From Bitch: What does it mean to be female? (2022), by Lucy Cooke:
“For the last thirty years Naomi Langmore, professor of evolutionary ecology at the Australian National University, has been studying the complex vocalizations of female songbirds and fighting to get their voices heard. She’s part of a pioneering group of scientists who, tired of dogmatic androcentric definitions of birdsong, took it upon themselves to trawl through all the available scientific data to demonstrate that, far from being dumb, 71 per cent of female songbirds sing.
What’s more, their calls are worth listening to; what these avian divas have to say challenges fundamental assumptions about Darwin’s theory of sexual selection.
According to Langmore, the century and a half of oversight isn’t simply another casualty of old-school sexist bias. This prejudice is mostly geographic in origin. Songbirds, or passerines, are the largest avian order, comprising 60 per cent of all known birds. The defining features of the six-thousand-plus species are highly developed toes that enable them to perch and a muscular larynx-like structure – the syrinx – that bestows their vocal dexterity. Beyond that, evolution freestyled to create dainty tits, soaring swifts and frivolous birds of paradise, amongst myriad other forms. Together the 140 or so families represent one of the most diverse vertebrate orders, thanks to an explosive evolutionary radiation in recent geographical times that’s enabled passerines to take over the world. The only continent where you won’t hear birds sing is Antarctica.
Despite their global domination, songbirds have traditionally been studied in Europe and North America. These mostly migratory species are from a recently evolved suborder called the Passeridae in which females are, indeed, more vocally subdued. Those females that do sing, such as the European robin, tend to lack sexual dimorphism and so are easily mistaken for noisy males.
It’s a totally different story in Langmore’s native Australia and across the tropics. Had Darwin lived down under he would have heard dozens of bush and backyard species, from the chainsaw-mimicking lyrebirds to delicate fairy wrens, making just as much noise as the males…”
Julia Upton 