1875.| MR. W. H. HUDSON ON THE HABITS OF HERONS. 627 
appears to become hereditary ; and the species in which they are 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. 
eiThe Scolopax frenata, 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 in- 
stinctively 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 ou the breast and strike out the feet as in swim- 
ming. 
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 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 
water ; a flock of these birds feeding reminds one of a line of mowers 
mowing grass. On dry ground, the Spoonbill seems unable to walk 
directly torward like other birds, but stoops, keeping the body in a 
horizontal position, and, turning from side to side, sweeps the air with 
its beak, as if still feeding in the water. 
In the foregoing instances (and I could greatly multiply them), 
in which certain gestures and movements accompany progressive 
motion, it is difficult to see how the structure can be in any way 
modified by them; but the preying attitude of the Heron, the 
waiting motionless in perpetual readiness to strike,.has doubtless 
given the neck its very peculiar form. 
Two interesting traits of the Heron (and they have a necessary 
connexion ) are its tireless watchfulness and its insatiable voracity ; for 
these characters have not, I think, been exaggerated even by the most 
sensational of ornithologists. 
In birds of other genera, repletion is invariably followed by a 
period of listless inactivity during which no food is taken or required. 
But the Heron digests his food so rapidly that, however much he 
devours, he is always ready to gorge again; consequently he is not 
benefited by what he eats, and appears in the same state of semi- 
starvation when food is abundant as in times of scarcity. An old 
naturalist has suggested as a reason for this, that the Heron, from 
its peculiar manner of taking its prey, requires fair weather to fish— 
that during spells of bad weather, when it is compelled to suffer the 
