This month's featured zoology books
at Amazon.com:

Red-tailed Hawk

Birds of Prey

The Raptor Almanac

Michael's Blog: A Day in the Life of a Zoologist

Red-tailed hawk nest monitoring (posted March 31, 2006)

Since the early spring of 2004, I've been monitoring the nests of three red-tailed hawk pairs at a reservoir owned and operated by a municipal water agency in southern California. They've been doing upgrades to the facililties there, and, per the Environmental Impact Record (EIR) written for the project, must conduct the construction in a way that does not harm the nesting raptors near construction areas during the breeding season. My company was hired to provide the biological services for the project. My duties include observing the nesting pairs during the nesting season in order to recommend an appropriate construction schedule, and construction activities, near nest sites.

It's been an amazing experience watching the hawks struggle to pass on their genes over the past two seasons. The first season was the most successful in terms of numbers of fledglings that left the nests - seven in all. But that season was not without some drama. The chick pictured here was approximately 6 weeks old at the time the photo was taken - this awkward-looking fellow was feeling a little ambitious one day and fell from the nest when hopping to a branch. At six weeks, red-tailed hawk chicks cannot fly, and there was no way he could get back into the nest. As you can imagine, the parents were freaking out. I was a bit concerned, too. I watched all day as the chick cried for its parents; the adult hawks tried feeding the fallen chick, but without much success. At the end of the day, I decided it was time to intervene and capture the chick. If it were left out all night, coyotes or a bobcat would certainly make an easy meal of him. I captured the chick, carefully placed him in a cardboard box, and transported him to a trailer located on the site. He spent the night there, and the next morning the construction crew brought in a manlift to help me place him back into the tree. Once in the manlift bucket, the operator lifted us as high and as close to the nest as possible before the branches of the western sycamore tree stopped us from getting any higher. We were a good eight feet shy of the nest, but I was close enough to a large branch that would safely keep the chick out of harm's way. I placed the chick on the branch, and snapped this photo of him. He successfully fledged a couple of weeks later.

The second season brought more drama as the same adult pair that fledged this chick lost two of their three chicks about three weeks after the eggs hatched. I searched for a reason for the loss of these chicks, but I was unable to find the cause of their demise. The surviving chick successfully fledged. In my third season at the site (this year) we've had more drama. It appears that one of the other pairs lost their eggs during a recent late winter rain storm. Storms are apparently a common source of nest failure, and unfortunately, this pair will have to wait until next year to nest again. Although nature has taken it's toll on the red-tailed hawk nesting pairs, I'm happy to report that the hawks have adjusted quite well to all the construction activities around them.

That's all for now. When I get a free moment, I'll post descriptions of some of the other projects I'm involved with, including habitat restorations for burrowing owl and coastal California gnatcatcher, and research on the ecology and conservation of desert tortoises.

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