For this final installation of How the Loon Terns, I'd like to very briefly address four different items of "common knowledge."
- Loons are driven off lakes by boaters.
- Loons use nursery pools.
- Loon are "ancient birds"
- "Loons winter in Mexico (or wherever)."
I've already discussed the first of these, and would simply like to restate the idea. During the 1970s or 1980s, depending on where one looked, loons were seemingly getting driven away from their native habitats by boating activity. Then, the loons seemed to start to grow somewhat accustom to boats, and this trend may have stopped or reversed. Perhaps loons are never going to be mallards when it comes to indifference to humans, but they at least do not disappear completely when human come around. My skeptical loons are now seen floating around, feeding, being loony, and are only slightly bothered by the boats.
But there are limits and I want to emphasize that it is still probably true that heavy boating traffic is bad for loons, possibly in a way that you may not have thought of. Heavy boat use means heavy use of a lake, and this is associated with shoreline development. Even if boats don't bother loons as much as they formerly did, this shoreline development will eliminate critically important nesting sites. So, just in case "the loons grow accustom to the boats" becomes common knowledge, you should know that the skeptical loon will not be satisfied with that cop-out on habitat preservation.
That loons use nursery pools is something I've read but not seen. These nursery pools are supposed to be used for a couple/few weeks after hatching of the chicks. The chicks move between the nest and the pool, and eventually give up the nest, then eventually give up the pool for the big wide world of the lake or pond. I'm sure this has been observed, but I'm not sure if all loons use a nursery pool. My loons seem to take the chick out on the the bay right at hatching, or very soon after. But that might just be my loons. Or maybe the bay is the nursery pool, in which case it is not a very useful concept as it is a very large bay.
That loons are ancient birds is obvious from several factors. They are the first bird in the bird book, and that is where you would put the ancient bird. They are ancient looking. They sound ancient. If you went back in time, in a time machine, to ancient times, you would hear loon sounds, for sure.
But it turns out that the several species of loons that exist today are part of a radiation that happened in the Eocene. That's old, but not really ancient by bird standards. We know this now because of DNA research that has resulted in the re-evaluation of bird phylogeny.
Regarding the last point: Yes, some loons winter in Mexico, but the way this all works is different than you might think, and it is rather interesting. Loons, as a whole, don't actually fly south for the winter. Rather, they go to sea. Many loons simply go east, like the Greenland loons, who go to coastal Europe, and loons from northern New England, that go to the Maine coast.
The idea here is to go to open water. Why? There are fish in the open water! The loons gather in huge flocks at night, floating around in the water together, and then during the day they disperse more evenly across the surface of the sea, not far from shore but usually not too near shore either, and eat fish. I don't know if they ever go ashore while they are at sea. They just float around and eat fish. All winter.
Which is, after all, what life is all about. For a loon.
The nicest lake developments I've seen have a road between the shore and the nearest houses. Those houses still have the lake side view. And may have docks and boat houses, which they must cross the road to reach. But the shore isn't sequestered. And obviously, there isn't as much development of the shore itself.
Russel: There are people in Minnesota who have just lit their torches and sharpened their pitchforks and are looking for you now.
Calling a species "ancient" has always annoyed me. Every extant species on Earth has evolved for the same amount of time! Some are morphologically or even genetically more conserved than others, but that (at least normally) has much more to do with a stable niche than with anything special about the species. Also, apparent similarity to examples in the fossil record doesn't mean they were really all that similar... biochemistry and behaviour are really important and tend to be more evolutionarily fluid.