Swans graze with elk and geese. Photo: John Gussman

Late Winter 2023–24 Update

This Conservation Matters column is expanded from the March — April 2024 Harlequin Happenings newsletter.

by Laura Davis and Liam Antrim

The winter of 2023–2024 started with a BANG! as our team counted a hundred swans pass overhead with a windstorm and still a week left in October. Half of them stopped over and swan counts settled down to relative low numbers that we would expect for a warm El Niño winter (as in 2014–15). See Figure 1. Our tallies this season have been one third to a half of what we typically experience. As the equinox approaches along with the restlessness of spring migration, we show a season high count of 89 and average of 60 swans at our daytime foraging locations between Sequim Bay and Agnew. See Figure 2.

*Figure 1: Peak and Average Numbers of Swans counted by OPAS Volunteers in the Sequim-Dungeness Valley, 2011–2024 (to date)*

*Figure 2: Numbers of Swans counted by OPAS Volunteers in the Sequim-Dungeness Valley, 2023–2024 (to date)*

The large, migratory Trumpeter Swans seem to travel only as far from their boreal forest breeding grounds as necessary. Our warm winter kept northern habitats open through December, and Trumpeter Swans found areas further north on their flyway to forage and roost – thus, the relatively low numbers of swans in our area this winter. El Niño periods may allow waterfowl distributions to be less compressed along the Pacific Coast, which eases food competition within and between waterfowl species. This may be a good thing for waterfowl in this region, but might not make for the best birding.

*Trumpeter Swans fly at dawn from Kirner Pond. Photo: John Gussman*

This fall, we hoped that broad dispersion across coastal and inland habitats would help reduce spread of the highly pathogenic avian influenza (HPAI). In fact, no HPAI has been seen in migratory waterfowl in our area except in mid-November, when 34 Cackling Geese and one American Wigeon succumbed in an outbreak primarily in the Schmuck Road area. WA Department of Fish and Wildlife (WDFW) and Discovery Bay Wild Bird Rescue Center are not aware of any other cases in swans or geese from our area.

The major story for January 2024 was the polar vortex that pushed an arctic cold front through our El Niño weather in mid-January. Low temperatures down to the single digits Fahrenheit with negative-degree wind chill factors and snow accumulations affected swan roosting and foraging in the lower Dungeness area. In spite of the severity of this storm, the swans stayed around. Salt water and shelter of Dungeness Bay allowed the swans to roost overnight as frozen inland freshwater bodies were slow to melt. Tidal influence on estuaries kept emergent vegetation available when pastures were snow covered. Warm temperatures returned after a few days, and we recorded an unseasonal 57 degrees during the January 31 survey.

*Trumpeter Swans on a February morning. Photo: Steve Koehler*

During the two coldest weeks of January and WDFW's mid-winter survey, we extended our scope east to Chimacum Creek in Jefferson County and west to the Wa'atch River near Neah Bay. While we counted 76 Trumpeter Swans in our area, 90 Trumpeters and one Tundra Swan foraged on rain-flooded pasture grass adjacent to Chimacum Creek, with conditions five degrees warmer than here. This is our first record of a higher count of swans on that valley's watery agricultural landscape than in our rain-shadow location. The Port of Port Townsend recently purchased the 253-acre Short’s Family Farm and is actively planning agricultural land conservation and drainage objectives. Habitat for migratory swans and geese are not currently included in their goals.

The food habits of the Pacific Coast Population (PCP) of Trumpeter Swans are unlike other swan populations and species. In our area, swans were first documented on Lake Aldwell, the reservoir created by the lower Elwha dam. Swans are drawn to water bodies and grass-like plants. They graze on grass fronds and grub for their rhizomes – whether on a wetland or agricultural landscape. Likely first attracted to rain-flooded fields, swans acquired the habit of grazing on dairy pastures in late 1970s.

Previous studies of Trumpeters Swans within the PCP indicate forage selection based on quality rather than availability. Pasture grasses are higher in protein than the estuarine foods. Applications of nitrogenous fertilizers and the frequent mowing has resulted in a feed high in protein for livestock. Swans' attraction to an area can be due to the availability of resources like dairy pastures. Swans first observed wintering along the Pacific Coast were found exclusively in pasture but today, swans feed on a half dozen other agricultural crops and continue to expand their geographic distribution. Here, that includes corn, winter wheat and other grains, and tubers such as carrots and potatoes.

*Swans graze with elk and geese. Photo: John Gussman*

Trumpeter Swan nutritional needs and overwintering habitats in the Pacific Flyway are neither well understood nor are data up to date. It has been 30 years since regional studies of Trumpeter Swan forage focused on the areas of their greatest overwinter use: the Skagit River valley and the Comox River estuary. Cal Poly Humboldt and WDFW are collaborating on a new research study, now underway in the Skagit, that will answer some of the key questions we have about the forage needs of over-wintering swans. Using data derived from GPS collars on 23 Trumpeter Swans wintering in the Skagit, the analysis will focus on swans' spatial distribution among certain crop types in relation to all available food resources. The researchers expect that quantifying forage resources on private land will provide the fodder for conversations about swan conservation.

With a lack of freshwater wetlands, swans in the lower Dungeness rely in part on water resources managed for people including for irrigation and for duck hunting. Swan movements between roosting and forage sites vary through the season, and from winter to winter. They have used nineteen separate fields this year and six overnight roosting sites. One of the roosting sites was a new observation this year: a reservoir in a rural subdivision offering pondweed for overnight grazing.

*Swans on Kirner Pond. Photo: John Gussman*

Foraging locations also change due to agricultural decisions regarding crops grown and farming practices. In recent years, we have seen herbicide applied in midwinter to some grassy fields where swans have been foraging; these are abandoned as the plants die off. Typically, we see these fields tilled and planted with corn the following spring.

Due to harvest methods, equipment and conservation goals, crop residues may be left post-harvest – a condition that has no match in the swans' natural wetland landscapes. We have seen swans attracted to abundant carrots remaining on the ground post-harvest. On the flip side, the efficiencies in clean harvest of local silage-corn fields may leave little of interest to returning swans. Winter cover crops planted this past fall to reduce erosion and soil compaction and to reduce fertilizer costs are an excellent source of protein in spring and extend swan use of corn fields through to migration.

*While corn residues at Mid Valley Farm attracted swans at season start, the winter cover crop draws them at season end. Photo: John Gussman*

Our understanding of Trumpeter Swans has skyrocketed over the course of our study due to the engagement of our team. If you are interested in joining the swan team, please contact us.

We would like to recognize the contributions of Kendra Donelson, our dear colleague and friend who passed on. Kendra has surveyed ever since the early days of the OPAS swan surveys. We miss her loving spirit.