Nesting ecology, health, and survival of scaled quail in the Southern High Plains of Texas

Scaled quail (Callipepla squamata) have been declining significantly for the past 30 years and there is no clear understanding of what is causing this decline. It has been suggested that reproductive failure is a probable source of this decline. I utilized radio telemetry to evaluate survival and nesting ecology of scaled quail in the Southern High Plains of Texas in 1999 and 2000. I radio-marked 66 hens (20 subadults, 43 adults, and 3 unknown) in 1999 and 72 hens (60 subadults, 12 adults) in 2000. Survival was not different between age classes within years, but hen survival, nesting success and chick survival were all higher in 2000 than in 1999. In 1999, 31 hens produced a total of 50 nests. Eleven hens produced two nests and 4 hens produced 3 nests. In 2000, 38 hens produced a total of 56 nests. Fourteen hens produced two nests and 2 hens produced 3 nests. All renesting occurred following loss of previous nest or chicks. I did not observe any double brooding. Chick survival was recorded at 21 days post hatch and was analyzed as present or absent, as exact numbers were difficult to determine. Two hens had chicks present at 21 days in 1999 and 16 hens had young present in 2000. High temperatures and amount of precipitation recorded during the first week post-hatch had a positive correlation to chick survival to 21 days, but each additional day of precipitation during week 1 had a negative impact on chick survival to 21 days. Stepwise logistic regression revealed predictive relationships for models with variables describing the area around the nest and the nest site itself as predictors of nest success during both years and for models predicting nest site locations.

Investigators have suggested that there is a link between increased nest predation and precipitation, known as the moisture-facilitated, nest depredation hypothesis. Moisture may increase scent production of incubating hens, thereby increasing the searching efficiency of many mammalian nest predators. However, in contrast to predictions of this hypothesis, precipitation is actually negatively associated with nest predation in this data set. Nests were 48% less likely to be predated with each 1 cm increase in precipitation.

I also collected blood samples from trapped scaled quail providing the first known packed-cell volume (PCV) and clinical chemistry values available for this species.