Overview
As a distinctly colored and marked quail, masked bobwhite quail (Colinus virginianus ridgwayi) are easily identified by their rich cinnamon tinted breast and the dark black head and throat. Males may have a distinct superciliary stripe and have mottled crowns of black and white that tend to darken with age. The back feathers show hues of browns, buff, rufous and black similar to other races of bobwhite quail. Females show less distinctive markings such as a buffy head and throat with a distinct white superciliary stripe. The earliest recorded sighting of masked bobwhite quail dates back to 1884, as documented by F. Stephens in 1885. However, H. Brown noted that by 1904, masked bobwhites were considered one of the rarest birds in Arizona.
Currently, the masked bobwhites range encompasses a small portion of the United States - Mexico border region in extreme south-central Arizona and northern Sonora. Historically, this species occupied level plains and river valleys that exhibited grassy savannah habitat with elevations ranging from 150 to 1,200 meters. Such locations included the Altar and Santa Cruz valleys in Arizona and Shreves’ Plain of Sonora, Mexico. Much of the decline in masked bobwhite quail populations is attributed to its limited range and the reduction of habitat within that narrow distribution, as documented in the 2021 implementation plan.
It is generally accepted that ranching and grazing expansion in the early 1900s led to the destruction of native grassland across the range of the masked bobwhite quail, and by 1950, it was nearly extinct in the wild. Unsuccessful attempts at reintroduction occurred in 1964 and the masked bobwhite quail was one of the original species listed as endangered under the Endangered Species Conservation Act, and later the Endangered Species Act in 1973. Experimental releases of masked bobwhite quail near the Mexican border resulted in a naturally reproducing population in 1977, but drought and declining habitat quality reduced this population to a few birds by 1983, as documented in the 1995 recovery plan. In 1985, the U. S. Fish and Wildlife Service purchased the Buenos Aires Ranch, which was established in 1864 by Pedro Aguirre Jr., explicitly for the recovery of the masked bobwhite quail. B. Leavengood noted in 2006, that at the time, this location was the last place in the Unites States containing suitable habitat for the species. Since 1985, Buenos Aires National Wildlife Refuge has continued efforts to reestablish masked bobwhite quail on the refuge through releases of captive bred chicks that are fostered by vasectomized Texas bobwhite (Colinus virginianus texanus) males. Other conservation measures include livestock removal and habitat improvement. In 1990, S.J. Dobrott noted that population estimates of masked bobwhite quail on Buenos Aires National Wildlife Refuge ranged from 300 to 500 individuals. Current estimates of masked bobwhite quail suggest approximately 200 individuals occur on the refuge.
Scientific Name
Identification Numbers
Characteristics
Physical Characteristics
The masked bobwhite is characterized by a rufous-red breast and black head and throat. Most individuals contain some white on the head, particularly through the eye and occasionally on the throat. The male’s back appears brown overall, however as it is mottled, other color combinations of black, pale yellow, rufous and gray occur. The female’s coloration is drabber than the males and resembles other female bobwhites, although more rufus coloration exists on the upper back and flanks.
Habitat
In Sonora, masked bobwhite quail habitat is relatively open, subtropic, summer active-savanna grassland within dry-tropic scrub. In the southern United States portion of the masked bobwhite quail range, vegetation composition of the scrub habitat shifts from subtropic to dry-tropic and desert grassland species. Here, mesquite (Prosopis velutina) is often the single component of overstory cover. In this landscape, masked bobwhite quail inhabit areas where a mosaic of bare ground and vegetation consisting of short and tall plants allows them to navigate the landscape and access cover, nesting site, brood rearing habitat, and food, as documented in the 2021 habitat implementation plan. Two habitat components that address these needs are useable space and arrangement. F.S. Guthery described this in 1997 useable space as the amount of space that contains permanent cover, which allows quail to access and utilize the entire landscape. The arrangement of habitat refers to a combination of suitable habitat types that occur on the landscape. Some studies have attempted to quantify the habitat characteristics that are favored by masked bobwhite quail. For example, masked bobwhites in the southern Altar Valley exhibit a preference for vegetation composition of 10 to 15% woody plants, 12 to 50% grass and 10 –to15% forbs, as documented by D. Brown and K. Clark in 2017. However, not all cover is equally suitable, as the structure structure
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Learn more about structure of the available cover determines its usefulness for masked bobwhites. For example, cover that is dense on the top and open underneath, like certain types of woody shrubs, allows for easy access while escaping threats. Within appropriate habitat types, home range sizes for masked bobwhite quail average 27 acres, as documented by K. Simms in 1989. Once established, individual quail seldom leave these locations.
