Contopus cooperi

A medium-sized (7-8 inches) flycatcher, the Olive-sided Flycatcher is most easily identified by its dark gray back and head, dark chest patches, and white wing tufts. Other field marks include a black bill, black legs, and a shallowly-notched tail. Male and female Olive-sided Flycatchers are similar to one another in all seasons. The Olive-sided Flycatcher occurs widely across central Alaska, Canada, and the northern United States. Smaller numbers breed at higher elevations in the Rocky Mountains south to Baja California and in the Appalachian Mountains south to North Carolina. This species winters from southern Mexico south to Andean South America. In summer, Olive-sided Flycatchers breed in northern evergreen forests, particularly those dominated by spruce, hemlock, or pine trees. On migration, this species may be found in evergreen or deciduous forests elsewhere in North America. Olive-sided Flycatchers spend the winter in humid mountain forests. Like most flycatchers, this species primarily eats insects, which it catches while in flight. In northern forests in summer, the Olive-sided Flycatcher may be most easily observed flying out from high perches to capture insect prey. This species may also be observed on a high perch singing its characteristic ‘quick, THREE BEERS!’ song. Olive-sided Flycatchers are primarily active during the day.

Threat Status: Near Threatened

Breeds temperate North America; winters south to Bolivia.

Contopus cooperi breeds across Canada (overlapping into eastern USA) and Alaska, and down the west coast of the USA as far as northern Mexico. There are also isolated populations in several states in the eastern USA¹. It winters primarily in Panama and the Andes Mountains, from north and west Venezuela south through Ecuador to south-east Peru and west Bolivia¹. Casual wintering also occurs in the Guianas, Trinidad, south Venezuela, Brazil and south Peru¹. Based on data from the Breeding Bird Survey the population has declined by 3.5% annually since 1980, equating to a 30% decline over a ten year period, but a 20.6% decline for the period 1993-2002. Given the apparent benefits to the species of some forest management practices in north America, populations may be being affected by loss or alteration of habitat in their wintering grounds.

occurs (regularly, as a native taxon) in multiple nations

Canada

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Breeding

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Breeding

Global Range: (>2,500,000 square km (greater than 1,000,000 square miles)) Breeding range extends from western, southern, and central Alaska and southern Yukon eastward to southern Labrador, south to northern Baja California, Arizona, New Mexico, the Guadalupe mountains of western Texas, and central Saskatchewan south through central Minnesota, northeastern Ohio, and Massachusetts, locally in Appalachians south to Tennessee and North Carolina (AOU 1983, Altman and Sallabanks 2000). During the northern winter, the range includes mountains of South America, mainly in the Andes from Colombia and Venezuela to southeastern Peru; in small numbers in Central America and southern Mexico (AOU 1983, Stiles and Skutch 1989); also in Amazonian and southeastern Brazil (Willis et al. 1993).

Length: 19 cm

Weight: 32 grams

In the hand, can be separated from the wood-pewees (Contopus sordidulus and C. virens) by the longer (96-117 mm) wing, and from Greater Pewee (C. pertinax) by plumage, tail length (63-74 mm), and by the horn-colored to blackish lower mandible.

Habitat and Ecology

Systems

• Terrestrial
• Freshwater

Comments: BRIEF SUMMARY: Olive-sided flycatchers breed in various forest and woodland habitats: taiga, subalpine coniferous forest, mixed coniferous-deciduous forest, burned-over forest, spruce or tamarack bogs and other forested wetlands, and along the forested edges of lakes, ponds, and streams Most nesting sites contain dead standing trees, which are used as singing and feeding perches. Nests are placed most often in conifers, on horizontal limbs 2-15 meters from the ground. During the northern winter, this species occurs in a variety of forest, woodland, and open situations with scattered trees, especially where tall dead snags are present.

