Adaptability Favours Survival

"An observer measures his/her distance to a resting bird with a rangefinder and then paddles slowly in the bird's direction, taking distance readings every few strokes. The final distance reading -- just before the loon dives to avoid us -- is our measure of tameness."
"In fact, some of our marked birds ... find our approach so innocuous that they simply veer slowly out of our patch, instead of diving."
"[If our conclusion holds up] tame loons will produce a large proportion of all offspring in the northern Wisconsin population, and tameness should increase in frequency in coming decades to the point where skittish loons are hard to find at all."
"This vast behavioural shift might go unnoticed by most observers, since there will still be loons on the lakes. But to an ecologist, it is exciting to think that we might be on the brink of learning the precise mechanism by which a population of an important animal can become tame."
Walter Piper, biologist, Chapman University, California

Loon Pat Wellenbach / AP

According to a survey of loons present on two hundred lakes in Wisconsin, studied by Dr. Piper whose focus is loon behaviour of northern Wisconsin, (absorbing his interest since 1993), loons have adapted to an environment that includes human presence by becoming more comfortable with that presence over time and exposure. His conclusion however, is not that the presence of humans make the loons more comfortable, but that because humans are present, the change has occurred.

While his team of students is out on the lakes banding and observing the birds, they also measure and record each bird's level of 'tameness'. The distance range they find, measures from less than two metres, all the way to over 50 metres before the loons become nervous at the human proximity and dive. The loons that Dr. Piper's group studies have led them to the discovery that 'tame' loons are more seemingly adapted to living around humans and to then reproduce near human habitation on their lakes.

There appears to be, according to Dr. Piper, "a strongly and statistically significant relationship" whereby tame loons breed tame chicks. That could be as simple as patterning and as complex as inheriting a subconscious acceptance of the presence of humans passed through generations, but not mentioned as a possibility, since Dr. Piper states the reasons are unknown to him. 

The study which he has detailed in his blog is not completed, but evidence suggests tame birds prosper on lakes with humans living nearby. The 'skittish' loons tend to migrate to other lakes a longer distance from towns and cottages which turn out to be smaller in size, less likely to represent an ideal food source for the birds since they're less productive.

Whereas the larger lakes circled by cottages tend to be more productive in their food sources for the diving birds. The end result is that the skittish loons produce undernourished , smaller chicks while the tame loons' offspring tend to be larger and healthier -- tilting toward loons tolerant of human presence.

When a loon paddles underwater, the cnemial crest functions as a lever. Illustration by Denise Takahashi

Over the years that Dr. Piper has studied loons, he has noted that solitary loons, seeking territorial advantage to be had by moving in to an area well stocked with feeding material -- usurping it from the birds whose territory it is -- looks for the presence of healthy chicks, realizing that successful parents occupy good breeding grounds.

"The effect is dramatic; the intrusion rate (rate of attempts to grasp territory) increases by 70 percent following a year with chicks. Raising a chick is like painting a great big target on their backs. Those little brown fuzzballs look cute in the moment, but their presence portends many battles with floaters the following year. No wonder parents take steps to hide their chicks, when they can", explained Dr. Piper.

Leading one to the conclusion that raiding others' territorial advantage is not only the purview of human sociopaths but appears to slop over into the animal world of other species as well.