[DANCE] — [Ed] It may look wacky, it may look funny, but these behaviors didn’t evolve to be wacky and funny. They evolved through sexual selection by female choice to be precise choreographed things that these males do time and time again, day after day throughout their whole lives, specifically to be attractive to females during courtship. — [Interviewer] Which birds-of-paradise dance? — [Ed] At some level you can say all of them do something that could be interpreted as a dance. But if you just hold up a pose and stand there static, while there could be the static-holding dance, I typically think of that not as a dance but just a pose, and dance is where there’s more motion involved or intricate steps. Parotias are good examples of dance, not probably coincidental that they’re also the ones that dance on the ground like they’re on a dance floor. They look a little bit more like the way humans dance. When you see something like a greater bird-of-paradise, or one of the other paradiaeidaes bouncing around, up and down a branch and turning and pivoting and putting its head down and letting its cascade of feathers fall over its back, I mean that’s clearly a dance. And even something like the wilson’s or magnificent bird-of-paradise, where they’re just doing most of their displays on a small little sapling and there’s not a lot of lateral motion. There’s just movement up and down the branch, but there are more parts of it that are definitely more dance-like and less just presentation than others, especially right before actual mating; where there’s a little bit of motion this way, motion that way, motion this way, motion that way. Small series of things that happen. I would call that a pre-mating dance, even in that species. One things that a lot of people don’t realize about bird-of-paradise is that they’re not born doing those courtship displays exactly the way that we see them and admire them as adults. For the first few years of their life they probably don’t do anything that looks like a courtship display at all. And then at some point in time the young males, they start going through transitions in their bodies and behaviors where they start doing rudimentary versions of it. They’re hardwired from their genes, through their DNA to start doing courtship displays. But yet they don’t have the feathers yet and they only do rudimentary versions of them. But they begin to essentially practice them. And they practice them in isolation by themselves. They watch adult males perform the real deal to actual females and mating. And then yet practice to each other. One young male plays the role of the female the other one plays the role of the male. This one practices his display and this one pretends like it’s watching and then they switch. And this goes on for hours at a time during the day, for months out of the year, for many years, in many cases three-four years of this kind of practice behavior. And so only then, when they transitioned into their first adult plumage do the start doing this thing that we recognize as the full courtship display. So it’s this incredible combination of learning behavior and feedback between practicing with your own body movement and the acquisition of your costume, if you will, and being able to then put those motions into place in the way that they’re suppose to be; and the genetics behind that, both the behavior and the feathers. I don’t think a lot of people have an appreciation of that’s what’s going on in these birds. When we’re thinking about traits in birds-of-paradise, or at least the different traits in males that females are keying into and have selected on in the past, it’s easy to think of the feather traits, the unusual ornaments, the shapes, the colors. But I don’t think everybody really thinks of behavior as being a trait just like any other, when in fact it is. These complex behaviors are parts of complex sequences of events that are genetic in their origin and yet they also have this component of being refined and learned, so they have an environmental component. But the thing is that’s true for all of those traits. The feathers don’t always grow the exact same way that they’re genetically wired to because the food wasn’t available in the same way that year. There’s an environmental component to those things that are easy to understand as traits as well. — [Interviewer] So dance is not just practiced but it’s actually a genetic adaptation, and literally there are genes for ballerina dance or waggle? There’s a gene for waggle? — [Ed] [laughs] I definitely don’t think we can simplify it to the point where there is a gene for a waggle or a gene for a psychedelic smiley face dance. But there are thousands or hundreds or dozens, some number of genes that are involved in producing those things and they are heritable. And that when a female bird of paradise selects a male for some component of his display behavior, that his sons inherit that behavior and some component of it. And they will be more likely to be more similar in that behavior to their father than to other males, just like they will be in plumage or shape of their feathers. [Explore more at birdsofparadiseproject.org, youtube.com/LabofOrnithology]