuals of these five species were captured and banded, with 11.6% of birds recaptured at least 1 d after initial capture and 3.1% recaptured on the same day. Using both regression and same-day recapture methods, all five species had positive hourly mass gains during fall migration; results were mixed for the subsequent-day analysis method. Trends were less consistent during spring migration. Using all three methods of estimating mass change, Red-eyed Vireos (Vireo olivaceus) lost mass, American Redstarts (Setophaga ruticilla) and Northern Waterthrushes (Parkesia noveboracensis) gained mass, and results for Yellow-bellied Flycatchers (Empidonax flaviventris), and Black-and-white Warblers (Mniotilta varia) varied with method. We found similar trends in mass change using the same-day recapture and regression methods. However, we found lower mean mass gain for most species using the same-day recapture method, suggesting that there may be a short-term capture and handling effect. Our results provide additional support for the use of regression models to compare changes in mass of migrating songbirds at stopover sites. RESUMEN. Estimando el cambio de masa en aves canoras migratorias en una parada: comparación de tres métodos diferentes La calidad de los lugares de parada muchas veces ha sido determinada utilizando cambios en la masa corporal de migratorios, siendo determinada con recapturas en días subsiguientes o mediante métodos de regresión. Comparamos estimados en cambios de masa utilizando estas dos técnicas para determinar el cambio en masa de aves recapturadas el mismo día. Utilizando datos de anillamiento durante la primavera y el otoño tomados desde el 1990-2007, en la isla Appledore, Maine, examinamos el cambio en masa corporal de las cinco especies más comunes. Durante el periodo indicado, 18,954 individuos, de las cinco especies, fueron capturados y anillados, con un 11.6% de las aves recapturadas al menos un día después de la captura inicial y de 3.1% de individuos recapturados el mismo día. Utilizando ambas regresiones, y el método de captura el mismo día, las cinco especies mostraron aumentos positivos en peso por hora, durante la migración otoñal; aunque los resultados fueron mixtos para el método de análisis del día subsiguiente. Las tendencias fueron menos consistentes durante la migración primaveral. Utilizando los tres métodos para estimar el cambio en masa corporal encontramos que Vireo olivaceus perdió masa, Setophaga ruticilla y Parkesia noveboracensis, ganaron masa, mientras que en Empidonax flavoventris y Mniotilta varia, los resultados variaron con el método utilizado. Encontramos tendencias similares, en cambio en masa, utilizando el método de recaptura el mismo día y con el método de regresión. Sin embargo, encontramos una ganancia menor de masa para la mayoría de las especies, utilizando el método de recaptura el mismo día, lo que sugiere que pudiera haber un efecto por la recaptura y la manipulación. Nuestros resultados proveen apoyo adicional para el uso de modelos de regresión en aras de comparar cambios en masa en migratorias canoras en lugares de parada.
