Original Research ARTICLE
Automated VHF Radiotelemetry Revealed Site-Specific Differences in Fall Migration Strategies of Semipalmated Sandpipers on Stopover in the Gulf of Maine
- 1School of Biology and Ecology, University of Maine, United States
- 2Bird Studies Canada, Canada
- 3Department of Biology, Acadia University, Canada
- 4Maine Department of Inland Fisheries and Wildlife, United States
- 5United States Fish and Wildlife Service (USFWS), United States
- 6Maine Natural History Observatory, United States
- 7School of Biology and Ecology, University of Maine, United States
The Gulf of Maine has long been recognized as a major stopover area for shorebirds in fall. Knowing how birds move within and beyond the region will be paramount to protecting threatened shorebird habitat. To determine stopover behavior during fall migration (2013-2017) in Maine, 180 (104 AHY, 76 HY) Semipalmated Sandpipers, Calidris pusilla, were tracked using VHF radiotelemetry and an extensive array of automated receivers (Motus Wildlife Tracking System). Birds tagged at three locations along the Maine coastline showed no effect of age class or stopover site on body condition (body mass, estimated fat mass) or stopover length (post capture detection period). However, movement after departure varied greatly among sites. Few birds captured at the northern-most site (“Downeast”, n=71), which had the greatest amount of mudflats and offshore roost sites and the least amount of human disturbance, were detected beyond the initial tagging location, suggesting that they, like birds in the Bay of Fundy just to the north, initiated trans-oceanic flights from that location. At the Downeast site, leaner birds remained significantly longer than fatter birds, suggesting that time of departure there depended on energy reserves, which would be critical for making extensive flights. In contrast, over half of the birds tagged further south (Popham Beach, n= 59; Rachel Carson NWR, n = 50) were later detected at coastal locations to the north (few) or to the south (most). Stopover period at these sites was independent of fat, suggesting that other factors (e.g. feeding/roosting site availability, human activity) influenced departure decisions. In Maine, Semipalmated sandpipers, regardless of age, may move north (Downeast) or south (e.g. Cape Cod, Rhode Island, Long Island Sound) where the local topography, habitat characteristics (feeding/roosting sites), and/or lower human activity, may best enable them to initiate trans-oceanic flights to the wintering grounds. Future study should determine if variation in stopover behavior is population-specific and if population-segregation occurs in Maine. Use of automated VHF radiotelemetry has lead to a greater understanding of stopover behavior and the degree of connectivity among stopover sites, which should be taken into account for conserving migratory bird habitat across broad spatial scales.
Keywords: Semipalmated sandpiper, Calidris pusilla, Migration, Stopover behavior, Radiotelemerry, shorebirds, habitat
Received: 29 Apr 2019;
Accepted: 14 Aug 2019.
Edited by:Brett K. Sandercock, Norwegian Institute for Nature Research (NINA), Norway
Reviewed by:Jaime A. Collazo, North Carolina State University, United States
Jonathan B. Cohen, SUNY College of Environmental Science and Forestry, United States
Copyright: © 2019 Holberton, Taylor, Tudor, O'Brien, Mittelhauser and Breit. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Prof. Rebecca L. Holberton, School of Biology and Ecology, University of Maine, Orono, United States, firstname.lastname@example.org