Long lasting impacts on nesting birds on Goose Island uncertain

The fire on Goose Island has damaged bird populations, though it’s too early to tell how much and if the birds will bounce back, according to Phil Green, Goose Island steward for the Nature Conservancy. The fire is still smoldering, and Green boated out to the island July 8 to check on the birds, though he did not go on the island because 50 harbor seals took up the landing beach.

Green noted in an email that, “The pelagic cormorant colony appears intact, there are dozens of glaucous-winged gull chicks, and many more glaucous-winged gulls are sitting on nests. The bad news is that the double-crested cormorant colony was abandoned except for one nest. All-in-all I find this very positive given the situation.”

Green said that the double-crested cormorants had been “hanging tough” when the fire was still active and that their nests did survive the worst, but they still left, potentially due to the human interaction.

Green says that human presence can have a considerable impact, citing a study on Colville Island, off the south end of Lopez Island. The study found that egg mortality did not increase with human presence but chick mortality did, as adults took flight to avoid humans and chicks fleeing nests were attacked by neighboring adults.

During Green’s visit to the island last Wednesday, he noticed gulls back on burnt nests, suggesting they may try a replacement clutch to replace eggs that were lost.

Madrona Murphy, botanist at the Lopez-based laboratory Kwiáht, said in her review of scientific literature she found that later-season nesting and high chick mortality seem to be correlated.

Murphy has studied other islands in the San Juans though not Goose Island itself, which is owned and managed by the Nature Conservancy. She has looked at how Coast Salish people used fire to lightly burn and maintain open landscapes. Those fires promoted growth and kept prairies open, but are unlike the recent fire on Goose Island.

“From my review, I’m not convinced that vegetation will be particularly rapid or positive, just from looking at the other small islands that we’ve studied,” Murphy said. “The fire on Goose Island was in no way comparable to traditional fire, which means I can’t predict what will happen.”

Long-lasting hot fires can burn vegetation down to bare ground, which can introduce wind-blown invasive plants such as thistle, reducing organic matter and soil fertility and induce erosion, Murphy said.

According to the Nature Conservancy’s management plan for Goose Island and Deadman’s Island, “The value of both islands lies in their lack of human disturbance and therefore makes them excellent habitats for ground nesting birds.”