As spring bursts forth, wild turkeys begin the mating game. Groups congregate in lawns and fields — and sometimes in the course of the road. Males puff out their iridescent feathers, fan their tails and drag their wings on the bottom in a vie for the suitable to breed. Their faces and necks turn dazzling shades of blue and red.
Once rare and elusive denizens of America’s woodlands, these heaviest of the galliform birds (chickens and their relatives) have gone urban. Wild turkeys live within the residential neighborhoods around my home in Madison, Wis.
A number of years ago, their elaborate courtship displays fascinated me a lot that I started to photograph them — and, as I’ve learned, there’s more happening than meets the attention.
For starters, turkeys of a feather flock together. Males, referred to as toms, can form lifelong flocks with their brothers. Dr. Alan Krakauer, a biologist and fellow photographer, studied this as a graduate student on the University of California, Berkeley. He discovered that toms in a flock were anywhere from full to half-siblings. These bands of brothers cooperated to court females, or hens, and chase off competing males.
Remarkably, though, only the dominant male mated and fathered offspring. The subordinate brothers served as “wingmen,” “bodyguards,” or “backup dancers,” to make use of Dr. Krakauer’s colourful descriptions. “They’ve what I believe of as a support role,” he said.
Despite the potential for lifelong celibacy, wingmen benefited from the arrangement, Dr. Krakauer found — no less than by the raw calculus of evolution. On average, dominant males with wingmen produced seven offspring a season, whereas solo males produced fewer than one. Because the males were closely related, those seven offspring contained more of the wingmen’s genes than in the event that they’d sired a single chick themselves.
“They’re helping their brother get lots more females than either of them would get on their very own, so this cooperation seemed particularly helpful,” explained Dr. Krakauer. “That appeared to be surprising for people on the time.”
Anyone who’s had a brother knows the vicissitudes of fraternal relations. While brothers generally cooperate throughout the mating season, intense fighting breaks out at other times, as they jostle for rank. Turkeys have formidable weapons: large bodies, powerful wings and spurred feet. On one occasion, I saw a fight so violent that spittle flew — like when a boxer is hit by a knockout punch.
While males are aggressive with one another, they aren’t aggressive toward females and don’t force copulations, despite being twice the scale of their mating partners. So while males may strut with abandon, females ultimately select their mates. They’re picky about partners and know what they need: males with long snoods.
Snoods are the fingerlike fleshy protuberances that flop over a turkey’s beak. The animals can contract and loosen up muscles and blood vessels of their head and neck, causing changes within the organ’s length and color. A tom sporting a protracted red snood draws the eye of hens like flies to honey — although, to their credit, the hens manage to be coy about it.
Dr. Richard Buchholz, a professor on the University of Mississippi, has spent his profession studying wild turkeys. He examined the role that various male ornaments — including snoods, caruncles (pebble-like bumps on the pinnacle and neck), skullcaps (thickened skin on top of the pinnacle), spurs (talons on the legs) and beards (tufts of hairlike feathers projecting from the chest) — play in female mate selection. He found that snood length was the first factor that explained which male a female selected as a mate. Even just a few extra millimeters made a difference.
“It did surprise me, especially for the reason that snood doesn’t appear to be a really functional thing to decide on,” Dr. Buchholz said. “Why the snood and never all the opposite ornaments on males?”
The reply lies in a phenomenon with deep roots in biology: Fancy accouterments may indicate good genes. For turkeys, a male who can afford to sport a killer snood should have had ample resources, which ostensibly reflects the standard of his DNA. Dr. Buchholz found that males with longer snoods had fewer coccidia parasites, which don’t harm adults but can sicken or kill chicks, and possess genes which will make them immune to coccidia.
“Early on there’s probably a big effect on chick survival,” Dr. Buchholz said, so by selecting longer-snooded males, females may provide their babies with lifesaving parasite resistance.
Dr. Buchholz remains to be uncertain concerning the role another male ornaments play. Like snoods, other fleshy structures on a turkey’s face and neck can change color during displays. For instance, males will drain all of the blood from the caruncles in order that they’re as white as a sheet of paper, Dr. Buchholz said. He stays unsure of what the change within the caruncles might signal, or why it’s essential.
And what about those fancy feathers? “I don’t know if females care,” Dr. Buchholz said. The feathers of male turkeys infected with coccidia reflect less ultraviolet light, which turkeys (but not we humans) can see. Nevertheless, nobody has studied whether females scoff at dull feathers the best way they do at puny snoods.
There’s still lots to find out about wild turkey mating behavior. “For a bird that’s such an amazing conservation success story, that’s so common and interesting to people, and that has a cultural connection to the American Thanksgiving, for us to not know more about its behavior is basically a shame,” said Dr. Buchholz.
Perhaps that’s not entirely surprising. Wild turkey populations are currently booming in lots of parts of the country, due to conservation efforts; in places like Latest England, Madison and Berkeley, they’re now so common that they get about as much notice from passing motorists as a traffic cone.
But that wasn’t all the time the case. Until recently, wild turkeys were rare in the USA — “which seems crazy now,” Dr. Krakauer said, “since they’re right on the town and blocking traffic.”