Michael Schrimpf is a PhD student at Stony Brook University, and studies seabird ecology. His work has taken him both to sea and to seabird colonies in the Atlantic and Pacific Oceans, and he currently works in the Antarctic and Southern Ocean.
Earlier this month scientists, birdwatchers, environmental advocates, and lots of others around the world paid tribute to seabirds on World Seabird Day.
July 3rd marked the 173rd anniversary of the extinction of the Great Auk, one of the clearest examples of a species wiped-out by human actions.
World Seabird Day calls attention to the many marine bird species that are still flying around the oceans (many of which are threatened) and shines a light on the fantastic conservation work involving seabirds all over the planet.
So what is a seabird anyway, and why are they important?!?
Generally speaking, any bird that is specially adapted to life on the ocean, and either spends a lot of time or hunts for food at sea, can be considered a seabird (some scientists still debate exactly where we should draw the line). Seabirds are actually pretty diverse, and several different groups of birds have independently evolved marine habits. These include some groups that are pretty familiar to us, like albatrosses and penguins, and other groups that many people have never even heard of, like diving-petrels and shearwaters.
Now I should probably point out that there are plenty of other waterbirds (like herons) and shorebirds (like sandpipers) that we normally associate with near-shore habitats, but we don’t usually treat them as seabirds. Real seabirds are most at-home in and on the open ocean. They feed on fish, squid, or small animals in the water column (like krill), and many of them can remain at sea for months or even years.
When Wandering Albatross (Diomedea exulans) leave their breeding colonies for the first time, they may spend the next six years at sea!
Many of these birds have special adaptations that allow them to exist far from shore, like wings adapted for swimming, hooked bills for hanging on to slippery prey, and glands that excrete the excess salt from the seawater they drink.
What about ‘seagulls’, you say?
Yep – those are seabirds as well. In fact, there are about 50 different kinds of gull around the world (taxonomists constantly revise the exact number).
All together there are about 300 different species that are normally considered seabirds. One of the things that make them so special is the dual nature of their life-cycle: they mostly live at sea, but all seabirds need to come ashore to raise their young. This is because all birds lay eggs that need to be kept out of the water.
Most seabirds breed in colonies, some of which are massive, containing millions of animals.
Unlike many other marine organisms, which spend the majority of their lives beneath the waves, out of sight, seabirds that collect into large colonies are comparatively easy to monitor. Scientists can visit the colonies during the breeding season to census the population, collect samples, attach remote transmitters, and watch behavior.
When they’re on the ocean, seabirds are often the most visible signs of life; people will even use the presence of bird flocks to help them find schools of fish. Marine birds also have played important roles in many of our cultures, from the poetic symbolism of the albatross in Samuel Taylor Coleridge’s The Rime of the Ancient Mariner, to the navigation skills of the Polynesians.
Scientists studying seabirds have been able to use them as indicators of ocean conditions, able to quickly assess when marine ecosystems are undergoing changes.
Some seabirds, like many of the gulls we regularly see on beaches, have done quite well as we humans have started to dominate the world’s oceans. Most species, however, have declined in the past century. The causes are numerous, and often hard to disentangle: invasive species on nesting islands, accidental mortality from fishing gear, plastic pollution in the oceans, overfishing of their food sources, and the effects of climate change all play a role in different places.
Fortunately more and more people are becoming aware of how amazing these birds are, and are taking steps to help. Buying sustainable seafood, reducing unnecessary plastic waste, and taking steps to slow climate change are all things that all of us can do, even if we don’t encounter seabirds in our daily lives.
The extinction of the Great Auk is a constant reminder of how much influence our species has on the rest of the world. If humans can learn to be good stewards of the oceans, we can continue to enjoy the presence of these amazing marine birds for generations to come.