Imprinting in the Wild and in Operation Migration
Visualization: A Whole New World
Imagine being a wild baby crane, wet and exhausted after
finally breaking out of your egg. How strange the world seems! With your
downy feathers still wet and plastered against your skin, every little breeze
feels cold compared to the constant warmth inside the egg. The light dazzles
your eyes, and there are so many bewildering sights! Everything sounds more
intense now that your ears aren't stopped up with fluid. It could be very
scary, but you know your parents are near.
But who, and where, are they? You've never seen anything in your life before
this, and all of a sudden there are bewildering sights in every direction.
You can see your nest, shrubs and trees, grasses and flowers, a puffy white
cloud in the sky, a frog jumping right past your face, a brightly colored
butterfly. A duck waddles close, and suddenly two long, black legs attached
to a big white, feathery body with a long neck and startling face chases
it away in a flurry of quacks and feathers. Every sight is strange, but
your eyes are drawn to the gold eyes, long black beaks, and especially the
bare red skin on the face attached to that big white body.
Its big beak
draws close and tenderly takes away some jagged pieces of eggshell, and
something clicks. Mommy! For the next 10 or 11 months, this bird and one
who looks just like her will be the most important things in your life.
You will feel anxious anytime you can't see or hear them. If one of them
takes a step with those long legs, you will take a dozen baby steps to
keep up. And when one of them flies and calls to you, you will beat your
little wings and run to try to keep up. One day in about two months, those
growing wings will beat so hard that they'll pull you off the ground a
bit, and by the time you're three months old or so, you'll be flying strong--just
to keep up with your parents.
baby cranes learn what food to eat, how to fly, and where
to migrate only because they can identify their parents and try so hard
to stay with them and imitate them. The critical time for a baby crane to
identify its parents happens within the first hours of hatching. We say
it gets imprinted on its parents. And once imprinted, a crane will
never accept anything else for a parent. In the wild, cranes nest in large
territories, isolated from other cranes. Baby cranes are large and tasty,
and would be in danger if they stayed on the nest too long. Imprinting is
a quick way of learning who their parents are, so they can follow them within
hours of hatching and won't get lost. Imprinting is also ultimately the
way cranes identify their own species, so when they grow old enough to choose
a mate, they will only consider birds that look like their parents. And
they will raise their own babies in the same way their parents raised them.
Migration: A Tricky Experiment
But what if you're a baby crane hatched as part of Operation
Migration? You don't see quite so many strange sights when you hatch: the
bars and rubber floor of your incubator, light fixtures and lab equipment.
The big white bodies you see don't have feathers. They don't have skinny
crane legs, either, but you do see what you somehow know you're supposed
to see--that bright red crane face. So you know you're safe, and you quickly
imprint on them. But they aren't really cranes. They're humans dressed in
billowy white costumes with a crane puppet on one hand.
Raising baby cranes in captivity to release them into the wild is a difficult
and tricky task. It's important for any growing baby to feel safe and comfortable,
but wild cranes are in terrible danger if they come too close to humans,
so releasable baby cranes must never become tame with their handlers. They
must never associate hands with food, or faces with love and kindness. The
scientists at Operation Migration know that the safest way to raise their
baby cranes is to keep the babies from ever seeing a human face or hands.
They badly want these cranes to grow up as healthy wild cranes, and eventually
to mate with other wild cranes and raise healthy wild babies. To give them
the best possible chance for this, they have developed a set of rules, or
a protocol, that everyone who comes anywhere near these babies must
follow. NO exceptions!
- Read the following official protocol for Operation
Migration, below. As you read, think of possible reasons why each rule
is important. Note reasons in your journal or on the chalkboard as you
discuss them in class.
- After your discussion, check to see what Journey North's
science writer thinks by clicking on the number for each of the 16 rules.
Protocol for Operation
Conspecific ( means "of the same species")
adults will be penned in the aviary and will have access to the sand
runs that are perpendicular to the aviary runs used by the chicks. These
adults will act as imprinting models. While the chicks are being
exposed to the running aircraft, these adults will be locked inside
and observed for tolerance to the disturbance.
designed to disguise the human form, will be supplied
by OM and used in conjunction with hand held puppets of adult cranes
and recordings of crane calls. Sleeve cuffs or gloves will cover the
handler's hands when working with the cranes. When necessary, the medical
staff may remove their gloves and work barehanded in order to properly
treat or examine the chicks.
Absolutely NO TALKING will be tolerated within earshot of
No human avoidance conditioning (HAC) will be attempted prior to
the release of these birds. The birds will be handled and examined in
costume. If medical or other procedures require the removal of the facemask,
the chicks will be hooded or protected from seeing the handlers.
Absolutely no feeding will be done from hand. All food used
as an incentive will be dispensed by methods other than hand tossing.
Mealworms or other treats will be pointed out using a puppet to encourage
The colts will be shielded from observing caretaking activities
such as pen cleaning and food/water changes as much as practical.
As much as practical the birds will be visually shielded from
manmade structures and equipment. Efforts will be made to disguise
the propagation building and surrounding areas in order to provide a
more natural environment.
The number of handlers will be kept to a minimum during
conditioning to reduce the amount of human contact, improve handler
safety and to minimize distractions.
Recorded wetland sounds will be played inside the aviary to create
a natural environment and mask outside human noise.
colts will be moved from the propagation building to
the large pond pens known as the "White Series" when
the caretaking staff agrees that weather conditions, socialization and
ages are appropriate. Heat lamps and additional shelter may be provided
The birds will be socialized in small cohorts based on
age and compatibility.
The duration and frequency of aircraft training will be based
on the response of the chicks. Each training session will be evaluated
for success and if the chicks are responding positively, additional
training will be curtailed temporarily to limit unnecessary human contact.
To reinforce the "follow the aircraft" response, efforts
will be made to minimize the number of times a chick is led by a
walking handler. However, during early conditioning, it may be safer
to lead chicks to the aircraft rather than to carry them.
The aircraft used for this training are registered in Canada but
are too large to be considered ultralights in the U.S. Through a cooperative
agreement between Transport Canada and the Federal Aviation Administration;
we are allowed to operate these aircraft within the U.S. providing we
abide by Canadian regulations. With the wing removed to conduct this
training they are not capable of flight but still must be operated properly
and only by qualified persons.
Dr. Bernhard Wessling
has provided the project with digital crane call vocalizers.
Each unit is capable of reproducing up to six adult crane calls that
handlers can use to communicate with the colts. Only pilots and qualified
handlers will use the vocalizers to broadcast any calls other than the
As a precaution, the primary handlers will familiarize the
cranes to the sound of their human imitations of brood calls. This
will be done sparingly to afford some control over the birds in the
event of equipment failure in the field. Only the handlers that will
accompany the birds after they leave Patuxent should conduct this exercise
and it should be done from a distance so as to not attract the chick's
attention to the handler's head.