Female Songsters

Last November dozens of migrating white-throated sparrows took refuge in our fields and forests during the early cold and snow. Despite the weather, they sang their “poor Sam Peabody, Peabody, Peabody” song and occasionally they were joined by a singing song sparrow. Like most birdwatchers, I assumed the singers were male, but I may have been wrong.

Researchers have found that northern female songbird chicks still have a brain area for singing that has atrophied in those species where females no longer sing. Furthermore, Karan J. Odom, at Leiden University in The Netherlands and Lauryn Benedict at the Cornell Lab of Ornithology published a paper in The Auk in 2018 asking scientists and birders to spread the word that the females of most tropical and some temperate songbirds do sing. Previous work by Benedict and others found that 42% of female songbird species found in the United States and Canada and 43% of European songbirds have some song.

Odom and Benedict appended to their paper a list of the singing North American female songbirds based on information from The Birds of North America (BNA) life histories of all North American bird species. (The BNA has recently been incorporated into Birds of the World.) Currently, there are 144 species, 67 of which breed, live year-round, or migrate through Pennsylvania.

The list favors those species where females are drab-colored and males flashy, such as common yellowthroats and red-winged blackbirds, which enable observers to easily tell them apart, but there are some, such as black-capped chickadees and tufted titmice, where the sexes look alike.

Sometimes females have their own unique song while others closely resemble the males’ song. For instance, northern cardinal females sing the same “cheer, cheer, cheer” song as the males, but female red-winged blackbirds sing a rapid “btut-tut-tut” in answer to the males’ “okalees.”

Of the birds I saw at my feeders and in the forest and fields last November, 10 species have singing females—American crows, black-capped chickadees, tufted titmice, house finches, eastern towhees, fox sparrows, song sparrows, northern cardinals, dark-eyed juncos, and white-throated sparrows.

Female chickadees sing a faint “fee-a-bee,” which is lower in volume than the males’ “fee-a-bee” during breeding, but females sometimes sing “fee-a-bee” loudly throughout the rest of the year as well as the “chick-a-dee” call, according to Susan Smith, who studied black-capped chickadees for decades and wrote the BNA account.

Male and female eastern towhees call “che-wink,” and once, back in 1958, a mated female towhee in Indiana sang an “unmusical, flat, somewhat squeaky” song, V. Nolan, Jr. reported. Jon S. Greenlaw in 1971 in New York state heard a female sing “two weak, husky, flat ‘shreeeeee’ trills from high perches and then flew, followed by her mate, who was nearby, according to his BNA paper.

White-throated sparrow females sing the same song as males, but their songs are shorter and their notes less steady in pitch. Occasionally, they sing even in fall migration and during the winter, J.B. Falls and J.G. Kopachena report in the BNA.

Other BNA research pieces report that tufted titmice females sing “peter-peter” like the males do, but the females’ song is lower in pitch. Fox sparrow females also sing the same song as the males, but their song is softer and shorter than the males’ song. House finch females too sing a simplified version of the males’ song, as do female song sparrows.

Margaret Morse Nice, who studied song sparrows intensively for decades in Ohio, found that female song sparrows sing rarely, especially in response to territorial conflicts with female intruders in the spring, and she reported in 1943 that only 11 out of 200 females she observed sang. Canadian researchers in 1988 seemed to agree with Nice’s research because they found that a mere 12 of 140 females they studied in British Columbia sang.

Odom and Benedict in their paper reported that they and their colleagues have started the Female Bird Song Project at Leiden University and the Cornell Lab of Ornithology. They asked that birders, researchers, and wildlife recordists around the world listen for female bird song and deposit their observations and recordings of female songs in biological collections. They further suggested that birders could easily upload their audio recordings of singing females to the Cornell Lab’s Macaulay Library with their eBird checklists. They also gave pointers on how to write descriptions of the songs and how and where they were heard as well as the kind of video recordings participants in the Female Bird Song Project should do. Their goal is to find as many female songbird singers as possible.

They suspect that migratory behavior among many northern bird song species may make it safer for the singing males to defend territories while the females quietly go about nest-building and tending young in the few months they have on their nesting grounds.

This seemed to be proved recently on the campus of the University of California in San Diego when dark-eyed juncos there stopped migrating and then the females started singing. According to Dustin Reichard, who is studying this phenomenon, the female juncos sing to stop other females from copulating with their mates.

Another recent singing female was observed in June 2017 by Alexander Sharp, a graduate student at Ball State University. In Yellow Wood State Forest in southern Indiana where Sharp was monitoring a cerulean warbler nest in a tree 50 feet above the ground, the male was singing. He also heard a higher-pitched but repetitive “zeet” like a male bird’s song coming from the nest. He thought, since it was mid-June, that it was a nestling learning the male’s song.

But the next day, when he returned to the nest with other university researchers, they heard the same different call. However, when the “singer” peered over the nest edge, they were shocked to see that it was a female.

Then, less than a week later, they found a second female singing a “truer song that was long, rhythmic, and complex.” She sang only while foraging with her mate, while the first singer seemed to be singing an encore to her mate’s song.

Even though Ball State University scientists had been studying cerulean warblers for 20 years, this was the first time they had recorded female bird song in this species. They not only wrote about their discovery in The Wilson Journal of Ornithology in June 2019, they made excellent video recordings of the female singers and put them up on YouTube where I enjoyed watching and listening to the female songsters.

Ornithologists are also looking more closely at female songbird behavior. Ornithologist Bridget Stutchbury, working in northwestern Pennsylvania, discovered that hooded warbler females were leaving their nesting territories every three hours to search for extra-pair copulations, she told writer Kathi Borgmann in her excellent article in Living Bird “The Forgotten Female Now a Focus of Study,” upending her belief and those of other ornithologists that only males look for extra-pair copulations. Stutchbury also found that female blue-headed vireos left their nesting territory after their eggs hatched to look for males. Then, when their young fledged, they left with another male and their first mates cared for the fledglings alone.

Ruth Bennett, formerly a doctoral student at Cornell and now a postdoctoral researcher at the Smithsonian Migratory Bird Center, studies Neotropical migratory songbirds on their wintering grounds. She has discovered that in two-thirds of the species she studies, the males and females use different habitats. This means that when conserving land for such species, most notably the rapidly declining golden-winged warblers that Bennett specialized in, both habitats must be preserved.

Kenn Kaufman, an extraordinary birder and the author of several books about birds as well as bird guides, recently wrote an article entitled “I Became a Better Birder When I Stopped Focusing on the Males” for Audubon online back in 2018. “Females pass judgment on whether a male’s display attracts them,” he wrote. “They also defend territories, usually build the nest, often travel farther than males and move to more distant wintering areas.” He adds that a female, “represents her species as well as the male could, and probably has more interesting behavior.”

As scientists continue their research on female bird song and behavior, all of us who are fascinated by birds will look forward to their findings. And I, like Kaufman, will spend more time observing our female songbirds.