Colinus virginianus

The Northern Bobwhite is one of the best known and most studied of Texas birds. It has considerable aesthetic appeal as well as being a game bird of high economic value; so there is much interest in its conservation and manage- ment. Unfortunately, over much of the range of this species, including Texas, habitats of this quail are rapidly disappearing as well as those of many other associated wildlife species. As a result, populations are declining (North American Breeding Bird Surveys [Sauer et al. 2005] and correlated Texas Parks and Wildlife Department hunter and harvest trend surveys). Ironically, many subdivisions are named Quail Run, Quail Creek, or some similar name; but, are totally devoid of any bobwhites. The book edited by Brennan (2007) provides the most recent, comprehensive source of information in Texas about Northern Bobwhite life history, ecology, habitat requirements, conservation and management practices, and future predictions.

DISTRIBUTION: The Northern Bobwhite occurs in all ecoregions of Texas, primarily east of the 102^ndmeridian in a great variety of habitats from forest and woodland to grasslands and brushlands. Their primary habitat requirements include interspersed native brush thickets, grassland, and woodland edges (Reid et al.1978). However, they occur in only the eastern-most portion of the Trans-Pecos ecoregion. where the lack of precipitation is probably the limiting factor. Also, these quail are not evenly distributed within ecoregion landscapes because of unsuitable local habitat conditions.There are 22 subspecies of Northern Bobwhite of which 7 occur north of Mexico and 3 are native to Texas (Johnsgard 1988, Gutiérrez 1993). Unfortunately, widespread, innumerable releases of tens of thousands of imported bobwhite from Mexico and pen-raised birds from a hatchery in Tyler have confused distributional ranges of subspecies and have obscured the distributional status of the species and origin of populations in southern Reeves, Jeff Davis, and Pecos counties in the Trans-Pecos ecoregion (Texas Game, Fish and Oyster Commission 1945, Wood 1956, Baker 1999, Lockwood and Freeman 2004).

SEASONAL OCCURRENCE: This resident breeds from early March to mid-October, exceptionally, to November (eggs obtained from March 15 to November 9 and young 4 days old as late as October 8 (Oberholser 1974). Late broods can occur in southern Texas in November-December, especially if rains occur in September (Hernández and Peterson 2007). Also, there is evidence that egg-laying may occur year-round in South Texas (Lehmann 1984). The length of the nesting season is strongly influenced by weather—shortened by drought or intense heat, or lengthened by rainfall and cool weather, especially in South Texas (Hernández and Peterson 2007).

The average lifespan of a Northern Bobwhite is short, about six months and the annual mortality can be as high as 80% (Brennan 1999). Therefore, the number of birds in winter is far less than immediately after breeding. They have a very high reproductive potential and many reproductive strategies that allow them to produce 2 or more broods (≥25 chicks) per breeding season (Brennan 1999). Therefore, their abundance can exhibit marked variation among years, probably influenced mostly by precipitation (Peterson 2001).

Except during the breeding season, Northern Bobwhite associate in coveys (social units) of about 10-15 birds at a density of about one bird per ha (2.5 acres) under ideal conditions with an optimal covey size of perhaps 12 birds (Guthery 2000). Where populations are moderate to dense, some birds move from covey to covey weekly if not daily especially during the fall (Dimmick 1992). Few birds move more than <0.4 km (<0.24 mi) during a season and 0.8–1.6 km (0.5-1 mu) annually (Dimmick 1992). However, there are records of birds moving 32 and 105 km (20 and 65 mi) from where they were banded in South Texas (Lehmann 1984). Most birds spend their entire lifespan within an area <1 km (0.6 mi) in radius containing 314 ha (776 acres) and, mostly, within an area of no more than 5-40 ha (12.5-100 acres; Dimmick 1992). Thus all annual habitat requirements to sustain a covey must occur within an area of about 256 ha (640 acres).

BREEDING HABITAT: At least 500 Northern Bobwhites are needed in an area of suitable habitat (2,000 ha  [5,000 acres]) to ensure long-term survival. However, a viable population (1,000-3,000) requires 4,000- 12,000 ha (10,000-40,000 aces) of stable, permanent cover of grassland with brush, brushland with grass, or open forests with low brush and grass in a block or set of small blocks interconnected with permanent travel corridors (Guthery 2000).

A range of key habitat features (Schroeder 1985) includes: herbaceous food plant canopy coverage, 25-75% of the ground should be shaded at midday; soil surface coverage at quail level (below 20 cm [8 in]), 30-60% of soil surface should be bare or lightly covered by plant litter; if crops are in the area, they should include corn, soybeans, sorghum (milo), cowpeas, or peanuts ideally unharvested or left as stubble after harvest; low woody canopy coverage, 40-80% and < 3 m (10 ft) high; herbaceous canopy coverage in summer, 40-60%; height of herbaceous cover in foraging areas, 25-50 cm (10-20 in); height of herbaceous cover for nesting, 40-60 cm (16-24 in); grass canopy coverage, 40-60% including dead stems, an important component; suitable nesting cover, 10% of area with perennial grasses 30-45 cm  (12-18 in) high; distance of escape cover from feeding cover, 68 m (75 yd); interspersion of cover types, no required cover type farther than 91 m (100 yd) from another required cover type; intermixing of habitat components, ≥80% of the area provides optimum winter conditions, ≥20% optimum cover, and ≥10% provides optimum nesting; and the size of the area for optimum conditions, the distance separating food, cover, and nesting should be ≤80 m (88 yd).

Bunchgrasses are common nesting substrates for Northern Bobwhite in Texas (Lehmann 1946, Lay 1954, Jackson 1969); but, they nest in a variety of other substrates including forbs and shrubs. Brood-rearing habitat consists of three components: shade, open herbaceous cover, and green, growing vegetation (Lehmann (1984).

