PROTECTIVE RESEMBLANCE 41 



brown lines and mottlings of the plumage, besides 

 that they blended with, and faded into, the sur- 

 roundings, had, both in pattern and colouring, a 

 great resemblance to the latter object ; the lighter 

 feathers exactly mimicking those patches which are 

 made by the flaking off of some of the numerous 

 layers of which the bark of the Scotch fir is com- 

 posed. This would only be of any special advantage 

 to the bird when, as in the present instance, it had 

 laid its eggs amongst pieces of such bark, fallen from 

 the neighbouring Scotch fir-trees, and did it invariably 

 do so, a special protective resemblance might, perhaps, 

 be admitted. This, however, is not the case. It lays 

 them, also, under beeches or elsewhere, where neither 

 firs nor fir-bark are to be seen. 



Unless, therefore, it can be shown that a large 

 majority of nightjars lay, and have for a long time 

 laid, their eggs in the neighbourhood of the Scotch 

 fir, the theory of a special resemblance in relation to 

 such a habit, due to the action of natural selection, 

 must be given up ; as I believe it ought to be in 

 some other apparent instances of it, which have 

 received more attention. Of course, there might 

 be a difference of opinion, especially if the bird 

 were laid on a table, as to the amount, or even the 

 existence, of the resemblance which I here insist 

 upon. But I return to the essential fact. At the 

 distance of two paces I looked full at a nightjar 

 sitting amongst flakes of fir-bark, strewed about the 

 sand, and, for some time, it appeared to me that 

 it was one of these. This is interesting, if we 

 suppose, as I do, that mere chance has brought 

 about the resemblance, for here is a point from 



