Movements and use of space by Mangrove Cuckoos (Coccyzus minor) in Florida, USA

I used radio-telemetry to track the movements of Mangrove Cuckoos (Coccyzus minor) captured in southwest Florida. Relatively little is known about the natural history of Mangrove Cuckoos, and my goal was to provide an initial description of how individuals use space, with a focus on the size and placement of home ranges. I captured and affixed VHF radio-transmitters to 32 individuals between 2012 and 2015, and obtained a sufficient number of relocations from 16 of them to estimate home-range boundaries and describe patterns of movement. Home-range area varied widely among individuals, but in general, was roughly four times larger than expected based on the body size of Mangrove Cuckoos. The median core area (50% isopleth) of a home range was 42 ha (range: 9 – 91 ha), and the median overall home range (90% isopleth) was 128 ha (range: 28 – 319 ha). The median distance between estimated locations recorded on subsequent days was 298 m (95% CI = 187 m – 409 m), but variation within and among individuals was substantial, and it was not uncommon to relocate individuals >1 km from their location on the previous day. Site fidelity by individual birds was low; although Mangrove Cuckoos were present year-round within the study area, I did not observe any individuals that remained on a single home range throughout the year. Although individual birds showed no evidence of avoiding anthropogenic edges, they did not incorporate developed areas into their daily movements and home ranges consisted almost entirely of mangrove forest. The persistence of the species in the study area depended on a network of conserved lands – mostly public, but some privately conserved land as well – because large patches of mangrove forest did not occur on tracts left unprotected from development.