Connecticut Warbler Oporornis agilis


Taxonomic source(s)
del Hoyo, J., Collar, N.J., Christie, D.A., Elliott, A., Fishpool, L.D.C., Boesman, P. and Kirwan, G.M. 2016. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Volume 2: Passerines. Lynx Edicions and BirdLife International, Barcelona, Spain and Cambridge, UK.
SACC. 2005 and updates. A classification of the bird species of South America. Available at: #

IUCN Red list criteria met and history
Red List criteria met
Critically Endangered Endangered Vulnerable
- - -

Red List history
Year Category Criteria
2021 Least Concern
2016 Least Concern
2012 Least Concern
2009 Least Concern
2008 Least Concern
2004 Least Concern
2000 Lower Risk/Least Concern
1994 Lower Risk/Least Concern
1988 Lower Risk/Least Concern
Species attributes

Migratory status full migrant Forest dependency Medium
Land mass type Average mass 13 g

Estimate Data quality
Extent of Occurrence breeding/resident (km2) 2,500,000 medium
Extent of Occurrence non-breeding (km2) 4,810,000 medium
Number of locations -
Severely Fragmented -
Population and trend
Value Data quality Derivation Year of estimate
No. of mature individuals 1800000 poor estimated 2019
Population trend Decreasing estimated -
Decline (3 years/1 generation past) - - -
Decline (5 years/1 generation past) - - -
Decline (10 years/1 generation past) - - -
Decline (10 years/3 generation future) - - -
Decline (10 years/3 generation past and future) - - -
Number of subpopulations - - -
Percentage in largest subpopulation - - -

Population justification: The global population is estimated to number 1.8 million mature individuals (Partners in Flight 2019).

Trend justification: The species is undergoing a large, significant decline (Partners in Flight 2019; Rosenberg et al. 2019). Short-term trends suggest a decline of 15% over the past ten years, though this value is non-significant (Pardieck et al. 2018).

Country/territory distribution
Country/Territory Occurrence status Presence Resident Breeding Non-breeding Passage
Antigua and Barbuda V Extant Yes
Aruba (to Netherlands) N Extant Yes
Bahamas V Extant Yes
Barbados V Extant Yes
Belize V Extant Yes
Bermuda (to UK) N Extant Yes
Bolivia N Extant Yes
Bonaire, Sint Eustatius and Saba (to Netherlands) N Extant Yes
Brazil N Extant Yes
Canada N Extant Yes Yes
Colombia N Extant Yes
Costa Rica V Extant
Cuba V Extant Yes
Curaçao (to Netherlands) N Extant Yes
Dominica V Extant Yes
Dominican Republic N Extant Yes
Ecuador V Extant Yes
French Guiana V Extant
French Polynesia V Extant
Guadeloupe (to France) V Extant Yes
Haiti N Extant Yes
Honduras V Extant
Jamaica V Extant Yes
Martinique (to France) V Extant Yes
Mexico V Extant
Montserrat (to UK) V Extant Yes
Panama V Extant
Peru N Extant Yes
Puerto Rico (to USA) V Extant Yes
St Kitts and Nevis V Extant Yes
St Lucia V Extant Yes
St Vincent and the Grenadines V Extant Yes
Turks and Caicos Islands (to UK) V Extant Yes
USA N Extant Yes Yes
Venezuela N Extant Yes
Virgin Islands (to USA) V Extant Yes

Important Bird and Biodiversity Areas (IBA)
Country/Territory IBA Name

Habitats & altitude
Habitat (level 1) Habitat (level 2) Importance Occurrence
Forest Subtropical/Tropical Moist Lowland major non-breeding
Forest Temperate suitable breeding
Wetlands (inland) Shrub Dominated Wetlands major breeding
Altitude   Occasional altitudinal limits  

Recommended citation
BirdLife International (2023) Species factsheet: Oporornis agilis. Downloaded from on 08/02/2023. Recommended citation for factsheets for more than one species: BirdLife International (2023) IUCN Red List for birds. Downloaded from on 08/02/2023.