Foraging for food on the ground, the western meadowlark uses a special behaviour known as ‘gaping’ to find food below the surface (2) (3). Inserting its closed bill into the substrate, the western meadowlark then uses strong muscles to force the bill open, creating a hole from which it can gather insects or grain (2).
The diet of this species varies with season, consisting mainly of grain in the winter and early spring, insects such as beetles, ants, weevils and grasshoppers in late spring and summer, and the seeds of weeds during autumn (2) (3). The western meadowlark will also occasionally feed on the eggs and young of other bird species, and also scavenge from carcasses during severe winters (2).
Breeding in the western meadowlark occurs between late March and August, with the males arriving on the breeding ground to establish a territory up to a month before the females (2) (3). To defend a territory, a male may use posturing, singing, chase-flights and jump-flights, which involve the male springing up to a metre in the air before flying to a point several metres away. While physical contact during territorial disputes is uncommon, it can be potentially severe (3).
On arrival at the breeding grounds, a female western meadowlark will pair immediately with a male, and males with the largest song repertoires tend to be paired first (3). Each male western meadowlark usually pairs with two females at the same time, and courtship typically involves aerial chases (2) (3).
The female western meadowlark alone is responsible for nest building, using the bill to form a cup-like shape in an existing small depression in the soil, such as a cow hoof print. This is then lined with soft, dry grasses and pliable shrubs (2). The nest is usually concealed in dense vegetation, and may also have a partial or complete roof, and a runway or an elaborate tunnel leading to the nest entrance (2) (3).
Between 5 and 6 white, spotted eggs are laid, and these are incubated by the female western meadowlark for 13 to 16 days (2). The young are fed mainly by the female, although the male will occasionally deliver food, and the young fledge 10 to 12 days after hatching (2) (3). The fledged young remain dependent on the adult birds for a further two weeks, and rely on dense vegetation and their cryptic colouration to avoid predation. A female western meadowlark may produce two broods per year, although several attempts may be made in the event of unsuccessful nesting (3).
The western meadowlark is vulnerable to natural predators, with mammals such as the racoon (Procyon lotor), birds of prey and snakes all predating the nests of this species. The brown-headed cowbird (Molothrus ater) may affect the reproductive success of the western meadowlark through brood parasitism (3).