Reflections in Nature: Inbreeding rare among bird families
During the month of March, the daily entries in my diaries have many notations indicating what I either have seen or heard about wildlife returning from their migrations south or awakening from their long winter naps.
It won’t be long before we will see and hear songbirds as they try to attract a mate to raise a family this spring. Have you ever wondered why species of birds do not interbreed in the wild?
Generally, there’s enough of the same species to allow for same species breeding; however, two birds of similar but different species, in captivity where there is only one option to satisfy their mating urge, could mate. If there is an offspring of this mating, it will be a hybrid and more than likely sterile.
For this interbreeding to occur, it must be a very similar species because birds (unlike dogs) can not interbreed with just any species of bird.
On our morning walks, many cars pass by, with the occupants either waving or beeping their horns because they recognize us. The same happens when making a telephone call and the person answering identifies the caller by his or her voice. Birds also recognize their own species by the bright colors of the males, their calls, songs and behavior.
Even though calls of the same species sound alike to us, birds can tell the difference. In studies done, it has been found that birds are able to recognize their mates in flight.
Mated pintail ducks have been known to identify each other up to 300 yards away, while bobwhite quail can distinguish each other in the covey.
A mated pair of songbirds protect their territory and, often, the female will chase another male away because she recognizes that the male is not her mate.
On the other hand, studies have shown that doves do not know the sex of a strange bird until they are at close quarters, and ruffed grouse do not have any sex recognition at all.
Some birds, such as Canada geese, mate for life while some remain together through at least one nesting season.
Birds such as wrens and swallows will pair with the same mate the following year and perhaps even for three years.
The pairing of hummingbirds can be so brief that it is called a promiscuous relationship. After the female builds a nest, she mates with the first male hummingbird she meets, lays her eggs and raises the young without any help from the male. The male seeks out another female and mates again. The ruffed grouse is another example of a promiscuous relationship.
When the female mates more than one male, it is known as polyandry. This is quite common in pheasants, turkeys and songbirds, including red-winged blackbirds and bobolinks.
When a male mates with several females, it is called polygyny and, usually, the females, in separate nests, will lay and incubate their eggs without any help from the males.
Polyandry is relatively uncommon. It is known among birds in which the role of the sexes in the family has been reversed. The female, which is larger and usually has brighter plumage, will solicit the male and defend a common territory, while the male, which is smaller and drabber, will build the nest. The female then lays the eggs, and the male does all of the incubation and most of the care for the young after hatching.
The female belted kingfisher is more colorful than the male, and the two appear to have switched roles.
Inbreeding within a family group is rare among birds in the wild because of the dispersal of the young after the nesting season is over and also the intolerance of the adults toward their young when grown.
Even though during the following spring, the young birds return to the home territory of their parents, there appears to be no interbreeding. Inbreeding is so rare that it only has been documented three times: once in a downy woodpecker family, a brother and sister mated; a barn swallow father and daughter mated, and a tree swallow mother and a son mated.
Soon the songbirds will be singing and doing their mating flights to attract mates, and we humans will have a front row seat to watch.
Bower retired after 34 years as a wildlife conservation officer for the state Game Commission. He has published several books about his experiences. Questions and comments may be sent to him at 153 Redington Ave., Troy PA 16947.