Tree Swallow
Tachycineta bicolor
Tree Swallows are common and recognizable birds in Oregon, often seen gracefully swooping over open areas near water. While both sexes share the general characteristics of the species, there are subtle differences in plumage that can help distinguish males from females, especially during the breeding season.
General Appearance (Both Sexes):
Size and Shape: Streamlined small songbirds, about 4.7-5.9 inches (12-15 cm) in length, with long, pointed wings and a short, squared or slightly notched tail. They have tiny, flat bills.
Color Pattern: They have iridescent upperparts and pristine white undersides (chin, breast, and belly). Blackish flight feathers and a thin black eye mask are also characteristic.
Flight: Highly acrobatic fliers, often seen catching insects in mid-air or skimming over water. They tend to glide more than other swallows.
Habitat: Found in open areas near water, such as fields, wetlands, marshes, and shorelines, especially where tree cavities or nest boxes are available for nesting.
Male Tree Swallows:
Plumage: Adult males typically exhibit a more vibrant and distinct metallic blue-green iridescence on their upperparts (back, head, and wings). This blue can appear quite brilliant in good lighting.
Breast: They have a stark, pure white breast and belly, with a sharp line of demarcation between the dark upperparts and white underparts.
Female Tree Swallows:
Plumage: Adult females are generally duller than males, with more brown mixed into their iridescent upperparts. While some older or "after-second-year" (ASY) females can be nearly as blue as males, many will show noticeable brownish tones, particularly on the head and back.
First-Year Females (Second-Year, SY): These younger females are notably different, often appearing mostly brownish above with only hints of blue-green iridescence. They may also show a weak, blurry gray-brown breast band, which juveniles also exhibit.
Other Differentiating Factors (Often Requiring Close Observation or Handling):
Brood Patch (Females): During the nesting season, females develop a brood patch – a bare patch of skin on their underside that helps transfer heat directly to their eggs and chicks. This is a definitive sign of a female.
Cloacal Protuberance (Males): Males in breeding condition may exhibit a swollen cloaca (cloacal protuberance).
General Appearance (Both Sexes):
Size and Shape: Streamlined small songbirds, about 4.7-5.9 inches (12-15 cm) in length, with long, pointed wings and a short, squared or slightly notched tail. They have tiny, flat bills.
Color Pattern: They have iridescent upperparts and pristine white undersides (chin, breast, and belly). Blackish flight feathers and a thin black eye mask are also characteristic.
Flight: Highly acrobatic fliers, often seen catching insects in mid-air or skimming over water. They tend to glide more than other swallows.
Habitat: Found in open areas near water, such as fields, wetlands, marshes, and shorelines, especially where tree cavities or nest boxes are available for nesting.
Male Tree Swallows:
Plumage: Adult males typically exhibit a more vibrant and distinct metallic blue-green iridescence on their upperparts (back, head, and wings). This blue can appear quite brilliant in good lighting.
Breast: They have a stark, pure white breast and belly, with a sharp line of demarcation between the dark upperparts and white underparts.
Female Tree Swallows:
Plumage: Adult females are generally duller than males, with more brown mixed into their iridescent upperparts. While some older or "after-second-year" (ASY) females can be nearly as blue as males, many will show noticeable brownish tones, particularly on the head and back.
First-Year Females (Second-Year, SY): These younger females are notably different, often appearing mostly brownish above with only hints of blue-green iridescence. They may also show a weak, blurry gray-brown breast band, which juveniles also exhibit.
Other Differentiating Factors (Often Requiring Close Observation or Handling):
Brood Patch (Females): During the nesting season, females develop a brood patch – a bare patch of skin on their underside that helps transfer heat directly to their eggs and chicks. This is a definitive sign of a female.
Cloacal Protuberance (Males): Males in breeding condition may exhibit a swollen cloaca (cloacal protuberance).