A New Device for Securing Birds' Pictures 195 



ping or folding almost in the face of the camera, and it was therefore 

 found necessary to devise some means by which the exposure could be 

 deferred until the bird was in repose. The result is shown in the accom- 

 panying figures. When the bird alights upon the perch a, the check 

 resting on the wheel b is removed and as the wheel revolves the heav- 

 ier of two weights c, sliding on rods, descends and enters d and e, the 

 negative and positive poles of a dry battery. The circuit is thus closed 

 and by means of a small electro-magnet on the camera the shutter is 

 released and exposure made. 



How the bird is to be induced to alight on the perch is a problem which 

 each user of this modern development of a bird trap must solve for himself. 



The accompanying pictures of Bluebirds were obtained by placing the 

 perch near their nest ; the camera was then focused on it and the whole 



BLUEBIRD ON ELECTRIC PERCH 



affair left until, on returning, the shutter was found to have been sprung, 

 when the exposed plate — representing, potentially, the trapped bird — was 

 removed, a new one introduced and the 'trap' set for another capture. 



No other trial has as yet been made, but in addition to its use near 

 nests, the apparatus could doubtless be employed with success in large 

 fields or meadows frequented by Hawks, or, carrying the comparison with a 

 trap still further, it might be baited with meat, seeds, or fruit which would 

 induce birds to alight on the perch and unconsciously leave their image. 



