190 HOW TO STUDY BIRDS 



and retire Into hiding, releasing the shutter by a 

 thread when the bird comes back to the nest. Be 

 sure to have a shutter adapted to thread release, with 

 a small lever to pull down and a hole in it for the 

 thread. Exposure by thread Is better than by pneu- 

 matic tube, which last arrangement introduces all 

 manner of troubles, too numerous to describe. 

 There is no trouble about the thread tangling, if 

 one will take reasonable pains to lay it out properly. 

 In making the exposure be sure not to jerk the 

 thread, but give a steady, gentle pull. 



Most birds are afraid of a camera set near the 

 nest, and some will not go near it at all. But most 

 of them will return before long, if the instrument is 

 properly disguised. I carry with me dull green and 

 brown hoods of thin cambric with which I can en- 

 tirely cover the camera, with a hole cut in each to 

 fit tightly around the lens-tube. In addition to this 

 I deck the camera with leaves or grass, and in like 

 manner conceal the tripod. Where it is feasible, I 

 avoid using the tripod by employing the tree-appara- 

 tus, screwing the camera to a branch or tree-trunk. 

 Where the bird is shy, use the single lens and thus 

 have the camera farther away. If the bird is to be 

 taken before she enters the nest, the exposure must 

 be a rapid one, in full sunlight. 



Most plates are hardly sensitive enough for in- 

 stantaneous exposures with the single lens amid green 

 foliage. But when the bird settles down to incu- 

 bate or brood, she will often keep still during a timed 



