by Don Flora (a real scientist)
“Of Eagles, Beaches, and Buffers”
The crudities of near-shore life can be repelling. It’s not nice that oysters defecate and that Orca’s rip the bellies out of salmon, seals and baby whales while they are still alive. If you are less than nine years old, do not read on.
Earlier this year there were ten eagles standing together on the beach watching the eleventh, their elder, eviscerate a dead cat. It’s a food chain thing, I know, with eagles among the champion predators and carrionizers. The cat was of the large, free-range feral sort. Cats, like raccoons, are regular bulkhead cruisers. And, just as all trees ultimately fall down, all cats die.
I mention this because of what used to be called the balance of nature. Now it’s diversity, sustainability, and restoration. The silly issue here is, if the ratio of well-fed eagles is one in eleven, do we have enough feral cats?
More serious questions are:
How can there be an obvious increase in eagles when human populations have grown as well?
If people pressure is bad, how can it get worse when 80 percent of Bainbridge Island’s shoreline is already residential, and 88 percent of eastern Kitsap County’s shoreline is already “disturbed”?
Was there any human activity or structure along the shoreline that created that unbalanced wildlife situation? (Clearly, NO.)
Are there asny tradeoffs among shoreline –using wildlife? (Yes-Indeed. A wildlife expert has told me that eagles are stealing eggs and chicks from herons‘ nests, leading to whole heron rookeries moving on or dying out. The heron decline is palpable where I live. This is an instance of dynamics, always and everywhere: plant and animal species jostling with each other for living space.)
Shoreline buffers have existed since the 1970s. Did they enhance or lessen the prey base for eagles and other raptors? (Never studied. The alternatives, lawns and landscaped yards, are, like estuaries, highly productive places. That means more invertebrates, birds, rodents, and other small mammals. Maybe even feral cats and coyotes, though we associate those with woody places.
Would wider buffers make a difference? (Not if more productive ecosystems, like lawns, are being pushed away.)
But what about nesting places for tidewater birds and eagles? (The state’s priorityspecies list names 17 marine birds that visit Puget Sound. Most pass through to nest far to the north. Four, including eagles and herons, may nest on Bainbridge Island; the same may be true of mainland Kitsap County. Nesting space does not appear to be a limiting factor, given the abundance of wetland buffers and other open space.)
It is interesting that the recent shoreline assessments for easterly Kitsap County and Bainbridge Island mention only habitat for salmon and forage fish. More on that and human-installed “stressors” later.