The bay-breasted warbler (Setophaga castanea) is a New World warbler. They breed in northern North America, specifically in Canada, into the Great Lakes region, and into northern New England.

These birds are migratory, wintering in northwest South America and southern Central America. They are very rare vagrants to western Europe.

This species is closely related to blackpoll warbler, but this species has a more southerly breeding range and a more northerly wintering area.

The summer male bay-breasted warblers are unmistakable. They have grey backs, black faces, and chestnut crowns, flanks and throats. They also boast of bright yellow neck patches, and their underparts are white. They have two white wing bars, as well.

Breeding females essentially resemble washed out versions of the male. The females are greyish above and white below, with much weaker head patterns. The females also only have chestnut markings on small flank patches, although tiny tints in their grey crowns have been observed.

Non-breeding birds have greenish heads, greenish upperparts and yellowish breasts. The yellow extends to the belly of young birds. The two white wing bars are always present in every stage of life. These birds differ from non-breeding blackpoll warblers in the absence of breast streaks.

Their breeding habitats are coniferous woodlands. Bay-breasted warblers nest 5–20 ft (1.5–6.1 m) up in conifer trees, laying 3–5 eggs in a cup-shaped nest. Incubation is 12 days. More eggs are laid in spruce budworm years.

These birds feed on insects, and the numbers of these birds vary with the abundance of the spruce budworm. These birds will also feed on berries and nectar in wintertime.

