758 



THE NATURE BOOK 



Wonderful that they can find their own 

 nesting liole in that wilderness of tumbled 

 stone ; wonderful that they can recog- 

 nise their mate amongst the teeming 

 throng ; more wonderful still that they 

 should distinguish friend and foe — unless 

 the organisation of the puffin city is greater 

 than we suspect. What if the birds nest- 

 ing in one small area consorted together 

 like neighbours in one street ? Then 

 perhaps were the riddle solved. 



Yet teeming as the life of the nursery 

 is, it must be as nothing compared witli 

 the infinite resources of the sea. All 

 these birds and their young have to be 

 fed for nearh' three months on fish caught 

 in the immediate neighbourhood. The 

 cormorant is said to eat considerably 

 more than its own weight of fish e\-ery 

 day, and it is certain that puffins, razor- 

 bills and guillemots are not far behind. 

 One hesitates to commit oneself to figures, 

 but in some nurseries there are tens of 

 thousands of birds, and the fish mortality 

 during the breeding season must amount 

 to many millions. Yet one rarely sees 

 the birds in any quantity more than five 

 miles from their breeding quarters. 



Stragglers, indeed, may be found 

 perhaps twice that distance, but the 

 time required to make the journey is 

 prohibitive when there is a hungry young 

 one waiting in the burrow. The puffin 



is not an e.xpert flier, nor, indeed, are any 

 of the diving sea-birds. The wings have 

 been reduced to a minimimi to allow of 

 their being used in swimming under water, 

 and the\' often e.xperience a difficulty in 

 rising from a calm sea. With head in- 

 variably turned to whatever breeze there 

 is, they flap their way over the water 

 like a frightened domestic duck, and 

 then taking advantage of some tiny 

 wa\'elet they launch into the air. Then 

 their weight gives them momentum, and 

 they travel at a great pace, making a 

 bee-line for their home. The densest fog 

 causes them no difficulty, though how 

 they take their bearings it is impossible 

 to say. I know one old skipper who 

 steered by their flight against the read- 

 ing of his compass, and it was not till 

 afterwards that he discovered that the 

 needle was affected by a quantity of iron 

 lying close by on deck. 



Then when all the labour of rearing the 

 3'oung is over, they are taken down to 

 the water to receive their education, and, 

 if the parent birds have any power of 

 thought, anxiously indeed must they 

 watch the sky lest in the stress of the 

 gale their weakly young ones are drowned. 

 It is Nature's redressing of the balance, 

 the safeguard against the exhaustion of 

 the food supply, and the relentless ocean 

 taking toll for the harvest it yields. 



A. J. R. Roberts. 



VEGETABLE GALLS 



WHAT THEY ARE AND HOW THEY ORIGINATE 



By HAROLD BASTIN 



With PhotoSraphs by the Author 



BY an aj)peal to the " life history " 

 of the oak-apple Gall-fly, I was 

 able, in a previous paper (p. 693), 

 to show that galls arc the direct outcome 

 of insect activity exerted upon the highly 

 sensitive meristem tissue of plants ; also, 

 that galls are, in effect, nurseries wherein 

 the earlier stages of the insects are passed 



in comfort and security. Moreover, we 

 had a glimpse of that amazing phenomenon 

 known as " alternation of generation." 

 But lest the reader should assume that 

 this phenomenon is characteristic of Gall- 

 fly life as a whole, I must enter upon a 

 brief explanation. 



Gall-flies must surely be classed among 



