1914] The Ottawa Naturalist. 163 



the size of Iowa, this species would consume about 800 tons of 

 seeds annually. 



It is important to point out, however, that the weed-de- 

 stroying power of graminivorous birds may be exaggerated if 

 the question is not investigated with great thoroughness, for 

 while the powerful gizzards of some birds may grind up the hardest 

 coated seeds, in other cases seeds may be capable of germination 

 after passing through the digestive tract, as Collinge has shown 

 in a number of cases in English birds. In such instances the 

 birds would act as disseminators of weed seeds. Then again, 

 in the case of insectivorous birds, besides destroying noxious 

 insects, they will destroy various kinds of insects which are useful 

 by reason of their parasitic habits upon noxious insects. These 

 facts indicate that the question of the economic status of a bird is 

 not always an easy matter to determine and demands thorough 

 investigation in each case. 



In certain instances useful birds eat grain or fruit. The 

 Horned Larks occasionallv eat grain, vegetable food constitu- 

 ting about 80 per cent, of their total food. Six-sevenths of this 

 total amount of vegetable food consists of the seeds of such weeds 

 as foxtail, amaranth, ragweed, and bindweed. It surely is not 

 too much to ask that, in view of the good they effect, a little 

 injury shall be overlooked, especially as thev make no charges 

 for the good work they accomplish. It has sometimes seemed 

 to me that in the case of those useful birds which sometimes take 

 to fruit eating, it is cheaper to protect the fruit from the birds 

 than from the insects. As insecticides, birds are the cheapest 

 and most generally efficient that can be found. 



The feeding habits of a few of our common species of birds 

 which should be protected may now be considered. The Robin 

 (Planesticus migratorius) probablv comes first. Early in the 

 year it feeds extensively on cutworms, those insidious enemies 

 of our garden plants and crops; in March they constitute over 

 a third of the robin 's food. It is accused of fruit eating, and yet 

 of all the vegetable matter it consumes a large proportion con- 

 sists of wild fruits ; 330 stomachs contained 58 per cent, vegetable 

 matter, of which 47 per cent, consisted of wild fruits and 4 per cent, 

 cultivated fruits.* The Bluebird {Sialic sialis) is not so common 

 as formerly in the Ottawa district, having probably been driven 

 away by the encroachments of man. Charming in its habits 

 it responds readily to encouragement, building in hollow trunks 

 and cavities. Insects such as grasshoppers, beetles and cater- 

 pillars constitute about 68 per cent, of its food. 



*Except where it is specifically stated otherwise, these analyses of stomach contents are 

 taken from the publications of the Biological Survey of the U. S. Department of 

 Agriculture, to which the reader is referred for further details. 



