How to Catch a Curlew

Well, add another entry to my list of stories about loading up on coffee and heading out before dawn to chase birds.  This time, I had jumped at the chance to help Jay Carlisle, a researcher from Boise State University, track and capture long-billed curlews at the base of Heart Mountain, north of Cody.

Spoilers: We were successful. Meet “JT.”

Jay and his graduate student, Stephanie Coates, have been monitoring curlews via satellite in different parts of their range, to gain a better understanding of their habitat use and migration patterns.  The species seems to be doing reasonably well—population estimates were recently adjusted from 60,000 to about 100,000—but it’s spread thin across the West, and its dependence on grass- and shrubland habitats makes it vulnerable to land-use changes or the spread of invasive species.

The Heart Mountain population seems to be secure from a habitat standpoint:  much of the mountain’s eastern slope is managed by the Nature Conservancy, and is in good enough condition to host sage grouse, pronghorn, and at least one grizzly.  We carried spray and stayed in groups of two or three, but any bears in the area were apparently just as ready to avoid us as we were to avoid them.  Just across the canal at the base of the mountain, irrigated fields stretched for miles across the Shoshone valley; the contrast was unsettling, but the fields breed insects that make up much of the curlews’ diet, and at least at this time of year, pesticide application seemed to be the exception rather than the rule.

Within a few minutes after we arrived, I was able to pick out our targets’ whistling calls.  Spotting them was a little more difficult, even when they were airborne:  although they’re good-sized birds, and fairly distinctive in shape, flight movements, and wing plumage, the calls seemed to carry for miles, and more than once we tracked a bird by sound only to spot it on the horizon, much too far away to follow to its nest.  But as the sky lightened, and more of the female curlews returned from their night searching for calories in the flatlands, the mountainside came alive with squeals and tremolos, and zeroing in on a specific bird to follow and capture became the real challenge.

The males—both the paired-off ones finishing their shifts on the nest, and the singletons still hoping to convince a female to start one with them—started to pay less attention to us, and at one point two of them faced off and fought only a few yards away.  The Powell Tribune’s outdoor writer, Mark Davis, managed to capture a photo of the fight for his article on the curlew study.

It was all a little distracting, but once we spotted the nearest female and gave her some distance, we were able to glimpse the “handoff” as her mate left the nest and she settled onto it for the day.  From several hundred yards away, we couldn’t see the nest itself, but we could place it to within twenty feet or so.  Using a spotting scope, Dr. Carlisle noted a few landmarks around the nest (most of which fell along the lines of “shrubs of a particular shape, one of which appeared to be in flower”), and we set up a mist net between two poles and prepared to pay a visit.  We stretched the net out and walked towards our landmarks, while Stephanie used the spotting scope to keep us on target.  When we got close, the curlew stayed perfectly still in the hopes that her camouflaged feathers would prevent us from noticing her, but at Dr. Carlisle’s signal, we gently set the net down over her and the nest.

Extricating her from the net was the most nerve-wracking step, largely because of the risk of damaging the eggs; fortunately, all I had to do was hold down one edge of the net while Dr. Carlisle reached under the other side to untangle her.  While he took her back to the car to band, measure, and fit with a satellite tracker, Mark and I carried the net back, holding it taut to keep it from tangling on the sagebrush.

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