2024–2025 Season Summary

Trumpeters land on Graysmarsh Farm. Photo: John Gussman

2024–2025 Season Summary

OPAS Swan Team's 2024—2025 data-analysis graphics

by Liam Antrim and Laura Davis

 
 

With fourteen years of surveys by Olympic Peninsula Audubon Society volunteers in the files, we have observations and data that help us define patterns for Trumpeter and Tundra Swan presence and habitat use in the lower Dungeness Valley. Yet each season comes with a few discoveries and broadens our understanding.

Arrival/departure dates – Considering the variability in weather conditions throughout the summer breeding habitats, the swans' migratory pathways and the thousands of miles travelled between these distant locations, the timing of swan presence in our area seems remarkably predictable. This past winter, swans were sighted on our surveys between October 23, 2024 and March 26, 2025, over a 155-day period (Figure 1). Although swans were seen locally a few days earlier, we are using only OPAS survey counts in this analysis. In past survey observations, our first Trumpeter swans were counted as early as October 25 (2023) and as late as November 18 (2015). Following the call northward, our last swans have been counted between March 17 (2019) and April 2 (2023). The 2023–2024 season was the longest we have documented, with swans present in our area at least 160 days. The shortest swan overwintering period was 2015–2016, with swans counted across 121 days.

Figure 1: Numbers of Trumpeter and Tundra Swans Counted During Midday Surveys by OPAS Volunteers, 2024–2025

Peak count – Our highest count of the season varies significantly from year to year, both in numbers of swans and timing. This may be partly driven by transient swans rather than simply representative of the overwintering flocks. The highest count this winter was 116 swans, recorded mid-winter on January 21, 2025, after which the count remained stable through mid-March (Figure 1). The peak counts for all OPAS swan-survey seasons in the Sequim-Dungeness area have ranged from 89 (2024) to 258 (2017), both peaks occurring in late February during the period of northward migration (Figure 2). We have also seen peak counts during southward migration periods. During the 2022–23 season, we counted an unusual post-breeding peak of 201 during the autumn southward migration on November 23. Observations from regional sources have helped us understand that as swans pass over the lower Dungeness Valley, some stop off for a short visit resulting in higher swan counts while some remain with us for their winter residence.

Figure 2: Peak and Mid-Winter Average Numbers of Swans Counted by OPAS Volunteers, 2014–2025

Mid-winter average population – We know that swan numbers in our area fluctuate as swans migrate to, from, and past our area in the fall and spring. By eliminating periods of shoulder season migration and variability, we can calculate what could be called the mid-winter average population. We selected the survey period between December 7 and February 15, which eBird designates as the overwintering period for our Pacific Coast Trumpeter Swan Population. Since 2014, our average mid-winter population has ranged from 68 swans (2023–24) to 201 swans (2020–21) (Figure 2), with an overwintering average over this period of 132 swans.

WDFW and the Northwest Swan Conservation Association conduct an annual regional swan count every year in mid-January covering the area between Sumas Prairie, B.C. and King County. They note similar population fluctuations on a larger scale – with counts roughly 100 to 150 times the swan population we tally locally.

Percent juveniles – Juveniles made up 14.5% of swans counted by OPAS in this 2024–25 season (Figures 1 and 2) and during the mid-winter period – a fairly typical percent juveniles in our surveys. Percent juveniles in mid-winter surveys were below 10% in one year (2022–2023) and greater than 20% in one winter (2015–2016). This metric depends on habitat conditions throughout the swans' year, as we have described in our previous reports. Weather conditions can contribute to lower juvenile survival both on the breeding grounds and during migration. Our 2022–23 population provided powerful examples of this. The cool Alaskan spring of 2022 delaying nesting and fledging, and hence, successful southward migration the following fall. Some swans may have faced the heavy snowfall across British Columbia during northward migration the following spring of 2023, or some may have altered their path to follow the warmer coast. Further, habitat conditions in the overwintering areas also contribute; adult swans that are well fed and in good condition at start of northward migration may have a larger clutch size and higher juvenile survival. We do not have a way to determine whether our overwintering swans are well fed and prepared for their northward migration before they leave us. That we rarely see dead juvenile swans indicates that swans that overwinter in our area find adequate nutrition for winter months.

