Connecticut Warbler

The Connecticut Warbler, Oporornis agilis, is a modestly sized member of the New World warbler family. Adults typically reach a length of 13–15 cm (5.1–5.9 in) with a wingspan of 22–23 cm (8.7–9.1 in). Upon fledging, they weigh approximately 10 g (0.35 oz), growing to an average adult weight of 15 g (0.53 oz). Prior to migration, they may increase their weight to a substantial 25 g (0.88 oz) to endure the arduous journey. Exhibiting olive upperparts and light yellow underparts, they possess a light eye-ring, pink legs, a lengthy tail, and a slender, pointed bill. The male is distinguished by a grey hood, while females and immature birds are more brown with a whitish throat.

Identification Tips

When attempting to identify the Connecticut Warbler, look for the light eye-ring and the contrast between the grey hood of the male and the more subdued brown tones of the female and young. The pink legs and long tail are also key characteristics to note.

Habitat

The Connecticut Warbler favors bogs or open deciduous woods near water, particularly areas with poplar, spruce, tamarack, or aspen. These habitats are often in remote regions, making data collection challenging.

Distribution

During the breeding season, this warbler can be found in central Canada and states adjacent to the Great Lakes. It migrates to the Amazon Basin in South America for the winter.

Behaviour

Connecticut Warblers are ground foragers, often seen picking through dead leaves or hopping along branches. They exhibit a solitary nature but may form small groups during migration. Males are territorial during the breeding season, defending areas of 0.24–0.48 hectares.

Song & Calls

The song is a robust series of "cheepa-cheepa" notes, similar in pitch to the Kentucky Warbler and the Ovenbird. Its call is a nasal, raspy "witch," typically heard during the breeding season.

Breeding

Breeding begins shortly after arrival at the breeding grounds, with males singing to attract females. They produce one brood per season, nesting in thick understory for protection against predators. Eggs are creamy with chestnut and bay speckles and blotches, incubated solely by the female. Fledglings emerge in late July to August, nourished by both parents with a diet of caterpillars, larvae, moths, and berries.

Similar Species

The Connecticut Warbler might be confused with other skulking warblers, but its unique song, eye-ring, and the male's grey hood help distinguish it.

Diet and Feeding

This warbler's diet consists mainly of insects, including spiders, snails, and caterpillars, with occasional supplements of seeds and berries. They are known for their "skulking" behavior, foraging within dense, low vegetation.

Conservation status

The Connecticut Warbler is currently listed as Least Concern by the IUCN. However, certain populations are at risk, and conservation efforts are hampered by limited research. Threats include collisions with man-made structures, habitat destruction, and the effects of pesticides and power lines on their breeding grounds. Conservation plans focus on preserving woody wetlands, the preferred habitat of this species.