Breeding ecology of the Sora, Porzana carolina, and the Virginia Rail, Rallus limicola

Abstract

The breeding behavior of Soras (Porzana carolina ) and Virginia Rails (Rallus limicola ) was observed under captive and field conditions, in Iowa and Minnesota during the 1963-69 field seasons. Territorial defense was accomplished primarily by males. The Soras' territories were well-defined and defended against both species; the Virginia Rails' territories were less defined and defended mainly against other Virginia Rails. Pair formation of both species appeared to be subtle; potential mates stood immobile near each other for increasing lengths of time and decreasing distances between them. Females of both species appeared to select the nest site on the day they laid their first egg. Clutch sizes of Soras were larger than those of Virginia Rails. Incubation was usually initiated before the clutch was completed in both species particularly in the Sora, and so the young hatched asynchronously. In both species the males and females incubated the eggs, brought food to the young, and brooded the young, but the relative role of the sexes varied from pair to pair.