Wintering Ecology of Thrashers in Southern Texas

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Abstract
Three sympatric thrashers, the brown [Toxostoma rufum], the long-billed [T. longirostre] and the curve-billed [T. curvirostre], were studied during the winters of 1977 and 1978 in San Patricio County, Texas. The species avoided competition primarily by occupying different habitats. Browth thrashers wintered abundantly within riparian woodlands, long-billed thrashers stayed mostly within shrub cover of chaparral and curve-billed thrashers inhabited the more open portions of the chaparral. All 3 spp. foraged mostly on the ground and were omnivorous. The foraging behavior of brown and long-billed thrashers was similar (sweeping debris aside with bill) and both fed only within cover. Curve-billed thrashers differed from the other thrashers in foraging techniques (reliance upon digging), diet and in feeding frequently outside of shrub/tree cover. Brown and long-billed thrashers maintained intra- and inter-specific winter territories. Both were highly philopatric, with 27% of the color-marked brown thrashers and 48% of the color-marked long-billed thrashers returning in 1978 to their 1977 winter territories. Brown thrashers apparently were superior competitors, mostly excluding long-billed thrashers from arthropod/gastropod-rich riparian habitats.