Composition of Mixed-species

cockaded woodpeckers fit most of the characteristics PECKERS used to describe nuclear members of foraging flocks, such' as conspicuous plumage and vocalization. They RICHARD R. SCHAEFER, Wildlife Habitat and aIso appear to be joined and foilowed more often than Silviculture Laboratory, Southern Research Station, they themselves join and follow other species. interest of researchers. Questions regarding the advan-Nacogdoches, TX 75965 tages and disadvantages of flock membership, species composition and relative abundance, and roles within DANIEL SAENZ, Wildlife Habitat and Silviculture the flock are just a few for which answers have been TX 75965 enhanced predator detection are the leading hypotheses to explain the benefits of mixed-species flock formation Several authors have defined or categorized Nacogdoches, TX 75965 members of mixed-species foraging flocks according to the role they play within the flock. Simply stated, some SHIRLEY J. BURGDORF,l Wildlife Habitat and species are referred to as nuclear or core species which Silviculture Laboratory, Southern Research Station, are instrumental in flock formation and appear to direct USDA Forest Service, 506 Hayter Street, the flock's movements. Others are termed attendant or Nacogdoches, TX 75965 satellite species and are flock followers tropical localities are often well-structured assemblages 98503-1263 of permanently resident species which will defend a territory from neighboring flocks of similar composition Abstract: Red-cockaded woodpeckers (Picoides (Munn and Terborgh 1979, Gradwohl and Greenberg borealis) are known to be regular members of mixed-1980). In temperate localities, mixed-species foraging species foraging flocks. We censused avian species flocks are most conspicuous during the non-breeding associated with foraging red-cockaded woodpeckers in season (Morse 1977). longleaf pine (Pinus palustris) habitat and in mixed The red-cockaded woodpecker inhabits mature, loblolly pine (l? taeda)-shortleaf pine (P echinata) open pine forests of the southeastern United States and habitat in eastern Texas during the non-breeding season. regularly associates with mixed-species foraging flocks We also censused random points in similar habitat. A (Morse 1970, Conner et al. 2001a). Historical accounts statistical evaluation of the census data indicated which describe it as abundant to fairly common in suitable species were most likely to be associated with red-habitat (Audubon 1839, Woodruff 1907). The species cockaded woodpeckers. A large percentage of the has since been extirpated from most of its former range, species detected were significantly more likely to be and its rarity now precludes it from being a significant found with these mixed-species flocks than at random flock associate in most of its current range. …