American redstarts (Setophaga ruticilla) are tuneful woodland birds, seen in migration passage across most of the United States. Males have bold black and orange coloring, with females a less noteworthy gray and pale yellow. But is their plumage the only aspect in which female American redstarts differ from males? Let’s take a look at their behavior and nesting habits and find out.
Female American redstarts are medium-sized members of the warbler family, and are active woodland birds, known for their acrobatic, showy displays among the branches while foraging for insects. Females are gray, white and yellow, unlike the more distinctive black and orange males.
Male American redstarts are vocal birds with a repertoire of high-pitched variable songs. In contrast, females are quieter but can be heard to call during courtship or in response to a threat to the territory.
In the field, females and first-year males look alike from a distance, sharing the same gray and yellow coloring, with young males not developing their full adult glossy black plumage until their second year.
Other telltale behavior also will help you spot the differences between male and female American redstarts, so please keep reading if you’re interested in learning more.
American Redstart (female), perched on a branch
Adult male and female American restarts are unalike in appearance and both have clear markings that make them relatively easy to distinguish from each other and from other similar bird species.
Male American redstarts are mostly black with orange patches on their wings and tail. Females have similar markings, but are a more subdued shade of light gray and pale yellow in contrast.
First year males are similar in coloring to females and do not develop their rich black and orange plumage until they reach their second year.
Female American Redstart
Male American Redstart
Female American redstarts are medium-sized warblers, with a long tail that frequently flicks and fans out when foraging for food.
In contrast to the striking black and orange plumage seen on males of the species, females are mainly gray, yellow and white. They have light gray faces, lightening to a whitish chin, throat, breast and underparts.
The upperparts and tail of female American redstarts are an olive-greenish gray, with distinct pale yellow patches on the wings, flanks, and tail. They have wide, flat, gray bills, and their legs are dark gray-brown.
Close up of a perched American Redstart female
Male and female American redstarts are roughly the same size, measuring between 11 cm to 13 cm (4.3 in to 5.1 in) in body length.
Typical mass for the species falls in the range of 6 g to 9 g (0.2 oz to 0.3 oz), with females recorded to be marginally heavier than males during the breeding season and males outweighing females by a matter of milligrams in the winter.
Pair of American Redstarts during nesting
Females tend to arrive on breeding grounds after males, and pairs form within their first day or two of their arrival. Females advertise their availability by visiting the territory of potential males, and quite often pair with the first male they approach.
Females display their colorful tail patches while being chased by the male, and instead of showing aggression or leaving the territory, females will circle the male and return to a nearby spot.
Male American redstarts are noted to be more territorial than females, exhibiting high levels of aggression when securing a breeding territory.
It’s also not uncommon for males to be polygynous, maintaining a second territory in a different location with a new mate once his primary mate is incubating her eggs. This behavior may lead to an excess of young, unmated males, as older males, even when already paired, take precedence in pairing up with available females.
Close up of a female American Redstart
Male American redstarts are known for their repertoire of up to 11 different high-pitched songs. Females are rarely heard to sing, and when they do, the sound is relatively weak and the meaning is unclear.
Female American redstarts do call in certain circumstances, including courtship (a harsh ‘chip’ sound) and defending a nest threatened by humans or other potential predators, when a high-pitched ‘titi’ sound can be heard.
Male American Redstarts are the most vocal
Potential nest sites are visited by American redstart pairs, with the male showing the female around his territory, and the female examining the different options before selecting her favorite.
Females take sole charge of nest construction, with the process taking up to 7 days.
Once complete, laying begins and the female incubates the eggs alone. Males occasionally bring food to the nest for their mate, and this behavior is more commonly seen in colder regions. Females will not usually leave their eggs unattended for more than 10 minutes at a time.
Once young hatch, males and females share care of the nestlings, with feeding duties divided between the two relatively evenly. Once the young have fledged, it’s common for American redstart pairs to divide their brood into two distinct groups, with each taking responsibility for protecting and feeding only their designated “half”.
Diet of male and female American redstarts is identical, with insects being the core component. Some evidence suggests that females forage at lower altitudes than males, finding prey on foliage around their nest site. Males are observed to catch more flies and other insects mid-air.
Female American Redstart singing
With their gray and yellow plumage, female American redstarts may be easily confused with several other similar-sized warblers, including the Magnolia warbler, Virginia’s warbler and yellow-rumped warbler. Magnolia warblers have a yellow belly and underparts in contrast to the whiter plumage of female American redstarts.
Female Virginia’s warblers have a similar gray head to female American redstarts, but have a white eye ring. They also lack the yellow wing and tail patches seen on American restart females, and have some yellow coloring on their breast.
Although female yellow-rumped warblers have similar yellow patches on their flanks, they can be told apart from female American redstarts as they have yellow rumps and a yellow patch on their throat.
Female American Redstart close up
Although a female American redstart incubates alone, males play a role in feeding young both before and after fledging. If her mate is lost, females will attempt to raise young alone, but fledging may be delayed by several days.
After fledging it’s common for a brood to be divided between parent birds, with each taking sole responsibility for care of their particular half. So theoretically, females do systematically raise young alone, albeit just half of a typical brood.
Female American redstarts are a mixture of light and dark gray, with flashes of yellow on their upper flanks, wings and tail. Their belly, breast, throat and chin are white.
Calls are used by female American redstarts to communicate with a mate during courtship, and when greeting the arrival of a visiting mate during incubation. High-pitched alarm calls are also made by females on the nest if an intruder approaches.
The song of male American redstarts is heard most during the breeding season, but they remain quite vocal throughout the rest of the year. Females, on the other hand, are barely heard, and when they do sing, their voices are weak and the purpose of their song is not clear.
Although female American redstarts do show some degree of intolerance of intruders on their patch, they are by no means as territorial or aggressive as males of the species, which do have a reputation for being rather feisty and intolerant of other male American redstarts paying so much as a fleeting visit to their patch.
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