1909- Moffat. — The use of Domed Nests. 165 



It does not, of course, follow because a domed nest serves a 

 particular purpose that it was constructed for chat purpose, or 

 that it serves no other. The " concealment " theory is doubt- 

 less of application in some cases, whether these be many or 

 few. But I would ask whether there can be any real pro- 

 bability that concealment is the end principally aimed at by 

 this type of architecture, in view^ of the fact that so few 

 species employ it at all, and that these, so far as our Irish 

 and British instances of it go, are not distinguished by any 

 greater need of concealment than the birds that build open 

 nests ; while the use of the dome itself is (at least in all 

 the species using it under our own observation) capable of 

 being quite differently explained. 



And would a domed nest be a good means of concealment % 

 This must depend more or less on the amount of reason- 

 ing power possessed b}' the creatures against whom conceal- 

 ment is needed. As against any intelligent enem\' to bird-life, 

 it must be very nearly as important to conceal the nest itself 

 as to conceal the bird sitting in it ; for any animal having 

 sense enough to know" that a nest is a nest would not be 

 deterred from examining it by the fact that no bird was within 

 view. The domed nest is, however, owing to its larger size, a 

 good deal more conspicuous than the undomed ; so that in 

 the case of the intelligent enemy it would probabl}- more often 

 betray than protect. On the other hand, it would be a real 

 protection against enemies of so stupid a type that the sight 

 of the nest would suggest nothing to them till they also saw 

 the contained bird or eggs. It has sometimes been sug- 

 gested that this degree of stupidity does prevail in the brute 

 creation, and that domed nests are consequently not liable to 

 be rifled except by human marauders, who alone know such 

 nests " for what they are." But I would suggest that this is 

 evidently not the opinion of the dome-building birds them- 

 selves. They act on the principle that they have intelligent, 

 and not merely stupid enemies to fear ; for the}- try to make 

 their nests as little conspicuous as possible by covering 

 them over, in many cases, with assimilative material — the 

 Long-tailed Titmouse covering hers with lichen, the Chiff- 

 chaff hers with withered leaves, &c. This shows that they 

 know well enough that merely to conceal the sitting bird is 



