146 ODD HOURS WITH NATURE 



teristics, and Darwin has commented on the 

 strange fact that those characteristics reappear 

 in the nest of the thrush of South America, 

 separated as it is from its European relative by 

 half the world, and, as it must be, by geological 

 ages in time. The foundation of the nest is laid 

 with rough grass roots, dead leaves, and root 

 stems. As the work proceeds, a finer kind of 

 root fibre is employed, and with this a bowl-shaped 

 structure is fashioned, which would pass for a 

 fairly well-finished nest if the bird did nothing 

 more. But it does more. Having built its nest, 

 it proceeds to plaster it. This is done with a 

 mixture whose composition varies with the 

 resources of the district. Sometimes mud alone 

 is used, with just enough fibrous material to give 

 it coherence. Not infrequently decayed wood 

 enters largely into the composition of the plaster, 

 and more frequently still horse or cow dung. 

 Whatever is used it is worked into a paste in the 

 beak of the thrush, which, at the nesting season, 

 may often be seen resorting to rain puddles for 

 the purpose. The plaster is laid on to the inside 

 of the nest with the beak, and if the nest is 

 examined at the right stage the soft coating will 

 be found scored all over with bill-markings. But 

 when the bird has finished its work the inside 

 is perfectly smooth. When the work is finished 

 the thrush leaves the nest to dry, and by the time 

 the first egg is deposited in it the whole cup is 

 firm enough and hard enough to hold water. It 

 would be difficult to say what special advantage 

 the mavis gets from a nest of this type, with its 



