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

Abstract

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 ofMangrove Cuckoos, andmygoal was to provide an initial description of how individualsuse space, with a focus on the size and placement of home ranges. I captured andaffixed VHF radio-transmitters to 32 individuals between 2012 and 2015, and obtaineda sufficient number of relocations from 16 of them to estimate home-range boundariesand 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 sizeof Mangrove Cuckoos. The median core area (50% isopleth) of a home range was42 ha (range: 9-91 ha), and the median overall home range (90% isopleth) was 128ha (range: 28-319 ha). The median distance between estimated locations recordedon subsequent days was 298 m (95% CI [187 m-409 m]), but variation within andamong 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 waslow; although Mangrove Cuckoos were present year-round within the study area, Idid not observe any individuals that remained on a single home range throughout theyear. Although individual birds showed no evidence of avoiding anthropogenic edges,they did not incorporate developed areas into their daily movements and home rangesconsisted almost entirely of mangrove forest. The persistence of the species in the studyarea depended on a network of conserved lands-mostly public, but some privatelyconserved land as well-because large patches of mangrove forest did not occur on tractsleft unprotected from development.