Migratory Connectivity of Ovenbirds

August 15, 2014 by Michael T. Hallworth

Understanding migratory connectivity is critical for interpreting population dynamics, seasonal interactions and for the implementation of conservation strategies of migratory species. We evaluated the migratory connectivity of a Neotropical migratory songbird, the Ovenbird (Seiurus aurocapilla) using archival light-level geolocators deployed at two breeding and four non-breeding locations while incorporating Ovenbird abundance as prior information using Bayes' Rule.

We also included band recoveries submitted to the United States Geological Survey's Bird Banding Laboratory to assess connectivity of areas where geolocators were not deployed. We created a probabilistic map of origin for each capture site and mapped spring migration routes between non-breeding and breeding locations. We found a complete separation of eastern and western populations of Ovenbirds throughout the annual cycle.

Breeding Ovenbirds from western Canada spent the non-breeding season throughout Central America and migrated through central North America during spring migration. Birds breeding in northeastern United States were distributed throughout the central Greater Antilles in the Caribbean and migrated through eastern North America during spring migration. Fall migration routes were not included because the timing of migration coincided with fall equinox when latitudinal estimates are unreliable. However, longitudinal estimates suggest no overlap between eastern and western populations during fall migration.

Ovenbirds with geolocators attached in Jamaica bred in the northeastern United States with the highest posterior probability of origin found in Massachusetts, while Ovenbirds captured in Florida and Puerto Rico bred primarily in the mid-Atlantic. Incorporating Ovenbird abundance as a prior into geolocator estimates decreased the area of origin by 90.37% ± 1.05% for the breeding season and 62.30% ± 1.69% for the non-breeding season, compared to geolocator estimates alone. Ovenbirds exhibited strong migratory connectivity between breeding and non-breeding season which has important implications for various aspects of the ecology, evolution and conservation.

This article summarizes the information in this scientific paper:

Michael T. Hallworth, T. Scott Sillett, Steven L. Van Wilgenburg, Keith A. Hobson, and Peter P. Marra In press. MIGRATORY CONNECTIVITY OF A NEOTROPICAL MIGRATORY SONGBIRD REVEALED BY ARCHIVAL LIGHT-LEVEL GEOLOCATORS. Ecological Applications. http://dx.doi.org/10.1890/14-0195.1

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