OREGON COAST — From the Simpson Reef overlook, two field technicians are holding out antennas, listening for marbled murrelets.
The crackle of the receiver can be heard above the wind and seals as it scans through 61 frequencies unique to each of the threatened seabirds that have been tagged.
The scans are part of a larger research project on the Oregon Coast that aims to learn more about the elusive bird and its nesting sites to help inform conservation planning for the species.
The study, led by Oregon State University assistant professor and senior researcher Jim Rivers, is the first to tag marbled murrelets on the open ocean.
“One of the things that’s worth emphasizing is that previous studies that have worked on murrelets have typically worked in inlets or bay,” Rivers said.
He said that’s not possible for Oregon, because there’s not that kind of topography on the coast.
“That’s a key point of emphasis because our study was the first one to do this in open-ocean,” Rivers said, “It’s up to mother nature as to whether or not we’ll get out on any given night.”
Because of rough weather conditions earlier this year, a majority of the tagging was done later in the capture window. Tagging ended in May.
The captures require researchers to get a large boat to go out past the breakers and then unload smaller inflatable rafts which are used to sneak up on the birds and net them.
After they’re captured, the birds are measured, tagged and released.
Most of the birds were tagged around Seal Rock and off of Siletz Bay, but murrelets are being detected as far south as San Francisco Bay.
Rivers said one reason for the bird’s migration south might be food.
“What we are hypothesizing is that it’s related to the ocean conditions and those birds might be moving south for the potential for food resources,” Rivers said.
Marbled murrelets feed on sea creatures like Pacific herring, anchovies and krill.
Rivers said he’s working with an outside group to get an infrared camera developed that will provide videos of the bird when it returns to feed the nest. The camera needs to have low-light video capabilities because marbled murrelets feed at the dawn and dusk hours.
Beyond providing insight into what the birds are eating, the footage can also tell researchers why the nests fail.
“We often don’t know what causes the failure of the nest, having a camera trained gives us that whole realm of understanding,” Rivers said, adding that he wants to be able to tie where the birds are nesting inland to where they’re foraging on the coast.
The seabirds favor mature or old-growth forest stands for nesting.
He said some basic information about the birds is unknown, like whether or not the same bird returns to a nesting site each year.
“Our level of knowledge has moved along very slowly and very incrementally,” Rivers said.
The assistant professor said marbled murrelets were the last species in America to have their nest formally described by science.
“That was not for lack of trying,” Rivers said.
Jennifer Bailey Guerrero, coordinator of the project, said last year served as a test run for this year’s project.
“You might imagine this is a huge project, so there’s a lot of different elements to it. So they were testing out a lot of the equipment seeing could this be done, how should this be done and setting up some of those protocols,” Bailey Guerrero said, “This is the first real year where we’ve taken the protocols that we’ve developed and put them into action to see what happens.”
Currently, the project has a two year timeline with the potential to continue for another couple years. River said the timeline’s flexibility is based on ocean conditions; if there’s another year of bad weather it might push the project back.
“Patience is going to be key here, it’s going to be a while before we can get enough data amassed before we can really know what’s going on with the birds,” Rivers said.
Part of the problem is the reproductive viability of each bird that’s tagged.
“Let’s say we tag 100 birds and we release them. Some are too young to breed, another segment will for reasons we don’t understand won’t go in and breed. Some we may be able to find their nest. Some may go inland to breed and their nest fails,” Rivers said.
Ultimately, he said the project aims to understand what the murrelets need in order to keep their populations from declining.
“We’re really trying to understand the terrestrial habitat needs that allow us to conserve their populations within a managed forest landscape,” Rivers said.