Use of imprinted northern bobwhite chicks to assess habitat-specific arthropod availability

摘要

Arthropod abundance commonly is used as an index for brood-habitat quality for northern bobwhite (Colinus virginianus) chicks. However, conventional arthropod sampling techniques may not measure the abundance of arthropods available to chicks. Human-imprinted chicks have been used to jointly measure arthropod abundance and availability; however, no studies have examined potential differences in growth rates and foraging behavior between pen and wild-strain chicks. Likewise, use of internal ligatures has not been tested. We compared growth (g/day) and foraging rates (g/chick/30 minutes) between pen and wild-strain chicks and foraging rates between ligatured and nonligatured chicks. At 9 days post-hatch, pen-strain chicks (LSMEANS=20.315, SE=0.456) weighed more than wild-strain chicks (LSMEANS=17.665, SE=0.556; F-1,F-1013=32.34, P < 0.001). Foraging rate did not differ between ligatured ((x) over bar =0.041, SE=0.007) and nonligatured (x=0.028, SE=0.004) chicks (t(38)=-1.69, P=0.100). Pen-strain chicks consumed slightly greater dry biomass than wild-strain chicks, but both consumed similar-sized arthropods. Ligatured, commercially produced chicks may serve as a reasonable biological assay for indexing arthropod availability and brood-habitat quality for wild northern bobwhite chicks.