For the Birds Radio Program: Mother-in-Laws, human and avian
(Recording of a Canada Goose)
Mother-in-law jokes are still around on the human scene, which set me to wondering how well birds get along with their mothers-in-law. Actually, most birds probably never get a chance to meet their mothers-in-law. The life expectancy of many species is so short that probably only a few songbirds ever see either their parents or their offspring after leaving the breeding grounds in fall. Most small birds die their first year, but once they make it through a migration and winter, their life expectancy does go up sharply.
Robins have lived over 11 years in the wild, and cardinals over 13. The record lifespan of a hummingbird is over 11 years–one adult female Broad-tailed Hummingbird banded in Colorado in 1976 returned to the same banding station in 1986. This bird may actually have been older than 11, since there was no way scientists could determine exactly how old she was in 1976–11 is the minimum age. That little bird was quite probably a great-great-great-great-great-great-great-great- great grandmother (That’s nine greats) with quite a few daughters-and sons-in-law. Hummingbirds are usually aggressive toward their own kind, and this one in particular was observed to run other hummingbirds away from the feeders at the Colorado banding station, so chances are if her children and their mates recognized her at all, she was still none-too-popular with them.
The young of many songbirds often return to the place that they were hatched and fledged in the spring, but if their parents have also survived, the older birds drive the young off to discover a new territory. The territorial imperative combined with the experience and dominance of older birds probably blacklists mother-in-law songbirds with the younger generation.
On the other hand, Canada Geese probably both know and get along with their in-laws. Geese live much longer, on average, than small songbirds–the life expectancy of an adult goose in the wild is over 20 years. Although mated pairs spend the summer on isolated territories, they join up with their children and their children’s children’s children from previous summers, during fall migration and on wintering grounds. Usually the oldest, most experienced geese are in the first and last positions in a long string of geese. Geese apparently learn their migration routes and wintering grounds from their parents, and spend all but the breeding season in tightly-knit clans. Not only do Canada Geese mate for life, they stick together with other family members for their lifetimes, too. Flocks wintering in central Minnesota and Wisconsin are made up of quite a few mothers-in-law. Unlike humans, geese often breed each year for their entire adult lives, so mother-in-law geese often have new babies as well as great-granchildren to look after. They and their mates act as sentinels for a feeding flock, calling a warning if a fox, coyote, or human enters the scene. So mother-in-law geese are well respected, unlike their beleaguered human counterparts.
The nicest human mother-in-law I know not only alerts us to foxes and coyotes–she also got me started as a birder. Sunday is her birthday, and I sure hope it’s a happy one.
(Recording of a Canada Goose)
This is Laura Erickson, and this program has been “For the Birds.”