Bobwhite and scaled quail responses to burning of redberry juniper-dominated rangelands
Leif, Anthony P
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Prescribed burning is used to remove downed woody debris and reduce canopy cover of redberry juniper (Juniperus pinchotii) on the Rolling Plains of Texas. These range improvement burns are commonly conducted in areas supporting northern bobwhites (Colinus virginianus) and scaled quail (Callipepla squamata). We investigated the long-term effects of redberry juniper-control burns on : (1) shrub, grass, and forb composition; (2) bobwhite and scaled quail food habits, gut morphology, and body condition; and (3) bobwhite population densities. Information on diet quality and annual variation in gut morphology and body condition of quail were also acquired. Four years after burning, redberry juniper-dominated rangeland had lower total canopy cover (%) than unburned rangeland and contained more common broomweed (Xanthocephalum dracunculoides), silver-leaf nightshade (Solanum eliangifolium), white aster (Leucelene ericoides), and senna (Cassia Roemeriana) than 8-year-oid burned or unburned juniper. Of these forbs, only common broomweed was important in quail (both species) diets and it comprised a higher proportion of quail diets in 4-year-old burned juniper than 8-year-old burned or unburned rangeland. Diets of quail in 8-year-oid burned and unburned juniper had proportionally higher amounts of green vegetation and grass seeds than diets of quail from 4-year-old burned rangeland. Common broomweed seeds were the highest quality quail food on our study area because of relatively high (25%) lipid content. Three years after burning, scaled quail had longer, heavier entrails and lower lipid reserves than scaled quail in unburned juniper. Bobwhites in 3-year-old juniper had heavier entrails but similar lipid reserves to quail in unburned rangeland. However, 4 years after burning, both species had shorter small intestines and bobwhites had higher lipid reserves than quail from unburned juniper. Gut morphology and body condition of quail in 7- and 8-year-old burned redberry juniper were generally similar to quail in unburned habitat. In a year of below-normal winter-spring precipitation, both species had longer entrails, lighter body weights, and lower lipid reserves than quail collected in a year of above-normal winter-spring precipitation. Fall bobwhite densities were 43.3, 55.1, and 60.5 birds/100-ha in 4- and 8-year-old burned and unburned redberry juniper habitat, respectively. To improve range quality while preserving quail loafing coverts, alternating 150-200 m strips orientated at 210Â° (direction of late-winter winds) could be burned. This multiple-use burn plan will increase forage production and enhance habitat diversity.