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Harpy Eagle Chick

On Monday, December 1, the San Diego Zoo welcomed its newest addition, a baby harpy eagle Harpia harpyja, the 14th hatched at the Zoo since 1994.

The Zoo’s pair of adult harpy eagles laid a single egg in their exhibit on October 10. Ten days later, the egg was pulled and set in an incubator, where its development could be carefully watched by the keepers at the Avian Propagation Center (APC). We weighed the egg daily to make sure that it was losing the right amount of water as the chick developed inside. We also monitored the progression of the embryo using a technique called “candling.”

When a bright light is shone through an egg, it allows the keepers to see what’s happening on the inside and keep an eye on the chick’s development throughout its incubation.

After 51 days in the egg, the chick began its escape the night of November 30, and after a long day of determined pecking, finally broke free at 7:15 the following evening. The new chick, wet and exhausted, weighed in at 2.58 ounces or 73.15 grams (or about half as much as a baseball). It was a humble beginning for one of the world’s largest eagle species. Female harpy eagles (the larger sex) can grow to be 20 pounds (9 kilograms); in the wild, they use their powerful feet and needle-sharp talons to snatch their prey from tree branches in the Central and South American rain forests. All of that seemed a little ambitious at that moment, though, as the freshly-hatched chick curled up to sleep off a long day’s work.

The following morning, we moved the chick into its new home in the APC’s “Brooder Room.” A brooder is a warm, humid box that mimics the environment under a parent bird. It is important that the chick never become imprinted on its human surrogates, so this particular brooder is covered with a towel, set behind a curtain, and continuously serenaded by a CD of soothing rain forest sounds to drown out the keepers’ voices. When it comes time to feed the baby, we put a sheet (or “ghost”) over our head and use a harpy eagle puppet to deliver the food.

The chick finally woke up and took its first small meal of diced pinkie mice at 4 p.m., 21 hours after hatching. It was the beginning of a gluttony that will turn this 73-ounce puffball into the most powerful avian predator on Earth!

Be sure to check back for regular updates.

Beau Parks is a keeper at the San Diego Zoo.

Read another blog about the San Diego Zoo’s harpy eagles