The awe-inspiring seasonal migrations of birds between breeding and wintering grounds has long at... more The awe-inspiring seasonal migrations of birds between breeding and wintering grounds has long attracted the interest of casual naturalists and professional ornithologists alike. Although new technologies improve our ability to follow individual migrants throughout their annual cycle, the scale and detail provided by banding records remain incredibly valuable. The focus of avian migration studies is often the most physiologically challenging migratory feats that sometimes leaves certain species or seasons relatively understudied. The Blackpoll Warbler (Setophaga striata) is well-known for its transoceanic migratory flight during fall migration, the season in which it is best studied, yet the details of its spring migration are not well known, at least not at a continental scale. Here we use spring migration banding data on over 15,000 Blackpoll Warblers from 28 banding sites across North America to describe the details of the spring migration patterns in this species. Our data, which spans almost 60 years, indicates that Blackpoll Warblers are migrating earlier at a rate of 0.5 days per decade. We also demonstrate an expected protandrous migratory pattern and an unexpected sex-dependent difference in migration speed with females migrating more quickly than males. Our analyses of longitudinal timing patterns reveal that passage through sites west of 85° occurs prior to passage at sites east of 85° and that this difference increases throughout the migratory period, indicating that birds using western sites are migrating faster. Additionally, we provide evidence vis-à-vis analyses of wing length that birds from eastern and western breeding locations mix at lower-latitude migratory sites but their migratory paths diverge as birds proceed north. These results indicate that birds migrating to western breeding sites differ in their migration speed and route thus compensating for the longer migratory distances traveled by western populations of Blackpoll Warblers compared to those breeding in eastern North America. Migration printanière de la Paruline rayée en Amérique du Nord RÉSUMÉ. Les migrations saisonnières combien admirables des oiseaux entre leurs aires de nidification et d'hivernage ont depuis longtemps attiré l'attention des naturalistes occasionnels tout comme des ornithologues professionnels. Même si de nouvelles technologies ont permis d'améliorer notre capacité à suivre individuellement les oiseaux migrateurs tout au long de leur cycle annuel, l'échelle et les détails fournis par les retours de bagues ont toujours une très grande valeur. Les études sur les migrations aviaires portent souvent sur l'incroyable défi physiologique qu'elles représentent, ce qui entraine parfois un relatif sous-examen de certaines espèces ou saisons. La Paruline rayée (Setophaga striata) est bien connue pour sa migration transocéanique durant l'automne, saison à laquelle elle est le plus étudiée, mais les détails de sa migration printanière sont peu connus, du moins à l'échelle continentale. Nous avons utilisé les données de baguage réalisé en migration printanière de plus de 15 000 Parulines rayées à 28 sites de baguage en Amérique du Nord pour décrire les tendances de la migration printanière de cette espèce. Nos données, qui s'étendaient sur presque 60 ans, ont indiqué que les Parulines rayées migrent plus tôt au rythme de 0,5 jour par décennie. Nous avons aussi observé un profil de migration protandre, auquel nous nous attendions, et une différence dépendante du sexe inattendue sur le plan de la vitesse de migration, les femelles migrant plus rapidement que les mâles. Nos analyses de la tendance de chronologie longitudinale ont révélé que le passage dans les sites à l'ouest du 85° se produisait avant le passage aux sites à l'est du 85°, et que cette différence augmentait durant la période de migration, indiquant que les oiseaux utilisant les sites dans l'ouest migrent plus rapidement que ceux dans l'est. De plus, nous avons obtenu des indices à partir d'analyses de longueur d'ailes indiquant que les oiseaux provenant des sites de nidification dans l'est et l'ouest se côtoient sur les sites migratoires à des latitudes plus faibles, mais que leur corridors de migration se séparent à mesure qu'ils progressent vers le nord. Ces résultats montrent que les oiseaux qui migrent vers des sites de nidification dans l'ouest ont des vitesses et des trajectoires de migration différentes qui compensent pour les distances de migration plus longues des populations de l'ouest de Parulines rayées comparativement aux oiseaux qui nichent dans l'est de l'Amérique du Nord.
The availability of detailed information that encompasses the geographic range of a species, span... more The availability of detailed information that encompasses the geographic range of a species, spans a long-term temporal range, and yields individual information (e.g., age and sex), is a principle challenge in ecology. To this end, the North American Bird Banding Laboratory maintains a unique and underutilized dataset that can be used to address core questions of phenological change in migratory birds. We used records from 1966 to 2015 to quantify how the timing of migration has shifted in a long-distance migrant, the Black-throated Blue Warbler (Setophaga caerulescens). Additionally, we examined age and sex differences in the timing of migratory movements. We observed that early spring migrants passed through sites ~1.1 days earlier per decade and the peak of spring migration also occurred earlier over the 50 yr of this study. Additionally, phenological change was more rapid with increasing latitude during peak spring migratory periods. During fall, the peak of migration stayed con...
