Moucherolle à côtés olive

En bref

Migratrice
  • Scientific Name: Contopus cooperi
  • Spanish Name: Pibí boreal
  • Famille : Tyrannidae
  • Known Nicknames: Olive-sided Pewee, Cooper's Flycatcher
  • Average Length: 18–20 cm / 7–8 in
  • Average Weight: 28–40 g / 1.0–1.4 oz
  • Envergure : 33–38 cm / 13–15 pouces
  • Key Feature: Large, dark olive-brown vest contrasting with white throat and belly; heavy bill
  • Primary Diet: Primarily Insectivore (aerial hawking of bees, wasps, flies, and beetles)
  • Range: Breeds across boreal and montane forests of North America; winters in South America (Andes and Amazon basin)
  • Habitat: Open coniferous or mixed forests, often near clearings, edges, or burned areas with tall snags for perching
  • Social Structure: Solitary (territorial during breeding; loosely migratory)
  • Nesting/Breeding: Conifer branch fork (usually high in a tree, 6–30 m above ground)
  • Statut de conservation : Quasi menacé (NT)
  • Évolution démographique : En baisse

The Olive-sided Flycatcher (*Contopus cooperi*) is a charismatic songbird of North American boreal forests, instantly recognizable by its distinctive, plaintive call that sounds like a spirited "quick, three beers!" This medium-sized flycatcher boasts a robust, top-heavy silhouette, with a large head, short tail, and a notably dark, olive-brown back that contrasts sharply with its crisp white throat and belly—a "vested" look that sets it apart from its plainer relatives. Its most unique feature is its aerial feeding style: it perches on the highest, most exposed dead branches (often called "snags") to sally out in long, looping flights after large insects like bees and dragonflies, rarely foraging among leaves. A powerful migrant, it travels from its breeding grounds in Canada and the western U.S. to winter in the dense forests of the Andes, making it a vital, long-distance link between ecosystems.

Faits amusants

The Olive-sided Flycatcher has a famously distinctive call that sounds like a cheerful "quick, three beers!"—a handy mnemonic for birders. It’s a master of aerial acrobatics, often sallying out from a high, exposed perch to snatch bees, wasps, and even dragonflies mid-flight, then returning to the same spot. One quirky adaptation: during the breeding season, males will sometimes perform a "flutter-flight" display, rising steeply into the air while singing, then parachuting down with wings held in a V-shape. This bird also has an unusually large mouth for its size, allowing it to swallow relatively large insects whole.

Habitats et répartition

The Olive-sided Flycatcher breeds across the boreal and montane forests of North America, from Alaska and Canada south through the western United States and into the northern Appalachians. Its preferred habitat consists of open coniferous or mixed woodlands, often near water, where it uses prominent dead snags or high exposed branches as perches to sally for flying insects. During migration, it can be found in a variety of forest edges and clearings. Its wintering range extends through Central America and into the northern Andes of South America, inhabiting montane evergreen forests, forest edges, and adjacent open areas.

Comportements & Reproduction

The Olive-sided Flycatcher is a solitary nester, with males establishing and defending large territories through persistent singing from high, exposed perches. Mating is monogamous within a breeding season, and pairs form shortly after males arrive on the breeding grounds. The female alone builds a shallow, cup-shaped nest of twigs, moss, and lichens, typically placed on a horizontal conifer branch well above the ground. She incubates a clutch of 3–4 eggs for about 16–18 days, while the male provides food during this period. Both parents feed the altricial young, which fledge in roughly 15–18 days. A unique reproductive strategy is their extreme site-fidelity and reliance on a specific, often ephemeral habitat: recently burned or logged forests with standing dead trees (snags) that provide abundant perches for foraging. This makes their breeding success highly sensitive to fire suppression and forest management practices, as they rarely breed in dense, unburned forest interiors.

Alimentation

The Olive-sided Flycatcher is an almost exclusively insectivorous bird, with a diet dominated by large flying insects such as bees, wasps, ants, beetles, dragonflies, and moths. It employs a distinctive "hawking" foraging strategy, perching prominently on high, exposed snags or treetops and sallying out in long, direct flights to snatch prey mid-air before returning to the same perch. An interesting fact is that its common name "Olive-sided" is unrelated to its diet, but its scientific name *Contopus cooperi* means "short-footed," reflecting its weak legs and feet, which are not used for ground foraging. Another fascinating aspect is that it will sometimes consume small berries, such as those from poison ivy or Virginia creeper, especially during migration or in poor weather when insect prey is scarce, though insects remain its primary food source.

Couleurs

The Olive-sided Flycatcher is a stocky bird with dark olive-brown upperparts and a white throat and belly, contrasting with dark, olive-gray flanks that create a distinctive “vested” appearance. It has a pale, unmarked breast and a slight, light wingbar, with no bold patterns or eye rings. Its cryptic coloration blends into coniferous forest perches, aiding camouflage against bark and foliage.