30 



THE MUSEUM. 



time carrying canker-worms to their 

 young. One of them was noticed to 

 take eleven canker-worms in its beak 

 at one time, and fly with them to the 

 nest. The vireos, warblers, chicka- 

 dees, cuckoos, orioles and chipping 

 sparrows were particularly active in 

 catching canker-worms, and the En- 

 glish sparrow killed them in consider- 

 able numbers. 



If the thirty-si.x pairs of birds whose 

 nests were found had succeeded in 

 raising their young, it is probable that 

 they would have disposed of most of 

 the canker-worms in the neighborhood. 

 Five thousand of these larvae are suffi- 

 cient to strip a large apple-tree. One 

 hundred and eight young would have 

 been reared, had each pair of birds 

 raised three. According to Professor 

 Augley's experience, sixty insects per 

 day as food for each bird, both young 

 and old, would be a very low esti- 

 mate.* Suppose each of these one 

 hundred and eight birds had received 

 its sixty insects per day, there would 

 have been 6,480 caterpillars destroyed 

 daily. The destruction of this num 

 ber of caterpillars would be enough to 

 save the foliage and fruitage of one 

 apple-tree. In thirty days the foliage 

 of thirty apple-trees could have been 

 saved, or 194,400 canker-worms des- 

 troyed. This does not include what 

 the old birds themselves would have 

 eaten. 



In these observations the influence 

 of insect parasites and predaceous in- 

 sects has not been entirely ignored. 

 Hymenopterous parasites were not 

 seen to be numerous, and as it was a 

 year when canker-worms were on the 

 increase, it is not probable that these 

 parasites would have been a prime 



* )st Eep. U. S. Ent. Com. 1877, p. 342. 



force in reducing the numbei^s of the 

 canker-worms had the birds not been 

 present. Even had they been numer- 

 ous they would have had little effect 

 in checking the ravages of the canker- 

 worm during the present year, as their 

 interest is identical with that of the 

 canker-worm, and they remain in its 

 body until it has finished feeding, al- 

 lowing it to defoliate the trees before 

 completing their deadly work upon it. 

 We do not know to what extent 

 such parasites are devoured by birds. 

 This we could not ascertain without 

 shooting the birds, which would have 

 defeated our main object. No paras- 

 ites of the tent caterpillar or canker- 

 worm were found in the stomachs of 

 the fewnbirds which were examined. 

 It is hardly safe to draw conclusions 

 from observations so limited in their 

 scope, but we may infer from what 

 was observed that the egg-eating birds 

 are of the greatest value to the farmer, 

 as they feed almost entirely on injur- 

 ious insects and their eggs, and are 

 present all winter when other birds are 

 absent. The summer birds which at- 

 tack the larvae are valuable also if they 

 can be so protected and fostered as to 

 become sufficiently numerous to do 

 the work required. It is evident 

 also that a diversity of plants 

 which encourages diversified insect 

 life, and assures an abundance of fruits 

 and seeds, as an attraction to birds 

 will insure their presence. In this 

 connection I wish particularly to note 

 the fact that the mulberry-trees, 

 which ripen their berries in June, prov- 

 ed to be a protection to the cultivated 

 cherries, as the fruit-eating birds 

 seemed to prefer them to the cherries, 

 perhaps because they ripen somewhat 

 earlier. 



