Breeding phenology of the Eastern Black Rail (Laterallus jamaicensis)

Abstract

The Eastern Black Rail (Laterallus jamaicensis jamaicensis) is listed as Threatened under the United States Endangered Species Act and as Endangered in 6 states along the Atlantic Coast. Black Rails are difficult to observe and documentation of definitive breeding evidence is limited. This, along with perceived overlaps between the breeding and migratory periods, has led to uncertainty about the breeding status of calling birds across a large portion of their range. To delineate breeding and migratory periods, I examined the phenology of breeding records (N = 170) and documented “presumed migrants” (N = 55) based on rails that hit radio towers, lighthouses, and buildings or were found in inner cities, on ships-at-sea, or on offshore islands. Nesting in Eastern Black Rails extends 3 months from mid-May to mid-August and peaks during the third week of June. Based on the available sample there is no evidence that egg dates vary with latitude along the Atlantic Coast. Presumed migrants were recorded from early March to early May and from early September to early November. Breeding observations and records of presumed spring migrants overlapped during the first 2 weeks of May. The overlap includes only 2.4% of breeding records. There was no overlap between records of presumed fall migrants and the breeding season.