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Full-Text Articles in Life Sciences

Stopover On Galapagos During Autumn Migration Of Bobolinks (Dolichonyx Oryzivorus), Noah G. Perlut, Rosalind Renfrew Dec 2016

Stopover On Galapagos During Autumn Migration Of Bobolinks (Dolichonyx Oryzivorus), Noah G. Perlut, Rosalind Renfrew

Environmental Studies Faculty Publications

The Bobolink (Dolichonyx oryzivorus) is the only landbird species that is known to stop every year in Galapagos while migrating; however, its stopover ecology while on the islands is unknown. In October 2015, we searched for and captured Bobolinks in the highlands of San Cristóbal. We found Bobolinks in two fields, separated by 9.15 km, at ∼425 m elevation. Average daily counts of Bobolinks on these two fields were 3.2 ± 1.8 and 4.8 ± 2.3 individuals. We caught nine individuals; body mass and fat reserves varied from 22.5–40.0 g and no fat reserves to 50–100% reserves, respectively. …


Why Come Back Home? Investigating The Proximate Factors That Influence Natal Philopatry In Migratory Passerines, Jenna A. Cava, Noah G. Perlut, Steven E. Travis Jun 2016

Why Come Back Home? Investigating The Proximate Factors That Influence Natal Philopatry In Migratory Passerines, Jenna A. Cava, Noah G. Perlut, Steven E. Travis

Environmental Studies Faculty Publications

Knowledge of which cues attract birds back to natal areas is important for conservation because the cues could be manipulated to attract breeders to source habitat or discourage breeders from settling in sink habitat. We examined the influence of intrinsic and extrinsic variables on natal philopatry using two metrics, short-distance natal dispersal and the probability of philopatry to the natal field, in two obligate-grassland bird species breeding in an agricultural landscape: the bobolink, Dolichonyx oryzivorus, and the Savannah sparrow, Passerculus sandwichensis. During 2002–2014, we detected 90 locally hatched Savannah sparrows and 129 locally hatched bobolinks breeding as adults …


Comparative Analysis Of Factors Associated With First‐Year Survival In Two Species Of Migratory Songbirds, Noah G. Perlut, Allan M. Strong May 2016

Comparative Analysis Of Factors Associated With First‐Year Survival In Two Species Of Migratory Songbirds, Noah G. Perlut, Allan M. Strong

Environmental Studies Faculty Publications

Our understanding of the full life cycle of most migratory birds remains limited. Estimates of survival rates, particularly for first‐year birds are notably lacking. This knowledge gap results in imprecise parameters in population models and limits our ability to fully understand life history trade‐offs. We used eleven years of field data to estimate first‐year apparent survival (φ1st) for two species of migratory grassland songbirds that breed in the same managed habitats but have substantially different migration distances. We used a suite of life‐history, habitat and individually‐based covariates to explore causes of variation in φ1st. The interaction …


Roof-Top Nesting In A Declining Population Of Herring Gulls (Larus Argentatus) In Portland, Maine, Usa, Noah G. Perlut, David N. Bonter, Julie C. Ellis, Margaret S. Friar Apr 2016

Roof-Top Nesting In A Declining Population Of Herring Gulls (Larus Argentatus) In Portland, Maine, Usa, Noah G. Perlut, David N. Bonter, Julie C. Ellis, Margaret S. Friar

Environmental Studies Faculty Publications

A number of colonial waterbird species have been documented nesting on roof-tops throughout Europe and North America. The most common hypothesis explaining why gulls (Laridae) select roof-tops for nesting has been that population growth rates are higher than territory vacancy rates in traditional (island) habitat, suggesting that roof-tops are a non-preferred habitat. Roof-top habitat may actually be equal to or higher quality than island habitat as anthropogenic food is abundant and lower nest density may lead to lower intraspecific aggression and predation. During 2011–2012, reproductive effort and success was monitored in a regionally declining population of Herring Gulls (Larus …


Morphological Variation Among Herring Gulls (Larus Argentatus) And Great Black-Backed Gulls (Larus Marinus) In Eastern North America, Gregory J. Robertson, Sheena Roul, Karel A. Allard, Cynthia Pekarik, Raphael A. Lavoie, Julie C. Ellis, Noah G. Perlut, Antony W. Diamond, Nikki Benjamin, Robert A. Ronconi, Scott G. Gilliland, Brian G. Veitch Apr 2016

Morphological Variation Among Herring Gulls (Larus Argentatus) And Great Black-Backed Gulls (Larus Marinus) In Eastern North America, Gregory J. Robertson, Sheena Roul, Karel A. Allard, Cynthia Pekarik, Raphael A. Lavoie, Julie C. Ellis, Noah G. Perlut, Antony W. Diamond, Nikki Benjamin, Robert A. Ronconi, Scott G. Gilliland, Brian G. Veitch

Environmental Studies Faculty Publications

Herring Gull (Larus argentatus) and Great Black-backed Gull (L. marinus) morphometric data from various eastern North American locations was collected to examine the sources of variation in body size within and among geographic regions. For Herring Gulls, significant differences in all commonly taken measurements at local and regional scales were found. However, most of the variation in measurements was due to sex differences and the natural variance seen within local populations. Herring Gulls breeding in the Arctic did not show any evidence of being morphologically different from other groups. A discriminant function derived from a Newfoundland, …