BREEDING: in forest and woodland, especially in burned-over areas with standing dead trees, in taiga, subalpine coniferous forest and mixed coniferous-deciduous forest (AOU 1983). In Ontario, they nest in spruce or tamarack bogs, along the forested edges of beaver (Castor canadensis) ponds and rivers, and in burned-over forests (Cheskey 1987). In New York, however, where forest fires have been suppressed for much of this century, they favor small bog ponds and quaking bogs, swampy edges of lakes, marshy streams, backwaters of rivers, and beaver meadows. Most nesting sites contain dead standing trees, which are used as singing and feeding perches, and are bordered by forest (Peterson 1988). Birds also use small mountaintop ponds. Forests surrounding these sites are usually coniferous or mixed with deciduous trees. Black spruce (Picea mariana) is frequently mentioned as occurring at northern sites, and red spruce (P. rubens) at sites farther south, along with balsam fir, tamarack, and eastern hemlock (Tsuga canadensis) (Peterson 1988).

Forbush (1927) and Griscom and Snyder (1955) mentioned that in southern New England, pitch pine (Pinus rigida) habitats, including pine barrens, are preferred for nesting. Nesting occurs in swamps and open woods or small clearings where fire, flooding or timber harvesting have left standing dead trees (Forbush 1927). High elevation spruce-fir forests are used in the mountains of Virginia and North Carolina (Bailey 1913, Potter et al. 1980).

Nests are placed most often in conifers (Harrison 1978, 1979), on horizontal limbs from two to 15 m from the ground (Harrison 1979, Peck and James 1987). In Ontario, nests were found in black and white spruce (Picea glauca) (14 nests), jack pine (Pinus banksiana) (two nests), and balsam fir (one nest) (Peck and James 1987). Adirondack nests were built on an outer branch from 7.6-13.7 m high in balsam fir or spruce (Peterson 1988). Even though the nest is bulky, it is well concealed and rather difficult to find.

NON-BREEDING: Includes a variety of forest, woodland, and open situations with scattered trees, especially where tall dead snags are present (AOU 1983). Primary habitat is mature, evergreen montane forest (Altman 1997). Migrants in Costa Rica occur almost anywhere, in exposed snags and open branches; in winter mostly around edges and clearings, or broken canopy of highland forest and semi-open areas (Stiles and Skutch 1989).

Non-Migrant: No. All populations of this species make significant seasonal migrations.

Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

Locally Migrant: Yes. At least some populations of this species make annual migrations of over 200 km.

Olive-sided flycatchers make the longest migrations of any flycatcher nesting in North America. They arrive in nesting areas usually in May (or sometimes as late as early June). Spring arrivals appear during the second and third weeks of May in Vermont (Fichtel 1985) and even into June in neighboring New York (Bull 1974, Peterson 1988). Most depart the northeastern United States by mid-September. They are present in Alaska from the middle of May to early September (Kessel and Gibson 1978); mean arrival date for males in Fairbanks for 1995 and 1996 was 24-26 May (range 11 May-8 June), with females arriving 7-9 days later (range 22 May - 10 June; Wright 1997).

Migrants move regularly through most of the western U.S. and Middle America, less commonly in the eastern U.S., casually along the southern Atlantic coast and in peninsular Florida (AOU 1983), although Duncan (1988) found this species to be a rare, but regular, fall migrant in extreme northwest Florida. Possibly because of their dependence upon flying insects as prey, these birds arrive rather late on their breeding grounds from South America.

Migrants move through Costa Rica late August-late October and mid-March to early June (Stiles and Skutch 1989). Individuals often return to the same wintering area in successive years.

Comments: Forages primarily by hovering or sallying forth, concentrating on prey available via aerial attack. Generally launches these aerial attacks from a high, exposed perch atop a tree or snag. Like others in the flycatching guild, this bird is a passive searcher, looking for easy to find prey, but is also an active pursuer, attacking prey difficult to capture (Eckhardt 1979, Terres 1980). The diet is made up almost entirely of flying insects, and this bird has a special fondness for wild honeybees and other Hymenoptera (Beal 1912, Forbush 1927, Bent 1942, Terres 1980). During breeding season in Central Alaska, most frequently preyed upon yellow-jacket wasps (Vespulla spp) and dragonflies (Odonata, Sympetrum spp and others) (Wright in Altman and Sallabanks 2000).

