96 ARDEID.E. 



away. But in the Herons it must be only by a great effort that the neck 

 can be wholly unbent ; for even if the neck cut out from a dead bird be 

 forcibly straightened and then released, it flies back like a piece of 

 india-rubber to its original shape. Therefore the effort to straighten the 

 neck, invariably the first expression of alarm and curiosity, must be a 

 painful one ; and to keep it for any length of time in that position is 

 probably as insupportable to the bird as to keep the arm straightened 

 vertically would be to a man. Thus the Heron flies at the first sight of 

 an intruder, whilst the persecuted Duck, Swan, or other fowl continues 

 motionless, watching with outstretched neck, participating in the alarm 

 certainly, but not enduring actual physical pain. 



Doubtless in many cases habits react upon and modify the structure 

 of parts ; and in this instance the modified structure has apparently 

 reacted on and modified the habits. In seeking for and taking food, 

 the body is required to perform certain definite motions and assume 

 repeatedly the same attitudes ; this is most frequently the case in birds 

 of aquatic habits. A facility for assuming at all times, and an involun- 

 tary falling into, these peculiar attitudes and gestures appears to be- 

 come hereditary ; and the species in which they are the most noticeable 

 seem incapable of throwing tbe habit or manner off, even when placed 

 in situations where it is useless or even detrimental. Tringte rapidly 

 peck and probe the mud as they advance ; Plovers peck and run, peck 

 and run again. Now I have noticed scores of times that these birds 

 cannot possibly lay aside this habit of pecking as they advance ; for 

 even a wounded Plover running from his pursuer over dry barren 

 ground goes through the form of eating by pausing for a moment 

 every yard or so, pecking the ground, then running on again. 



The Paraguay Snipe, and probably other true Snipes, possesses the 

 singular habit of striking its beak on the ground when taking flight. 

 In this instance has not the probing motion, performed instinctively as 

 the bird moves, been utilized to assist it in rising ? 



Grebes on land walk erect like Penguins and have a slow awkward 

 gait ; and whenever they wish to accelerate their progress they throw 

 themselves forward on the breast and strike out the feet as in swimming. 



The Glossy Ibis feeds in shallow water, thrusting its great sickle 

 beak into the weeds at the bottom at every step. When walking on 

 land it observes these motions, and seems incapable of progressing 

 without plunging its beak downwards into imaginary water at every 

 stride. 



The Spoonbill wades up to its knees and advances with beak always 

 immersed, and swaying itself from side to side, so that at each lateral 

 movement of the body the beak describes a great semicircle in the 





