“The fact that the Hawaiian Petrel has moved almost a whole trophic level down means that what they are eating now is estimated to be … around one-seventieth of what they ate before,” said Anne Wiley, MSU alumna and current Smithsonian postdoctoral researcher. “It’s a huge reduction in the average size of their prey.”

The Hawaiian Petrel is a dark gray-brown and white seabird that is known for its strong flying ability. Petrels can be found from the Equator to the most northern latitudes of the Western Hemisphere.

During her study, she examined isotope data from modern Hawaiian Petrels and bones from subfossils as old as 4,000 years to see how feeding habits have changed throughout the centuries. Older samples had consistently high nitrogen isotope ratios, which indicated a diet of large prey high on the food chain. In contrast, samples from less than a century ago — which is when industrial fishing began — had low ratios, indicating that they fed on smaller prey such as fish and squid.

American Bird Conservancy Vice President George Wallace said species that fail to adapt to change are most vulnerable to extinction. Thus, Petrels are proving to be resilient.

“The fact that they show elasticity in their response to changing resources out of the ocean is maybe a cause for some optimism,” Wallace said.

Wallace said birds are decreasing in number because of non-native species that kill them or degrade their habitat. Once found throughout the Hawaiian islands, today the Hawaiian Petrel is mainly restricted to Kauai, Lanai and Maui.

“This is a species, like many other native birds in Hawaii, that is under tremendous pressure,” Wallace said.

Psychology junior and Hawaiian native Carson Tabiolo said she has noticed a decrease in the amount of Petrels while growing up in Aiea, Hawaii.

“They need to do something to help their habitats,” Tabiolo said.