Expedition to the Arctic: Red Knot – June 26, 2003
In each of our five years of Arctic fieldwork we have encountered a critical problem that elsewhere would be minor. The first year we took insufficient food, a major difficulty when a plane drops you off and doesn’t return for 9 days. Two years ago we forgot oil for the generator and ATV, which made them unusable when the oil ran low. This year we forgot a critical cable that prevented us from sending reports from the computer to the satellite phone. Pete tried making an RS 232 cable using wires and plugs from the GPS units and a male plug from a dismantled computer. Unfortunately, we couldn’t jerry rig a replacement cable and now hope to obtain ours when we begin the next leg of the trip.
Our fieldwork progresses well. We have restarted point surveys, begun last year to create a second estimate of abundance in the same areas that were systematically swept for nests. We count all birds, seen and heard, and compare the results to the known number of nesting pairs. This year’s counts mirror the results of our first sweep of the main esker. We now estimate no more than 2 pairs along the 7km esker (Nancy found a second nest on our third day of searching.) Returning members of our team are struck by the absence of knots on the esker.
As of this writing we have swept both sides of the 7 km main esker, the 4 km southeast esker, the 4 km south esker and the 3 km shoreline of the unnamed lake at the end of the main esker. Although we have found nearly equal numbers of golden plovers and sanderlings as in previous years, we have found only one additional knot nest located on the south esker (3 total). We have great confidence in our method of finding nests, using 45 ft of rope with dangling strips of heavy black plastic between each of 10 people. Those on the outer edge, usually Pete, Mandy or Mark take frequent GPS readings so we can later plot the location of the swept area. This will insure good comparisons to previous years. On Thursday, we swept over 12 km of esker and lakeshore, leaving everyone exhausted.
We are testing a new method of estimating the exact date of egg laying. Following a method developed by Dr. Les Underhill of the University of Cape Town in South Africa, we weigh and measure length and width of each egg we find. At the end of our trip we will re-weigh the eggs. Using equations developed by Dr. Underhill, the difference in weight, relative to the constant size of the egg, will tell us when the egg was first laid. This year’s laying dates are vital to understanding the effects of the low number of horseshoe crab eggs on the Delaware Bay. The low number of eggs forced red knots and other species to stay longer on the Delaware Bay than they have for the last 17 years. Did this unusually long stopover prevent birds from nesting or did they just start later? Did they fail to reach the Arctic altogether?
We caught each of the incubating birds and banded them with a white flag, denoting the country of banding (Canada), and a yellow flag engraved with a unique combination of letters. We have banded a small group of knots in every year of our Arctic project adding up to no more than 30 knots. This compares to over 10,000 knots banded on the Delaware Bay, 1500 in Argentina, and 500 in Chile. These flagged birds provided the first estimate of survival rates in a shorebird species. Allan Baker and Patricia Gonzales used the resightings of flagged birds to determine that the survival rate had decreased in the last 6 years and suggested that if conditions persisted then the knots’ survival was endangered. We have seen the green flag of the Delaware Bay, orange flag of Argentina, and the red flag of Chile throughout the flyway, but it was only until this year that a white flag of Canada was seen (on the Delaware Bay this May.) If anyone sees one of the few birds we band this year, it will be a miracle indeed.