Experts wonder if Whidbey can sustain booming bald eagle population
July 10, 2008 · Updated 8:43 AM
From his rooftop in Coupeville, Whidbey Audubon Society vice-president elect Steve Ellis pounds new shingles into place. He watches an immature bald eagle fly over. An adult eagle hastily chases it off.
Scenes like this are ever more common on Whidbey Island, and because of increased public awareness, the eagle population has enjoyed sustained growth, amazing considering “20 or 30 years ago they were almost gone,” said Ellis.
The resurgence of America’s symbol of independence and strength, the bald eagle, has excited local ornithologists, but those same avian enthusiasts are wondering if Whidbey Island can sustain the increased numbers. Although the bald eagle was de-listed as an Endangered Species by the U.S. Fish and Wildlife Service in 2007, the state’s 1984 Bald Eagle Protection Act and the federal Bald and Golden Eagle Protection Act are still in effect and both protect eagle nesting zones from harassment and infringement.
“We’re pretty close to the limit of what we can sustain,” said Phil Sikes, Whidbey Audubon Society conservation chair for the north end and owner of the Whildbey Wild Bird store.
However, Ruth Milner, Washington Department of Fish and Wildlife Region 4 wildlife biologist, isn’t convinced that the bald eagle population has reached its pinnacle.
“We don’t know if it’s maxed out if you look at how the nesting territories are distributed,” said Milner, who has overseen eagle habitat for 16 years in the Puget Sound area. “My guess is that we’ll see a few more nests pop up on Whidbey Island.”
The delicate relationship between human and bird recently surfaced when a Washington State Department of Transportation paving project on Highway 20 south of Oak Harbor was delayed because a pair of nesting eagles took up residence there. Nests require a 660-foot radius from any would-be intruders.
While creating practical problems for the DOT, Ellis said that in some cases, the eagles themselves have engaged in in-fighting.
“Eagles are having territorial disputes on the island,” said Ellis, who closely monitors local eagle habitat. “We had an incident of an eagle mortally wounding another in Crescent Harbor three years ago.”
Milner said that Ellis’ example alone does not indicate that eagles have reached their limit on Whidbey Island.
“Eagles have always killed each other,” said Milner. “We’ve been seeing mortal wounding for decades.” She said factors such as overcrowding or mating can create disputes. Milner said eagle pairs don’t always stay together, and when a new mate competes for a new one, he must also compete for territorial supremacy.
According to Ellis, the local eagle population has remained constant, with approximately 40-plus pairs of nesting eagles observable in the summer months. These numbers are in line with a 2005 WDFW aerial eagle survey that cited 47 documented nesting pairs on Whidbey Island. That was the the last time such a survey was conducted. Milner said aerial surveys, which yield the most accurate data, used to be conducted yearly, but are now completed only every five years due to budget cuts.
“Part of (the reason for the sustained numbers) is awareness,” said Ellis. “People don’t shoot eagles indiscriminately any more.” He added that “young ones have gone off and matured, blanketing the Puget Sound” and have expanded to such locales as Hood Canal.
Milner agreed that “nesting sites are limited, finite and declining,” but because eagles “have gotten creative” with their nesting practices, this does not mean that the they’ve reached maximum capacity on Whidbey Island. She said that eagles are nesting in cottonwood and alder tress and even ground-nesting on nearby Smith Island. Their ideal nesting location, however, is atop old-growth conifers.
With so much construction on Whidbey Island, however, Milner warned that builders who are planning to clear large swaths of land should consult Island County first because bald eagle nesting zones are continually changing.
Although Ellis is grateful the eagle population has rebounded, his optimism is guarded because of impending environmental and policing concerns.
“Eagles are an important part of our ecosystem. Locally, we need to keep the government officials’ feet to the fire,” said Ellis. “The greater aspect is to make sure the water quality is there and we need to bring back the salmon runs. My prediction is that the numbers (of eagles) will fall because water quality will probably decrease.”
Milner agreed that eventually the eagle population might see lower numbers. She admitted that the question, “Has the bald eagle population reached maximum capacity on Whidbey Island?” is a difficult question to answer. The survival of the bald eagle is dependent on how humans impact the entire ecosystem.
“Nature is complex,” said Milner. “Bald eagles are complex. People first need to worry about taking care of the habitat.”