No abstract

Relationships between the abundance of 2 quail species and range site and grazing management during drought were evaluated in the northern Rio Grande Plain of Texas. Clay loam range sites provided better nesting cover and greater abundance of forbs for quail than sandy loam and shallow ridge range sites. Foliar cover and aboveground standing crop of grass were greater on the 3 range sites within the short duration and deferred rotation systems as compared with the yearlong system. During drought, grazing systems provided better nesting and protective cover for quail than yearlong grazing. Recent grazing studies have shown that the primary values of grazing systems are increased forage production and range improvement (Heady 1961, Mathis et al. 1974, Kothmann 1975, Pieper et al. 1978). Many questions remain concerning effects of specialized grazing systems on wildlife populations. Wildlife has always been a primary product of rangeland, and in recent years the economic value of game animals has become increasingly important to landowners in Texas. A growing interest in quail among Texas hunters points to the desirability of understanding effects of grazing management on quail populations. The objective of this study was to evaluate bobwhite (Colinus virginianus) and scaled (Callipepla squamata) quail indices of abundance in relation to vegetation parameters affected by grazing management and range site. Study Area The study was conducted from March through December 1980 on the Rio Grande Plain Experimental Ranch. The 4,228-ha ranch, located about 55 km west-southwest of Uvalde, Texas, is operated by the Texas Agricultural Experiment Station. The area has a subtropical steppe climate characterized by mild winters and hot summers. The average annual rainfall is about 50 cm, and periodic droughts are common. Over a 75-year period, 53% of the annual rainfall has been below average with 1 of 4 years having less than 40 cm (Waldrip 1957). The frost-free period lasts about 285 days. Mean air temperatures range from-4' C in January to 42" C in July. Total rainfall for 1980 was 48 cm, with major storms in May (18 cm), August (11 cm) and November (7 cm), contributing 75% of the annual total. Only about 4 cm of precipitation fell during January through April, so spring vegetative growth and most quail breeding activity were delayed until after the May rainfall. Above average temperatures were recorded during June and July, with total rainfall during this period of only 2 cm. Rainfall received in August