Swans forage on harvested corn fields (stubble) overplanted with cover crop winter grains along Lamar Lane in December. The residual grains of corn provide carbohydrates, and the winter grains provide green protein. Photo: Bob Boekelheide

Daytime habitat use and foraging – Early in their winter residence here, swans foraging during daylight hours typically target harvested corn fields in search of kernels of grain high in carbohydrates (Figure 3). This past winter, these fields were along Sequim-Dungeness, east of the Sequim Valley airport, and between Lamar Lane and Woodcock Road  (Figure 4). Through early December 2024, nearly all swans were foraging on fields between Sequim-Dungeness and Evans roads. All of these corn fields had been harvested then over-sown with a winter grain crop, which was just emerging at season start and then became increasingly attractive forage for swans as new green shoots grew through the winter.

Figure 3: Observed Swan Habitat Usage During Midday Surveys, 2024–2025

Figure 4: Observed Swan Location Usage During Midday Surveys, 2024–2025

Starting in mid-December, swans supplemented their foraging with pasture grasses, primarily west of the Dungeness River. Both grazed and new-growth grasses are high in the protein essential for egg development in advance of northward migration and nesting. Swans also were attracted to planted food crops like Brussels sprouts. We had two reports of swan damage this year to brassica crops and winter wheat – these at Graysmarsh Farm and Wheeler Farm on Ward Road. We put both farmers in touch with WFDW's local Biologist and Conflict Specialists.

Carbohydrates provided by carrots have sometimes proven irresistible to swans during cold snaps, causing extensive damage to valuable crops. Our last record of swans foraging Clapp Farm carrots was January to March of 2022 – the most recent crop of carrots at that Anderson Road location. Over these two past winters, 2023–25, carrots planted in No Goat Farm fields southwest of the intersection of Woodcock and Towne roads have not been visited by swans in spite of this field's proximity to the Kirner Pond roosting site. We don't know why; this may be in part due to timely cover cloth application during the coldest part of winter, which can protect the crop from both cold and swan damage.

Proximity to water – During the relatively dry conditions of the past few winters, we have seen more midday swan flights off the fields to freshwater sources, such as small ponds constructed for agricultural purposes. We continue to see wet fields – some undulating or with adjacent swales – draw swan usage and help provide adequate daytime water for digestion of forage. However, by late season, we are witnessing swans flying back and forth between food and freshwater sources while foraging pasture grasses and the fresh, green blades of winter grain plants. We saw these swan flights between forage and water near the airport these past two seasons – the pond being on Spath Road west of Carlsborg. This past season, we saw no use of Delta Pond near Schmuck and Port Williams roads.

We continue to be interested in the ever-changing relationship between swan selections for overnight roosting and daytime foraging, which our dawn surveys are often able to capture. Most of the swans roosting at Gierin Marsh in late February and March started their day with a one-minute flight to the Graysmarsh Farm fields mentioned above. This counts now as one of our more exceptional adjacencies of a roosting site to a foraging location.

Following overnight roost at nearby Gierin Marsh, swans land on a Graysmarsh Farm field of winter wheat near a Brussels sprouts crop. Photo: John Gussman

Roosting – Our once-per-month dawn roosting surveys offer a limited snapshot of where our swans spend their nights (data-analysis graphics). This frequency does not capture the short-term variability in roosting site use that we see from daily observations at a few of our roosting locations. Monthly roosting surveys have proven useful to help us understand which roosting locations are being used through the season, and to provide a check on how complete our swan counts are by comparing roosting to foraging numbers.

With daily roosting counts available, Kirner Pond provides insight into roosting site dynamics. As we have observed in the past, this relatively small body of water hosted the majority of roosting swans for much of the 2024–2025 season, with about 3/4ths of our swans from mid-November to late-January. In late January 2025 all but a few swans abandoned the site, a timeframe that coincides with the end of the waterfowl hunting season at other sites. Two weeks later, about half our swans returned to roosting at Kirner Pond, but their numbers decreased steadily as the northward migration began. Daily observations at Roberta's Pond off Three Crabs Road revealed a pulse of roosting swans when few were at Kirner.

