Harpy Eagles
Posted at 9:46 am September 16, 2008 by Mike Grue
The harpy eagles located on the Birds of Prey catwalk at the San Diego Zoo are a must see for both frequent Zoo visitors as well as for first-time guests. The first thing most visitors notice about these birds is the crest of feathers located on the top of their head. When the bird is relaxed these feathers give the eagle a cute, floppy look. But pay attention to their legs and feet! Those strong, thick legs and huge talons are anything but cute. Combined with their sharp beak, the harpy eagle is an impressive hunter. In their native range through much of South America, the larger female (14 to 20 pounds or 6.3 to 9 kilograms) will frequently capture monkeys and sloths from the high tree canopy.
The male (8.5 to 12 pounds or 3.8 to 5.4 kilograms) will hunt for smaller game in the same area as his much larger mate.
As with most raptors, harpy eagles have evolved to eat one big meal every few days as opposed to many little meals per day. For this reason, our harpy eagles are fed four times per week. When it is a feeding day, we place a thawed rat or rabbit inside the capture pen at the back of the exhibit. The male is almost always the first to make a move toward his meal. He becomes more and more vocal as he approaches his “kill.” He will even talk back to his keepers if we make a high-pitched whistle that mimics his own. When the male has his meal secured in his massive talons he will fly to his favorite perch in the aviary’s front right corner. This is a wonderful feeding habit as this perch is just inches away from stunned (and startled) visitors. If you happen to be in the area during the right time, you will hear a series of squeals coming from him before he starts to eat his catch. Sometimes I would swear that he is bragging about his tasty food to jealous onlookers!
As recently as a few weeks ago, the harpy eagles could be difficult to see in their enclosure. Their pen can get overgrown since harpies are too territorial to safely allow a tree crew to work next to the birds. This means the Bird Department has to wait for a chance to remove the eagles before working on their exhibit. Such a chance presented itself last month when the harpy eagles were caught for their annual West Nile virus vaccination. After the round up, we moved the eagles to a temporary holding area while the tree and bird crews overhauled the exhibit. The result is a beautiful exhibit with plenty of perching, shade, and great viewing opportunities! So come see the harpy eagles on your next visit to the San Diego Zoo. If you are especially lucky, you might see the male eating his lunch just feet away!
Mike Grue is a keeper at the San Diego Zoo.
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September 16th, 2008 at 1:09 pm
I’m kind of surprised they eat what you give them. Don’t they need to ” hunt” their meal? They don’t need to eat live animals? What would happen if something (like a rat or rabbit) went into their enclosure? Would they attack it?
September 18th, 2008 at 5:14 pm
thanks for the information on the harpy eagles. these are beautiful predators! we got to see them last week when we visited your wonderful zoo! the exibit is great. I like how we climb up the hill we are even with some of the trees and birds. they are huge. I see they are cousins of the american bald eagle! but, I didn’t see any bald eagles anywhere! can both predators be in the same enclosure? I really forget to take
into consideration about what species can be together and what ones cannot. were these eagles injured
at some time and unable to make in in the wild on their own? we did see some keeper walking along with a dead rat! maybe it was for the eagles?! loved it!
September 22nd, 2008 at 2:37 pm
Michelle,
To answer your questions: In the wild, many eagles will be more than happy to steal the kill from another animal…they don’t mind if they didn’t kill it. As far as captive eagles go there are very few zoos left in the world that will feed live prey to their predators. Though it can be hard to believe, there is an inherent danger in feeding live prey. Sometimes the prey can injure the predator, or the predator can injure itself during the chase.
You also asked about what happens if a small animal accidentally got into an eagle enclosure. If an animal accidentally wandered into a Harpy Eagle enclosure I believe the eagles would get their chance at catching live prey. I have seen our Harpy Eagles staring intensely at small mammals that are outside of their enclosure. I have the feeling that if both eagle and mammal were on the same side of the wire I would’ve been treated to a very interesting chase!
September 23rd, 2008 at 9:55 am
Thank you for answering my (many) questions Mike! I find it very interesting.
October 6th, 2008 at 10:24 am
Nancy,
I’m glad you enjoyed the exhibit! Our harpy eagles were not injured out in the wild, but were born in captivity about 20 years ago. Their many offspring (they get along very well) have since gone to other zoos around the world and even some have been released into the wild. We hope to have a new harpy egg in the nest in the next 2-3 weeks!
It was probably the Steller’s sea eagles that you saw were related to the bald eagle. The Steller’s eagle is a Russian cousin of our own eagle. If you get a good look at our Steller’s, you will see some similarities: the Steller’s is about 1/3 times LARGER than the bald. They are lacking the white on their head, but their bill and head shape is very similar. Both Steller’s and bald eagles are usually seen near water since their primary food source is fish.
Moderator’s note: We had a blog series about the Steller’s sea eagles if you’d like more information: http://www.sandiegozoo.org/wordpress/default/tracking-sea-eagles-part-3/
October 7th, 2008 at 10:39 pm
thanks Mike for the infomation on the harpy eagles and my misunderstanding of who was related to the bald eagle. I did go back and read all the previous information about the stellers eagle. very interesting!
it’s very sad that so many of these wonderful birds don’t live past that crucial first year! you sound very commited to your research and are to be commended! thanks again to your responce to my questions.
let us know about any harpy eggs! do they lay more than one? how long before they hatch? do both parents share in the care and feeding of the young? can you get a cam on the nest or is that too impossible? it would be really interesting if you could. I have witnessed cams on perigine falcon nests!
