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Cape Sable Seaside Sparrow
Sparrow, Cape Sable seaside
Ammodramus (=Ammospiza) maritimus mirabilis
Endangered, Federal Register, March 11, 1967
Cape Sable seaside sparrows are small birds about 13 centimeters or 5 inches long. Dorsally, they are dark olive-gray with olive-brown on the tail and wings. The greenish cast on the nape is generally difficult to detect. Ventrally, adults are light gray to almost white with dark olive-gray streaks on the breast and sides. Occasionally, the breast streaks converge forming a diffuse central spot. There is a dark whisker on either side of the white throat. These sparrows have yellow lores, brown eyes, and a gray ear patch behind the eye which is fringed by a dark line. There is a small patch of yellow on the edge of the wing. No sexual differences in the plumages are obvious.
Reproduction and Development:
The Cape Sable seaside sparrow's breeding season typically extends over nearly half of the year. Nesting may begin as early as late February and may persist into early August. The amount of summer nesting, which essentially means the number of third broods attempted, may depend on the characteristics of individual rainy seasons. Nesting activity decreases abruptly when the marsh they depend on becomes flooded. The cupped nests are built with readily available local materials. Cape Sable sparrows lay a clutch of three to four eggs (Werner 1978). The incubation period is more than 11 days. Young sparrows spend 9 to 11 days in the nest (Werner 1978) and after fledging are attended by parents for 10 to 20 additional days. Cape Sable sparrows usually nest two or three times per season.
Range and Population Level:
The Cape Sable seaside sparrow remains widely distributed over a large area of south Florida and continues to occupy much of its historically known range in Collier, Dade, and Monroe Counties. Most of the sparrow population occurs in and near Taylor Slough and in Big Cypress Swamp (Kushlan and Bass 1983). Populations appear quite ephemeral except for the two core populations previously mentioned. The population estimate in 1992 was 6,450 birds. In 1993, they numbered 3,347 and in 1994 they totalled 2,800 birds. The decrease is likely because of the devastating effects of Hurricane Andrew in August 1992.
The Cape Sable seaside sparrow inhabits brushless, subtropical marshes (prairies) of interior southern Florida. These habitats remain dry most of the year but are seasonally flooded with entirely fresh to slightly brackish water. Brushy or rocky marshlands are avoided as are extremely dense stands of cordgrass (Spartina bakeri) (Werner 1975, 1976).
Werner (1975, 1976) described Cape Sable sparrow habitat in terms of four major graminoid communities: muhly grass prairie (Muhlenbergia filipes), short sawgrass prairie (Cladium jamaicensis), prairies of tall, clumped cordgrass, and prairies of low cordgrass growing with an irregular spatial distribution. These habitats are subject to occasional flooding, which can be a major cause of nest loss.
Areas of land, water, and airspace in the Taylor Slough vicinity of Collier, Dade, and Monroe Counties, with the following components (Tallahassee Meridian): those portions of Everglades National Park within T57S R36E, T57S R36E, T57S R37E, T58S R35E, T58S R36E, T58S R37E, T58«S R35E, T58«S R36«E, T59S R35E, T59S R36E, T59S R37E. Areas outside of Everglades National Park within T55S R37E Sec. 36; T55S R38E Sec. 31, 32; T56S R37E Sec. 1, 2, 11-14, 23-26; T56S R38E Sec. 5-7, 18, 19; T57S R37E Sec. 5-8; T58S R38E Sec. 27, 29-32; T59S R38E Sec. 4.
Reasons for Current Status:
The principal reasons for the decline of the Cape Sable seaside sparrow and the greatest threats to its continued survival are vegetation changes, fire, development, and hydrologic alteration. Catastrophic storms, such as the hurricanes in 1935 and 1992, can lead to natural vegetation changes that make the environment unsuitable for Cape Sable sparrows, thus causing local extirpations. Hurricanes may also kill birds directly, as was likely the case in 1992.
Management and Protection:
Cape Sable seaside
sparrows are adapted to life in vegetation that burns periodically (Kushlan et
al. 1982). Timing of the fires, however, is critical. Fires that occur late in
the dry season or during and immediately after nesting threaten eggs and newly
fledged young. If burned too frequently, an area may never support a vigorous
population of nesting sparrows. Prescribed fires and natural wet season fires
can enhance marsh habitat and retard the invasion of native shrubs and trees
into the prairies occupied by sparrows. A natural fire regime resulting in a
burn mosaic is compatible with protecting sparrow habitat (Kushlan
et al. 1982).
Maintenance of water levels is also important to sparrows because periods of inundation are required to perpetuate the marshes on which they depend. The manipulative capabilities of the water management system can cause high water levels at the wrong time of year which can limit sparrow production by reducing the duration of the nesting season (Kushlan et al. 1982).
Kushlan, J.A., O.L. Bass, Jr., L.L. Loope, W.B. Robertson, Jr., P.C. Rosendahl, and D.L. Taylor. 1982. Cape Sable sparrow management plan. National Park Service, South Florida Research Center Report M-660. 37 pp.
Kushlan, J.A., and O.L. Bass, Jr. 1983. Habitat use and the distribution of the Cape Sable sparrow. Pages 139-146 in T.L. Quay, J.B. Funderburg, Jr., D.S. Lee, E.F. Potter, and C.S. Robbins, eds. The seaside sparrow, its biology and management.
**U.S. Fish and Wildlife Service. 1983. Cape Sable Seaside Sparrow Recovery Plan. Atlanta, Georgia. 52 pp.
Werner, H.W. 1975. The biology of the Cape Sable sparrow. Report to U.S. Fish and Wildlife Service. Everglades National Park, Homestead, Florida. 215 pp.
Werner, H.W. 1976. Distribution, habitat, and origin of the Cape Sable seaside sparrow. Unpublished M.A. Thesis, University of South Florida. 53 pp.
Werner, H.W. 1978. Cape Sable seaside sparrow. Pages 19-20 in H.W. Kale, II, ed., Rare and endangered biota of Florida, Vol. 2, Birds. Univ. Presses of Florida.
Source for the above information: Endangered and Threatened Species of the Southeastern United States (The Red Book), U.S. Fish & Wildlife Service Region 4, As of 1/95