Plants and Animals
Oporornis agilis Connecticut warbler
Key Characteristics
A large warbler measuring 5-6 in (13-15 cm) in length. Olive above and yellow beneath, males brighter than females. Males have a blue-grey hood, while females have a grey-brown hood. All individuals have a bold, complete, white eye-ring. Spends most of its time on or near the ground and walks rather than hops.
Status and Rank
US Status: No Status/Not Listed
State Status: SC - Special Concern (rare or uncertain; not legally protected)
Global Rank: G4G5 - Rank is uncertain, ranging from apparently secure to secure
State Rank: S3 - Vulnerable
Occurrences
| County | Number of Occurrences | Year Last Observed |
|---|
Information is summarized from MNFI's database of rare species and community occurrences. Data may not reflect true distribution since much of the state has not been thoroughly surveyed.
Habitat
In the Great Lakes area, Connecticut warblers breed in upland and lowland conifer forests. They have affinity for black spruce and tamarack but can also be found in jack pine barens. Connecticut warblers require a well-developed shrub layer for nesting and are more likely to be found in larger patches of suitable habitat.
Natural Community Types
For each species, lists of natural communities were derived from review of the nearly 6,500 element occurrences in the MNFI database, in addition to herbarium label data for some taxa. In most cases, at least one specimen record exists for each listed natural community. For certain taxa, especially poorly collected or extirpated species of prairie and savanna habitats, natural community lists were derived from inferences from collection sites and habitat preferences in immediately adjacent states (particularly Indiana and Illinois). Natural communities are not listed for those species documented only from altered or ruderal habitats in Michigan, especially for taxa that occur in a variety of habitats outside of the state.
Natural communities are not listed in order of frequency of occurrence, but are rather derived from the full set of natural communities, organized by Ecological Group. In many cases, the general habitat descriptions should provide greater clarity and direction to the surveyor. In future versions of the Rare Species Explorer, we hope to incorporate natural community fidelity ranks for each taxon.
Management Recommendations
Protect and maintain lowland coniferous, jack pine, and aspen forest. Within occupied habitats, maintain and promote well-developed shrub and herbaceous layers and maintain mossy ground cover. Low intensity prescribed fire to maintain jack pine and the shrub layer may benefit this species. Replacing red pine with jack pine in treated areas may increase suitable habitat. Low retention harvesting (10%) may be beneficial.
Management Avoidance Period: From first week of June to first week of August
Active Period
Migration from fourth week of August to third week of October
Migration from fourth week of April to second week of June
Nesting from first week of June to first week of August
Survey Methods
A standard survey methodology for warblers is to systematically place observation points every ¼ mile throughout suitable habitat. At each observation point an observer listens for 10 minutes and records all birds observed and/or heard within 50 meters and beyond 50 meters of the survey point. Another simple method is to simply walk along a transect through suitable habitat during the breeding season, recording individuals observed and/or heard. The use of taped playback calls in appropriate habitat can also be an effective method for surveys although they should be used with discretion to avoid disturbing birds needlessly. All surveys should be conducted between sunrise and 10:30 am during good to fair weather conditions (e.g., low winds, dry).
Visual, listen for song
Survey Period: From first week of June to first week of July
Time of Day: Morning (sunrise)
References
Survey References
- Bibby, C.J., N.D. Burgess, and D.A. Hill. 1992. Bird Census Techniques. Academic Press, New York.
Technical References
- Ng, A. M. B., and A. P. Kortenhoven. 2025. Species Abstract for Oporornis agilis (Connecticut warbler). Michigan Natural Features Inventory, Lansing, Michigan, USA.