BREEDING BIRD COMMUNITIES OF MIDWESTERN PRAIRIE FRAGMENTS - THE EFFECTS OF PRESCRIBED BURNING AND HABITAT-AREA

The effects of spring burning and habitat-area on breeding bird commun ities were studied on 11 Illinois prairie fragments between 1987 and 1 990. Comparisons of bird distribution and abundance patterns within pr airie fragments showed three species, the Henslow's sparrow, bobolink, and grasshopper sparrow, to be most influenced by prescribed burning. Henslow's sparrows completely avoided prairie areas that had been rec ently burned, whereas bobolinks and grasshopper sparrows tended to be more common on recently burned prairie areas. A comparison of the rela tive importance of habitat-area and prescribed burning showed that hab itat-area had a much greater influence on breeding bird community comp osition than prescribed burning. Ten of the 15 most common species exa mined were significantly influenced by habitat-area. An ordination of bird communities from the different prescribed bum categories showed t hat bird communities on small prairie fragments were, in general, more similar to one another than they were to bird communities on large pr airie fragments, regardless of the current management status of the pr airies. I suggest that optimal management strategies for small and lar ge prairie fragments need not be the same. Small prairie fragments can be burned with little regard to breeding birds because the occurrence of their characteristic bird species is not significantly influenced by prescribed burning. In contrast, large prairie fragments must be ma naged to provide a mosaic of burned and unburned areas to ensure the a vailability of suitable habitat for management-sensitive bird species, species that in the Midwest are experiencing significant population d eclines and are predominately restricted to large grassland areas.