Rooks were mentioned here the other day. A friend says there was a famous battle around Fermoy in 1930 in which starlings were the invaders and rooks the defenders, according to a writer of some time ago. And rooks, he wrote, have a capacity for military tactics which may be unexpected. The battlefield was two groups of tall trees - their tops. One was in Fermoy and one in an island in the Blackwater below Fermoy Bridge. Both used for nesting in spring and for roosting in winter by the rooks, which nightly congregated in hundreds.
A mile and a half away in a wood of young conifers, starlings had a big roost and on winter evenings flocks of them variously estimated at 10,000 to 20,000 passed there over the town of Fermoy. On November 2nd 1930, however, after the rooks had retired for the night, the homing starlings hesitated, wheeled round and round over the town for a while and then suddenly poured down into the rooks' dormitories.
The rooks protested vigorously and noisily, rising and flying round wildly, but the starlings refused to go away. After some hours of recrimination, things became quiet. Each night for a week the same thing happened. Then came November 9th When the starlings arrived, up rose not the usual 300 rook population but a black mass, estimated at between 1,500 and 2,000 birds, with great cawing. They did not attack the starlings, but hovered, densely packed, a few feet above the tree-tops. Four times the starling attackers poured down, four times the rooks rose in a dense barrage. In the end the starlings withdrew, defeated, to their own pine-wood.
True, one section of starlings held out for two days, when they were finally defeated. The rooks remained in abnormal numbers until November 14th, when they began reducing their garrison, until their numbers returned to the previous dimension.
All this was from an article by W.M. Abbot, published in Irish Naturalists' Journal in 1931. The most remarkable thing about the incident, he says, was the deliberate summoning and arrival of reinforcements by the rooks and the lowest form of passive resistance by which they vanquished their smaller but vigorous and aggressive invaders.
Now, how did the rooks summon their reinforcements? Smart birds, rooks. Lloyd Praeger was so impressed by this paper that he incorporated it in his great book The Way that I Went.