26 . NEW YORK STATE MUSEUM 



one half to completely digest a full meal, and the stomach is filled many 

 times each day. The rapidly growing young need far more food in propor- 

 tion to their size than the old birds. An adult crow will eat about eight 

 ounces of food daily. A young crow nearly fledged requires at least lo 

 ounces. 



Professor Treadwell found that a young robin needed one half its own 

 weight in solid beef or 48 % more than its own weight in worms dail)-, 

 to secure its healthy growth and development. It is now well known that 

 to these remarkable appetites we owe the repression of many of our insect 

 enemies. The smaller land birds feed largely upon insects. Where insects 

 are numerous birds eat them with almost incredible rapidity. JNIy assistant, 

 Mr F. H. Mosher, saw a pair of tanagers eat 35 newly hatched caterpillars 

 in a minute. They continued eating these minute insects at this rate for 18 

 minutes ; so that, if Mr Mosher's count is correct, they must have eaten in 

 this short time 630 of the little creatures. This would not make them a 

 full meal, as the entire number would hardly be ecjual in bulk to one full 

 grown caterpillar. 



By carefully watching two Maryland yellowthroats and counting the 

 plant lice they ate, he estimated that they destroyed 7000 within an hour, a 

 thing almost incredible, but still possible, when we consider the exceedingly 

 small size of the insects at the time, their swarming numbers, the activity of 

 this warbler and its remarkably rapid digestion. Dr Judd speaks of a letter 

 received from Mr Robert H. Coleman, in which he says of a palm warbler, 

 that it must have killed 9500 insects in about 4 hours. These may be 

 extreme cases, but even if we halve the numbers given, they will still serve 

 to show the bird's possibilities for good. 



The remarkable appetites of the young birds keep their parents very 

 busy. The old birds usually carry to the young from i to 1 2 insects at 

 each visit to the nest, although some visits are made for other purposes. A 

 pair of vireos visited the nest 125 times in 10 hours. A pair of chippies 

 made nearly 20oyvisits to their young in a day. Martins have been seen to 

 visit their young 312 times in 14 hours. Rose-breasted grosbeaks made 436 

 calls at the nest in i i hours. House wrens have been seen to enter the nest 

 from 30 to 71 times an hour. 



In view of these facts we may, in time, come to give credit to the state- 

 ment of Professor Wood that the daily food of a robin is equal in bulk to 

 an earth worm 14 feet in length. He tells us that were a man possessed of 

 proportionate food capacity he could consume each day 67 feet of a sausage 

 9 inches in circumference. 



The following facts recorded by Messrs Mosher and Kirkland" working 



under the direction of Mr Forbush, are of great interest, since they give 



'1899 Mass. Crop Rep't. Sep. p. 31-32. 