The timing of avian migration has evolved to exploit critical seasonal resources, yet plasticity ... more The timing of avian migration has evolved to exploit critical seasonal resources, yet plasticity within phenological responses may allow adjustments to interannual resource phenology. The diversity of migratory species and changes in underlying resources in response to climate change make it challenging to generalize these relationships. We use bird banding records during spring and fall migration from across North America to examine macroscale phenological responses to interannual fluctuations in temperature and long‐term annual trends in phenology. In total, we examine 19 species of North American wood warblers (family Parulidae), summarizing migration timing from 2,826,588 banded birds from 1961 to 2018 across 46 sites during spring and 124 sites during fall. During spring, warmer spring temperatures at banding locations translated to earlier median passage dates for 16 of 19 species, with an average 0.65‐day advancement in median passage for every 1°C increase in temperature, ra...
AяѠѡџюѐѡ.-Capture-mark-recapture models require estimation of parameters that may be either const... more AяѠѡџюѐѡ.-Capture-mark-recapture models require estimation of parameters that may be either constant or time-dependent. Open-population models have been adapted for use in estimating stopover duration of migratory songbirds. However, with data collected over an extended period or with relatively few recaptures, small sample sizes may preclude use of fully time-dependent models. Pooling is commonly used to reduce the number of parameters estimated in time-dependent models. In pooling, all captures and recaptures during a specifi ed interval are treated as a single capture event, which results in a loss of information about recaptures within the interval. Additionally, pooling of banding data of migratory songbirds appears to bias stopover-length estimates upwards. An alternative to pooling is use of multiple-dayconstancy models. Advantages of this approach include maintenance of all recapture data, simultaneous Akaike's Information Criterion-based comparison of models using diff erent constancy intervals, and unbiased stopover estimates.
Blackpoll Warblers (Setophaga striata) breed across Canada and the northern United States and fly... more Blackpoll Warblers (Setophaga striata) breed across Canada and the northern United States and fly across the Atlantic Ocean to South America in fall. Studies of fall migration in this species have centered on the extensive overwater flights but have ignored other aspects of this migration, including potential geographic variation. We used Blackpoll Warbler banding records from 3 coastal (Atlantic seaboard) sites and 9 inland sites to study the fall migration. The sites covered a wide range of the species' geographic distribution during breeding and fall migration in North America. The data spanned the years 1967-2013, though the particular years sampled varied considerably among the stations. We found that the Blackpoll Warbler's fall migration is occurring later by~1 day decade À1. Young birds generally moved through western sites before adults, whereas at eastern sites the reverse was generally true, which suggests that young birds are taking longer on migration. We also found that young birds were in poorer condition than adults, which may lead to an overall decreased rate of migration due to shorter flights and/or longer stops. Wing chords differed between western birds (longer wings) and eastern birds (shorter wings), and wing chords from the 2 more southerly coastal sites may reflect mixing of these groups. Birds were captured at coastal sites .10 days later than at inland sites, even when at similar latitudes. The heaviest individuals and those with the most fat were found at the 2 more southerly coastal sites from late September to mid-October. These results suggest that Blackpoll Warblers from the west move toward the east, where they develop the energy stores needed for their extensive overwater flights.
General and comparative endocrinology, Jan 24, 2015
Preparation for breeding may overlap extensively with vernal migration in long-distance migratory... more Preparation for breeding may overlap extensively with vernal migration in long-distance migratory songbirds. Testosterone plays a central role in mediating this transition into breeding condition by facilitating changes to physiology and behavior. While changes in testosterone levels are well studied in captive migrants, these changes are less well known in free-living birds. We examined testosterone levels in free-living Nearctic-Neotropical migrants of three species during their vernal migration. Testosterone levels increased during the migratory period in males of all three species but significantly so in only two. Testosterone levels in females remained the same throughout their migration. Our results support the extensive overlap between vernal migration and breeding preparation in male songbirds. The pattern of testosterone changes during vernal migration is far from clear in females.
