72 Stead, The Black Cormorant in Neiv Zealand. risf"oct 



do a great deal of good by their attacks upon the former. Some 

 years ago I shot 19 Shags on the Lower Selwyn, and cut them 

 open to see what each of them had in its stomach. Seventeen 

 had eels, one had some small fresh-water crayfish, and one had a 

 small trout about 7 inches long. Therefore, regarding even the 

 bird that was eating crayfish as doing damage by taking trout 

 food, the amount of good done by the 17 is out of all proportion 

 to the damage done by the two. I do not think that the harm 

 an eel can do trout is generally recognized. Being largely a 

 bottom -feeding fish, it is an especial menace during the spawning 

 season. A 2-lb. eel could easily eat all the spawn of a 5-lb. 

 trout, and it is just the right fish to find it. Some time ago 

 a 7-lb. eel was caught in our creek at Strowan. It had in 

 its stomach one goldfish half digested and another quite whole, 

 each of them weighing well over half a pound. I refer to this 

 as an indication of the quantity that an eel can eat, for I do not 

 think it would as easily catch trout as goldfish. But the damage 

 done by eels in trout streams is not confined to their depreda- 

 tions among the trout themselves. Owing to their large appetites 

 they eat enormous numbers of the small fish that would otherwise 

 serve as food for the trout. This effect of the presence of eels 

 may be likened to that of rabbits in sheep country. 



The reasons for a Shag's preference for eels are many. Weight 

 for weight an eel is more nourishing than a trout. But a Shag 

 can with ease swallow a i^-lb. eel, while it can only manage a 

 I -lb. trout with difficulty. That larger trout have been taken by 

 Shags I am well aware, but as a general rule my remark holds 

 good. The bird's method with an eel is to swallow it head first, 

 getting about 4 inches of the fish into its stomach, the remainder 

 being in its neck, fly to some convenient perch, and there sit 

 throughout the process of digestion, letting the eel slide down 

 gradually as it is digested. I remember once early in the 

 morning standing below a Shag on a poloar branch at the Lower 

 Selwyn and seeing about 2 inches of an eel's tail protruding 

 from the bird's bill. 



The Maoris, who were very observant field naturalists, have a 

 legend about a battle between the land birds and the sea birds, 

 which was brought about in the following manner : — 



During a storm a sea Shag came into a lagoon for shelter, and 

 there met a land Shag. Getting into conversation with the 

 latter he asked what kind of fishing was to be had in the fresh 

 water. "Very good," replied the land Shag, "dive and see ! " 

 The sea bird dived and brought an eel ashore. " Swallow it," 

 said the land Shag. The other did so. " Now disgorge it." 

 Gently but readily the eel slid out on to the sand. " That," 

 said the land Shag, as he preened his plumage while his friend 

 re-swallowed the eel, " that is the kind of fishing I have here." 

 The storm having abated, the sea Shag said, " Now come with 



