IVY WREN. ORNITHOLOGIST'S TEXT-BOOK. 213 



is worth a dozen hypotheses, I shall proceed to 

 state my objections to the above-mentioned suppo- 

 sition. 



First, then, though I have frequently discovered 

 these " fallow nests" near others containing eggs 

 or young, yet I have observed that such have invari- 

 ably been the first architectural attempts of young 

 birds of the year, or else that they have been built 

 as a winter retreat. Secondly, I have found, from 

 personal observation, that both birds assist in fabri- 

 cating the nest. And, in the third place, they are 

 always constructed at the beginning, or towards 

 the end, of the breeding season. For these reasons, 

 I confidently deny that the untenanted nests are 

 built by the males, whilst their mates are sitting. 

 And, indeed, I may be allowed to ask, why should 

 this bird alone possess so extraordinary an instinct 

 for the preservation of its nest ? I say preservation, 

 because it has been argued that they are built with 

 the view of preventing the discovery of the furnished 

 or inhabited apartment; but I am of opinion that 

 it would have exactly the opposite effect, namely, 

 that of encouraging the bird-nester to continue his 

 researches. Success naturally stimulates to further 

 exertion, and so, if I am not greatly mistaken, it 

 would be in this case. Accounting for the circum- 

 stance by supposing these dubious nests to be the 

 productions of young and inexperienced architects, 

 we find many parallel cases in other species. No- 

 thing is commoner than to meet with half finished 

 or clumsily constructed nests of the Garden Thrush, 

 Garden Ouzel, Hedge Dunnock, Goldcrested King- 

 let, and many others, which are invariably com- 

 menced very early in the season, as none of these 

 birds make any use of their nests but in the breed- 

 ing time. But the Ivy Wren often builds itself a 

 dwelling in autumn, and lodges therein on cold 

 nights. These are mostlv built in the usual locali- 



