232 Passing of the Flocks [FIRST WEEK 



no warmer than those birds which have gone to the far 

 tropics. And what of the flocks of birds which we occa- 

 sionally come across in mid-winter, of species which gen- 

 erally migrate to Brazil? It is not the cold which 

 deprives us of our summer friends, or at least the great 

 majority of them; it is the decrease in food supply. Insects 

 disappear, and only those birds which feed on seeds and 

 buds, or are able to glean an insect diet from the crevices 

 of fence and tree-trunk, can abide. 



This is the month to climb out on the roof of your 

 house, lie on your back and listen. He is a stolid person 

 indeed who is not moved by the chirps and twitters which 

 come down through the darkness. There is no better way 

 to show what a wonderful power sound has upon our 

 memories. There sounds a robin's note, and spring seems 

 here again; through the night comes a white-throat's chirp, 

 and we see again the fog-dimmed fields of a Nova Scotian 

 upland; a sandpiper "peets" and the scene in our mind's 

 eye as instantly changes, and so on. What a revelation if 

 we could see as in daylight for a few moments! The sky 

 would be pitted with thousands and thousands of birds, 

 flying from a few hundred yards to as high as one or two 

 miles above the earth. 



It only adds to the interest of this phenomenon when 

 we turn to our learned books on birds for an explanation 

 of the origin of migration, the whence and whither of the 

 long journeys by day and night, and find no certain 

 answer! This is one of the greatest of the many mys- 

 teries of the natural world, of which little is known, 

 although much is guessed, and the bright September 