STATUS: There are few written records of Northern Bobwhite in Texas prior to the late 19^th century; but early farming, lumbering, and grazing were beneficial until the beginning of the 20^thcentury; so, the period from about 1875-1910 might be appropriately designated as the era of maximum bobwhite abundance. Then, intensive farming, lumbering, and gazing began to destroy bobwhite habitats (Texas Game, Fish and Oyster Commission 1945). Also, prior to passage of the first game laws in Texas (to protect bobwhite on Galveston Island in 1860; then, a broader general law in 1879), sport hunting and market hunting were unregulated. This situation led to exploitation of many bird species including quail(Casto 1983).Then, beginning in 1903, quail bag limits were established and hunting seasons began to appear county-by-county about 1925 (Cooke 2007). About 1920, the State Game Department began to import and release quail (Texas Game, Fish and Oyster Commission 1945). By the 1930s, the decline of quail numbers and their popularity as game birds stimulated the Texas Game, Fish and Oyster Commission to establish the Mexican Quail Importation Program between 1937-1940 (Baker 1999); and, to inform the public about quail biology and management which resulted in construction of the Tyler Quail Hatchery in 1956 (Cooke 2007). In combination, hundreds of thousands of birds were released; but, survival was poor and the programs were terminated, the former in 1941 and the latter in 1965.

Both programs were not based on scientific studies and were economically wasteful; but, they were politically successful in establishing academic and state agency wildlife management programs (the late Dr. W. B. Davis, in litt., copy of interview (Nov. 5, 1976), Office of Research Historian, Texas Agric. Ext. Serv., Davis 1970, and Baker 1995). Important handbooks about regional quail management were prepared by Lay (1954) for east Texas and Jackson (1969) for west Texas.

During the past 20-30 years, Northern Bobwhite populations in Texas have declined significantly over much of their range. North American Breeding Bird Survey data for Texas (Sauer et al. 2005) give annual trends of 3.3% (1966-1979), -4.1% (1980-2005), and -2.2% (1966-2005). Their populations are mostly influenced by weather and habitat conditions (Hernández and Peterson 2007). However, there are also many mortality factors and factor interactions, e.g. predation (including hunting), diseases, and parasites (Hernández and Peterson 2007, Peterson 2007a). Pesticide mortality may occur in agricultural environments (Brennan 1999). Nevertheless, loss of habitat is the key cause of decline (Guthery 2000). Therefore, where suitable habitat includes minimal areas between 400-2,000 ha (1,000- 5,000 acres), bobwhites persist despite broad- scale declines (Brennan et al. 2007). Major causes of habitat destruction include wide- spread modern clean-farming, overgrazing, decline in use of fire to prevent brush encroach- ment, high-density planted-pine silviculture, and urban-suburban encroachment (Peterson et al. 2002). Minor causes of habitat destruction can be important regionally, e.g., industrial develop- ment involving oil fields, surface mines, petro- chemical centers, and transportation corridors (Gunter and Oelschlaeger 1997, Telfair 1999).

Annual population trends and major causes of adverse impacts on the Northern Bobwhite by ecoregion are: East Texas Pineywoods -8.3% 1967-2001, changing land uses in agriculture, forestry, and urban-suburban encroachment (Whiting 2007); Post Oak Savannah stable 1978-1987, -9.0% 1981-2001, conversion of cropland to nonnative monoculture pasture grasses, overgrazing, and landscapefragmentation (Silvy 2007); Blackland Prairies 6.1% 1965-1975, -10.0%, 1975-2000; vast urban-suburban areas, nonnative monoculture pasture grasses, overgrazing, brush encroachment, and cleanly farmed croplands (Peterson 2007b); Cross Timbers and Prairies -5.5% 1978-2002, landscape fragmentation, brush encroachment, and overgrazing, (DeMaso and Dillard 2007); Gulf Coast Prairies -2.3% 1978-2002, urban-suburban development, intensive agri- culture, nonnative monoculture pasture grasses, landscape fragmentation, brush encroachment, and nonnative plant invasion (Perez 2007); South Texas Plains no trend, annual fluctuations 1978-2002, brush encroachment, land conversion, nonnative plant invasion, landscape fragmentation (Hernández et al. 2007); Edwards Plateau erratic bimodal curve 1978-2002 with consistent decline since 1994, landscape fragmentation, brush encroachment, overgrazing (Baccus and Eitniear 2007); Rolling Plains -3.5% 1980-2002, overgrazing and excessive brush control (Rollins 2007); High Plains 2.11% with irruptions 1966-2000, overgrazing, intensive agriculture, nonnative monoculture pasture grasses, and landscape fragmentation (Dabbert et al. 2007); and, Trans-Pecos no trend peaks and fluctuations, landscape fragmentation but with land use shift from livestock to wildlife enterprises (Harveson 2007).

The ecoregions with the greatest negative impacts on Northern Bobwhite and associated wildlife habitats and least future for improve- ment are the Blackland Prairies, Gulf Coast Prairies, and southern Post Oak Savannah, where urban-suburban, industrial, and trans- portation encroachment will continue to rapidly increase (Gunter and Oelschlaeger 1997). In the other ecoregions, populations of Northern Bobwhites and associated wildlife can be restored and enhanced if there is enough incentive. However, although technology exists for effective wildlife management (Guthery 2002, Brennan 2007), problems are complex; solutions are not simple, nor immediate; and are expensive (Gunter and Oelschlaeger 1997, Telfair 1999).

Text by Raymond C. Telfair II (2007)

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