Site Fidelity, Philopatry, and Survival of Promiscuous Saltmarsh Sharp-Tailed Sparrows in Rhode Island

We investigated site fidelity and apparent survival in a promiscuous population of Saltmarsh Sharp-tailed Sparrows (Ammodramus caudacutus) in southern Rhode Island. Based on capture–recapture histories of 446 color-banded sparrows studied from 1993 to 1998 at our primary study site, Galilee, we observed significant variation in apparent survival rates among years, but not between sexes. Return rates of adult males (37.6%) and females (35.6%) were not significantly different during any year. Juveniles exhibited high return rates, ranging from 0 to 44%, with males (61% of returns) more likely to return than females (35%). In addition, we monitored movements of 404 color-banded sparrows at nine satellite marshes in 1997 and 1998, which supported our findings at Galilee and documented intermarsh movements by 10% of all banded birds. Lack of gender-bias in adult dispersal and strong natal philopatry of sparrows in Rhode Island occurs regularly among passerines possessing a variety of mating systems. Despite emancipation from parental and resource defense duties, adult male Saltmarsh Sharp-tailed Sparrows exhibited apparent survival rates similar to adult females. Availability of high-quality breeding habitat, which is patchy and saturated, may be the most important factor limiting dispersal for Saltmarsh Sharp-tailed Sparrows in Rhode Island

Nesting ecology of saltmarsh sharp-tailed sparrows in a tidally restricted salt marsh

We investigated population size, nest success, and nest-site characteristics of Saltmarsh Sharptailed Sparrows (Ammodramus caudacutus) from 1993 to 1998 in a salt marsh near Galilee, Rhode Island. From 1956 to 1997, tidal flow was restricted in the marsh by construction of a road with small culverts, which resulted in conversion of the marsh from short- and tall-form cordgrass (Spartina alterniflora) and marsh hay (S. patens) to one dominated by \u3e5 m tall common reed (Phragmites australis). In fall 1997, self-regulating tide gates were installed to restore the historic tidal regime and vegetation. We documented declines in adult sparrow population sizes (17-25% annual decline) and productivity (48% annual decline) while the tidal regime was restricted. Nest success was variable (10-83%) before 1998, with predators accounting, and short common reed. After restoration, sparrows nested where vegetation was taller, which permitted greater nest elevation. However, 91% of nests failed due to flooding following installation of new tide gates. We hypothesize that restoration efforts will have short-term negative impacts on Saltmarsh Sharptailed Sparrow populations until salt marsh habitats are restored in higher sections of the marsh