MARINE CORPS BASE HAWAII --
Four biologists captured, tagged and released more than 30 red-footed booby birds from June 1 through 7, 2014 in the Ulupa‘u Wildlife Management Area with assistance from Marine Corps Base Hawaii’s Environmental Compliance and Protection Department.
This was just one of several site visits coordinated by the U.S. Geological Survey Western Ecological Research Center to study various types of seabirds on multiple Hawaiian Islands since last year.
Funded by the Bureau of Ocean Energy Management, the studies are being conducted in light of current proposals to build new renewable energy sources, such as wind turbines, in Hawaii’s surrounding waters. Structures like these may potentially cause problems for seabirds, according to the USGS-WERC website.
“There are a growing number of observations and studies that show both direct take of seabirds at land-based wind facilities, and indirect effects like attraction or displacement from areas at sea,” said Josh Adams, a research biologist at USGS-WERC and lead principal investigator for the larger seabird study that encompasses findings from several site visits. “But the implementation of wind power at sea is relatively new, so the amount of knowledge is limited, but growing rapidly.”
During the study, the group taped GPS tags to the tail-feathers of each bird. Additionally, participants taped temperature depth recorders to more than half of the total birds.
“Hawaiian seabirds such as the red-footed booby spend most of their lives at sea,” said participant Michelle Hester, a biologist at Oikonos Ecosystem Knowledge. “We can’t follow them so we use miniature devices (like the GPS and TDR) to learn what they need and where the important areas are in the ocean for them.”
The birds were also marked on the head with a colored pen so they could be spotted faster upon returning to their nest. The birds wore the tags between three and six days. Some tags were removed after three days and reattached to new birds. Data was recorded and downloaded from both the TDRs and GPS tags.
“I really enjoyed it personally,” said Todd Russell, a natural resources technician with the Environmental Department, who accompanied the group and assisted with tagging the birds. “My background includes research on waterfowl and mammals, however, this was my first time tagging seabirds and I was happy to have the opportunity to participate.”
Russell said the project was conducted in the evening because many of the birds will usually be nesting and more accessible. The group tagged 29 birds within six hours the first day.
“The birds here are a lot tamer than in other sites in Hawaii,” said Lindsay Young, a biologist with Pacific Rim Conservation. “Usually red-footed boobies fly off their nest right away, but these guys are confiding and you can get closer to them, so they’re actually easier to work with than other red-footed boobies.”
Conducting this project, however, did present challenges. Russell said Ulupa‘u Wildlife Management Area is located at the end of Kaneohe Bay Range Training Facility, “an active range where unexploded ordnance is likely to occur.”
Therefore, for safety reasons, explosive ordnance disposal Marines continuously swept the area for potential hazards and escorted the group during the entire visit.
Participant David Hyrenbach, a biologist from Hawaii Pacific University, said the TDR provides new information every three minutes about the birds’ daily activities, from diving to flying. Occasionally, when a red-footed booby is captured, it may regurgitate its food, which is also collected for study.
“We’ll (examine the regurgitated food) to get a better sense of how they fit into the ecosystem in terms of what they’re eating,” Hyrenbach said.
Hyrenbach called 2014 a “unique oceanographic year,” because El Niño is approaching. “El Niño is characterized by unusually warmer ocean temperatures” in the tropics and decreased trade winds that affect the climate worldwide, according to the National Oceanic and Atmospheric Association and Hyrenbach. He said when they repeat this study in 2015, they will be able to compare how the birds “respond to changes in the ocean.”
In addition to understanding how renewable energy sources may affect seabirds, Hyrenbach added that the study provides information about the birds themselves.
“We’re really trying to build a comprehensive picture of how all these birds use the ocean around these main Hawaiian Islands,” Hyrenbach said. “It’s really cool that this is going to be part of a bigger picture, not only for the red-footed booby, but for the whole complement of the seabirds that share the ocean with us.”
The base hosts approximately 2,500 red-footed boobies, and is one of their two main nesting grounds in the Hawaiian Islands. The birds are white with blue bills, black wingtips, and, as their name suggests, red feet. They generally nest from April through September each year.
Under the 1918 Migratory Bird Treaty Act, red-footed boobies are protected from being killed, hunted or sold, among other prohibited acts. Despite the fact that the bird colony is very close to Kaneohe Bay RTF, the Environmental Department staff has taken steps to support their survival and safety, from trapping predatory animals to creating manmade nesting grounds away from the firing areas.
Russell said researchers plan to return to MCB Hawaii in August for a similar study, only with the wedge-tailed shearwater birds that dwell on base.
“I’m very excited to have such great collaborations in place to conduct these studies,” Adams said. “It could not be done without a huge coordinated effort of the biologists, as well as MCBH environmental staff and EOD experts who can ensure that our biology team operates with a high degree of safety in the field.”
Russell said studies like this benefit the base by providing new information about the birds that may otherwise be costly to obtain if the base conducted its own study.
“Our primary job is to manage the birds while they’re here on the base,” Russell said. “So it’ll be interesting for us to see where the shearwaters are flying at night. (When the boobies are) out at sea we don’t have any control of them, but the shearwaters (linger) close by the base. The shearwater data will be very interesting to help us manage the birds.”