The Acadian Flycatchers, Empidonax virescens, belong to the tyrant flycatcher family.
Description
The upper plumage is olive, darker on the tail and wings. White bars can be seen on the wings. The underparts are mostly whitish; the chest is washed with olive.
They have white eye rings and a wide bill. The upper beak is dark-coloured, and the lower beak is yellowish.
Habitat and Distribution
Acadian Flycatchers are Neotropical Migrant birds, meaning they spend part of their year in North America while the rest is spent in Central and South America. These birds can be found in the eastern United States during the breeding season, which is from late spring until early summer. They are also seen in the Midwest, Appalachia, and the Southeast.
Preferred Habitat
This flycatcher has a preference for deciduous forest and especially mature woods near rivers, streams or other bodies of water. This flycatcher is highly sensitive to environmental changes, such as those caused by deforestation and waterway alteration.
The ideal habitat for this species is a moist, shady forest with a dense canopy and an open understory. The habitat provides both the insect prey it needs and the support structure needed to build its nests. (More on this shortly.) This species prefers large tracts of forest and tends to stay away from edge habitats.
Immigration
The Acadian Flycatcher migrates south in the early autumn. They travel from the Gulf of Mexico through Central America, parts of northern South America, including Colombia and Venezuela. The non-breeding season is spent in lowland humid tropical forests. They often mix with other Neotropical migrants under the canopy of Central and South American rainforests.
The long migration highlights the species’ dependence on healthy ecosystems at both ends of their range, a theme that becomes central when conservation concerns are examined.
Breeding and Nesting
Breeding behaviour is just as fascinating as its appearance. Breeding starts from late May to June, depending on the latitude. Soon after arriving on breeding grounds, pairs form and nesting follows.
Nest Construction
Nests of Acadian Flycatchers are cup-shaped structures that are usually placed in the horizontal branch of a deciduous shrub or tree. Nests are usually placed between 6 and 20 feet above ground. However, they can nest higher in taller forests. The nest is usually near or above water. This provides a cooler microclimate and additional protection for developing chicks.
Nests can be made of grasses and roots, as well as bark strips and hair. They are held together by spider silk and decorated with lichen and leaves to camouflage. The female is responsible for most nest construction and incubation. According to Bug Guide, this species is well documented.
Eggs and Incubation
The typical clutch is composed of two to four eggs that are pale and speckled with brown. After a period of incubation lasting 13 to 15 days, the chicks will hatch altricial — blind, naked and helpless. The young are fed by both parents, who bring back an abundance of insects until they leave the nest 14-17 days later. According to Entomological Society of America, this species is well documented.
Brood Parasitism
The Brown-headed Cowbird, a brood parasite that is known to lay eggs in nests of Acadian Flycatchers, poses a major threat to successful reproduction. Flycatchers can raise the cowbird chicks at the expense of their own young. This reduces the flycatchers’ reproductive success. This can be a problem in forests with fragmented trees, where cowbirds tend to be more common.
Feeding and Diet
Acadian Flycatcher is a flycatcher that lives up to its name. The flycatcher is a “sallying”, or silent, flycatcher. It sits quietly on a branch and looks for insects in the air before darting to catch them.
Insectivorous Diet
Its main food source is insects that fly, such as moths and beetles. The most active times are in the morning and the late afternoon. They often return to their favourite perches.
They may hover near foliage for a few seconds to catch insects on the undersides or branches of leaves. The flexible strategy they use allows them to take advantage of different microhabitats in the forest.
Plant Material
The primary food source is insects, but small fruits, seeds and other plant material may also be consumed, especially in late summer or during migration, when the insect supply might be low.
Acadian Flycatchers Perched on a Tree
Conservation
The Acadian Flycatcher is not endangered at this time, but it faces a number of threats that have led to localised decreases in its southern range.
Population Trends
The population as a whole is classified as stable or moderately declining. However, declines are more apparent in fragmented and degraded habitats. The Acadian Flycatcher is a specialist of the forest interior. It suffers greatly when large forests are destroyed by logging, agriculture, or development.
Conclusion
The Acadian Flycatcher plays a significant role in the eastern forests of North America. It is a small but important thread. It is often overlooked because of its small size and elusiveness, but it is vital to the health of forests and insect control. Because it is dependent on intact, mature woodland, the Acadian Flycatcher is an important indicator species. When the Acadian Flycatcher goes extinct, this often indicates larger problems within the ecosystem.
This species is protected by preserving an entire habitat, which supports many other types of life. The Acadian Flycatcher’s presence is a constant reminder to all of us, whether we are seasoned birders listening for the sharp “peetsa!” or nature lovers wandering in a quiet grove.
Learn more about the unassuming forest dweller to better understand the complex relationships that support life, and how to protect them for future generations.
