Frogs and Toads 



a dog's back. What is the object of the stickleback's 

 ingenuity? Why should he trouble to build such an 

 elaborate nest? Well, the greatest enemies of stickle- 

 backs are other sticklebacks, and his nest is necessary in 

 order to protect his wife's eggs from enemies, particularly 

 those of his own kind. 



If a few stickleback eggs be taken from a nest and 

 thrown into a stream frequented by these fish "stickle- 

 backs rush at them from all sides and fight for them like 

 boys scrambling for halfpence." The male expends con- 

 siderable care and time in the construction of his nest ; 

 he selects his material to suit the locality, everything, 

 in fact, is done to render the nest as inconspicuous as 

 possible. The floor of the nest is first constructed. Pieces 

 of grass or water weed are brought from afar and laid 

 down with the utmost care on the bed of the stream. 

 Piece by piece they are placed in position, not at hap- 

 hazard, but interlacing with one another so as to form a 

 smooth fabric. 



When his weaving is finished the father fish gives off a 

 sticky substance from his kidneys which sticks the woven 

 plants together; then he places little pebbles upon the 

 structure to prevent it from rising to the surface of the 

 stream. Next he turns his attention to the sides of his 

 nest and, little by little, builds up an arch over his closely 

 woven carpet. The completed nest somewhat resembles 

 a lady's muff, except that the opening on one side is 

 smaller than it is on the other. Beautifully smooth and 

 well finished inside, it is rough and unkempt - looking 

 without. Having completed his early labours, the stickle- 

 back assumes his wedding attire of emerald-green, decked 

 with bright pink, and sallies forth to find a mate. By 

 dint of much persuasion he induces a female stickleback 

 to deposit her tiny yellow eggs inside the nest. Over the 

 nest he now keeps careful guard, waving his fins steadily 

 the while, to keep a current of water passing through the 

 nest, a necessity for the efficient hatching of the eggs. 



250 



