Florida Grasshopper Sparrow Distribution, Abundance, and Habitat Availability

Abstract

Remote sensing, geographical information system applications, and ground and aerial assessments revealed a fragmented distribution of 44,933 ha of potential habitat for the endangered Ammodramus savannarum floridanus (Florida Grasshopper Sparrow) with most of this habitat (30,262 ha, 67%) located on conser- vation lands. A continued decrease in available habitat since 1996 was indicated. Searches of potential habitat and information from surveys at known locations found 278 male Florida Grasshopper Sparrows at seven sub-populations during 2004. No previously unknown breeding aggregations were found. The current distribution evinces a considerable contraction in range compared to historic distribution; how- ever, other breeding aggregations may exist on private property (10,718 ha) where access was denied. Three formerly large sub-populations on Avon Park Air Force Range have declined and are now near extirpation. The low number of individuals and the paucity and fragmented distribution of suitable dry prairie will be limiting factors for recovery of this sedentary subspecies. Habitat expansion and manage- ment, and demographic improvements at existing locations may restore some Florida Grasshopper Sparrow sub-populations. Large areas (> 377 ha) of protected potential habitat in Manatee, DeSoto, and Glades counties offer the best opportunities for the establishment of additional sub-populations (> 50 pairs) to achieve recovery goals. The cooperative effort of public land managers from various agencies and of private landowners will be needed to prevent the extinction of this bird.