"Consider the albatross. A bird that mates for life and flies over 6,000 miles for food, the albatross has seen profound population declines over the past several decades. It appears now as though a harbinger for its own demise.

Or take the Fiji petrel, a black, tube-nosed bird that spends almost its entire life skimming the oceans. The petrel, the albatross and other birds suffer when the oceans are polluted and overfished and a new study in PLOS One suggests they are paying a heavy price. Since the 1950s, the study concludes that seabird numbers have dropped by nearly 70 percent.

'Seabirds are particularly good indicators of the health of marine ecosystems,' said University of British Columbia's Michelle Paleczny, a co-author of the study and a researcher with the Sea Around Us project. 'When we see this magnitude of seabird decline, we can see there is something wrong with marine ecosystems. It gives us an idea of the overall impact we're having.'"

Michael Casey reports for CBS News July 14, 2015. [2]