About the National Wind Coordinating Committee A U.S. consensus-based collaborative formed in 199... more About the National Wind Coordinating Committee A U.S. consensus-based collaborative formed in 1994, the National Wind Coordinating Committee (NWCC) identifies issues that affect the use of wind power, establishes dialogue among key stakeholders, and catalyzes activities to support the development of an environmentally, economically, and politically sustainable commercial market for wind power. NWCC members include representatives from electric utilities and support organizations, wind developers and equipment suppliers and support organizations, environmental organizations, state legislatures, state utility commissions, consumer advocacy offices, green power marketers, and local, state, tribal, and federal agencies, and agriculture and economic development orga nizations. RESOLVE, a non-profit environmental dispute resolution organization, provides a full range of facilitation services to create opportunities for NWCC members and other wind stakeholders to build long-term relationships, and to develop a number of landmark products resulting from significant negotiation and reflecting consensus of the Committee. Over 2,500 individuals from diverse sectors and wind resource areas across the country have participated in the NWCC's collaborative efforts.
Geometric morphometric methods of capturing information about curves or outlines of organismal st... more Geometric morphometric methods of capturing information about curves or outlines of organismal structures may be used in conjunction with canonical variates analysis (CVA) to assign specimens to groups or populations based on their shapes. This methodological paper examines approaches to optimizing the classification of specimens based on their outlines. This study examines the performance of four approaches to the mathematical representation of outlines and two different approaches to curve measurement as applied to a collection of feather outlines. A new approach to the dimension reduction necessary to carry out a CVA on this type of outline data with modest sample sizes is also presented, and its performance is compared to two other approaches to dimension reduction. Two semi-landmark-based methods, bending energy alignment and perpendicular projection, are shown to produce roughly equal rates of classification, as do elliptical Fourier methods and the extended eigenshape method ...
?seq=1&cid=pdf-reference#references_tab_contents You may need to log in to JSTOR to access the li... more ?seq=1&cid=pdf-reference#references_tab_contents You may need to log in to JSTOR to access the linked references. JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact
Key words: mark-recapture, migratory passerines, pooling, stopover length. ... Introduction Stopo... more Key words: mark-recapture, migratory passerines, pooling, stopover length. ... Introduction Stopover sites may provide places for migrants to rest, avoid predators, and feed to build or rebuild fat stores that fuel migration. Adequate stopover sites may be critical for the successful ...
Stopover-site quality has often been assessed using changes in the body mass of migrants estimate... more Stopover-site quality has often been assessed using changes in the body mass of migrants estimated from individuals recaptured on subsequent days or using regression methods. We compared estimates of mass change using these two techniques to estimates of mass change determined from birds recaptured on the same day. Using spring and fall banding data collected on Appledore Island, Maine, from 1990-2007, we examined body mass changes of the five most common species. Over this period, 18,954 individuals of these five species were captured and banded, with 11.6% of birds recaptured at least 1 d after initial capture and 3.1% recaptured on the same day. Using both regression and same-day recapture methods, all five species had positive hourly mass gains during fall migration; results were mixed for the subsequent-day analysis method. Trends were less consistent during spring migration. Using all three methods of estimating mass change, Red-eyed Vireos (Vireo olivaceus) lost mass, American Redstarts (Setophaga ruticilla) and Northern Waterthrushes (Parkesia noveboracensis) gained mass, and results for Yellow-bellied Flycatchers (Empidonax flaviventris), and Black-and-white Warblers (Mniotilta varia) varied with method. We found similar trends in mass change using the same-day recapture and regression methods. However, we found lower mean mass gain for most species using the same-day recapture method, suggesting that there may be a short-term capture and handling effect. Our results provide