Sul Ross State University

Demographic and Spatial Characteristics
of Gambel's Quail in Trans-Pecos, Texas

by Michael Gray, Michael R. Sullins (Texas Parks and Wildlife Department) and Louis A. Harveson

Gambel's quail (Callipepla gambelii) are listed as a gamebird with an open season in the state of Texas. However, virtually no information exists regarding the Gambel's quail ecology in Texas.

We initiated this study to describe:

1. population structure
2. home ranges and habitat utilization
3. nesting ecology, and
4. identify survival rates and cause-specific mortalities.

We established two study areas. The first area was six miles west of Sierra Blanca, Texas. The second area is located along the Rio Grande near the Indian Hot Springs approximately 20 miles south of the first study area. Both areas historically held high numbers of Gambel's quail.

In 2003, we captured 205 birds (19 recaptures) using milo-baited funnel traps. Captured birds were leg-banded, aged and sexed. We also took other morphological measurements for demographical purposes.

We radiomarked 77 birds that weighed >160 grams. We maintained a sample size per study site of 20-25 radio-marked individuals with a ratio of 75 percent females and 25 percent males to assist in gathering nesting ecology information. Radiomarked birds were located weekly using radio telemetry.

We used a homing technique to gain information about covey size and composition. Any mortality signals were located immediately to determine the individual's cause of death.

We measured an 80-percent mortality rate of radiomarked quail during 2003. Deaths were placed in one of four categories: avian predation, mammalian predation, human related or unknown. We determined avian predation as the dominant cause.

Gambel's quail nests found during radio telemetry were marked and then monitored from a distance until the nesting attempt was complete. Once the nesting attempt was completed we checked the nest for nesting success/failure, cause of failure, number of eggs and number of eggs successfully hatched. Any renesting attempts were also noted. Habitat conditions around each nest will be described.

Collected GPS coordinates of each Gambel's quail were entered into ArcView 3.1 to be plotted on study area DOQQs. Plotted UTM coordinates assisted in determining habitat types of high Gambel's quail use. High-use habitats were described using 100-meter belt and line-intercept transects for woody vegetation and 100-meter point-step transects for herbaceous vegetation and ground cover.

We measured annual and seasonal movements using the collected UTM coordinates and animal movement extension of ArcView. Survival estimates of radio-marked individuals were calculated using the Kaplan-Meier staggered entry design.

This research will provide the baseline information needed for future research needs and will facilitate Texas Parks and Wildlife Department Gambel's quail management schemes. 

 Cooperative funding was provided by Texas Parks and Wildlife Department, Sul Ross State University and the Texas Chapter of Quail Unlimited.