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Acadian flycatcher

Empidonax virescens

What do they look like?

Acadian flycatchers look very similar to closely related birds like alder flycatchers, yellow-belied flycatchers, willow flycatchers, and least flycatchers. Adults are small in size (13 to 15 cm long) and have triangle-shaped heads. They are olive-colored with white and sometimes yellowish side and belly areas, and usually have 2 white bars on their wings. The top of their bill is black and the bottom is yellow to pink. They have a thin, white ring around each eye, which makes them look different from similar species. Juveniles are more brown, have tan edges on their feathers, and darker tan bars on their wings. ("Birds in Forested Landscapes", 2011; "Patuxent Bird Identification InfoCenter", 2000; Bull and Farrand, Jr., 1998)

  • Sexual Dimorphism
  • sexes alike
  • Range mass
    11 to 14 g
    0.39 to 0.49 oz
  • Range length
    13 to 15 cm
    5.12 to 5.91 in
  • Average wingspan
    23 cm
    9.06 in

Where do they live?

Acadian flycatchers travel between the United States and Canada in the summer and South America in the winter. They arrive in their northern home between April and May, which can be anywhere from southeastern Minnesota to eastern Texas or anywhere east from there to the Atlantic Coast. A few are found in southern Ontario, Canada. They fly south across Mexico and the Caribbean, to northwestern Colombia, Ecuador, and Venezuela. They are native to the areas where they live. ("Acadian Flycatcher", 2011; "Empidonax virescens", 2012)

What kind of habitat do they need?

Acadian flycatchers have very specific requirements for their habitat. In the summer, they are found in older forests with leafy, shady trees. These forests are usually near wetlands, streams, ravines, or swamps. Acadian flycatchers live just below the tops of the trees, in an area called the understory. They spend winters in low tropical forests in South America. ("Wisconsin All Bird Conservation Plan", 2012; Bull and Farrand, Jr., 1998; Wilson and Cooper, 1998)

How do they reproduce?

Acadian flycatchers form bonds between males and females that can last more than one year. The pairs usually return to the same nest they made the year before and younger birds usually find other places to nest. Sometimes males mate with more than one female. Males quickly chase females to court them. Males sing often throughout the breeding season, while females only sing occasionally. Both sexes call to each other frequently. (COSEWIC, 2010)

Acadian flycatchers build nests that are like hammocks or cups. The nests are 3 to 9 m above the ground in branches of trees and shrubs. They are made of plant stems and fibers and held together with dried grass stems and spider silk. They also hang plants from the nests to hide them. These are called "nest tails." Nests are sometimes built over water or in open parts of the forest so they are easier to defend. ("Wisconsin All Bird Conservation Plan", 2012; Bull and Farrand, Jr., 1998; Wilson and Cooper, 1998)

In the United States, breeding is between May and August. Females lay 2 to 4 eggs once or twice in a season. The eggs are watched over and kept warm for for 13 to 14 days until they hatch. Then, both parents take care of the young for 13 to 15 days until they can fly. After leaving the nest, they are cared for by both parents for 12 more days. If the female starts laying a second group of eggs, the male takes over caring for the young. After 1 year, they are able to have their own chicks. ("Acadian Flycatcher", 2011; DeGraaf and Yamasaki, 2001)

  • How often does reproduction occur?
    Acadian flycatchers typically have 2 broods during the breeding season.
  • Breeding season
    Acadian flycatchers typically breed from late May to mid-August, peaking in early June-early July)
  • Range eggs per season
    4 to 8
  • Range time to hatching
    13 to 14 days
  • Range fledging age
    13 to 15 days
  • Average time to independence
    12 days
  • Average age at sexual or reproductive maturity (female)
    1 years
  • Average age at sexual or reproductive maturity (male)
    1 years

After the young hatch, parents care for them for 13 to 15 days until they can fly, and for 12 days after that. If females start to lay another set of eggs, males take over caring for the young. ("Birds in Forested Landscapes", 2011; COSEWIC, 2010)

  • Parental Investment
  • altricial
  • male parental care
  • female parental care
  • pre-hatching/birth
    • provisioning
      • female
    • protecting
      • male
      • female
  • pre-weaning/fledging
    • provisioning
      • male
      • female
    • protecting
      • male
      • female
  • pre-independence
    • provisioning
      • male
      • female
    • protecting
      • male
      • female

How long do they live?

Acadian flycatchers live about 10 years and 9 months in the wild, which is long for a small bird. The longest recorded lifespan in the wild was 10 years and 11 months. ("AnAge", 2009)

  • Range lifespan
    Status: wild
    10.92 (high) years
  • Average lifespan
    Status: wild
    10.75 years

How do they behave?

Acadian flycatchers are excellent at changing directions quickly while flying and can even fly backwards. This is great for catching insects in the air and grabbing insects or berries from branches. They don't walk or hop. Acadian flycatchers bathe by diving into water, striking their chests, and returning to a branch to clean themselves. They are sometimes hard to locate because they prefer dense, shady forests. Females will also leave a nest if a predator or other possible threat is within 23 m. They are somewhat social during the breeding season, forming pair bonds. ("Acadian Flycatcher", 2011; "Birds in Forested Landscapes", 2011)

  • Range territory size
    5000 to 17000 m^2

Home Range

Somewhere between 1 and 43 pairs of mating Acadian flycatchers have been found for every 40 hectares (the average was 22 males). Nesting territory size is generally 0.5 to 1.7 hectares for each breeding pair. (DeGraaf and Yamasaki, 2001)

How do they communicate with each other?

