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Innovative use of videos aids study of songbird communication

Interviewer: Can you talk a bit about the innovative procedures that you developed in this particular research?

Adrian O'Loghlen: Well, from a technical point of view, there wasn't really a lot of innovation because what we did is we basically took off the shelf webcams and took a flat screen computer monitor and the experiment was just built around just that set equipment. But, where we did have to get creative was actually finding a way to record cowbirds singing to a camera. That actually is quite difficult because when cowbirds sing and display to each other, they get really close together, within inches of each other and direct the sound directly at the other individual. So, what we have to do is figure out a way of how we could get a cowbird to sing to a camera in the same way that it would sing to a female, for example. And how we solved this was, we put a male and a female in small cages and put the cages side-by-side. We put a web cam in between the two cages with the lens pointing at the mail and we set this up in such a way that when the male sang to the female, he ended up seeing directly into the camera, so we've managed to capture a female's perspective of a male singing to the camera.

Stephen Rothstein: Taking this a step further, after we were able to get really good detailed video recordings of the male song and also the body gestures - the wing spread display that accompanies the song, we then wanted to look at how females respond to this. We have done many experiments in the past assessing how females respond to the sound alone, which many birds have - and that's something that's been studied in many bird species. We also wanted to see if all of these movements and gestures that the males carry out are important to the females, so we had to have some way of combining the audio and the visual signals together and that was done with a new type of chamber, in which females can reside for short periods when we play the stimuli back to them. But we also had to get the females used to not just sitting on a perch and waiting to hear a sound, but they also had to get used to the fact that a video screen would all of a sudden turn on. And one of the critical things there was habituating them to the video screen, the fact that it would turn on, so we actually showed them some neutral video images of other females just moving around - just to get them used to seeing a video image. And eventually, they became very habituated to the video screen when they were put in the chamber actually just seemed to sit there and wait for it to go on and then of course we can play back the things were especially interested in - both the sound and the video combined in various ways.

Interviewer: Why is the study of bird songs such a major focus of research among so many different scientific disciplines?

Stephen Rothstein: Well, song and songbirds is one of the best animal models, perhaps the best animal model we have for vocal learning. Songbirds have some attributes that make them very similar to people in terms of their development of their vocalizations - just like people can learn languages earlier, more easily early in life - there's a sensitive window of time, birds show the same exact phenomenon. In fact, in many species there's just a short period of several months when birds can only learn their species song. In cowbirds that window seems to extend for about a year or a little over a year, so there's that sensitive period. The other thing that really makes songbirds an appealing model for the study of learning, especially vocal learning is that it's so critical to human behavior. Yet, if we look at our closest relatives, the higher primates, the great apes, they don't show this same phenomenon. They have very little in the way of learned vocalizations. It's the songbirds that actually show the closest system of learning to human language in the animal kingdom, really. There are some mammals that do learn their vocalizations, but it's not other primates. It's things like whales and some other mammals.

Interviewer: What was the most surprising discovery in your latest studies of the singing behavior of the cowbirds?

Stephen Rothstein: I think the thing that many people will find surprising is the fact that what we saw the song spread display that the male does simultaneous with the audio, the song itself, is that this is done at a much more intense fashion when it's done directly to a male than when it's directed to a female. That's a really critical thing about this species song and most songbirds, is that the same audio signal is used to - for females - to make males more appealing and it's used in courtship, but it's also directed to males and there the signal is aggressive. So, really a critical question in all of this research is how does the same audio signal have all these different messages? And one thing that we've found is that the song spread display that accompanies the cowbird song is done at different intensities. For males and for females and the surprising thing for many people is that it's much more intense when it's directed to a male than when it's directed to a female. And that may be surprising to a lot of other animal behaviorists because usually we think that males are trying to show off and do the most extreme actions possible to try to impress a female, but that's not what's happening here with the cowbird.

Interviewer: What about the future? What's next for your studies?

Adrian O'Loghlen: Well, we're going to continue using these audio-visual playback procedures that we've developed to study how females - what it is about males that females find attractive about the way they look and the way they behave. One of the questions, for example, we're going to be asking is do females find older males more attractive than younger males? Because the older males and younger males differ in their physical appearance. We'll also be looking at questions relating to what Steve was just talking about - the use of these displays, these song displays as aggressive signals, so we'll be looking at questions relating to how males use the intensity of their display, for example, when they're interacting aggressively with another male.

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