Sunday, February 10, 2013

Regional Feeding Behaviors of the Golden Eagle

The Golden Eagle (Aquila chrysaetos) is one of the world’s most successful birds of prey and is found almost everywhere in the northern hemisphere. 

Probably because they can catch and eat so many kinds of animals, they can occupy many types of habitat.  The Golden Eagle primarily feeds on small mammals, but is known for its ability to take much larger prey, such as newborn goats, deer, and livestock.  With over 200 different species of prey known, the Golden Eagle is a formidable and opportunistic hunter.

Ordinarily the Golden Eagle is found on or near the slopes of mountains.  They have a few different ways of capturing food.  Most often they can be seen gliding on the thermals and updrafts created by the mountain slopes as they scan for prey.  However they have also been documented pouncing on unexpected prey from a high vantage point, catching birds in mid flight like an accipiter, flying to great heights and tucking their wings and going into a stoop to gain speed and catch prey like a Falcon, and finally Golden Eagles will steal and feed on prey from other predators.

Regionally the Golden Eagle will hunt a wide variety of prey.  In North America the primary food source consists of rabbits and ground squirrels, but are not limited to just small prey.  During the nesting season the adult eagles must feed their young and are forced to hunt much more frequently to feed the nestlings.  Another alternative is to take larger prey, and this drives the Golden Eagle to hunt prey items such as deer, goats, and small or young livestock (sheep/cows).   The majority of the time the Eagle will dispatch the larger prey items with their incredibly strong and large feet and very long talons, and frequently will return to visit the carcass, taking manageable portions to their young.

In Europe the Golden Eagle has shown its true adaptability when picking out its prey.  In the Southeast of Europe Golden Eagles have taken advantage of the abundance of tortoises.  Similar to the Lammergeier, the Golden Eagle will pick up the tortoise, gain altitude, and then drop the tortoise and let gravity take care of the rest.  

In the breeding grounds of a Caribou herd in the arctic tundra the Golden Eagle is one of the most frequent predators of newborn calves. 

On the island of Gotland in Sweden, the Golden Eagle has become a specialist.  Their primary food source in this area is Hedgehog’s, and they have developed the ability to peal the spiny backs off to avoid injury. 

The most famous Golden Eagle prey items in my opinion are the mountain goats of Kazakhstan.  There, Golden Eagles have been filmed swooping from the sky and picking up young goats to toss off the side of a cliff.

The Golden Eagle is foremost an opportunistic hunter that will prey on animals that it can overpower, but is not limited to only small prey due to the size of the Golden Eagle. This large eagle is for the most part the apex predator of the sky in its home range. The only place where they are not the apex avian predator is in Russia where the Stellar Sea Eagle claims that title.

The Golden Eagle is such a successful predator in part due to their opportunistic behavior, large size, and adaptability to different environments. 

To get a close-up view of this apex predator, visit the World Bird Sanctuary where there are several of these magnificent birds on display every day.  

 Submitted by Adam Triska, World Bird Sanctuary Field Studies Coordinator

No comments: