Birds and Birding's Guide to:

Watching THE MIGRATIONS OF BIRDS

Migration of Sparrows

The Sparrows as a group are also strictly migratory. Quite a number, such as the Tree Sparrow (Spizella monticola), Snowflake (Plectrophenax nivalis), and Longspur (Calcarius lapponicus), breed far to the north of the United States in Arctic districts, and come down in winter into the Northern States or irregularly farther south. Many species which breed mainly north of the United States only go into the Middle and Southern States during the winter, while a few may reach the West Indies, Mexico, Central America, or northern South America.

The Nighthawk is another example, some individuals spending the summer in Alaska ' and the winter in Patagonia, points separated by over five thousand miles, over I which they must travel in spring and fall.

But after having described these migration routes and the wonderful journeys over continents and vast oceans, the mystery of mysteries — How is it possible for the birds to find their way so unerringly ? — still remains without a wholly satisfactory answer. As in the case of theories propounded to account for the origin of migration, so numerous suggestions has been made to explain this wonderful faculty.

Thus Dr. Von Middendorff, a distinguished naturalist who studied exhaustively the migrations in the Russian Empire, suggests that because all the spring movements in that country are toward the magnetic pole, the migrating bird knows the location of this point and is enabled to direct its course accordingly. It is perhaps needless to say that this theory is not only unsupported by any serious data, but, as has been shown by Baird, is opposed to the facts of migration in North America.

If during the migrations the older and stronger birds always led the way, it might be said with plausibility that this faculty is due in large measure to experience, but here again the facts are either conflicting or directly opposed to such a • view, for it seems to have been demonstrated with reasonable certainty that in Europe the young birds not only precede the old, during the fall movement, but often travel by a wholly different route. In this country, however, observations on this point are limited and authorities differ, but the tendency is to believe that the old birds do actually lead. Observation is much needed to settle this question.

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