Summary

Description

The project proposed this report will provide data on the habitats of the eastern black rail through the use of radio telemetry, vegetative samples, and weekly surveys using vocalization tapes. The eastern black rail Laterallus jamaicensis jamaicensis is among the most poorly known of the birds of Florida, hampering the potential for habitat manipulations to encourage the species. The proposed research will provide some of these data; with the objectives of determining habitat preferences of breeding eastern black rails on both the macrohabitat and microhabitat levels; determining home range size, changes in home range boundaries, and movements of eastern black rails during the breeding season; refining censusing techniques for eastern black rails; and determining general life history parameters of eastern black rails in Florida. The study will be conducted by a masterslevel graduate student. A study site will be selected at one of several state or federal wildlife areas with tidal marsh habitat in northern Florida. Black rails will be trapped, fitted with radio transmitters, and tracked from fixed tracking stations using a computer assisted tracking system. Tracking will follow a systematic weekly schedule to avoid potential problems with independence of telemetric fixes. A cover map of the study site will be prepared from aerial photos and ground survey and will be digitized using a CIS system to determine distribution of cover types. Telemetric fixes of black rails will be superimposed over the cover map using the CIS system to determine cover type selection. Vegetative and physical habitat variables will be sampled at randomly selected sites and at sites intensively used by rails to characterize microhabitat selection. Home range boundaries of telemetered rails will be determined using the harmonic mean method. Sizes of home ranges will be compared among different seasonal categories and between sexes. Boundaries will be plotted to determine overlap and seasonal shifts in home ranges. Weekly surveys will be conducted using vocalization tapes to determine optimal timing and effects of weather variables on call counts. Telemetered birds will be monitored to determine movements of birds in response to tapes and the proportion of birds responding to tapes. Morphology, weight changes, sex and age criteria, molt, nesting biology, and food habits of black rails will be determined opportunistically from trapped and telemetered birds. Possible study sites include St. Vincent, St. Johns, and St. Marks National Wildlife Refuges and the Big Bend Wildlife Management Area.