ENTOMOLOGICAL SOCIETY OF ONTARIO. 61 



If the thirty-six 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 larva? are sufficient 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 estimate.* Suppose each of these one hundred 

 and eight birds had received its sixty insects per day, there would have been 6,480 cater- 

 pillars destroyed daily. The destruction of this number of caterpillars would be enough 

 to save the foliage and fruitage of one aj)ple-tree. In thirty days the foliage of thirty 

 apple trees could have been saved, or 194,400 canker-worms destroyed. This does not 

 include what the old birds themselves would have eaten. 



In these observations, the influence of insect parasites and predaceous insects has 

 not been entirely ignored. Hymenopterous parasites were not seen to he 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 force in reducing the numbers of the canker worms 

 had the birds not been present. Even had they been numerous 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 bjdy until it 

 has finished feeding, allowing 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 parasites of the tent caterpillar or canker-worm were found in the stomachs of the few 

 birds 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 injurious insects 

 and their eggs, and are present all winter when other birds are absent. The summer birds 

 which attack the larva? 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, 

 proved 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. 



I believe it would be wise for the farmer to plant rows of these trees near his 

 orchard, and it is possible that the early June berry or shad berry {Amelanchier Cana- 

 deyisis) might also be useful in this respect. It is a handsome shrub or tree, flowering 

 early in the season, and would be attractive at a time when other trees and shrubs 

 are not in bloom. 



At the present time, July 23, 1895, the trees in the orchard appear to be in good 

 condition. They have not suffered from the slight pruning of their foliage which was 

 effected by the few caterpillars and canker-worms which survived. The fruit is well 

 set, and it now remains to be seen whether the birds will have any considerable effect 

 in preventing the ravages of the codling moth. No other orchard in the neighbor- 

 hood will produce any fruit this season, with one exception. The nearest orchard, 

 situated directly opposite on the estate across the way, has not been ravaged by the 

 canker-worms. This exemption is due principally to the efforts of the owner, who has 

 banded his trees with tarred paper and has used tree ink faithfully and well upon the 

 paper. He has also taken pains to clear the nests of the tent caterpillar from the 

 trees. This orchard, being nearest to the one visited by the chickadees, was also an 

 object of their attention, and this may account somewhat for the reduction of the pests 

 in this place. 



The record of these observations, incomplete as it is, is given for what it is worth 

 as a contribution to the literature on this most interesting and important subject. 



* 1st Rep. U. S. Ent. Com. 1877, p. 342. 



