Behavior

Walking, Running, Hopping, Climbing, etc.

Often walks on the ground or among branches in dense thickets, unlike Mourning Warbler (Geothlypis philadelphia) and MacGillivray's Warbler (Geothlypis tolmiei), which hop (215 Ficken, M. S., and R. W. Ficken (1962). The comparative ethology of the wood-warblers: a review. Living Bird 1:103–122. Close ). Movements are very bouncy; the tail is raised and lowered rapidly, reminiscent of wrens and Spotted Sandpiper (Actitis macularius) (JP). Territorial males stride along horizontal limbs very much like an Ovenbird (Seiurus aurocapilla) (F. Gill and D. O'Brien, personal communication).

Flight

Flapping flight is similar to Mourning Warbler and MacGillivray's Warbler; it flies deftly among branches above ground (JP).

Swimming and Diving

Not known to occur.

Preening, Head-Scratching, Stretching, Sunbathing, Bathing, Anting, etc.

Information needed. Preening not described in detail, but see video below.

Sleeping, Roosting

Information needed.

Daily Time Budget

Information needed.

Physical and Communicative Interactions

Information needed.

Territorial Behavior

Information needed. Male is highly territorial during summer and establishes and defends breeding territory (216 Sadler, T. S. (1976). Alberta birds, 1961–1970, with particular reference to migration. Occasional Paper no. 1. Provincial Museum of Alberta, Edmonton, AB, Canada. Close , JP). Territory size ranged from 0.24 ha in open-canopy spruce forest to 0.48 ha in closed-canopy spruce forest in Minnesota (based on data from Niemi and Hanowski [217 Niemi, G. J., and J. M. Hanowski (1984). Effects of a transmission line on bird populations in the Red Lake peatland, northern Minnesota. Auk 101:487–498. Close ]). The average home range size for males (3.05 ha) was significantly larger than that for females (1.29 ha) (75 Blais, V. (2014). Caractérisation et utilisation de l'habitat par la Paruline à gorge grise (Oporornis agilis) dans les pinèdes grises du Lac-Saint-Jean, Québec. M.S. thesis, Université du Québec à Chicoutimi, Chicoutimi, QC, Canada. Close ).

Mating System and Operational Sex Ratio

Information needed.

Courtship, Copulation, and Pair Bond

Information needed.

Extra-Pair Mating Behavior/Paternity

Information needed.

Brood Parasitism of Conspecifics

Not known to occur.

Brood Parasitism of Other Species

Not known to occur.

Degree of Sociality

The Connecticut Warbler is not considered a social species, but families may join together to form small flocks of up to 25 birds before fall migration (7 Bent, A. C. (1953). Life Histories of North American Wood Warblers. Bulletin of the United States National Museum 203. Close ). It is reportedly solitary on overwintering grounds (197 Meyer de Schauensee, R., and W. H. Phelps (1978). A Guide to the Birds of Venezuela. Princeton University Press, Princeton, NJ, USA. Close , 10 Curson, J., D. Quinn, and D. Beadle (1994). Warblers of the Americas: an Identification Guide. Houghton Mifflin Company, New York, NY, USA. Close ), but pairs have been noted in fall migration (e.g., see video in Self-Maintenance).

