Sea Birds: not immune to environmental issues

There's one marine animal that, frankly, I don't pay much attention to in this blog and that is sea birds. Except for concern over their uncanny ability to bomb our cars, hats, and docks with globs of white, many people don't give them much thought - maybe the occasional shot of an oil-soaked sea gull catches our eye, but beyond that . . .

But these animals are at the mercy of environmental change like pollutants or global warming, just like any other species. And their loss would be ours too, as they play a role in maintaining a balanced ecosystem.

I was reviewing summaries of several scientific papers and found some interesting issues confronting several species:

One study looked at red knots that frequent the U.S. east coast. This time of year, red knots congregate in the Delaware Bay to feed on horseshoe crab eggs before they continue their northward Arctic migration to breed. The demand for horseshoe crabs as bait has dramatically increased over the past two decades, thereby greatly reducing the supply of eggs for the red knots. This has impacted the survivability rate of the red knot and returning populations in the Delaware Bay have dropped as much as 75 %. Of concern is that while efforts have been made to increase the horseshoe crab population, the number of red knots has not increased in kind.

Another study showed that Cassin's auklet, a cold-water sea bird, could face serious population declines due to climate change because, as a zooplankton feeder, it depends on prey like the copepod N. cristatus whose population drops when warmer waters are prevalent. The study showed that in past years, the population of the auklet fluctuated in direct correlation with copepod numbers that were impacted by warmer water temperatures. As temperatures consistently warm up, the auklet is at risk.

Not all is necessarily bad news. While some animals suffer from climate change because of an inability to adapt, the razorbill seems to be adjusting as it's dispersal and range has reported to have increased northward into the Canadian Arctic due to the northward movement of its fish prey, like capelin. As temperatures increase and a variety of flora and fauna expand their range, some animals are able to adjust, while others perish due to loss or reduction of prey or food.

If you adhere to the evolutionary concept of birds being ancestors of ancient dinosaurs, then it can truly be said that they are highly adaptive creatures. But with their long range migrations and breeding habits based on certain environmental conditions, there is a question as to their future in the face of what is happening today. Research is ongoing to determine the long-term effects of pollution and climate change on our feathered friends.