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Olive-sided flycatcher (Contopus cooperi) COSEWIC assessment and status report: chapter 11

Technical Summary

Contopus cooperi (Nuttall, 1831)

Olive-sided Flycatcher – Moucherolle à côtés olive

Range of Occurrence in Canada:
YT, NT, BC, AB, SK, MB, ON, QC, NB, NS, PE, NL

Extent and Area Information

Extent of occurrence (EO) (km²):
ca. 8 million km²
Specify trend in EO:
Apparently stable
Are there extreme fluctuations in EO?
No
Area of occupancy (AO) (km²)
Based on population estimate of 225,000 pairs X
territory size of 20 ha:
ca. 45,000 km²
Specify trend in AO
Data from Ontario Breeding Bird Atlas:
Declined by 7% in Ontario from 1985 to 2005
Are there extreme fluctuations in AO?
No
Number of known or inferred current locations:
Not applicable
Specify trend in #
Are there extreme fluctuations in number of locations?
Specify trend in area, extent or quality of habitat:
Unknown

Population Information

Generation time (average age of parents in the population):
Unknown; probably about 3 years.
Number of mature individuals [calculated from BBS data by
P. Blancher]:
ca. 450,000
Total population trend:
Declining
% decline over the last/next 10 years or 3 generations.
From BBS data (1996-2006):
29% decline over 10 years, 79% decline 1968-2006 (38 years)
Are there extreme fluctuations in number of mature
individuals?
No
Is the total population severely fragmented?
No
Specify trend in number of populations
Are there extreme fluctuations in number of populations?
List populations with number of mature individuals in each:

Threats (actual or imminent threats to populations or habitats)

Habitat loss or degradation on both the wintering and breeding grounds may be key factors. While this species uses harvested forest habitats, some studies indicate nesting success is significantly lower there. Declining insect populations may be important as well; other aerial insectivore bird species have shown similar population declines.

Rescue Effect (immigration from an outside source)

Status of outside population(s)?
USA:
(according to BBS data, US population declined by 74% between 1966 and 2005).
Declining
Is immigration known or possible?
Possible
Would immigrants be adapted to survive in Canada?
Yes
Is there sufficient habitat for immigrants in Canada?
Apparently
Is rescue from outside populations likely?
No

Quantitative Analysis

Current Status

COSEWIC:
Threatened (2007)
IUCN Red List:
Near Threatened.

Status and Reasons for Designation

Status:
Threatened
Alpha-numeric code:

Does not strictly meet any of the criteria, but assessed as Threatened because of a 79% decline from 1968 to 2006, a 29% decline since 1996, and because there is no evidence that the decline has ceased.

Reasons for Designation:

This songbird has shown a widespread and consistent population decline over the last 30 years; the Canadian population is estimated to have declined by 79% from 1968 to 2006 and 29% from 1996 to 2006. The causes of this decline are uncertain.

Applicability of Criteria

Criterion A: (Declining Total Population): Comes very close to meeting Threatened A2b using Canadian Breeding Bird Survey data (29% decline over last 10 years).

Criterion B: (Small Distribution, and Decline or Fluctuation): Range too large.

Criterion C: (Small Total Population Size and Decline): Population too large.

Criterion D: (Very Small Population or Restricted Distribution): Population and range too large.

Criterion E: (Quantitative Analysis): Not done.

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