32 



d — 



Fig. 3. — Oak bark pierced by 

 downy woodpecker. 



of large black ants. The bird had made four openings into these gal- 

 leries and in each case had uncovered hibernating black ants. By what 



sense these motionless insects were discovered 

 in their hidden burrows will perhaps always 

 remain a mystery. 



On March 30 a brown creeper was seen to 

 inspect 43 trees in an hour, getting its food 

 from crevices in the bark. 



Another downy woodpecker was seen on 

 March 31, 1899, taking the larva? of beetles 

 from beneath the bark of oak trees. The bird 

 seemed to know the exact spot to drill for each 

 larva, for it always cut a small hole directly 

 over the insect, finding the prey unerringly. 



The cut, Fig. 3, gives view of the outer sur- 

 face of a section of bark taken from a small 

 oak. From this small piece of bark the bird 

 probably secured at least six of the larvae that 

 were found in its stomach. The holes a, b, c, 

 d, e,f indicate those from which the larvae were 

 taken. 



Fig-. 4 gives a view of the inner surface of 

 the same piece of bark, showing how true was 

 the stroke of the bird, 

 for its beak, piercing 

 from the outside, 

 went directly to the 

 centre of the burrow 

 where the insect lay 

 entirely hidden from 

 view. The letters a, 

 b, c, d, e, f indicate 

 the holes, showing 

 size and shape, where 

 the bird's beak came through to the inner sur- 

 face. Seventeen larva? of bark beetles and 12 

 ants were found in the bird's stomach. 



During the winter the chickadees and jays 

 perform priceless service by destroying quan- 

 tities of the eggs of such insects as those of 

 the tent caterpillar and canker worm moths. 

 The owls and some of the hawks are useful, 

 not alone in the summer, when they destroy 

 many of the May beetles, larger caterpillars 

 and moths, and keep down the increase of the 

 mice and squirrels, but those that stay through 

 the winter are also useful then by keeping 

 squirrels, mice and hares in check. Hares and 

 mice sometimes do great damage by gnawing 

 the bark or roots of trees. All of these ani- 

 mals become injurious whenever abnormally 

 numerous. Witness the great plagues of field 

 mice in Norway, and the injury caused in our 

 western plains by the prairie hare or so-called 

 iack-rabbit. 



And so, day by day, throughout the year, 

 birds work for the good of the forest. In sat- 

 isfying their own appetites and providing for 

 their young they guard and protect the trees, which in turn provide them 

 with food and shelter. In satisfying their appetites on the fruit and seed 



Fig. 4. — Inner surface of the 

 same bark, showiDg the chan- 

 nels of bark beetles and the 

 woodpecker's perforations. 



