BIRDS AS CONSERVATORS OF THE FOREST. 26 1 



(Hyphantria cunea), and the white-marked tussock moth {Hemerocampa leucostigmd). 

 The former is eaten to such an extent that it constitutes at least half of the food 

 during the time when it can be obtained. Of the fifty stomachs taken while 

 the tent caterpillars could be found, seventeen contained these insects, and several 

 were entirely filled with them. In one stomach 250 were found. These, of 

 course, were small ones taken in the early stages of their growth, before they 

 had done much damage. The fall webworms are evidently another favorite food 

 of the cuckoo, as they were found in a number of stomachs, and in one 217 

 heads of these insects were counted. Twenty-eight species of caterpillars were 

 identified in the 155 stomachs, and, as many specimens were unidentifiable, it is 

 probable that there were more species than those noted. Other important insects 

 in the cuckoo's diet are the larvae of sawflies. These so closely resemble cater- 

 pillars that they have been called "false caterpillars" and the cuckoos appear to 

 like them as well as they do the real caterpillars. They were found in many 

 stomachs, and one contained over sixty individuals. Larvae of the largest species 

 of sawfly (Cimbex americand) were found in several stomachs. The other insects 

 eaten by cuckoos were distributed through several orders, but with no great 

 percentage of any one. The most important, from a forestry point of view, are 

 ants, which were found in many stomachs, but not in large quantities. 



The good done by these birds in their destruction of caterpillars can scarcely 

 be overestimated. In the summer of 1898 the writer observed the sugar maple 

 trees in the State of Vermont over a very extensive tract of country nearly 

 defoliated by the forest tent caterpilliar (Malacosoma disstrid). The damage was 

 so extensive as badly to affect the next year's crop of sugar. Had a sufficient 

 number of cuckoos been present to materially reduce the number of caterpillars, 

 much of this defoliation would have been saved, as the trees would stand a 

 moderate reduction of their foliage without detriment. The cuckoos are, unfortu- 

 nately, rather shy, timid birds. All foresters should know their value, and afford 

 them every protection. The following is a list of all the caterpillars which were 

 positively identified in the stomachs of the 155 cuckoos, but it is almost certain 

 that there were many more so badly mangled as to be unrecognizable. 



List of caterpillars identified in stomachs of cuckoos: 



Yellow-necked caterpillar Datana ministra. 



Handmaid moth Datana contractu. 



Nadata gibbosa. 

 Red-humped caterpillar Symmerista albifrons. 



Heterocampa manteo. 

 Army-worm Heliophila unipuncta. 