Acadian flycatchers are songbirds. Their songs sound like "peet-sah" or "tee-chup" and sound different from related species. Songs change depending on the time of day and their territory. Males make more noise when territorial neighbors are nearby. They also make more noise and become more aggressive when defending nests from predators. Females are usually quieter, especially while sitting on nests. Acadian flycatchers mostly use their senses of sight and hearing. ("Empidonax virescens", 2012; Wiley, 2005)

What do they eat?

Acadian flycatchers eat mostly insects such mosquitoes, flies, insect larvae, small moths, flying ants, small beetles and some spiders. Acadian flycatchers get their name because they are good at catching insects with their beaks from underneath leaves and even while flying. They occasionally eat fruits such as blackberries and raspberries. Juveniles mostly eat insects. ("Acadian Flycatcher", 2011; "Birds in Forested Landscapes", 2011)

  • Animal Foods
  • insects
  • terrestrial non-insect arthropods
  • Plant Foods
  • fruit

What eats them and how do they avoid being eaten?

Although Acadian flycatchers disguise their nests with bits of plant material hanging down, predators still find thier nests. Predators include hawks, red-shouldered hawks, red-tailed hawks, broad-winged hawks, American crows, blue jays, black ratsnakes, cats, southern flying squirrels, mice, squirrels, barred owls, and chipmunks. (COSEWIC, 2010; Cox, et al., 2012)

What roles do they have in the ecosystem?

Acadian flycatchers might be good a indicator species of declining forest habitat because they are sensitive to deforestation. Brown-headed cowbirds lay eggs in their nests in hopes that Acadian flycatchers will feed and raise their young. Parasites on the outside of their bodies include mites called Ptilonyssus tyrannus and Sternostoma longisetosae as well as deer ticks. ("Species Profile: Empidonax virescens", 2012; COSEWIC, 2010; Knee and Proctor, 2010; Peters, 2009)

Species (or larger taxonomic groups) used as hosts by this species
  • None known
Species (or larger taxonomic groups) that are mutualists with this species
  • None known
Commensal or parasitic species (or larger taxonomic groups) that use this species as a host

Do they cause problems?

Acadian flycatchers don't have any known negative economic impact on humans.

How do they interact with us?

Acadian flycatchers don't have any known positive economic impact on humans.

Are they endangered?

Acadian flycatchers are plentiful in most places they live. However, their numbers have declined in Minnesota, Wisconsin, and southeastern Canada. They are sensitive to habitat loss to farming because they need large areas of thick forests. ("Species Profile: Empidonax virescens", 2012; COSEWIC, 2010)


Amanda McDonald (author), Minnesota State University, Mankato, Robert Sorensen (editor), Minnesota State University, Mankato, Jeremy Wright (editor), University of Michigan-Ann Arbor, Catherine Kent (editor), Special Projects.


2011. "Acadian Flycatcher" (On-line). The Cornell Lab of Ornithology - All About Birds. Accessed February 08, 2012 at

2009. "AnAge" (On-line). The Animal Ageing & Longevity Database. Accessed April 25, 2012 at

2011. "Birds in Forested Landscapes" (On-line). Cornell Lab of Ornithology. Accessed March 28, 2012 at

2012. "Empidonax virescens" (On-line). IUCN Redlist of Threatened Species. Accessed March 28, 2012 at

2000. "Patuxent Bird Identification InfoCenter" (On-line). USGS - Patuxent Wildlife Research Center. Accessed March 28, 2012 at

2012. "Species Profile: Empidonax virescens" (On-line). Minnesota Department of Natural Resources. Accessed February 08, 2012 at

2012. "Wisconsin All Bird Conservation Plan" (On-line). Accessed March 29, 2012 at

Bull, J., J. Farrand, Jr.. 1998. National Audubon Society Field Guild to North American Birds. New York: Alfred A. Knopf, Inc..

COSEWIC, 2010. Assessment and Status Report on the Acadian Flycater Empidonax virescens in Canada. Committee on the Status of Endangered Wildlife in Canada, 1: 4-29. Accessed April 25, 2012 at


DeGraaf, R., M. Yamasaki. 2001. New England Wildlife: Habitat, Natural History and Distribution. New Hampshire: University Press of New England.

Knee, W., H. Proctor. 2010. "Interactive HTML-based Dichotomous Key to Female Rhinonyssidae (Mesostigmata) from Birds in Canada" (On-line). Accessed August 13, 2012 at

Peters, R. 2009. "Avian Tick Burdens Across an Urban to Forest Land-Use Gradien" (On-line pdf). Accessed August 13, 2012 at

Wiley, R. 2005. Individuality in songs of Acadian flycatchers and recognition of neighbours. Animal Behaviour, 70: 237-247.

Wilson, R., R. Cooper. 1998. Acadian Flycatcher Nest Placement: Does Placement Influence Reproductive Success?. The Condor (Los Angeles, Calif.), 100: 673-679.

University of Michigan Museum of ZoologyNational Science Foundation

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McDonald, A. 2012. "Empidonax virescens" (On-line), Animal Diversity Web. Accessed April 13, 2024 at

BioKIDS is sponsored in part by the Interagency Education Research Initiative. It is a partnership of the University of Michigan School of Education, University of Michigan Museum of Zoology, and the Detroit Public Schools. This material is based upon work supported by the National Science Foundation under Grant DRL-0628151.
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