Note: For many non-migratory species, occurrences are roughly equivalent to populations.

Estimated Number of Occurrences: 81 to >300

Comments: This species is represented by a large number of occurrences.

10,000 to >1,000,000 individuals

Comments: Total population estimated at 1,200,000, but suspected inaccurate (Rosenberg 2004a and b). Greatest densities occur in the Sierra Nevada, where 9.28 per Breeding Bird Survey (BBS) route are recorded on average (1966-2003; Sauer et al. 2004). Over the entire BBS survey area in North America, an average of 1.22 are recorded per route per year (Sauer et al. 2004).

Considered an indicator species of the coniferous forest biome throughout North America, although occasionally found in mixed deciduous/coniferous forests. Usually territorial in non-breeding areas (Stiles and Skutch 1989) and may display strong year-to-year site fidelity on breeding (Wright 1997) and wintering grounds (Marshall 1988, Altman 1997). In a study of 16 insectivorous, aerially-foraging neotropical flycatcher species, including the olive-sided flycatcher, that are seasonally sympatric in the humid Caribbean lowlands of Costa Rica, Sherry (1984) found that migrants are more opportunistic while wintering than the syntopic year-round residents.

Maximum longevity: 7.1 years (wild)

Courtship includes territorial fights between males, and males pursuing females across the canopies of coniferous forests. Courtship continues for at least two weeks until nest sites are chosen and pairing is completed (Bent 1942).

Reported egg dates include the following (see Wright 199, Altman 1999): late May to early July in California; late May through late July in northwestern Oregon; early June to mid-July in western Washington; late May through mid-July in British Columbia; mid-June through mid-July in Colorado; early June through early July in Massachusetts; mid-June through late July in Maine; early to late June in Ontario and New York; mid-June through early July in Nova Scotia. In central Alaska, first clutches were initiated from late May through mid-June.

Clutch size is usually 3-4. Incubation, by the female, lasts 14-19 days. Young leave the nest 15-23 days after hatching. Most fledging occurs in early to mid July, though young from renesting efforts may fledge late in July. In New York State records of unfledged juveniles on 22 June and fledglings from 10-24 July, and in Oregon most young fledged in 19-21 days (Altman 1999). In Alaska fledging recorded at 19-20 days after hatching of first egg for 2 nests (Wright 1997). Fledglings depend on parents for up to about a week after leaving the nest.

Renesting following loss of first clutch is common, second clutches may be smaller, three or even two eggs.

The following is a representative barcode sequence, the centroid of all available sequences for this species.

There are 4 barcode sequences available from BOLD and GenBank.  Below is a sequence of the barcode region Cytochrome oxidase subunit 1 (COI or COX1) from a member of the species.  See the BOLD taxonomy browser for more complete information about this specimen and other sequences.

Download FASTA File

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 3
Specimens with Barcodes: 4
Species With Barcodes: 1

Canada

Rounded National Status Rank: N4B - Apparently Secure

United States

Rounded National Status Rank: N4B - Apparently Secure

Year Assessed

Assessor/s

Reviewer/s

Contributor/s

Justification

History

• 2004
  Near Threatened

Rounded Global Status Rank: G4 - Apparently Secure

Reasons: Large breeding range in wooded areas of Canada, Alaska, and the western and northeastern U.S.; still secure in many areas, but a large, significant decline (a loss of 68% from 1966-2000) has occurred in recent decades, due probably to habitat changes in the breeding range and/or in migration and wintering areas.

Population

Population Trend

Global Short Term Trend: Decline of 10-30%

Comments: North American Breeding Bird Survey (BBS) data indicate declines since 1966 across much of North American range; from 1966 - 2003, population has declined by -3.5% per year based on data from 776 routes (Sauer et al. 2004); significant overall decline of -3.6%/year from 1980 to 2003 (Sauer et al. 2004). Declines are relatively similar across range, although they appear to be more severe in the central and eastern regions of the continent (Sauer et al. 2000).

