26* ODD HOURS WITH NATURE 



swallow and the sphere-shaped nest of the house- 

 martin are composed of finely worked mud or 

 clay. This clay the bird collects in suitable places 

 in mouthfuls and kneads into cohesiveness with its 

 own saliva. From the very nature of the case it 

 is impossible that much of the building can be 

 advanced at one time. The foundation layer is 

 attached to wall or beam by nothing but its own 

 cohesiveness, and till it is rigidly hard and dry 

 no more can be done. It is the same with every 

 successive layer ; it must dry before the next can 

 be attached to it, otherwise the whole fabric would 

 be brought to the ground by its own weight. In 

 moist weather the drying process must be slow, 

 and in the best of conditions it cannot be fast. 

 But, then, it must be remembered, a very large 

 proportion of swallows of both sorts do not build 

 their nest every year. They merely repair the 

 old ones, and if they were as speedy brood-rearers 

 as some of our native birds, the double brood of 

 these at least would be already on the wing. But 

 a house -martin's nest, which I have under observa- 

 tion just now, was found by the tenants on their 

 arrival in an almost perfect state so far, at any 

 rate, as the external masonry was concerned and, 

 nevertheless, the second brood is not yet far 

 advanced. 



Few of us in these days have ever an opportunity 

 of seeing the nest of either the house-martin or 

 the swallow in what may be called their natural 

 conditions, and for the very good reason that the 

 vast majority of them have adopted conditions 

 which, whatever the birds themselves may think 



