ARE THE BIRDS DECREASING 5 
seems to me that for various reasons some of our birds 
have withdrawn into regions that are not often visited 
by the great majority of observers, and that there has 
been a general drifting from the eastern toward the 
western states. A number of years ago I certainly 
never saw a red-headed woodpecker on Minnesota 
prairies. I call attention to these facts to show how 
difficult it is to take a bird census and to find a trust- 
worthy average for a large state with much variegated 
landscape features. 
