Initial sample collection in The Bahamas
We captured Kirtland’s Warblers on Cat Island, The Bahamas, in March and April of 2017 and 2018 using vocalization playback and mist nets. We classified individuals into two age categories (SY = second calendar year or ASY = after second year), sexed individuals following Pyle (1997), and attached a USGS metal band and three plastic colored bands. We then fitted a coded radio-tag (0.35g, Model = NTQBW-2, Lotek Wireless, Inc.) using a modified leg-loop harness (Rappole and Tipton 1991). Tags emitted coded pulses at regular intervals (29.3 s), which allowed for individual identification through handheld or automated telemetry receivers (Taylor et al. 2017). After attaching the radio tags, we collected fecal samples by placing birds in a wax paper bag for up to ten minutes. We transferred fecal materials from the bag to Whatman FTA Cards (Whatman, Florham Park, NJ) using Whatman sterile swabs (Whatman, Florham Park, NJ).