Loons are the fish eating canaries of secluded northern lakes. Actually, over the last several decades, loons seem to have gotten more used to people then they used to be, but are still not really big on development.
My personal belief (based on anecdotal observation) is that loons can identify, to at least some degree, individuals. When I am alone with the loons, at the lake, strange things happen that don’t happen to others or when others are around.
For instance, when I’m at the end of the dock fishing, the loons will commonly forage underneath the dock and all around me. The first time they did this, a loon took a live minnow off my lure! This caused me to stop fishing, of course, concerned that the loons were going to get hooked. But actually, I’m pretty sure that they get the difference between a lure and a real fish.
Late in the season last year, I was able to feed minnows to an adult loon who then passed them on to their offspring.
I did not try to make this happen. It was pretty spontaneous. Once I realized that this was not a random event (the third time it happened) I became slightly aggressive and scary and scared the loons away. They did not take me seriously, but they did get the point (to the extent that a loon gets a “point” made by a hominid) that this was not going to happen again any time soon. (One does not feed the wild animals! But we do of course have bird feeders for the seed eaters… so what’s the difference? I don’t know. It just feels different)
The reason all this loony talk even comes up is that a somewhat depressing study has been released showing that loons summering in the Northeastern US and Eastern Canada are affected by mercury coming from human emissions. This has a number of negative physical and behavioral effects, which are summarized in a Wildlife Conservation Society news release.
The 18-year study–conducted by the Wildlife Conservation Society (WCS), the BioDiversity Research Institute, and other organizations–confirms that human-generated mercury emissions degrade the health and reproductive success of loons in the Northeast.
Researchers caught and released common loons on 80 lakes in Maine, New York, New Hampshire, and other states and provinces, collecting nearly 5,500 samples of blood, feathers, and eggs to test for levels of methylmercury–the most toxic form of mercury that accumulates up the food chain.
Behavioral observations proved that loons with high levels of mercury–about 16 percent of the adult population in the study area–will spend about 14 percent less time at the nest. Unattended eggs are vulnerable to chilling and raids by minks, otters, raccoons and other predators. Loon pairs with elevated mercury levels rear 41 percent fewer fledged young than loons in lakes relatively free of mercury. The toxin also results in sluggishness, causing the birds to catch fewer fish for both themselves and their chicks.
The concentration of mercury in loons has physiological impacts as well: Afflicted loons have unevenly sized flight feathers. They expend significantly more energy than normal birds to fly, and may have trouble migrating and maintaining a breeding territory.
“This study confirms what we’ve long suspected. Mercury from human activities such as coal-burning power plants is having a significant, negative impact on the environment and the health of its most charismatic denizens, and potentially, humans,” said Nina Schoch of the WCS Adirondack Program. “Thus, it becomes even more urgent for the EPA to propose effective national regulations for mercury emissions from power plants that are based on sound science.”