The Delaware Sparrow

The tidal salt marshes of Delaware, which DC Audubon toured on a recent field trip, are home to a unique subspecies of Swamp Sparrow, the Coastal Plain Swamp Sparrow (Melospiza georgiana nigrescens). This subspecies is small in number and declining due to changes in the vegetation of coastal marshes. Because little is known, the Smithsonian Migratory Bird Center is currently studying the life history of the coastal plain subspecies.

It was only 55 years ago that the coastal plain swamp sparrow was identified and categorized as a subspecies of the more common swamp sparrow, says Shriver. And just last year Smithsonian researchers discovered where the bird winters -- a stretch of marshland from Charleston, S.C., to Beaufort, N.C. It's not a very long trek; most migratory birds fly far greater distances between their winter and summer homes. But Shriver explains that there's one crucial difference between the habitats -- freezes don't occur regularly in the coastal Carolinas. Coastal plain swamp sparrows feed on insects and spiders, which they find by poking around in the mud, so moving 500 or 600 miles south ensures a steady food supply in the winter months.

Mid-May marks the start of nesting season for the coastal plain swamp sparrow and the start of field research. Studies in Chesapeake Bay marshland have shown a steady drop in the number of sparrow nests since the late 1980s. Shriver and Greenberg want to see if that pattern is occurring in Delaware marshes. Coastal plain swamp sparrows like to nest in high marsh, which features a mix of tall and short grassy vegetation with shrubs mixed in. They often attach their nests to the base of the Hide Tide Bush, a common shrub, and then use tufts of Salt Hay to camouflage the nests. Finding these small, well-hidden nests is a bit like finding a needle in a haystack. Fortunately, the female vocalizes a distinctive "chip, chip, chip" call when
leaving the nest.

Coastal plain swamp sparrows like to nest in high marsh, which features a mix of tall and short grassy vegetation with shrubs mixed in. They often attach their nests to the base of the Hide Tide Bush, a common shrub, and then use tufts of Salt Hay to camouflage the nests. Finding these small, well-hidden nests is a bit like finding a needle in a haystack. Fortunately, the female vocalizes a distinctive "chip, chip, chip" call when leaving the nest.

Learn more about coastal plain swamp sparrows.