Nothing better demonstrates the axiom “familiarity breeds contempt” than the pigeon. Pigeons have remarkable navigation skills and are extremely powerful fliers. They perform courtship dances and mate for life (as much as any bird does, anyway). Both parents care for the chicks. They have an adaptation—”crop milk,” a substance that they produce and feed to their chicks, similar in concept (if not physiology) to how we mammals produce milk for our babies—that allows them to breed in habitats most birds could never hope to raise a family in. They thrive in urban environments, making them probably the first and most-often seen wild animal of many city-dwellers. They recognize each other as individuals. They are smarter than you think.
Concerning their usefulness to humans, pigeons are easily raised in captivity and edible. They have been bred into many domestic varieties with strange attributes, such as the propensity to roll over in mid-air. Charles Darwin studied domestic pigeons extensively, and they contributed to the formation of his theory of evolution by natural selection. They have been important message carriers in wartime; pigeons have received the Dickin Medal—like the Medal of Honor, but for animals—32 times, more than any other species (dogs are closing in with 31 medals).
And they come in sparkly colors with crazy eyes.
“Rats with wings,” people say—patently untrue: you can’t get plague from pigeons. “Dirty,” people call them; as if it isn’t our dirt they are wearing, and yet thriving anyhow.
Most of our familiar birds court potential mates only at specific times of year. This is why spring is such a melodious season in many places: the male songbirds are all singing for their mates. Male pigeons, however, seem to court all the time. It’s below freezing and snowing? Why, what a great time to puff up and bow and coo at the ladies!
Well… yeah. What’s your point?
This seems strange because we expect courting birds to breed soon after a successful courtship. Yet pigeons court in weather that seems like it would be terrible for breeding. What are these pigeons up to? Are the males really trying to convince the females to lay eggs in mid-winter?
The birds of paradise have been getting a lot of attention lately for the elaborate courtship dances of their males, and nobody is going to argue that they don’t deserve it. But it isn’t all “males dance, females judge” in the avian world. The displays of male birds of paradise reflect high reproductive skew: a few males mate a lot, a lot of males never mate. It’s worth it to the males to devote incredible amounts of energy and resources to attracting females, because if they’re successful, they may sire many chicks. They can afford to spend all that energy and resources on crazy feathers and tricky dance moves because that’s all they have to do, parent-wise: they don’t help females build the nest or incubate the egg or raise the chicks.
Male Greater Bird-of-paradise. Photo by Ivan Teage.
But birds are diverse; the birds of paradise reflect just one point on a spectrum of mating systems. Near the other end are birds with low reproductive skew. Males of these species look pretty much like the females, and they contribute about equally to parental duties. You might expect that these species would lack dances the same way they lack meter-long curlicue tailfeathers, but some of them have dances every bit as formalized and elaborate as the birds of paradise. The difference is that these dances are duets.
Laysan Albatross pair performing courtship dance. Photo by Michael Lusk.
(Note on videos: I know clicking on videos is annoying. But it’s worth watching the videos in this post, I promise.)