52 BOARD OF AGRICULTURE. [Pub. Doc. 



season only, when it feeds largely on insects, helping to hold 

 in check some of our most important pests. During army 

 worm invasions the bobolink has become known as the army 

 worm bird, because of its persistent attacks upon the worms. 

 Ants, wasps, grasshoppers, harmful beetles (including wee- 

 vils), caterpillars, plant lice and many other injurious insects 

 are eaten in numbers ; also grass and weed seeds. Prof. F. 

 C. Beal says that this bird destroys many parasitic hymenop- 

 tera. These are useful insects, and this seems to be the only 

 harm done by this bird in the north. During the past twenty 

 years the bobolink has greatly decreased in many parts 

 of Massachusetts. The early mowing, by machines, of the 

 fields in which it breeds, may be partly responsible for this, 

 for in this way many nests are either destroyed or exposed to 

 destruction by the bird's enemies. 



The cowbirds, as you all know, follow the cattle about the 

 fields and pastures, feeding largely on the insects which 

 always fly from the towering presence of large animals. 

 They seem to court the vicinity of the cattle for this reason, 

 as chickens often do and as swallows sometimes do for much 

 the same purpose. Such being their habit, their food is such 

 as might be expected, and they feed largely on grasshoppers 

 and other grass-inhabiting insects and cutworms. Their 

 young are sometimes raised at the expense of the lives of 

 other birds, although occasionally they are brought up in the 

 nest with the children of their foster parents. One often sees 

 young cowbirds tended and fed by other birds much smaller 

 than themselves. It is quite probable that the cowbird is as 

 useful to the farmer as the majority of the birds it displaces. 



The redwing and crow blackbirds are noted for their fond- 

 ness for white grubs, cut worms and other caterpillars. 

 Wilson says he believes that fifty of these larvae per day 

 would be a very moderate allowance for a redwing. He 

 estimates that a million pairs of these birds and their young 

 occupying this country in summer consume sixteen thousand 

 two hundred millions of such insects in four months. The 

 crow blackbirds certainly destroy some of the eggs and 

 young of other birds, but it is doubtful if this is a con- 

 stant habit of the species. Although individuals manifest it, 

 stomach examinations show little of it. All farmers know 



