Tuesday, November 25, 2008

Wintering goldens

Yesterday I drove through the sagebrush country of the Little Colorado Desert, which is always a pleasure as it serves as a winter home to migratory golden eagles. I’ve noticed our eagle population has substantially grown over the last few weeks – the birds arrive with winter temperatures. They come from the north, and most of our resident eagles head further south, although it appears there is some intermixing. A magnificent nearly black-colored golden arrived on our ranch a week ago. It is very shy, so I’ve been unable to get a photo yet.

But yesterday, there were three dark-colored goldens perched on fenceposts near a roadkill. Two were shy and immediately flew, but this youngster stayed around long enough for me to admire from afar. I stopped to watch these mainly because of where they were located – a small basin that gets a substantial wintering pronghorn antelope population. Over the last five years, Jim and I have watched goldens in this small basin as they actively hunt pronghorn in the wintertime – never at any other time of year (not hunting pronghorn fawns in spring). The eagles really get the herds running and spinning. We’ve never seen a kill occur though. So what’s the deal? Is this the same birds that keep coming back year after year to this certain spot? Is it learned behavior that we’ll be able to watch for years to come?

A few years ago, I was fortunate enough to witness a golden hunt and take down a pronghorn fawn, as the doe frantically struck the bird with her front hooves. This event happened a few miles from our house. What intrigues me about these other birds is that they are hunting relatively larger game. Any thoughts?


Steve Bodio said...

I know Goldens routinely hunt adult antelopes in the winter and personally know one biologist (and eagle falconer) who has seen the kind of hunting you describe result in a kill in the Red Desert. I would consider this "natural" behavior.

They can learn larger or stranger prey, both by themselves and from humans. You know about Kazakh wolf eagles and they also hunt roe, gazelle, saiga-- those three more or less equivalent to antelope (many have seen the Czech field meet video where the eagle knocks down a roe like a Gos with a hare).

The only recorded (and accepted by the Audubon Society-- see Incident at Eagle Ranch) case of CALF predation was on the Tigner ranch twenty miles from us in the seventies. It was messy. The culprits, subsequently trapped and moved I believe, were a single pair, who killed several. I know where a pair nests on that ranch now but there has been no recurrence.

Steve Bodio said...

I forgot to add-- if you Google it, Darren Naish has several good posts in his old blog on big prey and eagles, some with links back to us.

Reid Farmer said...

I just saw one of our wintering goldens on Thursday about 5 miles south of us while taking pix of a herd of yaks (?!) I saw on a small ranch down there. Got a pic of her (not as good as yours!) but will work it into a post in the next day or so.

Cat Urbigkit said...

Better post the yak photos too!