240 BIRDS OF NORFOLK. 



those that had not paired before their arrival. The nest 

 is constructed of dead vegetable matter, and either built 

 up from the bottom, or, if floating, it is securely moored 

 to the surrounding growth of reeds, and is generally 

 situated a short distance within the fringe of a reed-bed, 

 but never where the reeds are so close as to offer any 

 obstruction to the old birds leaving the nest by diving. 

 Prom the constant sliding on and off of the old birds, 

 after the nest has been used some time, it becomes 

 smooth and closely compacted on the surface, and has 

 the appearance of a mass of muddy weed with a slight 

 depression in the centre, and very little raised above the 

 surface of the water ; here the eggs are placed, and a 

 most wet and uncomfortable structure it looks. Mr. 

 Lubbock says, " opinions have varied as to whether 

 fermentation has aught to do with the warmth furnished 

 to the eggs of this bird." With a view to test this I 

 tried the temperature of three nests this year, and found 

 that a nest with three perfectly fresh eggs, into the 

 substance of which my thermometer was thrust three 

 inches and a half indicated 67 degrees ; the second nest 

 contained three eggs which were considerably incubated, 

 and the thermometer registered 72 degrees ; and in a 

 third, in which there were three eggs and a newly hatched 

 young one, the thermometer rose to 73 degrees, 

 showing that the nest, so far from being the cold and 

 uncomfortable structure by some supposed, was a real 

 hot-bed. On inserting the thermometer into a beauti- 

 fully neat and dry coot's nest, which the bird had just 

 left, I found the temperature to be 61 degrees. The day 

 was wet and cheerless, and the maximum reading of 

 the thermometer in the shade was 58 degrees. 



In almost all cases one or more of what are known to 

 the marshmen as "cocks' nests" will be found at no 

 great distance from the true nest, especially after the 

 birds have begun to set ; these hSve been variously 

 referred to as " play nests " or " look-out platforms " for 

 the male bird ; they are mere platforms of reed or other 

 material, slightly constructed, and altogether different 

 in structure from the true nest, and I am strongly of 

 opinion, although I have had no opportunity of proving 

 such to be the case, that they are constructed as resting- 



