Lake Maxinkiickee, Physical and Biological Survey 481 



THE BIRDS 



Introduction 



The scope of the investigation as originally planned included 

 as careful study of the vertebrate animals of the lake as time 

 and facilities at command would permit. It soon became evi- 

 dent, however, that no very satisfactory progress could be made 

 with those groups without consideration of the plants and of the 

 various groups of invertebrate animals of the lake. It also became 

 more and more apparent as the work progressed that no hard and 

 fast line could be drawn between the species directly related to the 

 lake and those only indirectly so related, or those thought to bear 

 no relation. 



Many illustrations could be given of the ways in which various 

 species of purely land animals and plants are related ecologically 

 to purely aquatic species inhabiting the lake. Mention will here 

 be made only of the birds. 



The larvre of certain dipterous insects of the genus Chirono- 

 mus are exceedingly abundant at the lake and constitute a very 

 important part of the food of the fishes, particularly of the young. 

 We discovered also that several of the birds feed upon the adult 

 insects. In September and October, when the larvae complete their 

 metamorphoses and the adult insects emerge from the water, the 

 air and the trees about the lake become filled in the evening and 

 on quiet days with vast swarms of these mosquito-like insects. The 

 air becomes vocal with the constant humming of the millions on the 

 wing. They are everywhere, — in the air from the ground to a 

 height as far as the eye can see, thickest perhaps at a height of 

 15 to 30 feet ; on the sides and roofs of the cottages, on the fences 

 and on bushes ; and on the trunks, limbs and leaves of the trees. 

 There were literally billions of them. Then it is that many species 

 of birds which had not been thought to bear any intimate relation 

 to the lake have a veritable feast. Among the birds which we 

 saw feeding upon the insects were the nighthawks, swallows, yel- 

 low-billed cuckoos, yellow-rumped warblers, red-headed woodpeck- 

 ers, and even song sparrows. And along the shore vast quantities 

 of casts of Chironomus larvae had been washed up and upon these 

 were feeding phalaropes, snipes, plovers, and even rusty black- 

 birds, redwings, and crow blackbirds. 



But the story does not end here. After the nuptial flight of the 

 Chironomi has been made, these insects, myriads upon myriads of 

 them, return to the surface of the water upon which they lay their 

 eggs, and there fall a prey to various species of fishes, from the 



