Arctic, Expeditions and Travels, Science

Knots At Last

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After 10 days in the field, 5 of them searching for knots, and with only one day before we must leave, we have at long last found knot nests – two, in fact. As we suspected, both still contained eggs, although one adult was also brooding a chick that was only hours old. Also as we suspected, we found them on small ridges in gravel-sized frost-cracked rock with very sparse vegetation.

The first nest we found had one hatched chick, so fresh you can still see the embryonic material in the shell.

The first nest we found had one hatched chick, so fresh you can still see the embryonic material in the shell.

Finding the second nest was lucky, but it wasn’t entirely an accident. Considering there are fewer knots than the number of potential knot nesting sites in our study area, knots could be following two possible strategies when they choose a nesting site: they could be fanning out at very low densities, or they could be clustering and keeping a certain distance apart. Our experience at our first red knot study site suggested the latter possibility. In the first few years, when knot populations were still fairly high, knots occurred along ridges one kilometer apart. This fell apart as the number of knots collapsed in the period between 1999 to 2006, but our experience suggested knots will stay together and keep territories of about one square kilometer. In other words, knots like their space, but they still want neighbors.

The second nest we found was on the side of an almost completely barren hill. Look closely in the center right to find the red knot nest. Here, the adult's head is visible.

The second nest we found was on the side of an almost completely barren hill. Look closely in the center right to find the red knot nest. Here, the adult’s head is visible.

See the red knot nest patch?

See the red knot nest patch?

After finding the first nest, we started searching about 1 km away in adjacent habitat and soon found a second nest. But by then it was close to the end of the day and we had only an hour or so to search for a third. Finding none, we rode the 4 miles of hard trail back to camp with some satisfaction. We will try again tomorrow to find more in the area, but unfortunately it will be our last day.

Finding a nest allowed us to capture the adult birds using a trap and attach geolocators, small devices that use light levels and the time of day to record location. We hope that next year (if there is a next year), we can find these birds again and retrieve the geos and their data.

Mark sets the trap to catch the nesting adult knot.

Mark sets the trap to catch the nesting adult knot.

The trap falls when the bird sits on a small line across the nest.

The trap falls when the bird sits on a small line across the nest.

Steve held the knots while we banded them and attached the geolocators, and Rick released them at their nests. Both birds immediately went back to brooding and incubating.

A geolocator, about to be attached to a red knot here in the Arctic

A geolocator, about to be attached to a red knot here in the Arctic

Josh holding a red knot before its geo is fastened.

Josh holding a red knot before its geo is fastened.

Steve held the knots while we banded them and attached the geolocators.

Steve held the knots while we banded them and attached the geolocators.

Rick released the knots at their nests.

Rick released the knots at their nests.

As this blog is written, rain is falling against our tent as it has through most of the night. Rain in the Arctic is always cold – more of a winter rain than one of summer. The knot nest with one chick will almost certainly have four by now, as it usually only takes 24 hours for all eggs to hatch. The adult will brood the chicks as best he can before and during the dangerous trip the young family must undertake to reach wetland feeding sites, sometimes a mile away. It’s not unusual for weather such as this to kill the young of knots, or the young of other shorebirds.

This is one of many reasons why Arctic nesting shorebirds have good productivity only once every 3 years or so. Arctic weather can be deadly and unrelenting. It’s the main reason why northbound stopovers like Delaware Bay must provide shorebirds with a good start every year.