Trumpeter Swans fly west across Kirner Road at dawn after power line removal. Photo: John Gussman
Mid-Season 2021–2022 Update
This Conservation Matters column is from the January - February 2022 Harlequin Happenings newsletter.
By Laura Davis and Liam Antrim
With such robust swan numbers in our Sequim-Dungeness area last winter, we watched the skies this fall and had to simply hold onto our hats. Predictions of colder and wetter-than-average weather due to La Niña were verified with rain and strong winds across the Salish Sea, which may have hindered or diverted the swans' migration across the Strait of Juan de Fuca and the Salish Sea. We counted over 20 swans by early November. The tally increased in mid-November and held steady at +/–80 swans through mid-December. Then, after several nights of a clear skies and bright moonlight, our team counted 132 swans on December 20. The temperatures, snow and hazardous travel conditions of late December risked safe survey by volunteers and delayed our counts until the new year 2022.
Our over-wintering Trumpeter Swan population has increased during the past ten years of OPAS surveys. The winter of 2020–2021 may prove to be exceptional, with average-count data reflecting a strong autumn arrival and swan numbers that remained high throughout the season. We counted 183 swans on December 1, 2020, versus 75 this year on November 30, 2021. We are now a third of the way into this winter, and it's still too early to know how this year will compare with previous. While annual differences in timing, numbers and usage may involve a complex interplay of many variables, we can expect to see longer-term change over time due to factors such as climate instability, wintertime habitat availability and habitat quality.
Our winter surveys document local numbers, distribution, habitat use, and changes in agriculture. For further information, download the OPAS Swan Team's 2020–2021 data-analysis graphics from our OPAS Community Science webpage.
Habitat and Forage
The Pacific Coast population of Trumpeter Swans that we see in western Washington spend summers along Alaska’s southern coastal plain, and the interior boreal forest and taiga habitats of Alaska, western Yukon and northwestern British Columbia. Studies show that the positive effects of breeding season habitats expanding northwards due to extended ice-free periods have outweighed the negative effects of wetland shrinkage in those habitats due to climate change. Researchers suggest the availability of sufficient wintering habitat may ultimately control and limit swan population growth. We can certainly see the changes in land use in our local area, with agricultural land converted to home lots and development encroaching on wetlands and small lakes. The swans are surprisingly tolerant during their daytime foraging activities adjacent to roadways, but are more sensitive to human disturbance at their roosting sites where there is also a negative association with nighttime lights.
As we write, freezing temperatures and snow cover are limiting access to both day and nighttime forage, as well as open freshwater for roosting. Nocturnal foraging helps generate body heat during the coldest time of the day. While we are seeing some swans on roosting sites that are totally frozen-over, others are seeking out locations that do not pose additional threats of predation, such as our saltwater bays.
Daytime forage for swans in winter includes pasture grasses, small grains, and tubers. This year, as is typical during our Sequim-Dungeness autumns, the swans have foraged largely on harvested corn fields, where they can find broken corn cobs and kernels. Fields over-seeded with cover crops in the fall become more attractive as plants grow and are available to diversify the menu. We also find the swans foraging on pasture grasses. Although our area has many fields managed for hay, we see the swans primarily on pastures and hay fields adjacent to previously harvested crops. Following our late-December snowfall, the swans discovered the carrot fields and shifted foraging usage in that direction. We are in touch with WDFW and the farmer to assist as requested in dissuading the swans from foraging on unharvested crop.
Trumpeter Swans forage in harvested corn field. Photo: Dee Renee Ericks
Through our regular counts and observations, we discover patterns that – fueled by our volunteers' interest and curiosity – spark further questions and commitment to the surveys. Researchers and ornithologists contributing to Cornell Lab of Ornithology's Birds of the World have identified gaps in understanding and research on swans' winter forage needs, information necessary to adequately protect and manage critical habitats into the future. These include:
foraging ecology and nutritional needs: differences between migratory versus sedentary swans, and between swans foraging on agricultural crops versus aquatic vegetation.
migration behavior and ecology: specific data on pre-migratory and migratory behavior and on the exact routes and sites used during migration.
Although the impacts of climate change on individual avian species are unknown, long-term and wide-spread monitoring programs – like the five-year North American Trumpeter Swan survey planned for mid-January – provide the best opportunity to identify population-level effects. We provide data and our team's analysis to WDFW, the Northwest Swan Conservation Society, and to the online audience via the OPAS website. We are grateful for our strong and reliable volunteer team dedicated to this long-term study. In addition to broad weekly surveys, volunteers also watch sites near their homes, participate in our monthly roosting surveys, and provide their observations when swans hit power lines or are otherwise injured.
Safe Flights and Power Lines
Even with successful mitigation efforts, power lines continue to pose a primary hazard to swans in our Sequim-Dungeness region. At Kirner Pond, the donation-funded power line removal project this past summer has prevented any further injury and casualty as swans fly from this important roosting site each dawn. This season, swans lifting off the pond to the west pass closely above the large willow shrubs at the Kirner Road edge – heights at which swans would have previously struck the power lines. Recent ice on the pond has meant some interesting take offs in a short amount of space. Volunteers continue to regularly monitor the pond this year, post-mitigation. Thus far, atypical prevailing winds, takeoffs to the east, and lower swan population are factors that may support continued observation beyond the current season.
Trumpeter Swans fly west across Kirner Road at dawn after power line removal. Photo: John Gussman
This season's hotspot for hazards has been Evans Road, as John Acklen and Shelly Ament describe in the January/February newsletter. Alerted by social media, swan-team members helped WDFW watch, assess the swan flights and locate the areas of potential hazard. This was the first year this field was planted with corn since OPAS swan surveys began in 2011. Shelly was able to attribute three early-season swan mortalities to a power line leading to an irrigation pump. PUD quickly and temporarily removed the short span. Markers on power lines adjacent to the Evans Road fields will make the lines more visible in low to no-light conditions – very important at this location between two of our main roosting sites. Because it can often be difficult to identify the cause of swan injury and mortality, it is so useful when neighbors contact PUD, WDFW or OPAS with descriptions of suspected problems.
We extend our Sequim-Dungeness surveys to the Miller Peninsula and Port Angeles to monitor usage at roosting sites, some of which are on private or restricted access land. We primarily view swans from public road edges and are especially grateful to our local landowners tolerant of our swan-monitoring and count activities. We also serve the community by informing WDFW if swans seem to be causing crop damage. Intensive use of the road edges by other bird watchers makes landowners more reactive to our weekly survey presence. Please be mindful of private property, but if you are aware of swans using unsurveyed sites, please be in touch.
We all gain sustenance from our community and by working on projects larger than ourselves. Our OPAS teams share camaraderie, service to the community and time spent in nature. If you have interest in joining our group of surveyors or site stewards, please contact the OPAS Conservation Committee co-chairs.