Canada Geese and Interesting Mating Games
If you’ve spent much time this spring around one of the nesting ponds or along the river, you’ve been hearing it, too. I’m thinking of the urgent pleadings of a love-struck Canada goose – Branta Canadensis.
Several proposed pairings have been regularly chasing each other over Evolutionary Abode these past couple weeks. This spring, those trips to and from Manastash Creek, Cove Lakes, nearby ponds or wherever have been loud and boisterous.
Each time I hear it, that piercing and heart-wrenching “car-uunk, car-uunk, cur-wahnk@ sweeps me back to a crisp early June 1995 morning on a tucked-in mountain lake in Central Colorado. The Hucklings and I were on a camping/fishing adventure. As we ate our sourdough pancakes, we watched and listened as one goose noisily chased another up and down the lake for the better part of an hour. The loud calls echoed again and again off the hills across the lake. Only the geese knew what was being said, of course, but it sounded to me like the desperate, pleas of a love-struck goose. Twelve-year-old Tena decided that it was a boy goose chasing a girl, and demanded to know what on earth could be so urgent. How does a father respond? I finally just said, “I’m sure we’ll have a lot of talks about that in the next few years.”
Over several decades of watching and listening, those springtime rituals in the Midwest, on the Colorado plains and around Paradise have never failed to hold my attention. What could be more pitiful than those pleading calls? I have often wondered just how much pleading one goose must do to get the other to seriously consider a relationship. A great deal of research over the past forty years has shown that most reproductive decisions are made by the females of species, and, of course, there is more to that story.
It was an off-the-cuff, but heated, discussion of goose relationships which led to some of the most interesting things I have learned about geese and their mating habits.
In late 1989, a few months into my Colorado outdoor column, I got drawn into a conversation about geese and their mating habits, as compared to men in general – and my conversation partner’s man in particular. She was pretty upset, and I happened to be the closest man as we left a hearing on problems with geese and city parks. In truth, I was simply the backboard off which she bounced her done-me-wrongs. She punctuated the completion of her list with, “Well, at least geese mate for life and know how to be faithful – put that in your male chauvinist pig attitude and smoke it!”
I couldn’t help myself. I was duty-bound to explore the question. It took very little research to discover what waterfowl specialists had found. In any given clutch of four to ten eggs on arctic breeding grounds, there was DNA evidence of fertilization by at least two ganders, and sometimes as many as four. Geese may, indeed, mate for life, but they fool around.
Mallard duck studies found similar situations in duck breeding grounds. And buddy Bob Hernbrode of the Colorado Division of Wildlife passed along a memo from the research center in Fort Collins; a fair percentage of twin deer fawns actually had two different daddies.
Then there was that January, 1999, issue of Scientific American. Attached to an article about DNA microsatellites was a sidebar titled “Searching for Papa Chimp.” Pascal Gagneux and David Woodruff of the University of California at San Diego, with Christophe Boesch from the University of Basel, used DNA tracers to probe the mating habits of a group of wild chimps in West Africa. Of 13 offspring, it was shown that seven could not have been fathered by any of the males in the group. Apparently, the authors concluded, “at least some of the female chimpanzees must have sneaked into the surrounding forest for trysts with males in other groups. Such adventures might explain how even small groups of chimpanzees maintain a great deal of genetic diversity.”
It all made sense, really; after all, a female must introduce as much genetic diversity as possible to sustain her species.
At the time, I felt a responsibility to pass along the findings of philandering geese, ducks, deer and chimps. Responding letters, as I recall, contained accusations of biased research and a few observations about my shortcomings as a writer and male of the species.
Be that as it may, I continue to be transfixed by the pleadings of spring geese so fervently committed to the future of their species.