Nonpredatory Interspecific Interactions

Information needed. Kells (83 Kells, W. L. (1889). Nesting of the Connecticut Warbler. Oologist 14:49–51. Close ) described a territorial fight with a Red-eyed Vireo (Vireo olivaceus) in Ontario in which the Connecticut Warbler sang and uttered call notes while being chased by the vireo in low thickets. It is known to participate in multi-species feeding flocks on the breeding grounds from mid to late summer in the southern boreal mixed-wood forest of Saskatchewan (218 Hobson, K. A., and S. Van Wilgenburg (2006). Composition and timing of postbreeding multispecies feeding flocks of boreal forest passerines in western Canada. Wilson Journal of Ornithology 118(2):164–172. Close ). During fall migration, it was infrequently observed within mixed-species flocks of fall migrant songbirds in central Pennsylvania (219 Rodewald, P. G., and M. C. Brittingham (2002). Habitat use and behavior of mixed species landbird flocks during fall migration. Wilson Bulletin 114:87–98. Close ), and was observed feeding with Blackpoll Warbler (Setophaga striata), 20 m above ground in large willows (Salix) (111 Forbush, E. H., and J. B. May (1939). Natural History of the Birds of Eastern and Central North America. Houghton Mifflin Company, Boston, Massachusetts, USA. Close ). During migration in Puerto Rico, it was observed foraging for caterpillars (Noctuidae) with Shiny Cowbird (Molothrus bonariensis), Greater Antillean Grackle (Quiscalus niger), Yellow-shouldered Blackbird (Agelaius xanthomus), Yellow-billed Cuckoo (Coccyzus americanus), and Venezuelan Troupial (Icterus icterus). Tropical residents were reported to be dominant over Connecticut Warbler on overwintering grounds (198 Keast, A. (1980). Spatial relationships between migratory parulid warblers and their ecological counterparts in the neotropics. In Migrant Birds in the Neotropics: Ecology, Behaviour, Distribution, and Conservation (A. Keast and E. S. Morton, Editors). Smithsonian Institution Press, Washington, DC, USA. pp. 109–132. Close ).

Kinds of Predators

Information needed. In Quebec, 2 of 7 nests were depredated by unidentified predators, but an Eastern Chipmunk (Tamaias striatus) was suspected to be responsible for at least one of the nests (27 Saulnier, M-C. (2011). Biologie de la reproduction de la Paruline à gorge grise (Oporornis agilis) dans les pinèdes grises du Lac-Saint-Jean, Canada. M.S. thesis, Université du Québec à Chicoutimi, Chicoutimi, QC, Canada. Close ). A first-fall (Formative Plumage) male was predated by a domestic cat (Felis catus) in early November from southern Maine (144 Perlut, N. (2019). Latest documented fall record of Oporornis agilis (Connecticut Warbler) in North America. Northeastern Naturalist 26:12–13. Close ).

Manner of Predation

Information needed.

Response to Predators

The female is very secretive near its nest, skulking low in underbrush in the presence of predators or intruders (7 Bent, A. C. (1953). Life Histories of North American Wood Warblers. Bulletin of the United States National Museum 203. Close ). Both parents respond to intruders near the nest with harsh scolding witch notes; parents may react directly to the presence of a predator or may be summoned by the distress notes of fledglings and nestlings (83 Kells, W. L. (1889). Nesting of the Connecticut Warbler. Oologist 14:49–51. Close ). The female scolds intruders from perches 6 m high in trees near the nest; scolding may last 30 min (213 Huff, N. L. (1929). The nest and habits of the Connecticut Warbler in Minnesota. Auk 46:455–465. Close ).

Adults feign injury to distract predators from the nest (10 Curson, J., D. Quinn, and D. Beadle (1994). Warblers of the Americas: an Identification Guide. Houghton Mifflin Company, New York, NY, USA. Close ); a bird holds its wings up and stretched out from the body. Running is another distraction display near the nest. It is very wary of potential predators; it may retreat from exposed perches to several different perches in thick foliage to observe intruders (7 Bent, A. C. (1953). Life Histories of North American Wood Warblers. Bulletin of the United States National Museum 203. Close ).

A fall migrant was attracted to a recording of Black-capped Chickadee (Poecile atricapillus) individuals mobbing an owl at the Parker River National Wildlife Refuge in Newburyport, Massachusetts, leading Ralph et al. (220 Ralph, C. J., J. Rousseau, L. L. Long, and S. L. Miller (2012). Landbird monitoring at northeastern National Wildlife Refuges 2008–2010: Results and recommendations for future monitoring. Submitted to U.S. Fish and Wildlife Service, LaCrosse, WI, in fulfillment of Cooperative Agreement No. 301818J152. Close ) to conclude that the Connecticut Warbler is able to detect predators by recognizing anti-predator vocalizations of chickadees.