Population decline has all Hawaii’s songbirds singing the same tune

Rapid population declines of songbirds may reduce overall song diversity and complexity, and increase similarity between learned songs, so all songbirds end up singing the same song

by GrrlScientist for Forbes | @GrrlScientist

NOTE: This piece was a Forbes Editor’s pick.

Historically abundant and widespread on the island of Kaua‘i, the population of Kaua‘i ‘amakihi (Chlorodrepanis stejnegeri), like other native Hawaiian forest birds, is now largely restricted to high elevation forest habitats, thanks to climate change and to avian malaria’s growing presence at lower elevations. (Credit: Lucas Behnke, Kaua‘i Forest Bird Recovery Project / USGS / Public domain)

Not long ago, I shared a report that the total population of migratory birds in North America has declined by roughly 3 billion individuals since 1970 (here). Three billion is a lot of birds. But how has that massive population decline across so many species affected social behaviors that are culturally transmitted?

The truth is that people don’t often think about avian culture, but birds, like people, do have their own cultures. For example, when we listen to songbirds, we are hearing their culture in their song. Songbirds learn their songs and calls from their family and neighbors. These sounds are critically important for social behaviors associated with same-sex interactions and for group cohesion. Further, female songbirds rely on song complexity and diversity as honest indications of the health and genetic quality of a prospective mate.

Considering how crucial song is to songbird culture, it may surprise you to learn that detailed studies of the acoustic…