Although Trumpeter Swan numbers have increased since the early 1900’s there are still some key concerns. The Canadian Egg Collection Project (CECP) was initiated to address these concerns which include: 1) Low heterozygosity (genetic diversity) in the Rocky Mountain Population of Trumpeter Swans due to low population densities and 2) Limited connectivity between breeding flocks.
The CECP was a three-year (2007-2009) cooperative effort between the Wyoming Wetlands Society, the United States Fish and Wildlife Service and respective Federal and Provincial authorities in British Columbia, Canada.
Goals and Objectives
The goals of this project are: 1) increase the numbers of swans available for range expansion and connectivity efforts within and adjacent to the core range of the Tri-state (Wyoming, Montana, and Idaho) flocks to achieve objectives specified in the Pacific Flyway Management Plan, 2) increase heterozygosity levels in the Rocky Mountain Population, and 3) reestablish historic migratory routes in the Rocky Mountain Population.
Collection efforts (annual trips) were conducted in late May to early June. Each collection effort consisted of a three-person team surveying from a helicopter to locate occupied Trumpeter Swan nest within the defined study area. Once a nest was located a single person would kayak to the nest and retrieve eggs. Project protocols required that at least two viable eggs were left in each nest and only nest with four or more eggs could be collected from. After each collecting effort the eggs were examined by a veterinarian and secured in portable incubators for transport back to Jackson, WY.
Canadian Wildlife Service officials conducted post-monitoring flights each year in August to determine if egg collecting efforts were causing nest territory abandonment. Cygnets were counted to compare the number hatched versus the number of viable eggs left in each nest. No discernable abandonment of territories or reduction in cygnet numbers was detected during this project.
A total of 180 eggs (60/year) were collected during this project. In 2007, 58 of the 60 (97%) eggs hatched. In 2008, 52 of the 60 (87%) hatched. And in 2009, 44 of the 60 (73%) hatched. June of 2010 marked the final release of swans produced from this project. Since Trumpeter Swans do not typically reach reproductive maturity until 4 or 5 years of age it is difficult to measure the success of this project. However, marked swans have been reported along migration routes, at wintering areas and returning to release areas annually. More importantly, some of the marked swans have been observed with other marked swans and wild-hatched swans exhibiting pair bonding behaviors.