CONCEALED OR COVERED NESTS 121 



persistent of these timber haunting species are the 

 Titmice (Paridae). These little birds rarely appear to 

 make a hole for themselves, except in very rotten 

 wood, although there is no doubt that they will alter 

 one to some extent, as I have repeatedly watched 

 them carrying material out of holes and picking away 

 bits of plaster and the like from walls. Neither is their 

 choice of site confined to trees, for they are perhaps 

 even more partial to stumps in hedgerows, gateposts 

 and so forth. Some of the species with a remarkable 

 sense of adaptability conceal their nests in most 

 unlikely places, such as flower-pots, pumps, cupboards 

 or boxes placed in trees for their special accommoda- 

 tion ; whilst their preference for walls and similar 

 artificial places shows how readily birds can avail 

 themselves of any new advantage in the matter of a 

 nesting site. For hole-builders the nests of the 

 Titmice are elaborate and well-made structures, cup- 

 shaped and composed of a great variety of materials 

 that are easily felted together, such as moss, wool, 

 hair, feathers, dry grass, leaves and so forth. As 

 illustrating the extreme complexity of the study of 

 birds' nests, we have in the present group of birds 

 species (Acredula) that make elaborate globular nests 

 in branches, whilst at least one other Titmouse con- 

 structs two very distinct types of nest. This latter 

 bird, the Great Titmouse {Pariis major), besides 

 making the usual cup-shaped nest in a hole, some- 

 times forms a beautiful globular nest of moss lined 



