A Study of the Breeding Biology of the Purple Martin (Progne subis)

Abstract

Migration of the martin is closely correlated with temp. Mean temp. of day of arrival at 4 localities was 5[degree]-14[degree]F above normal; of the week before arrival at 3 localities 6[degree]-7[degree]F. Avg. dates recorded for 5-55 years from s. to n. show the gradual progress of spring migration from Feb. 6 in Florida to Apr. 29 in N. Dakota. The male defends a room from other males; the female chooses a room and thereby obtains a mate. There is but one brood in the South as well as the North. Incubation is by the female alone; she spends some 70% of daylight hrs. on the nest in normal weather, 80% in colder weather. Incubation lasts 15-16 days; fledging usually 28 days. In 32 studies of 14 hole-nesting spp. reproductive efficiency ranged from 25.7% with Prothonotary Warblers (Protonotaria citrea) in Michigan to 93.7% with Tree Swallows (Iridoprocne bicolor) in Montana; the avg. success of 90,676 eggs came to 66.2%. Of 46 martins banded as nestlings and recovered from May to July from one to 6 years later, 28 were taken at their birth-places, 7 from 8-22 miles distant, 8 from 28-58 miles distant, one 100 miles northeast, one 170 miles s., one 210 miles northeast Greatest age attained by a banded martin was 8 yrs. This species is highly social in its nesting, roosting and migration.