We do not have swan roosting observations for Gierin Marsh on the Graysmarsh property except for our monthly roosting surveys. We survey this location by drone to reveal hidden portions of the marsh. Monthly surveys revealed that numerous swans had shifted to this roosting site in late January and February. Our network of observers in the Schmuck and Port Williams Road area did not observe any use at the local constructed reservoir this season. We are uncertain if this relates to the swans' roosting or foraging choices, however swans were also not seen foraging in adjacent fields.

An early February morning, before the swans fly from the wetland landscape near Sequim Bay. The swans only use Gierin Marsh when open water is sufficient. Photo: John Gussman

Further south, a small lake in Happy Valley offers another dynamic roosting site where daily observations revealed roosting use in mid-November, perhaps as a shorter stopover for swans migrating further afield, then very few roosting swans through the season with the exception of an occasional night when a dozen or more swans were sighted.

On the west side of the river, small ponds that provide daytime water have also hosted overnight roosting swans in the past two years. This year, we verified swan use of the pond on Spath Road west of Carlsborg providing both day and nighttime habitat and, two years ago, verified overnight roosting by swans at Solmar Lake.

In recent years, we have also observed loss of local roosting habitats, for example due to the encroachment of the non-native reed canary grass across the hunting-club ponds west of the Olympic Game Farm. This season, open-water wetland habitat was very limited in these ponds, while we recorded swans roosting January through March of the previous winter, 2023–24.

Tundra Swans – Tundra swans usually are observed migrating through our area in late October; most winters a few do remain in the lower Dungeness Valley mixed in with Trumpeter Swans. Although Tundras can be difficult to identify in a large group of Trumpeters, their smaller size and yellow near the bill in the adults distinguish the species. Careful observation of yellow bill markings can allow identification of individual Tundra Swans. Beginning in October, we observed a single juvenile Tundra Swan that was noted in our surveys through mid-January. Curiously, we saw three Tundra Swans during our New Year's Day 2025 survey – the one juvenile off Evans Road and an additional adult and juvenile by the airport.

GPS-Collared swan – An ongoing research collaboration between CalPoly Humboldt and the WDFW Waterfowl Section is studying swans' spatial distribution among crop types in relation to all available food resources. The study intends to characterize the requirements of migratory waterfowl here in Washington during the non-breeding season, as well as timing of migrations, locations of breeding grounds and migratory stopover sites. For this study, the research team installed GPS tracking collars on 19 Trumpeters in the Skagit Valley. We introduced this work in the March/April 2024 Conservation Matters column. In March 2025, Kyle Spragens, WDFW Waterfowl Section Manager, gave a presentation to the OPAS audience on this study highlighting the unique ways state-of-the-art tracking technologies can increase our understanding of migratory waterfowl.

Trumpeter Swan GPS collared for WDFW–CalPoly Humboldt study prepares for flight from the irrigation pond at Woodcock and Kirner roads, dawn of February 18. Photo: Bob Phreaner

Although most study swans overwintered in the Skagit Valley, one collared swan spent the winter in the lower Dungeness Valley, arriving on November 28 and leaving on March 17. The detailed track lines for this swan documented what we observe – regular daily movements between evening roosting and daytime foraging sites. More interesting was documentation of movement between multiple foraging sites in a day, some possibly exploratory excursions for food or company. As it left the area to migrate north on March 17, it flew from Gierin Marsh, landed at Roberta's Pond, then spent over an hour on the shoreline just east of the Dungeness River mouth before heading north up the east coast of Vancouver Island. It summered in the same Copper River drainage as the previous summer, just north of Glenallen, Alaska.

You can read more about the goals of this research and view Kyle Spagens presentation here:

Swan mortality – On a final note, we have no record of injured, ill or dead swans in the 2024–25 season.