Well, all our family members are busy digesting excellent Thanksgiving meals back in the States today while my own prediction came true for the two of us: peanut butter on dry bread with a slug of water and an orange to finish it off! But I am thankful, nevertheless. Sara and I are having a true adventure this year in Australia and I can imagine a point a decade from now in which we wouldn’t want to thrash around in the bush like this, chasing bowerbirds. But for now, it’s great, even if we have to miss out on family ties half way around the world.
People ask us why we chose to study bowerbirds. Well, there are many cool reasons, but one of the more obvious ones is that it is relatively easy to conduct simple, non-invasive behavioral experiments on them that potentially yield lots of data. And science needs data like fish need water!
Males build bowers and collect all sorts of decorations to adorn them with and therefore, if you can find a male’s bower you can be assured that he will visit it many times each day to do his work. This means that not only can we set up cameras and be guaranteed to capture stunning video of birds in action, but we know where to set up our behavioral choice experiments expecting that the bird will come in within an hour and make his selections, thus providing us with data to analyze.
But it’s not just about the data. These birds truly are unique and their types are only found in Australia and New Guinea. I believe there are about 20 species spread over those two land masses and they all build courtship arenas of one form or another. It’s definitely a genetic trait that evolved millions of years ago and as species split off from the ancestral form, the trait evolved with each species as well. And that’s why the satin bowerbird collects blue decorations while the great bowerbird collects red, greens, and white!
Very few animals in nature build things besides some type of basic nest or den for raising young. Exceptions include beavers which build dams, termites which build city-like structures, a weird fish that makes a courtship sunburst in the sand, and of course, bowerbirds. Well, humans bifold stuff too but I’ll keep them out of this list. When watching them do their bower-building work it’s easy to anthropomorphize and say things like, “They are thinking about levers and how to move those sticks around” or something like, “If he doesn’t get his bower rebuilt in time, the girls are going to find another party to attend”. On occasion, when we have come to check up on a particular bird, we have felt sorry for him, for reasons spelled out below. We try and keep the feelings out of science, but after watching these guys operate it is hard to not show some emotional connection with the birds.
I think our best example of this is of a bird that we call Green and Black. He is a nearly-mature male, probably about 6 years old, having yet to molt into entirely black plumage. Obviously, he is still learning how to be a bowerbird. I say this because of what we know has happened at his site. Let me give a short list.
1. Most of the blue decorations that he brings to his bower get stolen by mature males that have set up their own bowers nearby.
2. When he builds his bower, half the time he doesn’t seem to know what kind of sticks to use or where to place them (we know this from video recordings).
3. He often has younger males mucking about his bower, rearranging things; perhaps he should chase them out?
4. When he does display, we have seen him displaying to some of these same young males! Maybe he is just practicing.
5. During the two months that we have been following his progress, he has had his bower pulled apart and flattened by rival males on at least 3 occasions that we know of.
These birds are not pets and we only witness a tiny fraction of their lives, but we do feel that they have personalities and differences. For example, one bird we call the Puddey bowerbird, seems to have a short fuse with some of our decoration experiments. He will pull out all four colored leaves at once and dunk them well off the mat in a pile. To us, with our pea-brains, it seems that he isn’t even bothering to look at or think about what he is doing! Another bird has his bower along side a dirt road on a flat ledge approximately 5′ above the road surface. It is super easy to see him from the car and as a result, he is used to people and often doesn’t fly away until you get quite close. Our Emerald Beach bird has had a bower in the same spot for years and has had easy access to so much blue plastic trash that it seems it may not be all that valuable to him anymore. He reminds me of a person who lives in a house with a gorgeous view of the sunset, but they stop even looking at the sunset and would rather be inside watching television!
In closing, I’ll attach a couple of cool pictures that we have taken! Happy Thanksgiving to all :-)