Arthropod Communities Associated with Habitats Occupied by Breeding Swainson's Warblers

Abstract

Abstract. The Swainson's Warbler (Limnothlypis swainsonii) is an insectivorous songbird and a species of conservation concern in the southeastern U.S. Because it is specialized for foraging in the litter of the forest floor, it is dependent on a well-developed leaf-litter layer. However, this reliance on the litter layer likely reflects selection of habitats with abundant arthropods for food. To investigate this possibility, we examined relationships between Swainson's Warbler presence and both abundance and diversity of ground-dwelling and litter arthropods. In 2004 and 2005, using song playbacks, we surveyed 1453 sites and collected arthropods in litter samples and pitfall traps at 45 randomly selected occupied and unoccupied sites. In litter samples, total mean arthropod abundance, abundance of arthropods ≥5 mm in length, total abundance of adults, and taxonomic richness were significantly greater at sites occupied by Swainson's Warblers than at unoccupied sites. In pitfall data, however, we detected n...