During the breeding season, Least Flycatchers are most common in semiopen deciduous and mixed forests of all ages, but sometimes they use shrubby fields and forest edges. In winter, they use woodland edges, forested ravines, shrubby areas, and pasture edges in Central America, typically below 3,200 feet elevation along the Pacific coast or below 5,000 feet along the Caribbean slope. In Mexico they also use tropical evergreen forest. Back to top
Insects make up the majority of the Least Flycatcher's diet. They catch ants, beetles, flies, butterflies, and leafhoppers in midair or pick them off vegetation generally less than 50 feet above the ground. Occasionally they also eat black elderberry, blackberries, and grass seeds. Back to top
Males and females choose where to put the nest shortly after they pair. They pick a deciduous tree with an upright fork in the lower to middle canopy anywhere from 2–50 feet above the ground.
Female Least Flycatchers weave together strips of bark, grasses, plant fibers, and spiderwebs to form a compact cup nest. They line the nest with fine grasses, animal hair, feathers, and downy plant material. Sometimes they steal bits of nesting material from nests of other species nearby. It takes them about 5–7 days to build a nest that is around 2.5 inches wide and 2 inches tall.
|Egg Description:||Creamy white, unmarked.|
|Condition at Hatching:||Helpless, with only small patches of down.|
Least Flycatchers may be small, but they are quick to quarrel with any bird, no matter their size, that enters their territory. They frequently chase American Redstarts, Brown-headed Cowbirds, and even Blue Jays, which are more than twice their size, out of their territory. Males also fluff up their feathers, extend their wings, and flick their tails from a crouched position to threatened an intruder. On the breeding grounds, they nest in clusters, creating a flycatcher neighborhood with anywhere from 2 to 30 territories per cluster. Males in the best condition often get the center territory and they are the first ones in the neighborhood to pair. Males and females perform a perch-hopping dance during courtship, followed by silent flights through the territory and, eventually, mating. Males in the center of the neighborhood venture toward the border to mate with additional females, a behavior known as extra-pair mating. Females also seek extra-pair matings from nearby males, and their desire to seek more mates may be one reason why they nest in clusters. Nests in the center of the neighborhood tend to have a lower risk of nest predation, which could be another reason why they nest in clusters. Predators that enter a neighborhood are met with alarm calls that may persuade them to leave the area. On the wintering grounds, males and females defend separate territories with songs and calls. Back to top
Least Flycatchers are common across the East, but their populations have declined sharply by approximately 1% per year for a cumulative decrease of 43% between 1966 and 2019, according to the North American Breeding Bird Association. Partners in Flight estimates a global breeding population of 27 million, and rates them 11 out of 20 on the Continental Concern Score. Although common, Partners in Flight includes Least Flycatchers on a list of Common Birds in Steep Decline, for species that are still too numerous or widely distributed to warrant Watch List status but have been experiencing troubling long-term declines. If current rates of decline continue, Least Flycatchers will lose another half of their remaining population within the next 42 years, according to Partners in Flight estimates. Least Flycatchers appear sensitive to forest disturbances that create openings in the forest or alter the understory such as logging and excessive deer browsing.Back to top
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