The Backyard Birdman

Golden Eagle juvenile photo by Hans Nydahl

I was driving home this afternoon in northern California and saw a large bird soaring fairly low over a very large grassy field off the road.  I thought at first it was a Turkey Vulture, as they are abundant in our area, but I noticed it had a definite white tail with a wide black band.  I had to pull off the side of the road and watch it for awhile to make sure I could identify it once I got home.

Well, I kept watching as this beautiful large bird rode the air currents, never flapping a wing, until as it soared higher and neared the upper elevations over a wooded area, a Red-Tailed Hawk began harassing the much larger bird.  I had seen Bald Eagles previously in this same area but this was not a Bald Eagle.  Once I returned home, I identified it as a juvenile Golden Eagle (the photo above shows a juvenile Golden Eagle being harassed by a gull, but the incident I witnessed was a young eagle being harassed by a Red-Tailed Hawk).

Now it is way past breeding time in our area for Red-Tails so I don’t think this hawk was defending a nest but perhaps just defending it’s hunting grounds and trying to run off the young eagle.

I’ve seen this behavior many times with crows or other small birds harassing much larger birds of prey.  This usually is an attempt to drive off birds of prey to protect nesting grounds, feeding territory or young offspring.

There is another behavior known as “mobbing” described here by the Royal Society for Protection of Birds (RSPB):  “Mobbing is a noisy, obvious form of behavior that birds engage in to defend themselves or their offspring from predators.  When a predator is discovered, the birds start to emit alarm calls and fly at the predator, diverting its attention and harassing it.  Sometimes they make physical contact.

Mobbing usually starts with just one or two birds, but may attract a large number of birds, often of many species.  For example, a chorus of different alarm calls coming from the same tree is often a good sign of a roosting owl or cat.  Mobbing behavior has been recorded in a wide range of species, but it is particularly well developed in gulls and terns, while crows are amongst the most frequent mobbers.”

The hawk and the eagle went at it a few times before the young eagle soared off toward my property but it was a very interesting interaction to watch.  Below is a photo of a mature Golden Eagle along with information on this beautiful bird of prey.

Golden Eagle (Aquila chrysaetos) photo by Walter Ammann

Size: 30-40 inches; Wingspread: 7 1/2 feet.  Adult; dark brown above with golden brown nape and white at base of tail.  Immature; seen in flight from below show well-defined white patches at base of primaries, white tail with distinct dark terminal band.  Inhabits mountainous or hilly terrain, hunting over open country for small mammals, snakes, and birds, also eats carrion.  In flight, tips of flight feathers are outspread and upcurved; soars high then dives for prey; occasionally hovers.  Nest is bulky stick mass on tree or high cliff.  Lays 1-3 white, blotched with red-brown eggs.  Resident from Alaska to Mexico, rare in the east, fairly common in the west.

If you have any information on birds of prey being harassed by smaller birds or other birds of prey, please share your experience with the rest of us so that we may all be better informed.

Thanks to Hans Nydahl and Walter Ammann for their super photos of these magnificent birds!  You can view more of their great photos by clicking on the Bird Forum link in the blogroll.

This entry was posted on Monday, October 15th, 2007 at 9:39 pm and is filed under Raptors, Bird Sightings. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.