December 20th, 2008 at 10:58 am
I was just reading about your new chick. Had to come see what the adults look like! Very cool…I will definitely stop by to see these wonderful birds in person my next visit. Thanks for all the interesting information. I’m a recent bird fan (fueled by volunteering at Zoo Atlanta and getting to know the cool birds we have here).
January 7th, 2009 at 4:07 am
Great Info, They said that Steller’s, Philippine and Harpy Eagles are the 3 largest eagles in the world? and the most powerful are the Philippine and Harpy eagles both with enormous legs and large sharp claws capable of killing and carrying prey as large as deer and monkeys. they are adept in snatching monkeys, large birds and other animals from trees with continious flight and with great precision and agility in dense forests.
Any comment?
January 8th, 2009 at 12:26 am
I agree they are comparable but I think Harpy eagle is not the most powerful raptor in the world.
Records show that the Philippine eagles was documented to take and carry off heavier prey than Harpy eagles and more ferocious one like large snakes, monitor lizards and (macaques) large male monkeys can weigh as much as 20 lb, a 14 kg Cervus deer was found at one of the nest in MIndanao Island and It was also documented to attack a large python. (page 14-16 of ECOLOGY)
On record Harpy’s largest or heaviest prey item was a two toed sloth and red howler monkeys which can weigt up to 17 lb which the eagle cannot carry the whole prey weight and old world monkeys are heavier than New world monkeys of Central and South America.
Source:NatGeoMagazine/February 1995 issue
Authors: Neil Rettig and KIM Hayes
February 19th, 2009 at 7:32 am
What can students do to help conserve this species? If your curious as to why I ask I’m doing an endangered species project and I chose the Harpy as my species. I’m educating my class about the species and what they can do to help it live on.
March 4th, 2009 at 9:03 am
Mike, I enjoyed your description of the eagles and their ability as effective hunters.
Your work sounds fascinating and your real interest in the birds you care for is evident.
March 8th, 2009 at 4:50 pm
Dear Mike,
I am in third grade at Athens Christian Academy in Athens Texas. I am doing a science report on “Why Harpy Eagles only raise one of the eggs”. Do you have any information on this topic?
Thank you,
Paschall
March 14th, 2009 at 11:41 am
Paschall,
You asked “Why do Harpy Eagles only raise one of their eggs?”
It is a very good question. As you know, harpys usually lay two eggs per clutch, but only one egg usually hatches. Normally the first egg hatches and the second is ignored. So why does the female lay two eggs? The second egg acts as an insurance policy just in case there is something wrong with the first egg. If the first egg fails to hatch, the second egg has a decent chance of hatching–saving the parents the need to start over with a new egg!
March 15th, 2009 at 4:09 pm
Hi, Mike!
I am a fourth grader and would like to know what I could do to help the Harpy Eagle. I am doing a report on why they are endangered and would like to know how I can help keep this eagle here on earth!
Thanks,
Clarissa
March 16th, 2009 at 4:52 pm
Clarissa,
Thank you for your interest in helping harpy eagles in the wild!
One of the things that you and your class can do to help harpy eagles and many other animals living in South and Central America is buying shade-grown coffee beans instead of buying sun-grown beans. Coffee beans grown in the shade are more environmentally friendly than those grown in the sunlight. Why? In a nut-shell, shade-grown beans do not require the massive clear-cut fields that sun-grown beans need. The amount of clear cutting used to grow sun-grown coffee beans has unfortunately contributed to a reduction of rain forest habitat (thus reducing the harpy’s range).
Thanks for your interest, Clarissa!
March 17th, 2009 at 6:39 pm
Thank you for writing me back! I will tell everyone at school about this…even my teachers who like no, LOVE coffee!
Harpy Eagles are so pretty and strong. I hope we can find great ways to help the Harpy Eagles exist. I wish I lived closer to your zoo so I could see the eagles. Do you know of any places in the Northeast area of the United States that would have them? I know it gets cold here but I would love to see them up close.
Thanks,
Clarissa (and my mom)
March 24th, 2009 at 1:46 pm
I’m glad you sound excited to spread the word about shade-grown coffee, Clarissa! You asked if there are any harpys that might be on exhibit near where you live. To answer your question, I don’t believe that there are any harpys located in the Northeast. It’s great that you realize that these birds are most comfortable in warm climates, thus may be hard to keep in colder climates such as New England.
According to ISIS (International Species Information System)–a centralized database of collection animals–there are 36 harpys being kept by zoos around the world. There are 15 individuals in the States: a pair of harpys are in Oklahoma, while the remaining are found in Florida, Texas, and California. I hope you get a chance to see harpys in person very soon!
April 21st, 2009 at 5:10 pm
I’m in 7th grade and doing a report on Harpy Eagles. In all of my research, I have not been able to find a current population size. Would you have incite into what I should include in this part of my report? I keep seeing that unfortunately they only get counted once they are hunted and dead. So sad. Any idea of an estimate of a number I could use? Thanks! And thanks for all you do for these beautiful birds.
May 8th, 2009 at 8:44 am
How many are estimated to be alive?
May 12th, 2009 at 3:12 pm
i love harpy eagles
May 12th, 2009 at 6:31 pm
I’m doing a 3rd grade endangered species science project on harpy eagles. I need to show on a map both their current home and the area that was once their home, to show how much their range has decreased. I found their current home area to be northern Argentina to southern Mexico, but can’t find any maps or information about where they’ve disappeared from. Thanks for any information that you can give me!