The Nature Writers of Texas

The best nature writing from the newspaper, magazine, blog and book authors of the Lone Star State . . .

Thursday, June 18, 2009

Courtship Feeding
by Ro Wauer

Cardinals and a few of my other yard birds are currently feeding one another. Much of that, of course, is an adult bird feeding one of its babies. Fledglings will follow their parents about for a considerable time, depending on how long the adults feel it is necessary. Some birds, like roadrunners, as soon as their youngsters can feed themselves, will lead their offspring away from their nesting territory and essentially loose them. Some humans need to do the same.

But there also is a lot of courtship feeding still underway. That is the behavior of one of the adults, usually the male, feeding his mate or his potential mate. In cases where the female takes the lead in courtship, such as with some sandpipers, the female will feed the male. This behavior is considered part of avian courtship, and it may start very early in the breeding season and may last for a few weeks after the last nestlings have fledged.

Early courtship feeding is a way for the dominant individual to attract a mate and develop a bond. This pair bonding, or the honeymoon period, may last for a considerable time, or at least until copulation occurs. Although courtship feeding is likely to continue, the individuals will also feed themselves. Ornithologists believe that courtship feeding not only forms a bond but also tends to maintain the health of the female and leads to greater nesting success. The number of eggs and clutch weight are partly determined by the female’s nutritional status. As Paul Ehrlich and colleagues wrote in “The Birder’s Handbook, feeding of the female “seems apparent that he is increasing his own reproductive success by keeping her fat and healthy.”

Males usually continue feeding the female through much of the nesting process or at least until the nestlings require both adults gathering food on a full time basis. Then the feeding behavior changes dramatically. As the nestlings grow and demand more and more food, feeding by the adults become all consuming. This is the time of year when more nutritional foods are necessary. For the majority of songbirds, such as cardinals, wrens and mockingbirds, insects and other small creatures become essential. Some studies suggest that songbirds must consume up to 80 percent of their weight on a daily basis. Adults with nestlings must therefore capture an amazing amount of food for themselves and young each and every day.

Once the young are fledged, in spite of the fact that they will continue to beg food from the parents, their diet begins to change from insects and other highly nutritional food to other things like seeds and fruit. Young cardinals for instance will very soon join their parents at seed feeders. And by late summer fruit usually becomes part of their daily diet. It is interesting that even some Neotropical flycatchers, species that nest in the United States and Canada where they specialize in insects, will switch to a diet dominated by fruit on their wintering grounds in the tropics.

The majority of songbirds that we find in our yards must feed constantly, especially when feeding young. During a normal day, however, most songbirds feed most heavily during the early morning hours, again during mid-morning, and then again in the late afternoon prior to going to roost for the night. Seed eaters that frequent seed feeders follow the same pattern, but they also are constantly on the lookout for insects and other more nutritious creatures. All birds are opportunists!