BIRDS NIDIFICATION. 297 



to a nest already sufficient in strength and size to answer every 

 end. My swans generally form their nest on an island quite 

 above the reach of a flood ; and still the sitting bird never ap- 

 pears satisfied with the quantity of materials which are provided 

 for her nest. I once gave her two huge bundles of oaten straw, 

 and she performed her work of apparent supererogation by apply- 

 ing the whole of it to her nest, already very large, and not 

 exposed to destruction had the weather become ever so rainy. 



This same author continues : 



It is probable that this disposition to accumulation, in its 

 general bearing, has reference to heat rather than the flood ; but 

 that the wild swan has a foresight regarding danger, and a quick 

 perception as to the means of securing safety, appears from an 

 instance mentioned by Captain Parry, in his Northern voyage. 

 When everything was deeply involved in ice, the voyagers were 

 obliged to pay much attention to discern whether they were 

 travelling over water or land ; but some birds, which formed 

 their nest at no great distance from the ships, were under no 

 mistake in so important a matter ; and when the thaw took 

 place it was seen that the nest was situated on an island in the 

 lake. 



The following cases are likewise taken from Couch (loc. 

 cit., p. 225) : 



This swan was eighteen or nineteen years old, bad brought 

 up many broods, and was highly valued by the neighbours. 

 She exhibited, some eight or nine years past, one of the most 

 remarkable powers of instinct ever recorded. She was sitting 

 on four or five eggs, and was observed to be very busy in collect- 

 ing weeds, grasses, &c., to raise her nest; a farming man was 

 ordered to take down half a load of haulm, with which she most 

 industriously raised her nest and the eggs two feet and a half; 

 that very night there came down a tremendous fall of rain, which 

 flooded all the malt-shops and did great damage. Man made 

 no preparation, the bird did; instinct prevailed over reason. 

 Her eggs were above, and only just above, the water. 



During the early part of the summer of 1835, a pair of 

 water-hens built their nest by the margin of the ornamental 

 pond at Bell's Hill, a piece of water of considerable extent, and 

 ordinarily fed by a spring from the height above, but into which 

 the contents of another large pond can occasionally be admitted. 

 This was done while the female was sitting ; and as the nest 

 had been built when the water level stood low, the sudden influx 



