The 25th of September, 2024, brought a very rare warbler species for New Brunswick and a couple of good birders together near Black’s Harbour. The warbler, a Connecticut Warbler (Oporornis agilis), is so rarely found in NB that it excited birders immediately. The few sightings we have in NB are primarily in the fall. Along with several undocumented sightings beginning in 1932 one was photographed from Machias Seal Island in 1966 and two were banded on Kent Island in 1972. Most sightings have been from southwestern NB but a singing male was seen in the north at Eel River Bar in 1974.
The Connecticut Warbler breeds across North America in a relatively narrow band from east central British Columbia across Alberta, Saskatchewan, Manitoba to southern Ontario and south into northern parts of Minnesota, Wisconsin and Michigan. This species winters in north central South America. It has different spring and fall migration routes. In the spring it travels northward up the central flyway and in the fall it travels south usually in an area bounded by the Great Lakes and New England and then southward to the Caribbean islands and on to South America. Those birds that migrate further east fly over the Atlantic Ocean to South America.
Connecticut Warbler Showing Remnant of Hood [Photo by Mark Morse]
The main identifying features of this species are its bold eyering, its unusual shape, and its unusual walking behaviour. Pete Donne says that its ‘distinctive, round, white, no-nonsense, complete, staring, eyering makes all other characteristics almost superfluous.’ Wow, it would be interesting to hear from those lucky enough to see this individual if the eyering jumped out at them like this! See the white eyering on this bird in the two photos above.
The Connecticut Warbler is a big, bulky oddly-shaped warbler (15 cm long). It is described as oddly shaped because its head appears slim, tail short and it has a pot belly. This doesn’t sound like a sleek warbler! This species is monotypic with the spring plumage showing a bluish-gray hood covering the head and throat and upper breast, olive-green upperparts, yellow underparts and olive-green on the sides. The spring female is similar except the hood is brownish and she may have a buffy or whitish throat. In the fall both genders are duller and the white eyering may be broken behind the eye. First season birds are similar to the female. This warbler shows very long undertail coverts and no wing bars. Note the undertail coverts extend more than halfway to the end of the tail.
The photos in this blog are from the actual fall-plumage bird see at Black’s Harbour. In the photos above, note the eyering, the olive-green dorsum and yellow underparts, and the pink legs. The remnants of the hood can be clearly seen. In the photo shown below note the olive on the sides and the extension of the yellow to include the vent. The bird appears large and chunky with a short tail extension and a long primary extension (not shown in the photos).
[Photo by Mark Morse]
The behaviour of the Connecticut Warbler makes it hard to see. It is a ground-loving species and it walks with an odd gait, somewhat like the Ovenbird. It bounces and tail-bobs as it walks along. It often sits motionless for long periods. Its ground-loving behaviour can help distinguish it from the Mourning Warbler which prefers hopping around the branches of trees. While the Mourning Warbler sits across the branch in ‘normal’ fashion, the Connecticut will sit along the branch, 90º from the ‘normal’ perching behaviour. When the Connecticut Warbler is nervous it will move its head in odd jerks and it will reverse its position on the branch in 180º hops.
The Connecticut Warbler is a loner. It likes to forage in thick tangles close to the ground. This causes it to be mistaken sometimes for a thrush. Its preferred habitat is wet moist woodlands, spruce-tamarack forest and bogs, muskeg and poplar thickets. The song of this warbler is loud and rich. It consists of halting phrases which gain in volume and tempo. It is described variously but one example is ‘chuckity-chuckity-chuckity-chuck’. It sounds a bit like the Common Yellowthroat.
Similar species that we need to distinguish the Connecticut Warbler from are the MacGillivray’s Warbler and the Mourning Warbler. The former would be extremely rare here but we do see the Mourning Warbler. The Mourning Warbler lacks an eyering and the breeding male plumage shows black on the lower part of the hood as it extends onto the breast. The occasional Mourning Warbler shows an eyering but they are a smaller warbler, their undertail coverts are shorter, they have brighter underparts, and they lack the peculiar gait. Occasionally one might confuse a dull female Yellow Warbler or a Common Yellowthroat with the Connecticut Warbler. But both species are smaller and have a yellowish throat.
The Connecticut Warbler nests on the ground. The nest is made of bark pieces and grass and is lined with fine plant materials and mammal hair. Two to five white eggs marked with brown and lavender are laid and incubated 11 to 12 days by the female. This species feeds on insects, spiders, berries, seeds and snails. The young leave the nest by late July and both adults feed them.
Despite the name of the Connecticut Warbler, it is rarely seen in Connecticut. It was named by Alexander Wilson who first saw this species in Connecticut. This species is difficult for birders to find. It is a much sought-after species. It is easy to mistakenly try to turn other species into this one but it is said that it is difficult to second-guess a real Connecticut Warbler!