Brains of birds synchronize when they sing duets

Date:  June 12, 2019

Source:  Max-Planck-Gesellschaft

When a male or female white-browed sparrow-weaver begins its song, its partner joins in at a certain time. They duet with each other by singing in turn and precisely in tune. A team led by researchers from the Max Planck Institute for Ornithology in Seewiesen used mobile transmitters to simultaneously record neural and acoustic signals from pairs of birds singing duets in their natural habitat. They found that the nerve cell activity in the brain of the singing bird changes and synchronizes with its partner when the partner begins to sing. The brains of both animals then essentially function as one, which leads to the perfect duet.

White-browed sparrow-weavers (Plocepasser mahali) live together in small groups in trees in southern and eastern Africa. Each bird has a roosting nest with an entrance and an exit. The dominant pair will have a breeding nest which is easily recognisable by the fact that one passage is closed to prevent eggs from falling out. In addition to the dominant pair, there are up to eight other birds in the group that help build nests and raise the young. All group members defend their territory against rival groups through duets of the dominant pair and choruses together with the helpers.

White-browed sparrow-weavers are one of the few bird species that sing in duet. It was assumed that some cognitive coordination between individuals was required to synchronise the syllables in the duet, however the underlying neuronal mechanisms of such coordination were unknown.

Continued

Hitting the right notes

Biologist studied how songbirds in remote areas of Costa Rica learn new duets when paired with a new mate 

Date: January 30, 2017 
Source: University of Miami

Karla Rivera-Cáceres, a University of Miami biology graduate student, plays a harmonious duet of singing wrens from a recording she captured out in the field during a recent trip to Costa Rica.

"The song sounds like one bird but if you listen closely, it's a male and female wren singing a duet in perfect unison," said Rivera-Cáceres.

Along with songbirds, many animal species perform duets, an uncommon vocal interaction that can occur between mated or unmated species, such as frogs and crickets. But the coupled wrens Rivera-Cáceres recorded in Costa Rica sing alternating phrases, or parts, of the song so smoothly and with such complexity and fast tempo that the untrained ear may hear just a single bird.

For years, Rivera-Cáceres studied the "duet codes" (non-random association of song types) of paired wrens and wondered if the ability to perform their complex and seamless music was a skill the birds were born with or learned during juvenile or adult stages of life. Now, after two months of intense listening in Costa Rica, she knows that they can learn new songs with new partners, even as adults. She says the newly learned songs are akin to prenuptial agreements.



continued