Degree of Threat: Medium

Comments: Causes of decline are not well known.

WINTERING HABITAT AVAILABILITY: As a neotropical migrant that may spend only three to four months of the year on its North American breeding grounds, this flycatcher is at risk from deforestation on its wintering grounds in Central and South America. Forest land in Middle America is being cleared at a high rate (Terborgh 1980). In California, Marshall (1988) found that some forest birds breeding on Redwood Mountain in Tulare County in the 1930s were no longer present in the 1980s. Although portions of virgin giant sequoia forest within Kings Canyon National Park remained, the flycatcher had disappeared. Marshall (1988) speculated that the disappearance from suitable, unchanged habitat was caused by the destruction of corresponding forests in Central America, where these birds maintain their winter territories.

NESTING HABITAT AVAILABILITY/QUALITY: Olive-sided flycatchers prefer openings with dead standing trees; these areas are naturally found near water (mountain tarns, backwaters of lakes and rivers, beaver flows), burns (both natural and those set by aboriginal peoples), and blowdowns. Many studies in western North America conclude that this species is more abundant in some types of logged forest (especially those with suitable structural features retained) than it is in unlogged stands (Altman and Sallabanks 2000). Fichtel (1985) felt that continued logging in Vermont probably created habitat by creating openings in the forest. Hall (1983) observed that recently lumbered and burned areas supported flycatchers in West Virginia. However, the continuing increase in availability of logged forest openings is at odds with the documented overall decline in numbers of this species. Perhaps logged forest, although attractive to flycatchers, is an 'ecological trap' (Altman and Sallabanks 2000) and is actually a low quality breeding habitat. This hypothesis is supported by preliminary study in western Oregon, where nest success was substantially higher in postfire habitat than it was in several types of harvested forests (Altman and Sallabanks 2000). Fire suppression throughout the breeding range undoubtedly limits the acreage of available habitat; large areas of dense, second growth forests growing up following cutting or fires are being maintained as closed canopy forests through intensive fire control. A likely threat to habitat in the southern Appalachians is acid precipitation and insect damage. A forest dominated by dead trees would not support these flycatchers (Peterson and Fichtel 1992).

OTHER FACTORS: Pesticide applications to control blackflies, mosquitoes, or injurious forest insects could have a severe local impact upon the prey base of this flycatcher, both in North America and on its wintering grounds, but this hypothesis lacks documentation. This species apparently is a rare host to the brown-headed cowbird, with just three records of cowbird parasitism (Friedmann 1963, Terres 1980).

Major Threats

Conservation Actions

Restoration Potential: The potential for restoration of peripheral populations in urban, coastal and southern portions of its range is unknown, but may be worthy of investigation. Restoration efforts might include habitat manipulation, such as selective use of small patch clearcuts or wildfire, beaver restoration or flooding or girdling of trees where there were once historic populations or where vestigial populations remain. Retention of snags should be a consideration during timber harvesting operations in known inhabited areas. Recovery of beaver populations in the Northeast has provided breeding habitat via the creation of forest openings and greater amounts of pond shore habitat with tall, standing dead trees. Provided that beaver populations do not plummet as they once did, these habitats should persist. The potential for recovery of the population in the Northeast, assuming that declines are real, is less certain, since the real problem of breeding numbers may lie in the deforestation of the American tropics. Without addressing the problems on the wintering grounds, any recovery efforts directed solely at the breeding grounds may be too narrow to succeed (Peterson and Fichtel 1992).

Preserve Selection and Design Considerations: Large blocks of montane spruce-fir or lowland boreal forest habitat will be necessary to ensure breeding habitat. At least 20 ha may be necessary to sustain a single territorial pair. Natural processes (e.g., fire and creation of beaver impoundments) and management (e.g., small patch clearcuts) are important for maintenance of proper breeding habitat. Public ownership of these lands, or conservation easements or management agreements to protect suitable forest habitats will be necessary (Peterson and Fichtel 1992).

