Just finished "The Loon, Voice of the Wilderness" by Joan Dunning. A quick read and a great introduction to the life cycle of these strange birds.
Most fascinating of all was the Loon/Human timeline. If the line below represents 60 million years( the length of time Loons have existed on the planet), the human race, in comparison, has existed for only one million of those years ( or the space between the final two brackets.)

Loon/Human Timeline:

(---------------------------------------------------------------------------(-)


This fact, along with Dunning's fascinating explanations of the intricate, intelligent and fragile workings of the birds social and migratory life, make me feel foolish and invasive for ever having "imitated" the call of these creatures when I've encountered them.
Some respectful silence and listening would probably yield a lot more.