Land on which the natural dominant plant forms are grasses and forbs.
Food
Masked bobwhite quail consume a diet similar to other northern bobwhite races and includes seeds, invertebrates and green plant material. J.A. Larson and others documented in 2010 that this diet varies in quantity across seasons. Seeds, particularly hard-coated seeds from grasses and forbs, make up 60% of their diet in the spring and up to 80% in the fall, as noted by A.S. James and others in 2015. During spring and summer, invertebrate consumption by bobwhites increases to approximately 25% of their diet, as insects provide a higher source of crude protein, 45%, for reproductive adults and growing juveniles. A.S. James and others also noted that chicks will exclusively consume invertebrates for their first few weeks. Lastly, they noted that plant material, such as legumes, make up the smallest part of a quail’s diet and generally provides the least amount of crude protein. Quail must drink water daily or obtain it from their food.
Behavior
Masked bobwhite quail share similar behaviors as other bobwhite quail races. Most notably, these species share a characteristic bob-white call that is often vocalized by males perched on rocks or bushes. As with most quail, masked bobwhites spend much of their time on the ground, typically flying short distances only to avoid disturbance and predation. Masked bobwhite quail forage on the ground and use vegetative cover to avoid predation. During the winter, masked bobwhite quail will live in coveys of up to 20 birds. During warmer seasons, masked bobwhite tend to be more active in the early mornings and late afternoons to avoid extreme temperatures.
Similar Species
In 1884, two masked bobwhite quail, a male and female specimen, were obtained by H. Brown who originally identified them as eastern bobwhite. G.B Grinnell subsequently identified them as a race of northern bobwhite formerly (Ortyx graysoni) that inhabited Mexico, as noted by R.E. Tomlinson in 1972. In 1884, on a collecting expedition to Sonora Mexico, a male type specimen was collected and given the name Colinus ridgwayi, which was made official in 1886, as documented by J.W. Allen in 1886. In 1944, the name was changed to Colinus virginianus ridgway to better distinguish this subspecies from other subspecies of bobwhite quail, as documented by R.E. Tomlinson in 1972. Masked bobwhite quail are one of the 23 recognized subspecies of bobwhite quail.
Life Cycle
Masked bobwhite quail live in social groups called coveys for a significant part of the year - fall, winter and early spring. Coveys consist of individuals from both sexes and multiple age classes, and pairs bonds form in this convey unit. As breeding season approaches, masked bobwhites begin to pair off, usually in late June. Breeding season starts with males calling usually in late June into early July. Masked bobwhite quail are ground nesters and success of nests is highly related to the amount of cover and concealment provided by vegetation. Hatching occurs in late July through late September, and brood size on average is 11 chicks. The timing of breeding, nesting and hatching in this species is highly linked to summer rains, also known as the monsoon season, which influences the availability of invertebrates and plant for food, as well as cover. Masked bobwhite quail experience high, but similar mortality rates as other bobwhite races, which W. Rosene documented in 1969 to be approximately 70%.
Geography
Historically, the masked bobwhite quail occurred in southern Arizona, in Altar and Santa Cruz valleys, and in larger portions of Sonora Mexico. The eastern and southern limits of its distribution is restricted by transition of Sonoran savanna grassland, which is comprised of summer-active grass and forbs, to Sinaloan thornscrub, and consists of thicker woody vegetation and shrubs; here elegant quail replace masked bobwhites. As such, no masked bobwhite occurrences have been documented south or east of the Rio Yaqui. To the north and west, the savanna grassland community transitions into desert scrub, and at higher elevations, to temperate desert grasslands. In these ecotone regions, scaled quail (Callipepla squamata) begin to replace masked bobwhites.
Timeline
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