additional support for the use of regression models to compare changes in mass of migrating songbirds at stopover sites. RESUMEN. Estimando el cambio de masa en aves canoras migratorias en una parada: comparación de tres métodos diferentes La calidad de los lugares de parada muchas veces ha sido determinada utilizando cambios en la masa corporal de migratorios, siendo determinada con recapturas en días subsiguientes o mediante métodos de regresión. Comparamos estimados en cambios de masa utilizando estas dos técnicas para determinar el cambio en masa de aves recapturadas el mismo día. Utilizando datos de anillamiento durante la primavera y el otoño tomados desde el 1990-2007, en la isla Appledore, Maine, examinamos el cambio en masa corporal de las cinco especies más comunes. Durante el periodo indicado, 18,954 individuos, de las cinco especies, fueron capturados y anillados, con un 11.6% de las aves recapturadas al menos un día después de la captura inicial y de 3.1% de individuos recapturados el mismo día. Utilizando ambas regresiones, y el método de captura el mismo día, las cinco especies mostraron aumentos positivos en peso por hora, durante la migración otoñal; aunque los resultados fueron mixtos para el método de análisis del día subsiguiente. Las tendencias fueron menos consistentes durante la migración primaveral. Utilizando los tres métodos para estimar el cambio en masa corporal encontramos que Vireo olivaceus perdió masa, Setophaga ruticilla y Parkesia noveboracensis, ganaron masa, mientras que en Empidonax flavoventris y Mniotilta varia, los resultados variaron con el método utilizado. Encontramos tendencias similares, en cambio en masa, utilizando el método de recaptura el mismo día y con el método de regresión. Sin embargo, encontramos una ganancia menor de masa para la mayoría de las especies, utilizando el método de recaptura el mismo día, lo que sugiere que pudiera haber un efecto por la recaptura y la manipulación. Nuestros resultados proveen apoyo adicional para el uso de modelos de regresión en aras de comparar cambios en masa en migratorias canoras en lugares de parada.
The role of migratory birds in the dispersal of Ixodes scapularis ticks in the northeastern U.S. ... more The role of migratory birds in the dispersal of Ixodes scapularis ticks in the northeastern U.S. is well established and is presumed to be a major factor in the expansion of the geographic risk for Lyme disease. Population genetic studies of B. burgdorferi sensu stricto, the agent of Lyme disease in this region, consistently reveal the local presence of as many as 15 distinct strain types as designated by major groups of the ospC surface lipoprotein. Recent evidence suggests such strain diversity is adaptive to the diverse vertebrate hosts that maintain enzootic infection. How this strain diversity is established in emergent areas is unknown. To determine whether similar strain diversity is present in ticks imported by birds, we examined B. burgdorferi strains in I. scapularis ticks removed from migrants at an isolated island site. Tick midguts were cultured and isolates underwent DNA amplification with primers targeting ospC. Amplicons were separated by gel electrophoresis and sequenced. One hundred thirty-seven nymphal ticks obtained from 68 birds resulted in 24 isolates of B. burgdorferi representing eight ospC major groups. Bird-derived ticks contain diverse strain types of B. burgdorferi, including strain types associated with invasive Lyme disease. Birds and the ticks that feed on them may introduce a diversity of strains of the agent of Lyme disease to emergent areas.
In seasonally migratory species, the overlap between the migratory and breeding life history stag... more In seasonally migratory species, the overlap between the migratory and breeding life history stages is a balance between the physiological and behavioral requirements of each stage. Previous studies investigating the degree to which songbirds prepare for breeding during spring migration have focused on either circulating hormone levels or direct measures of gonadal recrudescence. In this study, we evaluated the phenology of breeding preparation in a long-distance migratory songbird, the Swainson's Thrush (Catharus ustulatus), by assessing hypothalamic-pituitary-gonadal (HPG) axis sensitivity with gonadotropin-releasing hormone (GnRH) bioassays throughout the migratory period. During spring migration both males and females had a significant response to GnRH injections as reflected in elevated testosterone levels. The magnitude of response to GnRH injections, R, in females stayed consistent throughout spring migration; however, R in males increased as the migratory season progress...
Uploads
Papers by Sara Morris