THE OOLOGIST. 



45 



Value of Our Warblers. 



It being a well-known fact, that 

 birds have an important bearing up- 

 upon agriculture, the family, War- 

 blers, comprising as it does of so 

 many species, must play an import- 

 ant part in the beneficial or harmful 

 work done by birds. The number of 

 representatives of this family in Con- 

 necticut is about twenty-two, (except- 

 ing a few rare or occasional visitors). 

 Of the principal foods of a few of the 

 more common species, I shall present- 

 ly speak. Let us, however, consider 

 first, the food of the family as a 

 whole. 



From the fact that they are almost 

 exclusively insectivorous, and that 

 they are soft-billed, two deductions, 

 (which show in what field they exert 

 the greatest influence), may be drawn. 



Being insectivorous, little if any in- 

 fluence is exerted by them in the de- 

 struction of vegetable forms wild or 

 cultivated, and being soft-billed, all the 

 insects taken must be the soft bodied 

 species, for the capture of which their 

 bills are admirably suited, while the 

 hard-shelled beetles or those insects 

 on the wing, are taken by a few spe- 

 cies only. 



The insects eaten by these birds 

 must then comprise the soft-bodied 

 kinds and inasmuch as the birds are 

 arboreal, the plant-inhabiting species, 

 their foods may therefore be divided 

 into three classes: (1) Leaf-inhaoit- 

 ing insects and those which hover 

 around leaves and blossoms; (2) Bark- 

 inhabiting insects; and, (3) the eggs 

 of both. 



Ground beetles are eaten by the 

 Ovenbirdi; snails and other ground- 

 slugs are also eaten. 



Certain hibernating insects are ta- 

 ken by the migrants, but of these we 

 shall speak later. 



From these statements, it may seem 

 that the Warblers are a benefit to the 



orchard grower, and to all the trees in 

 general, since their foods is made up 

 of insects which infest trees mostly. 



Part of these are eaten by the adult 

 birds, 'but a greater portion of the 'in- 

 sects destroyed by Warblers are eat- 

 en by the nestlings. The quantity of 

 food consumed by them is enormous. 

 From the moment of hatching to the 

 age of from four to six weeks, they 

 seem to be made up of little else but 

 mouth and stomach. Their constant 

 demands for food keep both parent 

 birds busy in supplying it, chiefly 

 small, very soft insects, caterpillars, 

 plant lice and eggs. 



From this we see how great an in- 

 fluence the nestling birds exert indi- 

 rectly to lower the number of noxious 

 insects. 



The statements, however, are only 

 in regard to summer residents. We 

 still have the migrant warblers to deal 

 with. 



These summer north of us and win- 

 ter south of us and, in migrating, pass 

 to and fro through our region, and, 

 while it is true their stay is brief yet 

 the chill of approaching cold weather 

 makes them all the more active in 

 search of food. As I said before, hi- 

 bernating insects during their migra- 

 tion, form a large per cent, of their 

 food. These are taken from dried 

 leaves, the under side of twigs and 

 from crevices in the bark. 



Taking a few species representative 

 of the different groups of warblers 

 which will show us how this insect 

 destruction is carried on, we shall con- 

 sider: (1) Those that take their food 

 from leaves and blossoms; (2) Those 

 that take their food from crevices in 

 the bark; (3) Those that take a great 

 part of their food on the wing, after 

 the manner of flycatchers, and (4) 

 Those that take their food from the 

 ground. Only one or two representa- 

 tives from each group will be dealt 

 with. 



