“Bald eagles, as I’m sure you know, are making quite the comeback in New Hampshire (along with much of North America). New Hampshire Audubon and the Loon Preservation Committee wondered what effect this large fish-eating predator was having on another iconic fish-eating bird, the loon.
The answer, they say, is “not much”.
The team looked for evidence of predation attempts by an increasing eagle population, and whether this was limiting how successful loons are at raising young or if eagles provoked changes in where loons nest. The scientists found that eagle nest proximity may be contributing to about 3% of observed loon nest failures, but that this pressure does not account for local declines in loon abundance. Loons face a wide range of other simultaneous threats, including mortality from lead tackle poisoning, avian malaria, and entanglement in monofilament fishing line.
“We confirmed that eagles have joined a wide range of stressors currently impacting loons in New Hampshire,” said Loon Preservation Committee Senior Biologist John Cooley. “This result is great motivation to keep reducing the impacts caused by humans, like lead tackle poisoning, so that eventually the primary challenge for nesting loons can once again be natural predators like eagles.”