262 BOARD OF AGRICULTURE. [Pub. Doc. 



eggs than with four. In the case of the cowbird, which is 

 usually reared in the nest of a much smaller bird, nature 

 provides that only one young cowbird is ordinarily left to 

 the care of its little foster parents. Perhaps only one mar- 

 tin's egg should be placed in a swallow's nest and the young 

 swallows should be all removed soon after they are hatched. 



The experiment of closing up the martin box in the night 

 and removing it, with the old and young enclosed, to another 

 locality has been tried at least twice, but in both cases the 

 old birds deserted the young. In one case most of the young 

 were successfully reared by hand, and the colony was main- 

 tained for two years, after which the birds disappeared. In 

 the other case they all contracted disease and died. 



Adult birds caught and sent to other localities have dis- 

 appeared at once. Young birds partly grown have been sent 

 to new localities and reared by hand. This is a hopeful 

 method for those who know how to rear the birds, and are 

 willing to take the necessary trouble, but I know of no per- 

 manent colony having been established in this way. 



We can do something to attract the chimney swifts and 

 to increase their numbers by kee])ing open chimneys without 

 fires during the months from April to October. The tree 

 swallows may be attracted and increased by building small 

 boxes for them, and all that is necessary to increase the barn 

 swallows is to leave openings in the farm buildings for the 

 birds to get in, and if the rafters are smooth it is well to nail 

 up a block, cleat or any piece of wood along the rafters. The 

 illustration of the barn swallow on the nest shows how a pair 

 of these birds located their home in a barn within a few feet 

 of the back of a cow, for the reason that here they found a 

 projecting end of a board on which the nest could be safely 

 placed. (See Plate I.) 



Investigations of the Destruction of Birds by Spray- 

 ing. 

 Investigations of the possible poisoning of birds by spray- 

 ing trees with arsenical insecticides were continued through 

 the summer of 1909. The result was inconclusive, but from 

 what we now know it seems probal)le that the fatal effects of 



