How do we learn to become human? From fellow humans, of course! We are raised by humans, fed and cared for by humans, and taught language by humans. Parents, relatives, friends, teachers, and other people around us teach us language, cultural norms and values, and the ins and outs of social interaction. From them, we learn the information and skills we need to function as members of our society at any given time in our lives. As we grow, we gain companions, friends, enemies, co-workers, rivals, and perhaps mates who will shape our lives and help us raise the next generation of children to instill with our cultural norms and values.
The same is true of animals. Peregrine falcon and bald eagle parents spend a lot of time interacting with their young: brooding them before they old enough to thermoregulate, stuffing them with food at every opportunity, vocalizing (think of a peregrine falcon chupping encouragingly at a hatchling), and playing post-fledging chase and hunt games in the first few weeks of flight development. Birds learn to be birds from other birds: the vocalizations, songs, or calls of their species, flight skills (think of fledgling peregrine falcons chasing one another, or a flighted predator chasing down flighted prey) and, among birds that are social, the intricacies of social interaction. As they grow, they learn how to acquire food, avoid danger, find mates, and raise the next generation of young.
In birds and mammals, this process starts with imprinting, defined as "Rapid learning that occurs during a brief receptive period, typically soon after birth or hatching, that establishes a long-lasting behavioral response to a specific individual or object, as attachment to parent, offspring, or site". In short, we first recognize our parents, which lays the groundwork needed for us to recognize and interact with our species and eventually find mates. This type of imprinting is referred to as "filial imprinting".
But what happens when a human is responsible for raising a bird? If humans are a bird's only role models and source of food or protection, than it will imprint on humans for species recognition. As a sexually mature adult, it will reject its own species and seek the attention of humans. People raising birds for release in the wild take steps to prevent human imprinting from happening, including foster-parenting and puppet-feeding.
When Bob was raising falcons for release, he turned young birds over to a female 'foster-falcon' at around 10 to 12 days of age. By feeding and caring for them, "Freddy" imprinted the young falcons with a falcon model. As juveniles and adults, they sought a bond with their own kind rather than with us.
|Philippine Eaglet feeding. Photo by Kike Arnal.|
However, foster parenting isn't always an option, especially among critically endangered birds. Kike's photo shows Philippine Eagle Center staff puppet-feeding a Philippine eagle nestling. The person behind the mask imitates a Philippine Eagle parent: vocalizing, interacting with the eyass, feeding it, and providing protection. The eaglet's room is painted to look like the forest it will eventually live in and contains the sounds that will surround it as an adult. These steps imprint the young eaglet on a Philippine Eagle model, establishing a behavioral response to other eagles and forest habitat, rather than human beings and an urban habitat. The puppet is our way to teach a Philippine eagle that it is an eagle, not a human.
Imprinting is a fascinating topic and we'll write more about it later this year. There is a reason that adult eagles chirp to hatching eggs!
Things that helped me learn and write about this topic:
- Personal comm. Bob Anderson. He was very excited about this back in 2013 and discussed it quite a bit with me.
- Imprinting in birds. A great blog on the topic: https://dangleason.wordpress.com/avian-biology/172-2/
- My life as a turkey: http://www.pbs.org/wnet/nature/my-life-as-a-turkey-whos-your-mama-the-science-of-imprinting/7367/
Learn more about the "Father of imprinting", Konrad Zacharias Lorenz.
- The man who walked with geese: http://www.pbs.org/wnet/nature/flight-school-the-man-who-walked-with-geese/2656/