1903 . Moffat. — The Spriyig Rivalry of Birds. 161 



the rookery, there would be rivalry if another rookery was 

 started within a certain radius. That has frequently happened, 

 and I remember a case myself in which some Rooks attempted 

 for several years to form a new rookery which was always 

 pulled to pieces by the inhabitants of a more anciently estab- 

 lished one. In another case, however, not far from the same 

 spot, a few pairs of rooks succeeded, one spring, in building 

 without molestation in a new site. Of this experiment, two 

 facts deserve notice. Firstly, the nests were not built till about 

 the end of April, when the birds of the older colony were busy 

 feeding their full-fledged young ; and secondly, the success 

 was very short-lived, for at the commencement of the following 

 spring the rooks of the old rookery came in force and carried 

 away the sticks from the new one to rebuild their own nests, 

 and thus the infant colony came to "an end. Whatever was 

 the motive here, it shows that to found a new rookeiy near an 

 old one is no easy matter. 



I will now mention another case of a bird that failed in its 

 matrimonial hopes, although the failure was not exactly 

 illustrative of the sort of competition I consider to be the 

 common rule. At Ballyhyland we have no Sparrows. Con- 

 sequently, the arrival of a pair of these birds in the farm -yard 

 in the spring of 1898 excited some interest ; more especially 

 as on the very first day of their visit they attempted to gain 

 possession of a House-martin's nest with the obvious intention 

 of making it their own. The House-martin is not so powerful 

 a bird as the Sparrow, but there were four pairs of House- 

 martins nesting in the yard, and the eight Martins at once 

 combined and beat the Sparrows away. On the following day 

 the two Sparrows were still ranging about the place, but no 

 sooner did the cock-bird show himself in the neighbourhood 

 of the row of Martins' nests than he was again attacked and 

 mobbed so severely that he retired to the other end of the 

 yard. He then set covetous eyes on another nesting site, 

 but that happened to be occupied by a pair of Blue Titmice. 

 I regret to say that I was not present as a spectator of the 

 engagement which followed, but I am told by one who was — 

 and I can well believe the assurance — that the battle between 

 the Titmice and the cock Sparrow was very fierce. The up- 

 shot, however, was that the aggressive cock Sparrow once more 

 suffered a bad defeat. And from that day the hen Sparrow was 



