SOME BIRDS' NESTS 147 



indurated interior, the great majority of passerines 

 showing a marked preference for a soft lining 

 to the house destined to accommodate helpless 

 and featherless young. The point to be noted 

 just now is, that it is a physically possible thing 

 for the inmates of such a nest, given the intelli- 

 gence, to see and lay up a mental picture of it, 

 outside and in. Assuming them capable of the 

 examination, most of the nest is open to their 

 inspection. 



But examine the nest of the blackbird, which 

 is also a thrush with a difference. In size, general 

 form, and external appearance it is the same as 

 the nest of the mavis. Inside, however, instead 

 of the hard lining of dried mud, there is a yielding 

 lining of fine root and other fibre. It would 

 seem, therefore, that the blackbird, as nest -builder, 

 makes a simpler nest than its 'cousin the thrush, 

 leaving off operations at that point where the 

 mavis begins its plastering. And so it is repre- 

 sented in more than one book of natural history. 

 But the truth is very different, as any one who 

 takes the trouble to carefully break up an old 

 or deserted blackbird's nest finds out. The first 

 stage of the building process is the same in both, 

 and the second stage is not very different. Like 

 the thrush, the blackbird lines with mud a nest 

 which has already a passably finished look about 

 it. The plastering is not so carefully done, as 

 in the case of the thrush, particularly in the matter 

 of finish, but it is done. Having completed it, 

 the blackbird proceeds to a third stage, and lines 

 the plastered lining with soft fibre. The com- 



