Trends in Rail Migration Arrival and Departure Times Using Long-Term Citizen Science Data from Mississippi, USA

Abstract. Little is known of rail migration ecology, consequently limiting efforts to effectively conserve rail populations. Therefore, we investigated changes in the migratory arrival/departure dates for Virginia Rails (Rallus limicola), King Rails (Rallus elegans) and Sora (Porzana carolina) north of Ocean Springs, Mississippi. Using citizen science data collected over the last 25 years, we inspected summarized data for patterns of primary arrival and departure windows indicated by first or last observations of each species at the lagoons, respectively, alongside 10th/90th quantiles that controlled for outliers (i.e., early arrivals, late departures). Regression models found no differences in spring migration departures for any species. In fall migration we found a difference only in Virginia Rail arrivals, which became later over time. King Rail arrived in autumn first in mid-September (September 22nd) followed by Sora (October 5th) and Virginia Rails (October 21st). In spring migration, Virginia Rails departed first (March 19th), then King Rails (March 24th), and Sora (April 20th). Trends for King Rails may have been skewed by some individuals having non-migratory behavior. Despite limitations, citizen science efforts were useful for an initial investigation of rail migration ecology, and future applications could be used to identify and assess factors affecting migration timing (e.g., climate change, habitat availability, weather shifts).