Dusky Seaside Sparrow (Ammodramus maritimus nigrescens) (top)Cape Sable Seaside Sparrow (Ammodramus maritimus mirabilis). Field Museum of Natural History, Chicago. Dusky Seaside Sparrow conservation status: extinct. Declared extinct in 1990, the Dusky Seaside Sparrow was one of 11Ammodramus subspecies that inhabit coastal marshlands on the Atlanticseaboard of the United States. A. m. nigrescens was non-migratory andlived only in the marshes of the St. John's River and Merritt Island onFlorida's mid-Atlantic coast. A 70% decline in population wasrecorded following the use from 1942 to 1953 of DDT to controlmosquitos on Merritt Island. In further efforts to eliminate mosquitos in1956 in the Kennedy Space Centre region, Merritt Island nesting groundswere flooded to make mosquito control impoundments, causing anotherdrop in numbers. Then marshes along the St. John's River were drained toaid highway construction, putting yet more pressure on the population.By 1980, six remaining individuals, all males, had been captured to establish a captive breeding program that was eventually unsuccessfulbecause no females were ever found. They lived out their lives in a WaltDisney World nature reserve called Discovery Island. The last male died in June 1987.