Female vocalization: Part 2 

Last week’s column was about how songbirds in the tropics — birds who don’t migrate — maintain their pair bond throughout the year, and how the female partner’s singing likely plays a major role in maintaining both the pair bond and the shared defense of their breeding territory.  

Making such observations for tropical species is relatively easy because males and females typically look very different (researchers new to a location sometimes initially identify the differing sexes as two different species). But what about a local nonmigratory species, such as our common song sparrow, where the sexes appear identical? 

A song sparrow.

Liam Hutcheson | For The JOLT

The seminal research on song sparrows, including the study of whether or not females sing, was conducted from 1928 to 1937 by Margaret Morse Nice in a floodplain area near Ohio State University in Columbus, Ohio. She was one of the first people to study how birds behave rather than simply collecting and examining dead specimens and cataloging the range of their species’ distribution.  

Her study method addressed the challenge of identifying specific birds by adding individual color-coded bands to the standard U.S. Fish and Wildlife Service aluminum leg bands. During banding, when live birds were in-hand, she measured wing length (males typically have longer wings) and weight (males typically are heavier). The data, plus the presence of a seasonal naked brood patch where the feathers of females are worn off by rubbing against eggs and nestlings, allowed her to document behavioral differences between the two sexes.  

Her primary research interests were to document the full range of behaviors of these common species. Almost in passing, she identified that females were singing, noting that they sang primarily in the early spring prior to nest building and egg laying. But as far as she could determine the actual notes, or the song’s vocabulary, females’ songs were mostly the same as male song sparrows. 

Her long-term study was, and still is, world renowned, and the Margaret Morse Nice Prize is a prestigious recognition awarded annually for important contributions to ornithological field work.  

It is a reasonable inference from this and other studies that females of many of our songbird species sing at some time of the year. But reliable documentation is rare, either because of the sex identification problem or simply because the dominance of male song hinders the ear from paying attention to possible variations.   

In North America, including our own Thurston County, many of the songbird species migrate each year from southern wintering sites back to their breeding territories. During migrations, pair bonds between mates usually are not maintained. Thus, for most of our songbirds, even some that do not migrate, a new breeding pair is often established and territory acquired each spring. Of course, the mating songs of males are a critical part of this seasonal activity. 

However, based on extensive fieldwork over decades, ornithologists have documented some excellent examples of female singing. The northern cardinal is a common songbird in eastern and central North America. The crested male is bright red, sings a cheery song and, for many folks in the east, it is that one first bird that started a lifetime of birding. (Liam’s photo is from Arizona; cardinals there are not a bright red like cardinals back east). 

A northern cardinal.

Liam Hutcheson | For The JOLT

Female cardinals are dull greenish, although they still exhibit a crest, and that large, bright orange bill. Female cardinals sing a totally different song than males, often from the nest. Females may use this song to "persuade" the male to remain nearby and even to feed her as she incubates eggs. Here is a video of a female northern cardinal’s nest song.

Closer to home, we can study the Bullock’s oriole, a species that occasionally nests in Thurston County, although many range maps for the species do not include our area. This spring a pair of Bullock’s orioles were singing at our Nisqually refuge, although I haven’t observed whether they actually nested.   

These are robin-sized birds that spends much of their time in trees hunting insect larvae, although they sometimes eat pollen and fruit. They are related to a large family of birds that primarily nest in tropical and sub-tropical locations. Like their tropical relatives, the sexes of this species look very different. 

A bullocks oriole.

Liam Hutcheson | For The JOLT

Male Bullock’s orioles exhibit a dramatic yellow-orange and black appearance, with striking white wing bars — unmistakable. Female orioles look very different. They’re smaller, and a dull gray with an orangish wash around their head, breast and rump. Like the males, they also have white wing bars.

A female bullocks oriole.

Liam Hutcheson | For The JOLT

The two sexes sing a very similar song. It starts with a rough scratchy note, followed by rich whistled notes. It’s a short song, only about three seconds. Males sing from trees, while females sometimes sing from the ground. 

The oriole’s nest is sack-like, woven from grasses and other fibers and suspended from a tree branch, 10-25 feet high. Sometimes we only learn about nearby breeding orioles by seeing the remains of the gourd-like nest after nest tree’s leaves have fallen.  

Careful research has documented female vocalization in a few other bird species that we find locally, including cedar waxwings, house finches, common yellowthroats and European starlings. But for many species, the answer for the female singing question is, “We don’t know for sure.”  

And that poses a nice challenge for all of us. When we hear a song, especially one that seems a little unusual, we can try to see if we can identify by sight the sex of the bird singing. This will be much easier for species like warblers, where males and females look much different. By documenting what you hear and see, you might add another paragraph to a future North American female birdsong treatise.  

George Walter is environmental program manager at the Nisqually Indian Tribe’s natural resources department; he also has a 45+ year interest in bird watching. He may be reached at george@theJOLTnews.com 

Photos for this column are provided by Liam Hutcheson, a 19-year-old Olympia area birder and avid photographer.