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of food, they come down from the Scandinavian mountains headed for the 
sea coast in great hordes, swimming streams and lakes, devastating the 
country across which they swarm, not stopping until they reach the sea, 
in which vast numbers are drowned. During these dreaded migrations 
farmers from elevations or tall trees signal the coming of the lemmings so 
that as much of their crops as they can protect may be saved from the 
hunger-driven rodents. During their migration they are preyed upon by 
hawks, owls, weasels and foxes. 
The regular migrations of seals to their breeding grounds and the 
migration of salmon to the head waters of streams to spawn are well- 
known phenomena. 
All of the migrations so far mentioned are easily explainable, but the 
migrations of birds from regions where food is abundant, across great 
bodies of water, thousands of miles of tropical forests and barren deserts, 
to the inhospitable arctic regions for their nesting are an unsolved mystery. 
Many plausible reasons are given by ornithologists. Some appear reason- 
able and others merely guesses. Whatever the origin of this tremendous 
movement of birds each spring and autumn may have been, we do know 
where most of them spend the winters and when to look for their return 
to the United States. But why, remains an unsolved mystery. 
Long before the weather becomes definitely springlike, the birds have 
started and they often arrive too soon, for no one provides food sufficient 
for their needs. Consequently in a land of abundance, frozen ground, snow 
and ice may make them go on enforced fasts. Severe storms take heavy 
toll of migrating birds and at intervals are so destructive that certain 
species, such as bluebirds, may become scarce for a number of years before 
they regain their normal population. 
Several routes are used in the great northward trek from South 
America. Strong flying birds boldly cross the Gulf of Mexico, a 700 mile 
non-stop flight. Others use the peninsula of Florida as a ‘‘way station,” 
definitely shortening the “over water” trip. Still others follow Central 
America to avoid the water hazard. Many birds however, such as robins, 
meadowlarks, blackbirds and others, spend their winters in the southern 
states. 
The valley of the Mississippi River and those of its more than two 
hundred tributary streams make the most traveled north-south highway for 
the smaller migratory birds on the North American continent. We are 
accustomed to say that food and water are the most important life factors. 
The late Dr. Robert Ridgway, world famous ornithologist, reversed the 
statement, saying that water was more important temporarily than food. 
The Mississippi-Illinois-Desplaines Rivers route furnishes the necessary 
water and food and uncounted thousands of large and small birds use this 
incomparable natural highway. 
Just how soon the urge to migrate “back home” starts the vast throng 
moving north we do not know, but in February and March the presence 
of robins, meadowlarks, song sparrows, grackles, killdeer and many other 
hardy birds advises that migration has started. Weather is naturally a 
