Female red-winged blackbirds can be very challenging to identify and often confuse even experienced birders because of their strong resemblance to marsh-loving sparrows. To properly identify these females, these clues are essential:
Bill: Like the male, the female red-winged blackbird has a sharply triangular black bill. Depending on the angle of viewing, it can seem that the bill slopes at the same angle as the forehead, without a severe dip at the base where the bill and head join. Her bill is typically longer than a sparrow's bill, and more sharply pointed.
Facial Colors: There is a distinct yellowish tinge to a female red-winged blackbird's face, particularly on the lores, chin, and throat. The extent of the yellow can vary but provides a good clue to this bird's identity.
Facial Markings: A pale eyebrow, dark eye line, and dark malar stripes are distinctive markings on the female's face.
Shoulders: While the female red-winged blackbird lacks the bold scapulars of the male, she may show a tinge of red or rust on the shoulder and throughout the upperparts. This can be very difficult to see, however, particularly at a distance.
Underparts: The female's underparts are buff but are heavily and thickly streaked with dark brown or black. Unlike most sparrows or finches, the heavy streaking continues all the way to the undertail coverts, without fading or narrowing.
Tail: The medium-long tail is slightly rounded but may show a faint central notch depending on posture and how the tail is held.
Habitat: These blackbirds prefer marshy, reedy areas, particularly where cattails are abundant to provide a supply of soft nesting material. They will often cling to a single stalk or may straddle between two when perched. Females often perch lower and are more hidden than males, who may perch right at the top of a stalk.
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