Acadian Flycatcher

(Empidonax virescens)

Status: Endangered (ESA 2008 & SARA 2003)

Table of Contents:

Species Identification
Diet
Habitat and Range
Biology and Behaviour
Similar Species
Threats/Reasons for Being Endangered
Conservation and Recovery Strategies
How You Can Help

Photo by Andy Reago & Chrissy McLarren https://flic.kr/p/HphWUP

Species Identification:

The Acadian Flycatcher is a small song bird, 15 cm long and 12- 14 grams. They have an olive-green crown, back and tail with a pale whitish throat and breast. The most prominent feature of this bird is the bold white ring around the eye, and two white-ish horizontal bars on the wing. Their beak is short but has a wide base, allowing a big opening for snatching insects out of the air. Males give a distinct “peet-sa” call.

Diet:

The Arcadian Flycatcher mostly feeds on insects and insect larvae found on leaves and low vegetation, and they will often snatch insects in the air. Diet staples include bees, wasps, ants, moths, beetles, spiders, and flies.

Photo by: Gary Leavens https://flic.kr/p/269CvK2

Habitat and Range:

The Acadian Flycatcher breeds in the eastern United States and north into Ontario. Within Canada, the Acadian Flycatcher only breeds in Southern Ontario, especially within the Carolinian zone in the southwest corner of the province. There are scattered populations east of Lake Simcoe and occasional sightings across The Land Between. Winter range extends from Nicaragua, to Costa Rica, Panama, and parts of Colombia, Venezuela and Ecuador.

The Acadian Flycatcher is sensitive to habitat size, preferring large patches of deciduous or mixed forest. An Ontario study found that 56% of breeding flycatchers were found in forest patches >100 ha, and 92% were in patches >25 ha. They also breed more successfully with high canopy cover around their nest site. They prefer forests with a relatively open understory, sparse ground cover, pools, steep ravines, and streams. Typical breeding sites have a combination of maple, beech, oak and/or hemlock. Wetlands in the landscape are also a common feature. In the winter they range in low-lying or premontane mature forests.

Biology and Behaviour:

Males start to arrive in Ontario mid-May, and females arrive about a week later. They often return to the same breeding territory. The female builds a loose cup nest on a horizontal branch of a small tree like American Beech, Witch-hazel, Sugar Maple, Eastern Hemlock, or Eastern Flowering Dogwood. They lay 3 eggs on average, which are incubated by the female for two weeks. After hatching, the young are fed by both adults for another two weeks, and will stay close to the nest for a week after that. The male’s territorial “peet-sah” call is frequently heard, and both sexes call to each other with characteristic vocalizations. Fall migration begins from late July to early September. Nest predation is fairly common. Likely predators include raptors, snakes, small mammals, and Blue Jays

Photo by Andrew Weizel https://flic.kr/p/Vjb27k

Similar Species:

There are 15 other Empidonax species in the Americas that look fairly similar. The Acadian Flycatcher is best distinguished by its “peet-sah” call.

Threats/ Reasons for being at Risk:

1.Loss of large-diameter trees: Diameter-limited forestry in Ontario removes the largest trees that create canopy cover, and is detrimental to Acadian Flycatchers.

2. Activities that change water and moisture regimes in forests: Standing water in the forest landscape helps to prevent dense understories from growing. Irrigation and drainage in surrounding areas may lower the water table, and therefore affect forest structure.

3. Development in or adjacent to forests: In the Carolinian region especially, high human habitation has resulted in forest patches that are too small and fragmented to support breeding Acadian Flycatchers. Any further development in and around intact forests is a threat to this species. Fragmented stands increase the threat of predators, brood parasitism, and may change their food distribution.

4. Invasive plants and insects: The presence of Garlic Mustard, Multiflora Rose, and Common Buckthorn in some ravines has created dense, undesirable understory cover in stands that would otherwise be suitable breeding habitat. Invasive forest insects like the Emerald Ash Borer, Hemlock Wooly Adelgid, and tree diseases have the potential to kill many trees in Ontario. The loss of forest cover, especially hemlocks, would be detrimental to the Acadian Flycatcher.

5. Recreational vehicles: Off road vehicles like ATVs and snowmobiles lead to soil compaction which is linked to soil erosion and the spread of invasive species.

Photo by: Kelly Colgan Azar https://flic.kr/p/afx2BJ

Conservation and recovery strategies:

The Acadian Flycatcher is representative of a group of neotropical migrants that are vulnerable to shifts in forestry practices in Canada and the United States. It is considered a good indicator, as it is vulnerable to a range of habitat disturbances.

The provincial strategy involves identifying key areas to conserve, and to encourage the consideration of habitat needs in management planning. They also have plans to better survey populations, monitor threats, and expand Ecological Land Classification surveys. The province aims to maintain the current population level of 35 to 50 pairs.

Forestry practices that use selective logging that intentionally leaves large-diameter and older trees. Selective logging can also prevent forest fragmentation and risks of brood parasitism.

How can you help?

Landowners can steward their lands to prevent disease and insect outbreaks, and should avoid practices that will draw down the water table.
Buy Fair Trade, shade-grown coffee whenever possible to help reduce the pressure for deforestation in South America.
Support sustainable forestry practices by buying FSC wood and paper products.

Additional Resources:

Cornell Lab, Birds of North America profile.
COSEWIC Assessment and Status Report, 2010.
Ontario Recovery Strategy, 2016.

Photo by: Bettina Arrigoni https://flic.kr/p/2kV6Kzs

Sources:

COSEWIC. 2010. COSEWIC Assessment and Status Report on the Acadian Flycatcher (Empidonax virescens) in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. X + 38 pp.

Environment Canada. 2012. Recovery strategy for the Acadian Flycatcher (Empidonax virescens) and the Hooded Warbler (Wilsonia citrina) in Canada. Species at Risk Act Recovery Strategy Series. Environment Canada, Ottawa, Ontario. viii + 32 pp.

Ontario Ministry of Natural Resources and Forestry. 2016. Recovery Strategy for the Acadian Flycatcher (Empidonax virescens) in Ontario. Ontario Recovery Strategy Series. Prepared by the Ontario Ministry of Natural Resources and Forestry, Peterborough, Ontario. v + 5 pp. + Appendix.