Giving a whole new meaning to “tweeting,” two UCSB scientists have used video recordings to document how auditory and visual displays of communication by male birds can affect the responses of their female counterparts.
Ecology, Evolution and Marine Biology research scientist Adrian O’Loghlen and zoology professor Stephen Rothstein conducted the first study in history to successfully use video footage to show that female brown-headed cowbirds respond to the visual elements of a male cowbird’s song and dance. By placing the birds in two separate cages near a webcam, the scientists were able to record the nuances in the birds’ audio and visual presentations.
According to O’Loghlen, the new technological findings stress the significance of visual communication in mating.
“This is the kind of breakthrough that we’ve been trying to develop,” O’Loghlen said in a press release. “We’re able to communicate visual information to the female cowbirds. It’s really good evidence that they’re extracting visual information. The potential for this research is mind-blowing.”
Consistent with most studies, the researchers found that only the male birds sang. While scientists already knew that the birds sing to show aggression toward other males and courtship to females, the study’s video footage revealed a subtle differences between the two songs.
“Until the work we’ve done recently, it looked like it was the same signal to the male and female,” Rothstein said in a press release. “Just the receiver of the information knew it had different meanings. But what we found is that there is some difference in how the song is presented to a male by a male, and the way a male presents a song to a female.”
When displaying aggression toward other males, the videos showed that the birds spread their wings and bowed deeply. However, the motions in the presentations toward females were consistently less extreme. After recording the displays, the researchers then used LCD monitors to show the recordings of male-to-female songs to female birds, who reacted strongly to the footage.
According to O’Loghlen, the females would freeze in copulation solicitation displays upon seeing the videos.
“She’s actually saying, ‘Whoa, that’s really sexy, you can mate with me,’” O’Loghlen said in a press release.
Because of the similarities in the developmental stages of both birdsong and human speech, O’Loghlen said research into bird communication could hold important biological clues about human development.
“There are many parallels to language development in humans,” O’Loghlen said in a press release. “The birds go through various stages that are very similar. Babies babble. Birds babble. Babies memorize a lot of sounds before they ever try to produce them. Birds do the same.”
Additionally, Rothstein, who has studied birds for a majority of his 38-year career at UCSB, concluded that birdsong research may potentially shed more light on the process of cultural evolution.
“It has a parallel with genetic evolution, where the structure within a species changes over time,” Rothstein said in a press release. “Our lives are totally different than they were over a hundred years ago because of cultural changes, yet we have undergone little or no genetic evolution. The best example of cultural evolution within species in non-human animals is with these birds and their different song dialects. They clearly have evolved different cultures in different places.”
Rothstein said the parallels between bird and human development create an interesting common ground for the two species.
“Birds are both visual and auditory creatures,” Rothstein said. “It’s one of the reasons bird-watching is so popular, because people and birds see the world in the same way — through sight and sound.”