Bobwhites are small birds (140 to 170 grams) with rounded wings and a square tail. They range in length from 20.3 to 24.7 cm with a wingspan from 9 to 12 cm. Males and females differ in facial and throat coloration, wing feathers, and beak color. Adult males have white facial stripes and throat in contrast to the buff coloration of females and juveniles. Wing feathers of males have sharply contrasting black markings while female wing feathers lack these markings. The base of the bill is black in males and yellow in females. White edges, dark bars, and fine, wavy streaks of color on the reddish brown back and white breast create a mottled appearance to the feathers. (Dimmick, 1992)
Northern bobwhites can be found from southeastern Ontario to Central America. Highest population densities are reached in the eastern United States and Mexico. Bobwhites can also be found throughout Cuba. Disjunct populations exist in Washington, Oregon, Idaho and northwestern Mexico. (Dimmick, 1992)
In forest habitats, northern bobwhites prefer areas of forest regrowth, such as areas that have recently been disturbed by fire, agriculture, and timber-harvesting. Northern bobwhites are also found in grassland habitats. Bobwhite habitats must contain a diversity of invertebrates, seeds, and herbaceous plants. Cover that provides protection from predators, weather, and provides nesting material is also essential. Water is not normally an important factor in habitat determination because ample water can be obtained from dew. (Brennan, 1999; Dimmick, 1992)
Bobwhites were originally thought to maintain pair bonds during a breeding season. However, new evidence suggests that males and females have more than one mate in each breeding season. (Brennan, 1999)
Courtship and pair formation can begin as early as February in south Texas while occurring later in more northerly areas. Nest building, egg laying, and incubation occur intensively from May to August. The beginning of the nesting season in Texas is associated with rainfall and the availability of new plant growth. Bobwhites mate in their first year of life and rear one brood per year after that, although sometimes multiple broods are raised. Nests destroyed before hatching will be rebuilt, while broods lost after hatching are usually not replaced.
Breeding pairs build ground nests of dead grasses. Nests are saucer-shaped softball-sized depressions in the ground, 85% are domed or covered with a canopy. Nests with no canopies are more common later in the breeding season. Nest construction occurs over two days and can take approximately 4 hours. Both males and females build the nests. The female lays one egg per day after the nest is completed. In some cases more than one female lays eggs into a single nest. Clutches range from 6 to 28 eggs and incubation lasts about 23 days. The young chicks begin to leave the nest about two weeks after hatching. (Brennan, 1999; Dimmick, 1992; Klimstra and Roseberry, 1975; Stokes, 1967)
Bobwhite hatchlings are able to walk about and follow their parents almost immediately following hatching. Both males and females incubate the eggs, brood the hatchlings, and provide for the young until they reach independence at about 2 weeks old. Both parents have been observed to defend young by attacking perceived aggressors and by performing broken wing displays. (Brennan, 1999)
Northern bobwhites have a short life span and high mortality rates. Few individuals live longer than five years, and about 80% live less than one year. Exposure is an important source of mortality during the winter. Deep snows and prolonged periods of cold may cause extensive losses. Also, feeding in agricultural environments can lead to exposure to contaminants which often have lethal effects. (Brennan, 1999)
Beginning in late summer bobwhites form small flocks called coveys that include parents, offspring, and unsuccessful breeding pairs. By autumn family groups have become dispersed in different coveys through random joining and leaving of individuals.
Bobwhites have many calls that start and direct group movement; 1 call for food location, 11 to aid in the avoidance of enemies, 6 calls used in mating or between competing males, and 2 parental calls.
Bobwhites are active during the day, especially during the early morning and late afternoon. They can fly relatively short distances, with the average flight lasting 5.1 seconds, but spend most of their time on the ground. (Brennan, 1999; Dimmick, 1992; Stokes, 1967)
Northern bobwhites usually stay in the same area throughout the year, especially in areas with good habitat.
Home range sizes vary quite a bit depending on the quality of habitats. Males without mates have larger home ranges than those with mates.
The well known "bob-white" call is only one of the many calls used by northern bobwhites. They have a wide variety of calls that have to do with group movement, food-finding, avoidance of enemies, mating interactions, and parent to offspring communication. Nonvocal communication is also important. For example, head-shaking, head-scratching, and preening may show which birds are more dominant in the social hierarchy. (Brennan, 1999)
The diet of bobwhites consists mainly of seeds but also includes green leafy material, fruits, and invertebrates. About 85% of the diet is vegetation and 15% animal matter, but these proportions change with the seasons.
In early spring, leafy material is an important source of vitamins. Insects are important from spring until autumn; during these months they may make up 25% of the diet. Females consume more insects than males because they need more protein for egg laying. Fruits are also an important summer source of calories. Seeds and legumes make up the majority of bobwhite diets in fall and winter. Hatchlings are completely dependent on insects as a food source.
Predation is an important source of mortality for northern bobwhites. Known predators include Cooper's hawks, raccoons, opossums, skunks and foxes. When adults with chicks encounter predators, they perform distraction displays such as fluttering and wing-dragging. This anti-predator behavior seems to be learned and is rarely seen in captive-reared birds. Their coloration helps to make them hard to see in the dense undergrowth that is their preferred habitat. (Brennan, 1999)
Northern bobwhites are host to parastic worms. These worms do not often kill their host, but their presence is associated with low body weight in northern bobwhites and this may negatively influence survival and reproduction. Northern bobwhites also host a wide variety of external parasites such as lice, ticks, mites, and fleas. (Brennan, 1999; Brennan, 1999)
Northern bobwhites are important prey for birds of prey and small, terrestrial predators. They are also important seed and foliage predators and may influence the plant communities in which they live.
There are no known adverse affects of northern bobwhites on humans.
Economically, northern bobwhites are one of North America's most important game birds, especially in the southern and midwestern United States. Annual harvest in 1970 was estimated to be 35 million birds in 37 states and 2 Canadian provinces, the largest harvest of non-migratory upland game birds. Northern bobwhites are one of the most extensively studied species of birds in the world. They have played a major role in captive laboratory studies to test the physiological and behavioral effects of pesticides on wildlife. They also were the subject of the first modern systematic study of a wild animal's life history in relation to environmental and habitat factors that influence its abundance. (Brennan, 1999; Dimmick, 1992)
Populations of northern bobwhite are declining. Habitat loss, particularly due to the increase in large-scale farming and the reduction of fence rows and suitable habitat plots are thought to be the major factor in the decline. One subspecies, the masked bobwhite (Colinus virginianus ridgwayi), is considered endangered. Northern bobwhite are listed as near threatened by the IUCN. (Brennan, 1991)
Kathleen Bachynski (editor), University of Michigan-Ann Arbor, Tanya Dewey (editor), Animal Diversity Web.
Kari Kirschbaum (editor), Animal Diversity Web.
Matthew Chumchal (author), Southwestern University, Stephanie Fabritius (editor), Southwestern University.
"Northern Bobwhite" (On-line). Discover Life in America. Accessed March 17, 2004 at http://www.dlia.org/atbi/species/animals/vertebrates/birds/odontophoridae/northern_bobwhite.html.
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Landers, J., B. Mueller. 1986. Bobwhite quail management: a habitat approach. Tall Timbers Research Station Miscellaneous Publication, : 1-39.
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