Lark buntings are medium-sized sparrows that are native to northern America. In early summer on the western plains the male is a common sight as it flies up from the ground to perform its varied flight song. During winter, when both males and female have a streaky brown pattern, the birds are more subtle. Winter flocks are sighted in dry open fields, looking like chunky, big-billed sparrows. However, when they fly in compact flocks, swooping low over the ground, numbers of birds will flash patches of buff or white in their wings.
Lark buntings breed in the Great Plains from Saskatchewan and southern Alberta (Canada) to North East New Mexico and northern Texas (USA). They winter from the southern Great Plains along to Central Mexico. These birds breed in meadows, plains and habitats as high as 8,000 feet. They are found in shrubby steppes on high plains and in areas that are cultivated. During migrations in spring and fall, they live in habitats that are similar. They winter in brushy and cultivated areas, and desert.
Lark buntings hop along the ground to forage. They walk or run when pursuing prey. They are disturbed easily, usually flying to a low branch or fence when alarmed. The male sings persistently from a perch that is exposed, usually by the edge of an area that is wooded. To establish and maintain his territory, a male performs a display. From a height of about 7 to 8m, he makes a steep ascent, rapidly beating his wings. Then, his wing beats become slower and deeper, almost mechanical. To finish, he makes a final glide to the ground or perch, making jerky flaps towards the end of his glide. Lark buntings in winter and during migration are gregarious. Flocks may number a few dozen or several hundreds birds, but around abundant food resources they may be thousands. When threatened or alarmed, these birds may sound alarm calls and perform displays to defend the nest and chicks. They will also perform distraction displays such as the “mouse-like run” or “broken-wing act”.
Lark buntings are predominantly insectivorous, but also eat grains, seeds and fruits during winter. In summer, they eat insects such as grasshoppers, beetles, bugs and ants, and the seeds of wild plants, plant matter and grains.
Lark buntings are monogamous (where one male mates with just one female), though occasionally a male will have a second mate. The male and female during the courtship period spend much time together on their territory, and during this time the male is almost totally silent. No obvious courtship display takes place at this stage. The nesting season runs from the middle of April through July. The female chooses the nest site, visiting sites, followed closely by the male. Once she has selected a place, the female scrapes under a shrub with her feet. The male then collects materials such as grass to build the nest, which typically is built in a hollow on the ground, a cup-shaped depression that they line with grass and stems. 3 to 6 eggs are laid, light blue in color. Incubation is for around 10 to 11 days, mostly by the female, which is occasionally fed by the male. The altricial chicks are fed and brooded by both adults. The male may bring food to the female while she feeds the young. The chicks leave their nest 8 or 9 days after hatching. They cannot fly and remain near the nest, concealed by vegetation. Both parents feed them for some days more.
Lark buntings are a widespread species and not endangered. Nonetheless, they are under threat from pesticides used to control grasshoppers, collisions with vehicles during the breeding season and migrations, degradation of their habitat and changes due to overgrazing, and disturbances at nest sites.
According to the What Bird resource, the total population size of the Lark bunting is around 27 million individual birds. According to the All About Birds resource, the total breeding population size of the Lark bunting is 9.1 million individuals, 98% of these spending some part each year in the U.S., in Mexico 56%, with 2% breeding in Canada. Overall, currently this species is classified as Least Concern (LC) on the IUCN Red List, but its numbers today are decreasing.
The Lark bunting eats grasshoppers, some species of which cause major damage to crops, so may provide some measure of pest control.