Recently I gave a talk for Vashon Audubon on the state of Vashon birds. The last decades’ work by Island birdwatchers and naturalists indicates that bird populations on the Island appear largely stable. In the next Loop, I’ll discuss how this in part reflects the successful work of the Island’s citizen action networks.
When I first published The Birds of Vashon Island in 2005, the Island bird species list totaled 239. In the eight years since, fifteen new species joined the list and three came off after better research showed that their inclusion incorrect. Only one species moved to inactive/extinct status, the California Quail. Changes in population status occurred for more than a quarter of the species with increases outnumbering decreases.
Despite the addition of fifteen new species and nearly 30 species showing increases in sightings, a detailed look demonstrates populations as stable rather than necessarily growing larger. Fourteen of the fifteen new species consist of vagrants and very rare birds that will be observed in the future at most every few years. The big number reflects more observers and increasingly knowledgeable ones at that which share their sightings and make sure the observations get into the data base. Two-thirds of the species that have increased sightings entail birds that hide well like snipe and owls so that again the larger number of observations reflect more observers spending more time watching. Other birds with an increase in numbers include hard to identify species like the Thayer’s Gull which take more expert observers to correctly tell apart from the other gull species. The remaining third of the species with increased sightings are mostly birds showing larger numbers on a regional basis such as the Western Scrub-Jay, a species that is still expanding its range into the Puget Sound area. The decreasing species involve birds that the work of more knowledgeable observers show to be rarer on Vashon than originally thought.
In the second edition of The Birds of Vashon Island coming out in January, I describe the changes in status for each species in detail. The fairly exact knowledge of each species comes from the now large network of Island naturalists and birdwatchers sharing the information in a way that didn’t occur in the past on this scale. Vashon Audubon’s classes on birdwatching and the citizen involvement in science work of the Vashon Nature Center and the Vashon Maury Land Trust created a lot of opportunities to find out more about birds and Island ecology in general. The data generated by citizen science on the Island will be increasingly valuable in protecting habitat and sensitive areas in the coming years. If you would like to join in discussions on animal life on Vashon and share sightings, check out the vashonbirders list group on Yahoo, look at the Vashon Nature Center website at www.vashonnaturecenter.org, Vashon Audubon at www.vashonaudubon.org and you can send bird sightings to me at firstname.lastname@example.org. The new, second edition of the Birds of Vashon Island is available for order at www.theswancompany.com.