Human-imprinting in Birds and the Importance of Surrogacy

One essential aspect of wildlife rehabilitation is to keep animals wild, with an appropriate fear of humans. This can be challenging for some wildlife species, particularly birds, because of how they learn and develop. 

What is imprinting?

Imprinting is a form of learning in which an animal gains its sense of species identification. Birds do not automatically know what they are when they hatch – they imprint on their parents during a critical period of development. After imprinting, they will identify with that species for life.

Imprinting for wild birds is crucial to their immediate and long-term survival. For example, precocial baby birds (such as ducks, geese, and turkeys) begin the process of imprinting shortly after hatching so that they follow the appropriate adult, providing them with safety.

Imprinting allows baby birds to understand appropriate behaviors and vocalizations for their species, and also helps birds to visually identify with other members of their species so they may choose appropriate mates later in life.

The timing of the imprinting stage varies from species to species, and some species of birds are more susceptible to imprinting inappropriately on human caregivers for reasons not fully understood.

What happens if a bird imprints on humans?

If young birds imprint on humans, they will identify with humans for life. Reversing the imprinting process is impossible – these birds will identify with humans rather than with their own species for the rest of their lives. 

Human-imprinted birds are not necessarily “friendly” toward humans, nor does it mean they always enjoy being near humans. Human-imprinted birds have no fear of people, and this lack of fear can sometimes lead to aggression and other complicated behavioral issues. It’s not unusual for an imprinted bird to exhibit territorial behaviors toward humans just as it would with members of its own species.

Human-imprinted birds also frequently have difficulty communicating with other birds of their own species– vocalizations, postures, and a fear of humans are all things that birds learn from their parents, siblings, and other birds. They are typically not accepted by other birds of their species, likely because human-imprinted birds display odd behaviors and cannot communicate properly.

Ultimately, imprinted birds find themselves in a “gray area” – they cannot appropriately interact with either humans or their own species.

Birds who are human-imprinted are deemed unsuitable for release back into the wild due to these inappropriate interactions. Some of these patients might be appropriate education animals; at times, the Wildlife Center has several human-imprinted birds as education ambassadors. 

What does the Center do to prevent young birds from imprinting on humans?

Of course, captive-rearing wild birds is never preferred if baby birds can be reunited with their parents or wild-fostered into a different family. But when orphaned or injured baby birds must come into care, Center staff take special precautions to prevent young bird patients from inappropriately imprinting. Human contact is kept to a minimum; the rehabilitation staff only handles birds during feeding and cleaning. The rehabilitation staff, students, and volunteers do not talk to the patients, and sometimes caregivers wear masks and hats to disguise human features.

Ensuring birds are with others of their own species is also an important aspect of raising young wild birds in captivity. For many songbird species, keeping babies together in groups of the same species is typically enough to prevent them from imprinting on humans. With young raptors, an adult role model seems to be more critical for appropriate rearing. Center staff often try to place young raptors with a surrogate parent of the same spaces. 

Two catbirds perch in an outdoor aviary together
Tell me more about how surrogate parents help young birds. 

Surrogates provide an adult role model to young members of their species to counter their interaction with human caregivers. The surrogate parent demonstrates proper behaviors for their species and reinforces their wariness of humans. This enables the young birds to be released back into the wild with appropriate behaviors, vocalizations, and reactions to humans.

The level of interaction between surrogate and baby differs in each situation. Some surrogates take an active role in caring for their “adopted” young by feeding or preening them. Other surrogates show no maternal or paternal instinct, but their presence ensures that the babies can visually imprint on the appropriate species.

Sometimes a recovering wild bird patient is used as a surrogate parent; staff will set up a crate or other enclosure for a baby raptor within a larger enclosure where an adult of the same species is recovering from its injuries. In the past, the Center has had resident non-releasable surrogate raptors; most notably, Papa G'Ho, a resident Great Horned Owl, lived at the Center for more than 20 years and helped raise dozens of owlets. 

 

Do you have to worry about baby mammals imprinting on humans?

The critical development period of mammals differs from birds. Mammals do not visually imprint on their caregivers, but they can become tame or habituated to humans if not handled appropriately. This is particularly true of mammals that have a prolonged juvenile period – White-tailed Deer fawns and Black Bear cubs are prime examples.

Deer fawns are herd animals, and housing fawns together or near each other in the Center’s outdoor enclosures helps to prevent them from becoming habituated to humans. Single fawns raised alone have a higher risk of inappropriately bonding with their human caregiver. Similar to any young wild patient, the Center staff also take precautions to limit contact with the fawns, only interacting when necessary for feeding and care. The staff also have a special fawn mask which helps disguise human features!

A person wearing a large deer mask bottle-feeds a fawn

While some young mammals are more vulnerable to habituation to humans, many species of small mammals have a relatively short juvenile stage and are less likely to bond with their human caregivers when appropriate rehabilitation care is given. With all species of baby mammals, the staff strives to be as hands-off as possible, to reduce stress on the animal and risk of taming and habituation.

Learn more about patients of all ages on Critter Corner and Critter Cams