Check out my latest contribution to the bird blog 10,000 birds:
Faithful Loons and Human Lunacy
Every year there manage to be two Loons out in front of the cabin, up in Minnesota’s lake country. They nest on the same, ever-expanding semi-floating but occasionally shrinking nest over behind the point, so we can’t see the nest without going across the marsh in a canoe. It is a great place to nest, but for one small detail. Behind the embayment formed by the point is a tall bluff, the edge of an ancient river valley that passed through the area during one or more (probably a few) prior interglacials. Maybe it was a version of the Mississippi River, maybe it was a version of the Warren River, likely both. Atop the ridge, where no one will ever build cabins because it is too high up, is a grove of white pines. A good way up one of the tallest pines is an Eagle’s nest.
Every year there manage to be two eagles up there in that nest. Plus hungry offspring.
So the Loons produce, probably, two chicks. Often …
These are the kinds of books you get if you are either a scientists studying bird migration and related issues, or a very serious bird geek. The first two can be obtained at very low prices used, but the third will set you back at least 50 bucks US$ if you want a used copy. Note the spread of publication dates. It is not the case that the oldest book is out of date in all respects: Quite the contrary. Alerstam reviews theory and ideas that have not been revisited or revised to any great degree. Also, it is interesting to see how changes in the field develop over a decade or so. In any event, I’ve labeled the books by year of publication to make it very clear that I’m not showing you hot off the press items here.
1993: Bird Migration by Thomas Alerstam is a general overview of bird migration with an excellent overarching discussion of the context in which migration has evolved followed by a focused study of nine different ecologically defined categories of birds. There is also a detailed discussion of what was known about navigation at the time of publication.