BIRDS OF YOSEMITE NATIONAL PARK 79 



with Conspicuous Blue Markings" in the key, since this bird is largely blue. 

 As to size it best fits the category "Intermediate, between Brewer's black- 

 bird and crow"; therefore eliminate all other birds. When you have found 

 a description in this group that fits the bird, turn to the page indicated 

 in the index and read the more detailed description for further verification. 

 Walk slowly and quietly through the region selected for field study, stopping 

 now and then. Birds are frightened by quick movements. Try imitating 

 the call of a bird in distress by sucking the back of your wrist. Birds may 

 appear. 



One of the greatest pleasures the birds may offer you is through their 

 songs; learn to listen and to recognize the birds' voices, whether bird hunt- 

 ing or not. Whenever a new note is heard, if possible, trace it to its maker. 

 Accurate recognition is often dependent upon the bird's song or call. 



Learn to see correctly and to interpret wisely. Many see the apple 

 pecked and the wheat kernel disappear, but do not see the activities of 

 the same bird which mean the death of a coddling moth or a grasshopper. 



Observation is so inaccurate that state and federal authorities make 

 stomach analyses of birds in order to determine whether they are harmful 

 or not, on the basis of their food habits. While many birds are killed in 

 different localities at diflferent times of the year for this purpose, thousands 

 of other birds are protected by legislation which results from such studies. 



Some bird groups. — Characteristics of some of the bird groups may aid 

 identification. Hawks, eagles, and owls are usually of large size, have power- 

 ful hooked bills, usually stout legs, and long talons. Some hawks soar when 

 foraging, others dart through thickets to pounce on their prey. Owls are 

 large-headed birds with broad, rounded wings; they usually forage at night. 

 Thrushes are brown above, sometimes spotted below. They are trim, timid 

 birds that forage near the ground. Vireos are small, active birds frequently 

 with short, slender bills. There is a predominance of gray in the plumage. 

 Flycatchers range in size from 5/2 to 9 inches. They may be dull or bright 

 in plumage, sometimes have wing-bars, an eye-ring, or white outer tail 

 feathers. They have a marked habit of taking flight from a perch to return 

 to the starting point on capturing an insect in the air. This act is often 

 repeated. Raised feathers on the head often give the effect of a crest. 

 Wrens, with few exceptions, are small, brown birds usually with dark bars 

 on tail and wings and in some species a whitish line over the eye. As a rule, 

 wrens, when foraging, hold the tail upward at a sharp angle to the bodv. 

 They forage near the ground. Woodpeckers have stout, chisel-like bills, 

 two toes in front and two behind (one exception), and stifT, pointed tail 

 feathers. Black, white, and red are dominant colors. These birds forage 

 around trunks and large branches of trees, bracing themselves with the tail 

 as food is sought. Sparrows are generally grayish or brownish with rather 

 short, conical bills and they forage close to the ground. Warblers, as a rule, 

 are small, active, brightly colored birds with short, slender bills. The line 

 over the eye, characteristic of vireos, usually is wanting on warblers; their 

 relatively bright colors aid one in distinguishing them from vireos. 



Banding of birds. — In order to obtain accurate information about the 

 movements, longevity, and habits of birds, the federal government, working 

 through the Fish and Wildlife Service, bands thousands of birds each year. 

 Birds are trapped and aluminum bands numbered and marked "Notify 

 F. & W. Serv., Wash., D.C." are fastened to their -legs. They are given 

 their freedom at once. Records are sent to W'ashington, D.C. where com- 

 parisons are made. 



