USA - Warming Ocean, Old-Forest Loss Put a Squeeze on an Elusive Seabird, the Marbled Murrelet
CORVALLIS — Squeezed by changing ocean conditions that limit their food options and the long-term loss of old forest needed for nesting, marbled murrelets would benefit most from conservation efforts that take both ocean and forest into account, new research by Oregon State University shows.
Published in Conservation Letters, the findings are based on two decades of murrelet surveys at nearly 20,000 sites in the Oregon Coast Range and illustrate how the elusive seabird is at risk of its habitat gradually shrinking to the point of local extinctions or worse. The study did not extend to Southwest Washington, but essentially identical conditions and issues confront murrelets on both side of the Columbia estuary. Nesting sites in Clatsop County were included.
“It turns out that the same ocean conditions that influence salmon returns, including the forage fish murrelets need to successfully nest, had a huge influence on the likelihood that murrelets will come inland to breed,” said lead author Matt Betts, a researcher in the Oregon State College of Forestry and the director of the OSU-based Forest Biodiversity Research Network. “Given that these prey items tend to be in lower abundance when ocean temperatures are high, changing climate conditions could reduce prey availability as well as the tendency for murrelets to nest in the future.”
Marbled murrelets are closely related to puffins and murres, but unlike those birds, murrelets raise their young as much as 60 miles inland in mature forests. Disturbance in either the ocean or forest environment has the potential to impact murrelet populations.
“There aren’t many species like it,” said study co-author and project director Jim Rivers, also a faculty member in the College of Forestry. “There’s no other bird that feeds in the ocean and commutes such long distances inland to nest sites. That’s really unusual.”
The dove-sized bird spends most of its time in coastal waters eating krill, other invertebrates and forage fish such as herring, anchovies, smelt and capelin. Murrelets can only produce one offspring per year, if the nest is successful, and their young require forage fish for proper growth and development.