Arctic Shorebirds – Our second expedition 2001 – July 15
We must be among the few biologists who study the habits of innocent tiny bird chicks while armed. Because two bears set up temporary residence within sight of our esker we must now split into only two groups, each with shotguns. Our fifth bear, massive and slow, hauled himself over the ridge south of camp, lay down, and slept for the next three days. He slumbered near two of our three instrumented birds with broods, leaving little chance to work on them. Our sixth bear rested near the south ridge close to our only other instrumented knot. We attempted to work on our second to last day on the island but were forced to return to camp because both bears were out of sight. After working odd jobs around camp, Mark and Bruno found another brood close to camp. We followed them until dinner.
That night the second bear, our sixth, finally started moving. At 11:00 p.m., he started heading north on our esker directly toward camp. Johnny and I lit off in the ATV. The relatively small bear, either a female or young male, galloped away from us as fast as his long white legs would carry him. Although his limbs moved slowly, he covered a great distance with his long strides and within five minutes ran out of sight on the eastern horizon.
When not contending with bears, we concentrated our work on following four different knot broods, each in separate portions of our study area. Fighting wind, cold, fatigue and a burning desire to go home, we observed bird behavior and habitat use never recorded on North American knots. Nancy, Mandy, Steve, and I tried to follow the brood closest to the bear, but gave up when our only choice to follow them would have brought us too close. Mark, Bruno, Brad, and Barry successfully followed another brood while locating our seventh brood.
By the end of our trip the picture looks much clearer than two weeks ago. Although we need to combine our data with weather and snow information we can make some preliminary conclusions.
It appears that knots nest much earlier than the other species on this area of Southampton Island, which may have nested earlier this year than normally. While knots hatched more than a week ago, most of the other species hatched as we packed to leave. Because the knots nest so early, they seem more dependent on areas free of snow. In some years snow blankets this area well into the middle of June so the need for space can be critical, forcing birds close to the tops of the wind swept ridges. Last year the snows persisted forcing birds to nest in relatively small areas making them easier to find.
This year, however, the snow melted earlier. Early melt left more areas open for nesting so the knots spread out making them difficult to find. All the nests we found this year, used and abandoned, occurred further out from the ridges than last year. Over the course of our study, we found more nest cups used this year. We also found seven broods, five of those in areas searched last year.
Nevertheless, even late arriving species may be dependent on snow. We observed knot nests, golden plover nests, and long-tailed jaegar nests in close proximity. The association must be one forced by habitat availability. Jaegers feed their young the young of other species, a fact that cannot be lost on golden plovers nesting 50 meters away.
Numbers Getting Lower
In the final account, numbers were still lower than last year. We ruled out predation as a major influence because we lost less than 10% of the 70 nests in our study area. This included birds that nest on ridges, like the purple sandpiper and king eider, birds that nest near ridges, including long-tailed jaegers and golden plovers, and those that nest in the wetlands, like semi-palmated sandpipers and dunlins.
We have also ruled out our own negative effect, though not entirely. Our single nest pair included an instrumented bird from last year. We eventually found broods in most of last year’s territories. We are certain we lost pairs in the northern part of the esker near last year’s camp, but the reason may be that the area had very little snow free habitat. The esker is also poorly defined and more vulnerable to high winds. Only repeated surveys will tell us more.
One possible cause for abandoned nests was the windstorm that swept the region for two days in mid-June. The knots nesting close to or on the more exposed areas of the ridges may have abandoned their nests or had them destroyed by wind-driven rain close to hurricane force. We found over 200 nest cups that were primarily on exposed ridges. We found several abandoned cups. Steve found one with a long-dead egg.
Concludions the 2001 Shorebird Expedition to the Arctic
In the final analysis, it appears nest density fell this year because of conditions in the Arctic. It took a lot of work to conclude this but the experience was invaluable for several reasons. First, we now have a much better understanding of the important influences on nest density and productivity that we can discriminate from those of the Delaware Bay. Future trips will only improve our ability to detect changes, ascertain the reason, and determine whether they are related to the Arctic or the Delaware Bay.
Second, we learned much more about the behavior of these very complex birds. They stand out amongst other Arctic nesters. While they continued to baffle us with ingenious behavior tricks meant to confuse any animal from finding their nest or brood, we had little trouble with all other species. The experience will make our job easier in the future. We now know that we must arrive earlier in the Arctic, possibly early enough to see the last snow cover and the initial territorial behavior of knots and the other species.
Finally, our study matured this year from simply studying knots breeding on a few eskers to a broader study of knots as part of a rich arctic landscape of many habitats and bird species. Our difficulty in assessing the condition of knots pointed out the need to expand our emphasis to other species. This not only helped understand more about knots but also focus our attention on other species that come through the Delaware Bay. We know now that Southampton sanderlings come through the bay, and can reasonably conclude that semi-palmated sandpipers and dunlins do as well. In addition, this season’s forced emphasis on brooding chicks pointed to the enormous influence of the wetland complex that surrounds our eskers. All together, the expansion helped us tease apart the different influences of weather, predation, and snow cover from the influence that concerns us most, the decline of Delaware Bay horseshoe crabs.
Our work this year broadened our perspective to something closer to reality. The same shift has taken place in our work on the Delaware Bay. Initially, as we came to realize the importance of the bay as a stopover for shorebirds, all our effort went into protecting the bay’s beaches, where birds feed on horseshoe crab eggs. Through continued study, we now know the birds’ needs weave together all the habitats of the bay and adjacent Atlantic Ocean coast and that each species represents a different part of a sometimes very complex story. As improbable as it seems, NJ is a lot like the Arctic.
Our crew endured significant threat and hardship this year. Although chastened by this vast and wild land, they still worked hard with admirable good nature. All should be congratulated for a job well done.
We wish to thank the people who helped but were not with us. Kathy Clark took care of urgent needs including the airlift of oil. We missed her sorely from the team this year. Pelagie Sharp from Skyward Aviation helped right up to the end of our trip. We especially thank her for the oil drop. Shaun and Ed. our pilots, got us in and out without mishap. As Ed likes to say, I guess we got lucky once again.
We especially thank Jeff Tash and Jeff Smith for the creation of this web site. They set it up and pre-treated my field reports to make them web worthy. One of the chief functions was to inform our families and friends of our adventures. We all thank Jeff and Jeff.
Finally, we thank the Division of Fish and Wildlife’s Director Bob McDowell and Asst. Director Marty McHugh for their support. This work would be impossible without the financial assistance from the Wildlife Conservation Society, in particular Bill Weber and Stacey Lowe. Thanks as well to the Dodge Foundation and Lisa Garrison. Brad Winn received support from the Wildlife Resources Unit of Georgia Division of Natural Resources. The NJ field office of the US Fish and Wildlife Service supported this project and we thank Cliff Day and Annette Shearer. We also received flex funding from the Service through the Chesapeake and Delaware Bay Ecosystem team. Once again the entire effort would be impossible without the help of the Linda Tesauro and the Conserve Wildlife Foundation.