38 



fruit growers, feed on neai'ly all species of injurious caterpillars of the 

 orchard or woodland. The cuckoos are always and everywhere present 

 with the caterpillars, and by many are believed to head the list of cater- 

 pillar destroyers, but in woodlands there are no birds more useful in 

 this respect than the beautiful scarlet tanagers or the busy chickadees. 

 Of all the warblers the redstart seems to be the most indefatigable in 

 pursuit of caterpillars, capturing even the most repugnant species. 

 The list of birds feeding on the different species are not believed to be 

 complete by any means. Most of them probably attack with less 

 avidity the hairy and spiny species, the smaller birds taking them 

 mainly when the caterpillars are small and the larger birds when they 

 grow larger. 



Injury done by Birds to Woodlands. 



There can be no doubt that some slight injury may be done to the 

 trees by birds. The grosbeaks and the purple finches eat buds and 

 blossoms ; grouse feed largely on young buds ; crows and jays eat nuts ; 

 crossbills take the seed and buds from coniferous trees ; and woodpeck- 

 ers sometimes bore into sound trees, but the injury done is so slight 

 compared with the benefits conferred by birds in protecting trees from 

 their enemies, and in distributing and planting seeds, that it need hardly 

 be considered in making up the account. It is now said in favor of the 

 much-abused sapsucker that it is the perforations of its beak which pro- 

 duce much of the appearance called " birdseye " in the maple, which 

 greatly increases the value of this tree for timber use. Forest birds 

 appear to have been especially designed to maintain that balance of 

 forces in the forest which is essential to its preservation, and we may 

 well fear that without their assistance profitable forestry would be im- 

 possible. In this matter there is no higher authority than the distin- 

 guished entomologist, Prof. S. A. Forbes of Illinois, who says that 

 estimates of the average number of insects per square yard in that State 

 give ten thousand per acre for the entire area, and that if on this basis 

 the operations of birds were to be suspended entirely the entire State in 

 seven years would be carpeted with insects one to the square inch. This 

 would certainly happen unless the insects were checked by some provi- 

 dential means. Professor Forbes says that this is intended only as an 

 illustration and not as a prediction of the consequences of the total de- 

 struction of birds, which he says would not be so simple, but apparently 

 fully as grave. He also estimates that should the people of the State 

 succeed in taking measures which would increase by so much as one 

 per cent the efficiency of the birds of the State as insect police, the effect 

 would be to save to the agriculturists of the State seventy-six thousand 

 dollars per year, but he regards five times this amount as a very modest 

 estimate, for he says the figures on which his estimates are made 

 " will be regarded by most naturalists as absurdly low." 



HOW TO INCREASE THE NUMBER OF BlRDS USEFUL IN WOODLANDS. 



Some practical lessons have been leai'ned from the study of the food 

 of the wood birds. As birds go where they find food most abundant 

 many birds of the swamp, field and orchard go from their usual haunts, 

 one-half mile or more, to the woods to feed on insects plentiful there. 

 Thus the bobolink in the meadow goes to the woods for aphids, and the 

 oriole in the orchard and the blackbird in the marsh go there for cater- 

 pillars. On the other hand, the chickadee, blue jay, tanager and the 

 warblers go from the woods to the orchards and gardens for caterpillars. 

 In an orchard near the woods we noticed that the wood birds came fre- 

 quently to those trees nearest the woods, and by adding their work to 

 that of those living in the orchard soon cleared the canker worms from 

 the trees nearest the woods. 



