Partnered with the Washington Department of Fish and Game (King County), United States Forest Service (Colville District), Spokane Audubon, and Hancock Timber Resource Group, BRI is investigating Common Loon population trends throughout the state. Since beginning annual banding efforts in 1995, BRI has banded more than 100 Common Loons in Washington State.
Above: Washington Common Loon population study area. Loons from Bonaparte, Swan, and South Twin Lakes represent individuals who have held territories for the longest terms. (Age of each loon assumes age at first breeding is six years.)
The statewide breeding loon population is currently 22 known pairs, with an estimated six pairs in the western range and 14 pairs in northeastern Washington.
In Washington the number of known territorial pairs has ranged from 6 to 23 from 1996-2019. This variation over the 24-year time period is typical for bird species.
Productivity in Washington for the last 24 years was above the well-established sustainability threshold value of 0.48 chicks surviving per territorial pair. For the past seven years in particular, productivity has remained above threshold levels, and this may be related to the increase in territorial pairs now being observed.
Protection of loon breeding habitat is critical to maintaining the integrity of loon populations and avoiding increased degradation of suitable breeding habitat. Because of its status at the top of the food web, high visibility to people, limited dispersal ability, and relatively slow replacement rate, the loon is widely used as an indicator species for tracking aquatic integrity.
General threats to this population during the breeding season include: (1) direct human disturbance to nests and chicks; (2) water level fluctuations of territorial lakes and reservoirs; (3) changes in prey abundance; and, (4) contaminants. Washington’s wintering loon population is susceptible in marine waters (see Figure 1) to hazards such as oil spills and commercial fishing nets. Loons are long-lived and have relatively low fecundity—therefore, Washington’s breeding population is at particularly high risk to anthropogenic stressors.
Evidence of the loon’s ability to acclimate to changing conditions demonstrates that properly designed conservation efforts can be beneficial. General threats to North America’s loon population are well-established. We recommend prioritizing the following actions to help maintain their long-term sustainability.
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