BIRD-PHOTOGRAPHY 159 



thread which may be passed around the focusing 

 screw and then carried to any distance. The au- 

 thor uses a spool of ordinary linen thread, which 

 enables him to retire to any distance desired. 

 Each method has its advantages, the chief ones 

 of the latter being perhaps the slight expense 

 involved, the small weight to carry on field-trips, 

 and the easy adaptability to any desired length. 

 The advantages of the rubber tubing are that 

 it is not disturbed by the wind and there is not 

 the risk of the shutter's being operated accident- 

 ally that there is with the thread. The author 

 has used the thread entirely in his work, and has 

 found it on the whole quite satisfactory, though 

 perhaps, everything considered, the tubing may 

 be superior. 



Time to photograph. — In order to approach 

 a bird closely enough to photograph it, one must 

 take advantage of some strong instinct, or feel- 

 ing, which will offset the fear caused by the near- 

 ness of the camera. The two feehngs which may 

 be used to the best advantage are the parental 

 instinct shown in rearing the young, and the feel- 

 ing of hunger. Opportunity for using the former 

 means is furnished by those birds which nest in 

 houses ; and for using the latter means by those 

 which will come to the winter feast. 



