Midwest Fish & Wildlife Conference 2018

AUTHORS. James Hansen, The Ohio State University; Nicole Hengst, The Ohio State University; Brendan Shirkey, Winous Point Marsh Conservancy; John Simpson, Winous Point Marsh Conservancy; Robert Gates, The Ohio State University

ABSTRACT. Secretive marsh bird surveys using the Standardized North American Marsh Bird Monitoring Protocol have been established across much of the upper Midwest over the past decade to assess population trends for numerous marsh bird species. However, sampling frameworks have varied between monitoring authorities, and species-specific and sub-region specific recommendations for various sampling frameworks have not been evaluated. Sora (Porzana carolina) and Virginia rails (Rallus limicola) are of particular interest in Ohio because of their status as game birds with liberal harvest regulations. We aim to evaluate the efficacy of contrasting sampling designs in regards to estimating population parameters of the Virginia rail and sora, study their intraseasonal movements, and estimate breeding season survival. Point count surveys using the national protocol were conducted at Winous Point Marsh Conservancy in Northern Ohio, with points located on dikes and within interior portions of wetlands to draw comparisons between the two survey location types.  Virginia rails and soras were captured and fitted with VHF radio-transmitters and tracked daily to investigate bird movements between, within, and out of survey sites during secretive marsh bird monitoring windows to elucidate effects of bird movements on parameter estimates from point count surveys. Data from 2016 and 2017 indicated that 161 of 209 radio-marked rails (73 of 98 and 88 of 111, respectively) left the study area during the breeding season, with 49 and 55, respectively, of the emigrant rails departing the study site during the current three national secretive marsh bird survey windows. Mean home range sizes for Virginia rail and sora was 6.51 and 3.67 ha (SE = 1.40, n = 57 and SE = 0.95, n = 7, respectively). Probability of survival decreased across the breeding season (0.341 – 0.944). This work will lend greater understanding of rail ecology and management in Northern Ohio.