108 THE HERON. 



over the meadows. How the herons find out these 

 occasions, it is difficult to say ; but we have seen several 

 pairs come, after a flood, to a river which they never 

 visited upon any other occasion ; and within many miles 

 of which a heronry, or even the nest of a single pair, 

 was never observed. 



Few birds are more generally diffused than the 

 common heron. It is found in all latitudes and all 

 longitudes. In some places they migrate, in others 

 they merely spread themselves, or shift their quarters 

 in the same latitude, and in others again they remain 

 quite stationary. The power of changing their abode 

 is necessary for their comfort, and even for their exist- 

 ence. They are exceedingly voracious ; and their 

 powers of digestion are equal to their powers of swal- 

 lowing. The seventeen carp mentioned by Willoughby, 

 were only a meal for six or seven hours. The absolute 

 necessity of food for the preservation of the life of the 

 animal is not, however, quite so great as its rapacity ; 

 for it can not only subsist for a long time without 

 food ; but when old ones are taken alive, they prefer 

 freedom to luxury, and starve themselves to death, 

 even though food be placed within their reach, and 

 kept there till they could eat it unobserved. 



Herons appear, like many other animals, to have 

 some instinctive perception of the approach of rain ; 

 as their favourite time for flying, and at which they 

 take their loftiest flights, is just before a fall of rain. 

 Their elevation then is greater than that of the eagle ; 

 and their flights are also longer at those times than 

 when they are merely in search of food. It is possible- 

 that their elevation may be chosen as an instinctive 



