OPAS Swan Study Update (March 2019)
by Laura Davis and Liam Antrim
By the end of March, the Dungeness Delta will be bidding farewell to the last of our winter-resident Trumpeter Swans, and so we reflect here on the study year in progress.
Drawn by the swans’ magnificence and grace, in the context of beautiful agricultural habitats, wetlands, geese, and other birds, volunteers have generously committed their time to this OPAS community-science project. We were fortunate to have a dedicated group of 24 trained and experienced volunteers returning this year; half in their second season and several in their eighth. Counting Trumpeters and also watching for their smaller relatives, the Tundra Swans, we survey extensively from Three Crabs south to Happy Valley, from Port Williams to Agnew. Every week from November through March, two teams count simultaneously at midday – one west of the Dungeness River and one east.
Why study these swans? Mortality due to lead poisoning sparked the study in 2011. We watch for sick, injured or dead swans for rescue or necropsy. Currently, the largest local hazard is collision with live power lines. Ongoing concerns also include the swans finding suitable habitat for their foraging activities without causing significant economic damage to our working landscapes. Problems are reported and data submitted to the state’s Priority Habitat and Species database and shared with Martha Jordan of the Northwest Swan Conservation Association (425‑787‑0258) and Shelly Ament, our local Washington Department of Fish and Wildlife agent.
This year, we took on two additional areas of study: 1) where are the swans roosting at night? and 2) where are the swans at risk from power lines?
Roosting. The swans move from field to field during the day, and then fly to separate locations suitable for night-time use – typically open water. Arriving after sunset, they leave for forage locations soon after sunrise. For our roosting surveys, a small but determined group of volunteers worked in the challenging light conditions and blustery weather of December and January dusk and dawn. We found the swans using Roberta’s Pond, Kirner Pond, wetlands at Graysmarsh, and a pond west of the Olympic Game Farm. One late January afternoon, Laura nearly rolled away like a tumbleweed in the 48 mph gusts, as she tried to focus on the poorly illuminated swans landing on the murky surroundings at Roberta’s Pond. The next morning, the team found a dead swan off Clark Road – apparently having collided with power lines as it flew toward a night roost.
Power lines. Over the past six years, swan casualties from wire strikes in our area have mostly occurred in low visibility conditions like winter fog. For well over a month this winter, Bob Phreaner studied the swans’ success in clearing the power lines near Kirner Pond by counting and filming birds most mornings at dawn. Apart from one collision without injury, the new reflectors seem to help prevent collisions.
Habitat. While it’s a challenge to find all the night-roosting spots used by the swans, the task is easier in the light of day; however, questions still remain. Week by week, where do we find them? Do they prefer a harvested corn field, pasture, a carrot field or winter crop? Does swan distribution in our area shift as the available forage changes over the winter, and is this forage also important to others? You may know that Trumpeter swans love carrots and gulp them whole straight from the field. Nash’s Organic Produce has shifted its carrot harvest practices, and to minimize crop loss pulls them all in the fall when the swans show up. Seed crops on Schmuck Road have required additional fencing and reflectors to deter the swans’ use. This February, a new challenge arose that clearly demonstrated the potential impacts of habitat loss – in this case, a temporary one. During our week of snow, Dungeness Valley swans largely abandoned pasture locations covered by snow and descended on a few acres of winter plantings, picking brassica plants down to the nub and causing tens of thousands of dollars of crop damage, with slim hopes of recovery. From initial research, it seems that compensation to farmers is available for damage from elk, deer or wolves, and from natural disasters – but not from migratory waterfowl.
With one February survey and the month of March remaining, we have been seeing about 164 swans per week, however numbers often peak in late February and early March. Although our weekly counts are not reported online, eBird is a good website for following their migration north. Ahead lies data analysis, then sharing further the patterns meaningful for habitat protection in the context of complementary and competing human uses.
Finally, if you haven’t seen John Gussman’s recent video showcasing the wondrous beauty of our local swans near Schmuck Road, please follow link: vimeo.com/312860698.