Management Requirements: In the northeastern U.S., known breeding areas should be managed by selective patch cutting or burning and also by retaining standing dead trees; maintaining beaver populations should result in the creation of favorable habitat conditions (Peterson and Fichtel 1992). In western North America, silvicultural practices should probably mimic natural disturbances; examples include clearcuts that leave snags and trees and selection cuts. After a fire, some standing, dead trees should be retained or some areas should be left unsalvaged. Trees to be retained should have varying heights, with some at or above the canopy of the surrounding forest (Altman 1997).

Management Research Needs: Even in Canada, where the flycatcher is considered widespread or fairly common, its distribution can be quite thin or widely scattered (Peterson and Fichtel 1992). The reason for the sparse occurrence in the far north is unknown, but lack of preferred prey, climate, or ancestral ranges may be factors. Whatever the cause, the limiting factor for the presence in the far north does not appear to be lack, loss, or destruction of habitat, although hydroelectric projects pose a possible danger. A better understanding of both the ultimate and proximate factors affecting habitat selection is needed. Site specific studies involving banding/color banding of individual birds are needed to gain information on movements, longevity, causes of mortality, and other aspects of the natural history.

A standardized wintering bird census network, which will cover a variety of habitats, elevations and disturbance regimes throughout Central and South America and the Caribbean, is urgently needed. Although the flycatcher is known to winter over a wide area, census work could clarify whether the majority of the wintering population is concentrated in a particular region. Banding studies are necessary to reveal where specific breeding populations winter. Studies of winter habitat preferences should be undertaken to identify what management approaches are necessary to sustain populations on the wintering grounds.

Future state Breeding Bird Atlases should be coordinated to take place simultaneously in all states and provinces, using a common block size and mapping system, and universal codes for breeding criteria. This effort should attempt to survey all blocks in each state or province. A scale of abundance for each species within every block should be employed, as was done in Ontario (Cadman et al. 1987).

Biological Research Needs: Even in Canada, where this species is considered widespread or fairly common, its distribution can be quite thin or widely scattered (Peterson and Fichtel 1992). The reason for the sparse occurrence in the far north is unknown. Whatever the cause, the limiting factor for the presence in the far north does not appear to be lack, loss, or destruction of habitat, although hydroelectric projects pose a possible danger. A better understanding of both the ultimate and proximate factors affecting habitat selection is needed. Site specific studies involving banding/color banding of individual birds are needed to gain information on movements, longevity, causes of mortality, and other aspects of the natural history.

A standardized wintering bird census network, which covers a variety of habitats, elevations and disturbance regimes throughout Central and South America and the Caribbean, is urgently needed. Although the flycatcher is known to winter over a wide area, census work could clarify whether the majority of the wintering population is concentrated in a particular region. Banding studies are necessary to reveal where specific breeding populations winter. Studies of winter habitat preferences should be undertaken to identify what management approaches are necessary to sustain populations on the wintering grounds.

Global Protection: Few to several (1-12) occurrences appropriately protected and managed

Comments: Many occurrences are in national, state, and provincial parks and refuges, but habitat management in such areas may not be compatible with conservation of this species.

Stewardship Overview: Nests along the edges of lakes, rivers, and beaver meadows and in open forest sites that have been cleared or burned. In northern New England and the mountains of Virginia and North Carolina, they nest in coniferous sites of spruce, fir, and hemlock, mixed with deciduous trees, while in southern New England, they nest in pine habitats. Snags are an important habitat component used for singing and feeding perches, from which they forage for insects. BBS routes since 1966 have indicated a significant annual decline of 2.6% in the eastern U.S., and approaching 6.1% across the entire North American range. Reforestation and suppression of forest fires in northern New England and loss of habitat to suburban sprawl in the Northeast are possible causes for the decline, although habitat disruption along migration routes and on their wintering grounds in the mountains of Central and South America could contribute significantly to population declines. Further information is needed on the status of wintering populations and habitat. Known breeding areas in the Northeast should be managed by selective patch cutting or burning and also by retaining standing dead trees.