BISET OR WILD ROCK-PIGEON. 149 



vantages not possessed by the square, giving an 

 easier access to the breeding birds to their nests, 

 and a greater facility of taking the young, and in- 

 specting and clearing out the holes, by means of a 

 ladder turning upon an axis. Around the interior 

 of the tower, about three or four feet from the bot- 

 tom, a horizontal ledge of eight or ten inches in 

 width ought to project, in order to prevent rats, 

 weasels, and other vermin, destructive to the eggs 

 and young, from scaling the walls and entering the 

 pigeon-holes, and if this ledge be covered on its un- 

 der surface with tin or sheet-iron, it will the more 

 effectually prevent the entrance of such intruders. 

 A second ledge of less width, and about midway up 

 in a pigeon -house of considerable height, may also 

 be of advantage, not only for additional security 

 against enemies, but as a resting-place for the pigeons 

 when they enter the house. The holes or nests are 

 best built in quincunx order, and not directly over 

 one another, and they ought to be sufficiently large 

 to allow the old birds to move in them with freedom, 

 and to stand upright, in which position they always 

 feed their young. 



Frequent attention to the state of the holes is ne- 

 cessary, and they ought regularly to be inspected 

 and cleansed after each great flight, that is, towards 

 the end of May, and again before winter. The 

 dung accumulated at the bottom of the house should 

 also be removed every three or four months, as the 

 eftiuvium which arises from it when in a large mass, 



