31 



kind of food a few of his notes are given in brief below. In most cases 

 it was impossible to count all the caterpillars eaten by a bird during its 

 visit, for it was likely to be partially hidden from the observer a part of 

 the time by twigs or leaves. The results given show only the number 

 of caterpillars each bird was actually seen to eat. The observer in 

 many instances notes that the bird must have eaten many more, as it 

 was almost continually eating during its visit. 



To prepare the reader for the somewhat startling facts which follow 

 it is necessary to consider some of the physiological characteristics of 

 the bird. Birds as a class are among the most highly organized of 

 vertebrate animals. In this class we find the extreme of activity and 

 the highest temperature of the blood. Their remarkable activity, es- 

 pecially in flight, causes a tremendous waste of tissue. To supply 

 the waste caused by this great expenditure of nervous energy a large 

 quantity of food is required. Natui'e has made ample provision for the 

 digestion and assimilation of this great quantity of food, supplying the 

 bird with a remarkably perfect digestive apparatus, the action of which 

 is very rapid. The writer has recorded elsewhere the results of experi- 

 ments with two crows, which show that the food passes through the 

 entire digestive tract in about one and one-half hours, and it is known 

 that digestion is much more rapid in some of the smaller insect-eating 

 birds. The amount of food required by the crow is given by Mr. E A. 

 Samuels as eight ounces per day. In reading what follows one should 

 take into consideration not only the enormous amount of food required 

 daily by the birds, but also note the dates on which the observations 

 were made. It would seem impossible for some of the smaller birds 

 mentioned to stow away in their small stomachs so many caterpillars 

 in so short a space of time. But the dates alone will indicate to those 

 familiar with the life histories of the insects that where the greater 

 numbers were eaten the caterpillars were quite small, and such is the 

 fact. 



The facts given below were ascertained by Messrs. Mosher and 

 Kirkland : — 



Birds Feeding on the Gypsy Moth Caterpillars. 



May 12. — A yellow warbler ate 15 caterpillars in less than 5 minutes. 

 May 12. — A Nashville warbler ate 42 caterpillars in one-half hour, in 



the meantime taking many more. 

 May 18. — A scarlet tanager ate upwards of 30 caterpillars within 5 



minutes. 

 May 18. — Two scarlet tanagers together ate small caterpillars at the 



rate of 35 a minute for 18 minutes. 

 May 20. — A crow blackbird ate 40 caterpillars in a little over 3 minutes. 

 May 26. — A Maryland yellow throat ate 52 caterpillars while moving 



in and out among trees. Time could not be taken. 

 May 26. — A redstart ate 31 caterpillars while moving about. Time 



could not be accurately taken. 

 - - A red-eyed vireo ate, in four brief visits to an infested tree, 



37 caterpillars. 

 July 13. — A yellow-billed cuckoo ate 1 every 2 minutes for 36 minutes. 

 July 13. — A red-eyed vireo ate 73 in 40 minutes. 

 July 14. — A yellow-billed cuckoo ate 81 in 48 minutes. 

 July 15. — A towhee ate 7 pupa? and 2 caterpillars in a very short time. 



Exact time not noted. 



Birds Feeding on the Brown-tail Moth Caterpillars. 



May 2. — A robin pecked into a mass of caterpillars five times, taking 



a number each time. They could not be counted. 

 May 11. — A pair of blue jays ate 47 caterpillars in IX minutes. 

 May 11. — A black-and-white warbler ate 15 caterpillars in 10 minutes. 



