A couple of days after returning from the Black Oystercatcher trip, I went out to Dusky Camp again to do Artificial Nest Island monitoring. The Artificial Nest Island Project was established in the 1984 on the Copper River Delta as a means to create more nesting habitat for dusky Canada Geese, following the earthquake of 1964 which greatly impacted the habitat of the Delta. In 1970, there was an initial increase of the Dusky Canada Geese population, however, after the post-earthquake succession and expansion of trees and shrubs on the delta, nesting habitat decreased due to the increase of perch sites for predators which led to an increase of predation. Dusky Canada geese populations drastically decreased in the early 1980’s and have since been listed as a “focal species” for the U.S. Fish & Wildlife Service, a “management indicator species” for the Chugatch National Forest and a “sensitive species” for the U.S. Forest Service Alaska Region. Thus, the Artificial Nest Island Program was created.
These artificial nests were designed and installed into 20 units (pictured below) across the Copper River Delta. They have been vegetated for good nesting cover using transplants, anchored into different ponds and monitored yearly. The Artificial Nest Island Program was created to provide safe, alternative nesting sites for dusky Canada geese. Since 1968, the average nest success of the 381 artificial nest islands has been 65%, which is nearly double the success of natural nesting sites on the Copper River Delta.
Monitoring these nest islands consists of evaluating every island for availability, species use and possible maintenance that the island may need to continue the effectiveness of providing safe, alternate nesting habitat. Maintenance needs consists of reattachment of anchors, vegetation landscaping for good nesting cover and relocation or rebalance of the island. Ideally, a nest island will be well anchored with at least 35% sweet gale vegetation for cover and a nest with clear indicators of successful hatchings will be found on the island. In these instances, we take data on the eggs and their success. When Ducky Canada goslings hatch, they peck their way around the nest from the inside out leaving them a perfect exit. Hatched eggs are left in two very distinct parts and the membranes of the eggs peel off from the inside of the eggs easily from successfully hatched egg shells. We use signs such as these in order to make reliable judgments about what happened to the nest and if it was predated or a successful hatch. For example, if we find a nest with many egg shells scattered around the nest island with no eggs in two distinct parts then there is a good chance that the nest was predated. There are many successful nests on artificial nest islands and it’s always a pleasure meeting sweet goslings during our work day.
To get to each of the nest islands, we airboat to appropriate starting locations where we then use a type of boat called a poke boat (it’s similar to a kayak) that we paddle from pond to pond around the delta. The Copper River Delta is full of sloughs and Alder line so there is a good amount of poke boat dragging and beaver dam crossing which is difficult and keeps us in shape throughout the season. Now that all of the artificial nest islands have been visited and we have collected data on which islands need maintenance. This week we are going back out into to the field, now that the peak hatching time of dusky Canada geese is over to revisit the nests that need some work. It will be a week full of learning about tools and preparing each nest island for success next year.