Birds of Indian Subcontinent

Adaptations to Tidal Marshes in Breeding Populations of the Swamp Sparrow

Publication Type:Journal Article
Year of Publication:1990
Authors:Greenberg, R, DROEGE, SAM
Journal:The Condor
Date Published:1990
ISBN Number:00105422
Keywords:Corvidae, Corvus, Corvus corone, Emberizidae, Melospiza, Melospiza georgiana, Zonotrichia, Zonotrichia georgiana
Abstract:The Coastal Plain Swamp Sparrow (Melospiza georgiana nigrescens) was originally described from a small number of specimens from the tidal marshes of the Nanticoke River in southeastern Maryland. Based on our quantitative analysis of a larger series of specimens, we found that Swamp Sparrows collected during the breeding season from the Chesapeake and Delaware bays (and tributaries) and near the mouth of the Hudson River are generally less rusty, have more black in the crown and nape, and have larger bills than other Swamp Sparrows. Contrary to earlier accounts, we found M. g. nigrescens to be migratory, arriving after the spring migration and departing before the fall migration of the inland subspecies through the tidal marshes. The location of the wintering grounds of M. g. nigrescens is unknown. We argue that the morphological and life history differences characterizing M. g. nigrescens reflect adaptation to tidal marshes. We base this hypothesis on the nature of the morphological differences, which are convergent with other tidal marsh breeding sparrows and other terrestrial vertebrates.
Short Title:The Condor
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