Imprinting: Who Am I, Really?

As seen in Nature News, Liberty Wildlife's E-Newsletter. To subscribe, click here.

William, the baby pronghorn mentioned in Nature News, received a lot of publicity while he was at the Liberty Wildlife facility. He was a patient of Liberty until he was old enough and healthy enough to join other pronghorns living in a controlled situation.

One of the issues that the news articles mentioned was that of “imprinting.” There are two kinds of imprinting. The most common is the one that occurs naturally, as a baby bird or animal observes food delivery from parents and learns to imitate the sounds that its parents make. In short, it learns to be a baby eagle and to identify properly with others of its same species.

The other kind of imprinting is “improper imprinting,” and it is a major concern for wildlife rehabilitators. Put simply, a baby bird or animal that is exposed to humans can become confused about its identity for the rest of its life. Instead of choosing a mate of its own kind, an imprinted animal or bird will try to romance a human. This might sound funny, but it can be dangerous. Even a male llama, thought to always be gentle, has a roughhouse mating ritual, including chest butting the male competitor. The force is so strong that the chest-butt can seriously injure a human.

Liberty Wildlife receives many infant birds and animals, and must find ways to prevent improper imprinting and encourage natural imprinting. It is believed that natural imprinting greatly improves the chance of survival of a young bird or animal released back into the wild. Improper imprinting means that the animal cannot successfully be released and must be maintained in captivity. There are many variables to consider and experts do not all agree on the details. In short, however, raising the young one as close to natural is the best approach and has resulted in the greatest success.

A key tool in achieving natural imprinting is the use of Liberty’s permanent residents, who cannot be released back into the wild, as foster parents. One such resident, a great horned owl, Hogan, traveled for years to classrooms and community events as an education bird. Two summers ago, Liberty placed an orphaned great horned owl chick with Hogan, and her new career was born. Instead of a seeing a human hand as a source of food, her foster chicks see an owl beak. Instead of human voices, they hear her hoots and calls. Hogan has now successfully fostered numerous chicks for two years.

When a foster parent isn’t available, Liberty’s rehabilitators get creative. They use puppets that look like the biological parent to offer food to the babies. These puppets can even attempt to nurture the young ones. Recordings of the different sounds that the natural parents would make as they enter and leave the nest are played to babies when possible. The ultimate goal is to get them in an outside flight cage with another of their own species so that their experience is as close to the real thing as possible.

As the news articles about William said, one of the special things about him for Liberty volunteers is that they got to encourage him to run, play and exercise—things necessary for his proper development but contrary to almost every other instance of raising a wild baby. Since he will be living in a controlled situation, not in the wild, William was a rare exception to Liberty’s policy of promoting only natural imprinting.