506 Mr. Rennie on the Contrivances 



saw a number of these birds (probably a young family with 

 their parents) on a tree on a fir plantation sitting so closely 

 together that they all seemed to be rolled up into a single ball. 

 Little is known of the roosting of these birds ; but among 

 smaller species the habit in question is not uncommon. Even 

 during the day, in severe winter weather, I have observed a 

 similar practice in the house-sparrow (Passer domesticus, RAY). 

 On a chimney-top, which can be seen from my study window, 

 I have often remarked the whole of a neighbouring colony of 

 sparrows contest by the hour the warmest spot on the project- 

 ing brick ledge, which was in the middle. Here the sun shone 

 strongest, the kitchen-fire below sent its most powerful in- 

 fluence, and here the middlemost bird was best sheltered from 

 the frosty wind, which swept by its more unlucky companions 

 that had been jostled to the two extremities of the row ; but 

 none remained long in quiet: for as soon as the cold air pinched 

 them on the exposed side, off they popped to the middle, 

 scolding and cackling most vociferously, and, as those who 

 held the best places refused to give them up, the new comers 

 got upon their backs and insinuated themselves between two 

 of the obstinates, wedge-fashion, as you thrust a book into a 

 crowded shelf. The middle places were thus successively con- 

 tested, till hunger drove the whole colony to decamp in search 

 of food. 



I once witnessed, near Eltham, a similar contest for places 

 among a family of the bottle- tit (Parus caudatus, RAY), whose 

 proceedings I had been watching, while they flitted from spray 

 to spray of a hawthorn hedge in search of the eggs of a coccus 

 (Coccus Cratcegi 9 FABR.). The ground was covered with 

 snow, and as evening approached, the little creatures, whose 

 restless activity had no doubt tended to keep them warm, re- 

 treated from the open hedge to the shelter of a thick holly ; 

 ' the leading bird,' as Mr. Knapp correctly describes, * uttering 

 a shrill cry of twit, twit, tunt, and away they all scuttled to be 

 first, stopping for a second, and then away again *.' When 

 they, had all assembled, however, on an under bough of the 

 holly, they began to crowd together, fidgeting and wedging 



* Journal of a Naturalist, p. 164. Third edition. 



