Trumpeter Swans flying over power lines—Photo: Bob Phreaner

Swan Study History and Background, updated

May 31, 2026

by Laura Davis and Liam Antrim

During the winter of 2010–2011, five Trumpeter Swans were found dead in the Sequim area. Necropsies of the birds attributed their deaths to lead poisoning. Since it can take up to three weeks to die from lead poisoning, the swans could have ingested the lead before flying to this area. These mortalities set in motion OPAS's dedicated surveys to track the swans' local movements and numbers. No further lead poisoning deaths have been recorded in the Sequim-Dungeness area until a single instance in February 2026.

Immediate reporting of an injured, sick, or dead swan allows Washington Department Fish and Wildlife to assess and, if appropriate, remove the swan to determine the cause. In the case of lead poisoning or a contagious illness, this reduces risk of transfer to raptors and other scavengers feeding on the carcass.

Power lines can be a significant cause of mortality for overwintering Trumpeter Swans – heavy-bodied birds that need plenty of room to take off and land. The installation of power line bird diverters by Clallam County PUD has helped mitigate the issue.

*Trumpeter Swans flying over power lines (note the diverter). Photo: Bob Phreaner*

Trumpeter Swans have been known to visit the Sequim–Dungeness area since four were reported during the 1982 OPAS Christmas Bird Count (CBC). CBC swan counts remained between zero and ten with the exception of 1986 (21), 1999 (25) and 2000 (34). Swan numbers generally increased with double-digit counts from 2005–2015, reaching triple digits in 2016 where they remained, though variable, until 2023 – a warmer winter due to El Niño.

Although the single-date December numbers are usually lower than the mid-winter average we draw from our weekly counts, the CBC survey provides 35 years of additional data – back to 1975. We determine this average from the eBird-defined overwintering period, which excludes shoulder periods of swan migration. Numbers of swans typically increase and peak after December, raising the mid-winter average counts. Our swan study volunteers recorded the highest survey count of 258 Trumpeter Swans on February 23, 2017. Learn more about the swan use in our area by looking at the season summaries on our Swan Study webpage.