When spring arrives, wild turkeys begin their courtship routine. Flocks congregate in lawns and fields, sometimes in the middle of roads. Males fluff their iridescent feathers, fan their tails, and drag their wings along the ground as they compete for breeding rights. Their faces and necks turn dazzling shades of blue and red.
Once elusive and rare birds of America’s forests, these heaviest birds (chickens and their relatives) have made their way into cities. Wild turkeys live in the residential areas around my home in Madison, Wisconsin.
A few years ago, I became so fascinated by their elaborate courtship displays that I started photographing them, and as I learned, there’s a lot more going on than meets the eye.
First of all, turkeys flock together. Males are called toms and live in groups with their siblings for life. Biologist and photographer Dr. Alan Krakauer studied this as a graduate student at the University of California, Berkeley. He found that the males in the herd ranged from full siblings to half-siblings. These fraternal groups work together to court females, or females, and ward off competing males.
But to their surprise, only the dominant males mated and produced offspring, while their subordinate siblings served as “wingmen,” “bodyguards” and “back-up dancers,” in Krakauer’s colorful descriptions. “They have what I would consider a support role,” he said.
Dr. Krakauer found that despite the possibility of lifelong celibacy, the wingmen benefited from the arrangement — at least by the raw calculations of evolutionary theory. On average, dominant males with wingmen give birth to seven offspring in a season, while solo males give birth to less than one. Because the males were closely related, these seven offspring contained more of the wingman’s genes than if they had produced a single chick on their own.
“This cooperation seems particularly useful because they help their brother obtain many more females than either of them would have obtained on their own,” Dr. Krakauer explained. “It seems to have come as a surprise to people at the time.”
Anyone with siblings knows the vicissitudes of sibling relationships. During mating season, brothers typically cooperate, but at other times of the year, fierce battles break out for position. Turkeys are formidable weapons: their large bodies, powerful wings, and spurred legs. I once witnessed a fight so fierce that saliva flew everywhere, like a boxer receiving a knockout punch.
Males are aggressive towards each other but not towards females and do not force them to mate despite being twice the size of their mate. So while the males may roam free, the females ultimately choose their own mates. The female is picky about her partner and she knows what she wants. It’s a male with a long snood.
The snood is a finger-like fleshy protrusion on the top of a turkey’s beak. Animals contract and relax muscles and blood vessels in their head and neck, causing changes in the length and color of their organs. The tom, wearing a long red snood, attracts the attention of the hens like a fly to honey. To their credit, however, the hens manage to be coy about it.
Dr. Richard Buchholz, a professor at the University of Mississippi, has spent his career studying wild turkeys. He has looked at the role that various male ornaments, including the snood, caruncles (pebble-like protrusions on the head and neck), skullcap (thick skin on the top of the head), spurs (claws on the legs), and baleen (a tuft of hair-like feathers protruding from the chest), play in female mate choice. He found that the length of the snood was the main factor explaining which male a female would choose as a mate. Even a difference of a few millimeters made a difference.
“This really surprised me, especially since snoods don’t seem to be a very functional choice,” Dr. Buchholz said. “Why a snood and not other men’s jewelry?”
The answer lies in a phenomenon deeply rooted in biology: flashy ornaments may indicate superior genes. In the case of turkeys, a male who could afford to wear a killer snood must have had ample resources, which ostensibly reflects the quality of his DNA. Dr. Buchholz found that males with longer snoods had fewer coccidia parasites. Coccidia does not harm adults but can sicken or kill chicks, and they carry genes that may confer resistance to coccidia.
Dr. Buchholz said that “early stages probably have a big impact on chick survival,” so by selecting males with longer rakes, females may be able to give their babies life-saving parasite resistance. He said he could not.
Dr. Buchholz is still not sure what role other men’s jewelry plays. Like the snood, other fleshy structures on the turkey’s face and neck can also change color during display. For example, Dr. Buchholz said, males drain all the blood from the caruncle, making it papery white. He doesn’t yet know what the changes in the mounds indicate or why they are important.
So what about those fancy feathers? “I don’t know if females care,” Dr. Buchholz says. The feathers of male turkeys infected with coccidia reflect less ultraviolet light that turkeys (which humans cannot see) can see. But no one has studied whether females scoff at plain plumage in the same way they scoff at puny snoods.
“There’s still a lot we don’t know about wild turkeys’ mating behavior. “Turkeys are a great conservation success story, a bird that’s so familiar and fascinating to people, and a bird with a cultural connection to American Thanksgiving, so it’s a real shame we don’t know more about their behavior,” Dr. Buchholz said.
Perhaps that’s not surprising at all: Thanks to conservation efforts, wild turkey populations are now booming in many parts of the country. In places like New England, Madison and Berkeley, turkeys are now so common that they attract as much attention from passing motorists as traffic cones.
But it wasn’t always this way: Until recently, wild turkeys were a rarity in the U.S. “It’s crazy now, because they’re all over the city, blocking traffic,” Dr. Krakauer says.
