DOI: 10.5061/dryad.s4mw6m97h
title: Lesser Yellowlegs location data describing the occurrence of birds within harvest zones in the Caribbean and South America

description: Shorebirds have experienced a precipitous reduction in abundance over the
 past four decades. While some threats to shorebirds are widespread (e.g.
 habitat alteration), others are regional and may affect specific
 populations. Lesser Yellowlegs (Tringa flavipes) are long-distance
 migrants that breed across the North American boreal biome and have
 declined in abundance by 60-80% since the 1970s. The documented harvest of
 Lesser Yellowlegs in the Caribbean and northeastern South America during
 southward migration is a possible limiting factor for the species, but it
 is unknown to what extent birds from different breeding origins may be
 affected. To address the question of differential occurrence in harvest
 zones during southward migration, we used PinPoint GPS Argos transmitters
 to track the southward migrations of 85 adult Lesser Yellowlegs from
 across the species’ breeding range and 80° of longitude from Anchorage,
 Alaska, USA to the Mingan Archipelago, Quebec, Canada. We classified
 migratory locations as inside or outside three zones with high levels of
 harvest (Caribbean, coastal Guianas, and coastal Brazil) and then fit
 generalized additive mixed models to estimate the probability of
 occurrence of Lesser Yellowlegs in harvest zones according to their
 breeding origin. Individuals from the Eastern Canada population had a
 higher probability of occurrence within one or more harvest zones and
 remained in those zones longer than individuals breeding in Alaska and
 western Canada. Linear regressions also suggested that longitude of the
 breeding origin is an important predictor of occurrence in harvest zones
 during southward migration. Lastly, our findings, combined with other
 sources of evidence, suggest that current estimated harvest rates may
 exceed sustainable limits for Lesser Yellowlegs, which warrants further
 investigation.
description: Location data was collected using Lotek Argos PinPoint-75
 transmitters attached to Lesser Yellowlegs using a leg-loop harness
 method. Lesser Yellowlegs were tracked from six geographically disparate
 populations. The PinPoint-75 model receives and transmits location data
 remotely through the Argos system, which allows data to be dowloaded
 without the need to recapture the bird. All data was accessed in ArgosWeb
 (https://argos-system.clsamerica.com/argos-cwi2/login.html) and processed
 through a proprietary sofware called Lotek Argos-GPS Data Processor V4.2.
 This processor outputs human-readable .csv files which include the
 latitude and longitude of locations in decimal degrees. To run the
 analyses outlined in the manuscript (probability of occurence in harvest
 zones and predictors of occurence in harvest zones) we truncated the data
 to only include locations from July 1 through October 21 of each year. We
 restricted our analysis to southward migration, ending on October 21 for
 three reasons. First, harvest policies in the jurisdictions of the harvest
 zones we examined indicate that most Lesser Yellowlegs harvest occurs
 during southward migration when flocks of shorebirds stop in the Lesser
 Antilles and northeastern South America due to seasonal weather events
 such as hurricanes and tropical depressions. Second, the predefined GPS
 tag schedules limited the number of transmissions received after October
 21 in 2018, 2019, and 2020. Lastly, of the 69 (82%) individuals tracked
 throughout the non-breeding period, none of the individuals occurred in
 harvest zones after October 21 that had not already been previously
 observed there. To run a continuous-time state-space
 random walk model we used package <i>foieGras</i> 0.4.0 in
 program R. To run a binomial generalized linear model we used
 package <i>MASS</i> 7.3-53 in program R. Code is provided in
 association with the location data .csv files.
description: The dataset does not include any missing values. The description
 of each column header for each spreadsheet is provided in an associated
 ReadMe file. The steps to follow for each analysis are provided in the R
 code files.