Their songs are a repetitive high-pitched si si si.
Bay-breasted Warbler
Date Location Count
2021-07-18 09:30Long Point--Backus Woods North1
2021-07-02 07:25Algonquin Provincial Park--Pog Lake Campground1
2021-07-02 08:25Algonquin Provincial Park--Big Pines Trail1
2021-06-27 09:20RN Kenauk--zone générale1
2021-07-12 07:55PN du Mt-Tremblant--Lac à l'Ours1
2021-06-26 08:30Crawford Path1
2021-07-10 12:23Pondicherry NWR, Jefferson/Whitefield1
2021-07-21 13:14RN du Boisé-des-Douze1
2021-07-03 07:47Dixville Turbines to Rte 26 via W. Branch Clear Stream Rd.2
2021-06-28 09:43Turbine access road north from W. Branch Clear Stream Rd., Millsfield/Dixville2
2021-07-19 06:14Old Speck Mountain1
2021-07-20 06:30Scott Bog Rd., Pittsburg1
2021-07-04 07:44East Inlet, Pittsburg1
2021-07-07 08:48PN du Mt-Mégantic--sommet du Mt-Mégantic1
2021-07-15 08:45PN du Mt-Mégantic--Mt St-Joseph1
2021-07-22 15:30Forêt Piché-Lemoine (sentiers de l'école Buissonnière)1
2021-06-29 07:15PN La Mauricie--Lac Normand1
2021-07-10 07:33Biscotasi Lake Provincial Park2
2021-07-22 06:00PN d'Aiguebelle--Lac Sault6
2021-07-17 06:45RF de Portneuf1
2021-07-24 09:47RN du Marais Léon-Provancher1
2021-07-12 07:15ZEC Batiscan-Neilson4
2021-07-03 11:29Parc Les Saules1
2021-07-22 08:53Cimetière Mt-Hermon2
2021-07-02 08:27South Porcupine--Bart Thompson Trail1
2021-07-01 08:15PN de la Jacques-Cartier--Sentier Les Loups1
2021-07-10 11:20PN de la Jacques-Cartier--Sentier le Scotora2
2021-07-03 09:26Borestone Mtn. Audubon Sanctuary1
2021-07-19 10:30Peaks-Kenny SP Campground1
2021-07-24 04:30PR du Massif-du-Sud2
2021-06-30 05:38Forêt Montmorency1
2021-07-02 12:05RNF du cap Tourmente--secteur La Petite Ferme1
2021-07-10 07:05PN de la Jacques-Cartier--Secteur Jumeau6
2021-07-02 13:37RNF du cap Tourmente1
2021-07-06 11:49Acadia NP--Western Mountain Rd.1
2021-07-23 13:00Pancake Bay PP1
2021-06-26 06:39Harvester Road1
2021-07-23 08:50Daicey Pond, Baxter State Park1
2021-07-13 11:45Baxter SP--Nesowadnehunk Field Campground1
2021-07-22 09:20Baxter SP--Tote Rd.1
2021-07-11 10:10Baxter SP--Hunt Trail to Treeline1
2021-07-15 08:00Baxter SP--Abol Trail2
2021-06-27 09:22Nesowadnehunk Campground1
2021-07-10 06:00Lake Superior PP--Agawa Bay Campground1
2021-07-08 08:48Isle-aux-Coudres1
2021-07-24 08:30Katahdin Woods and Waters National Monument1
2021-06-27 09:00PN des Hautes-Gorges-de-la-Rivière-Malbaie--Sentier Le Lac-Sans-Oreille13
2021-06-27 10:50PN des Hautes-Gorges-de-la-Rivière Malbaie--Sentier Les rapides2
2021-07-03 04:45PN des Hautes-Gorges-de-la-Rivière-Malbaie3
2021-06-26 07:30PN des Hautes-Gorges-de-la-Rivière-Malbaie--Sentier L'Érablière16
2021-07-02 07:40Canards Illimités, Marais St-Fulgence1
2021-07-12 06:11Parc Aventures Cap Jaseux2
2021-07-10 11:35Camping de la Batture SEBKA2
2021-06-29 05:55PN des Monts-Valin (SVP choisir des endroits plus précis)3
2021-07-04 06:10PN des Monts-Valin--Lac des Pionniers12
2021-06-26 11:12Burn Rd., Topsfield1
2021-07-05 06:35PN du Fjord-du-Saguenay (SVP choisir des endroits plus précis)2
2021-07-06 08:04Baie des Rochers2
2021-07-09 12:08Cobscook Bay SP1
2021-06-26 10:37PN du Fjord-du-Saguenay--embouchure Rivière Ste-Marguerite2
2021-07-08 13:25Pointe-aux-Alouettes1
2021-07-12 06:33Parc côtier Kiskotuk--Secteur marais du Gros-Cacouna1
2021-06-28 05:30Grève de Tadoussac1
2021-07-22 07:44Parc côtier Kiskotuk--Secteur des Roitelets1
2021-07-11 17:32Rg St-Joseph (ouest)1
2021-07-06 05:34PN du Lac-Témiscouata--Secteur Anse-à-William2
2021-07-18 07:47Rg St-Joseph (est)1
2021-06-26 10:30Brier Island--Lighthouse Rd1
2021-07-05 05:46PN du Lac-Témiscouata--Sentier Montagne-de-Chert1
2021-07-02 06:08Pointe à Boisvert1
2021-07-10 15:15PN du Bic--Secteur La Ferme-Rioux2
2021-07-08 07:53Sentier du littoral1
2021-07-04 08:28Peshekee Grade3
2021-07-02 07:08Tourbière, Pointe-au-Père1
2021-07-05 08:51Parc de la rivière Mitis2
2021-06-30 09:15Jardins de Métis1
2021-07-23 07:32Middleton Sewage Treatment Plant1
2021-07-13 12:18Fundy National Park--Caribou Plain Trail1
2021-07-08 07:23Mont Blanc7
2021-07-19 09:25Cape Split Trail2
2021-07-04 06:39Sentier du Mont Nicol-Albert3
2021-07-03 11:58Sentier pédestre L'Éperlan1
2021-06-27 08:39Blomidon Provincial Park3
2021-07-21 07:16PR du Mt-St-Joseph1
2021-07-04 06:26Baie des Capucins2
2021-07-17 15:30Hurkett Cove CA2
2021-06-27 11:07Sackville--Walker Road Trails1
2021-06-26 14:15Sentier de la rivière St-Siméon1
2021-07-21 10:00PN de la Gaspésie--Mont Albert6
2021-07-02 12:49Domaine des chutes du ruisseau Creux2
2021-07-06 10:00PN de la Gaspésie--Sentier Mont Albert
2021-07-18 15:15PN de la Gaspésie--Camping/Refuges du Mt-Albert2
2021-07-07 11:49PN de la Gaspésie--Sentier du Lac-aux-Américains
2021-07-16 12:54PN de la Gaspésie--Secteur Lac aux Américains2
2021-07-02 11:15PN de la Gaspésie--Sentier du Mont Xalibu1
2021-06-27 07:26Myra Road Trail1
2021-07-17 07:39PN de la Gaspésie--Secteur Mont Jacques-Cartier2
2021-07-06 09:28Gunflint Trail--Moose Viewing Trail2
2021-07-19 08:30Sentiers ski de fond Rapido1
2021-07-13 18:03Mt-Blanc6
2021-07-13 11:31PN Forillon--Sentier La Taïga1
2021-07-04 12:52PN Forillon--Penouille3
2021-07-13 09:03PN de l'Île-Bonaventure-et-du-Rocher-Percé1
2021-07-18 15:29Pointe St-Pierre--Sentier de la Pointe Verte1
2021-06-29 18:00PN Forillon--Sentier La Chute1
2021-07-17 16:48PN Forillon--Sentier La Vallée2
2021-07-23 11:46PN Forillon--Sentier du Mont St-Alban5
2021-07-12 12:38PN Forillon--Sentier Les Graves1
2021-07-10 15:15PN Forillon--Sentier Le Castor2
2021-06-29 09:20Chutes Manitou1
2021-06-30 07:10Anse aux Fraises1
2021-06-27 10:35Grotte à la Patate1
2021-06-29 10:40PN d'Anticosti--Canyon Observation2
2021-07-17 12:53PN d'Anticosti--Secteur Baie de la Tour1
2021-07-02 13:36Cape Breton Highlands NP--Bog Trail1
2021-07-05 07:11Spruce Islands Provincial Park1
2021-07-18 10:22GMNP--Visitor Centre2
2021-07-11 07:03Forteau--Brook marsh1
2021-07-11 15:35Prince Albert NP--Waskesiu2
2021-06-26 06:15Prince Albert NP--Mud Creek Trail1
2021-07-22 19:14Prince Albert NP--Narrows Road1
2021-06-26 18:32Prince Albert NP--Treebeard Trail1
2021-07-01 11:13Sir Winston Churchill Provincial Park3
2021-07-07 06:28Beatton Provincial Park1