Where's My Mommy?
Imprinting in the Wild and in Operation Migration

Background Visualization: A Whole New World

Crane egg photo by USGS Patuxent Wildlife Research Center

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.


photo by Florida Fish and Wildlife Conservation Commission

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.

Operation Migration: A Tricky Experiment

photo by USGS Patuxent Wildlife Research Center

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!

  1. 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.
  2. 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 Migration
  • photo by USGS Patuxent Wildlife Research Center

    1. 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.

  • 2. Costumes,

    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.

  • 3. Absolutely NO TALKING will be tolerated within earshot of the birds.

  • 4. 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.

  • 5. 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 foraging.

  • 6. The colts will be shielded from observing caretaking activities such as pen cleaning and food/water changes as much as practical.

  • 7. 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.

  • 8. 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.

  • 9. Recorded wetland sounds will be played inside the aviary to create a natural environment and mask outside human noise.

  • 10. The

    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 as needed.

  • 11. The birds will be socialized in small cohorts based on age and compatibility.

  • 12. 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.

  • Watch a Whooping Crane chick follow its handler and learn how to follow the ultralight!
    Circle pen training clip courtesy Operation Migration

    13. 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.

  • 14. 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.

  • 15. 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 brood/contact call.

  • 16. 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.