98 BIRDS OF LA PLATA 
reacted on and modified fe 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 readiness for assuming at 
all times, and an involuntary falling into, these 
peculiar attitudes and gestures appears to become 
hereditary ; and the species in which they are the 
most noticeable seem incapable of throwing the habit 
or manner off, even when placed in situations where 
it is useless or even detrimental. Tringe 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 utilised 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 for- 
ward on the breast and strike out the feet as in 
swimming. 
The Glossy Ibis feeds in shallow water, thrusting 
