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Factors affecting the distribution and abundance of autumn vagrant New World warblers in northwestern California and southern Oregon

Birds found outside their typical range, or vagrants, have fascinated naturalists for decades. Despite broad interest in vagrancy, few attempts have been made to statistically examine the explanatory variables potentially responsible for the phenomenon. In this study, we used multiple linear regress...

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Autores principales: Ralph, C. John, Wolfe, Jared D.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: PeerJ Inc. 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6305120/
https://www.ncbi.nlm.nih.gov/pubmed/30595974
http://dx.doi.org/10.7717/peerj.5881
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author Ralph, C. John
Wolfe, Jared D.
author_facet Ralph, C. John
Wolfe, Jared D.
author_sort Ralph, C. John
collection PubMed
description Birds found outside their typical range, or vagrants, have fascinated naturalists for decades. Despite broad interest in vagrancy, few attempts have been made to statistically examine the explanatory variables potentially responsible for the phenomenon. In this study, we used multiple linear regression to model the occurrence of 28 rare warbler species (family Parulidae) in autumn in northern California and southern Oregon as a function of migration distance, continental population size, distance, and bearing to both closest breeding population and breeding population center. In addition to our predictive model, we used capture data from the California coast to 300 km inland to examine relationships between the presence of vagrant warblers, regional warbler species richness and age class distribution. Our study yielded three important results: (1) vagrancy is strongly correlated with larger North American population size; (2) vagrants are more common at some coastal sites; and (3) where young birds are over-represented, vagrants tend to occur—such as on the coast and at far inland sites. Of the many explanations of rare and vagrant individuals, we feel that the most likely is that these birds represent the ends of the distributions of a normal curve of migration direction, bringing some few migrants to locations out of their normal migratory range as vagrants. We also examine the underrepresented species that, according to our model, are overdue for being recorded in our study area.
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spelling pubmed-63051202018-12-28 Factors affecting the distribution and abundance of autumn vagrant New World warblers in northwestern California and southern Oregon Ralph, C. John Wolfe, Jared D. PeerJ Animal Behavior Birds found outside their typical range, or vagrants, have fascinated naturalists for decades. Despite broad interest in vagrancy, few attempts have been made to statistically examine the explanatory variables potentially responsible for the phenomenon. In this study, we used multiple linear regression to model the occurrence of 28 rare warbler species (family Parulidae) in autumn in northern California and southern Oregon as a function of migration distance, continental population size, distance, and bearing to both closest breeding population and breeding population center. In addition to our predictive model, we used capture data from the California coast to 300 km inland to examine relationships between the presence of vagrant warblers, regional warbler species richness and age class distribution. Our study yielded three important results: (1) vagrancy is strongly correlated with larger North American population size; (2) vagrants are more common at some coastal sites; and (3) where young birds are over-represented, vagrants tend to occur—such as on the coast and at far inland sites. Of the many explanations of rare and vagrant individuals, we feel that the most likely is that these birds represent the ends of the distributions of a normal curve of migration direction, bringing some few migrants to locations out of their normal migratory range as vagrants. We also examine the underrepresented species that, according to our model, are overdue for being recorded in our study area. PeerJ Inc. 2018-12-21 /pmc/articles/PMC6305120/ /pubmed/30595974 http://dx.doi.org/10.7717/peerj.5881 Text en © 2018 Ralph and Wolfe http://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ) and either DOI or URL of the article must be cited.
spellingShingle Animal Behavior
Ralph, C. John
Wolfe, Jared D.
Factors affecting the distribution and abundance of autumn vagrant New World warblers in northwestern California and southern Oregon
title Factors affecting the distribution and abundance of autumn vagrant New World warblers in northwestern California and southern Oregon
title_full Factors affecting the distribution and abundance of autumn vagrant New World warblers in northwestern California and southern Oregon
title_fullStr Factors affecting the distribution and abundance of autumn vagrant New World warblers in northwestern California and southern Oregon
title_full_unstemmed Factors affecting the distribution and abundance of autumn vagrant New World warblers in northwestern California and southern Oregon
title_short Factors affecting the distribution and abundance of autumn vagrant New World warblers in northwestern California and southern Oregon
title_sort factors affecting the distribution and abundance of autumn vagrant new world warblers in northwestern california and southern oregon
topic Animal Behavior
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6305120/
https://www.ncbi.nlm.nih.gov/pubmed/30595974
http://dx.doi.org/10.7717/peerj.5881
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