The Time of Attack.
It would be unwise to say in what month of the year the keas are most destructive to the flocks, because all the sheep that are killed are not found, and naturally when musterers are out on the ranges they will see more results of the keas' work than when they remain, on the homestead. From the records that I have received, they seem to attack mostly in the winter and the spring, and frequently at midsummer.
There are several reasons which may account for their attacking in winter. Firstly, when the ground is covered with snow, or frozen hard, the birds will have much difficulty in finding sufficient food, and hunger, no doubt, would make them ferocious. Secondly, the sheep are made an easier prey owing to the depth of the snow, and often they are buried in it, so as to be almost unable to move, and so would give the birds very little trouble.
In early spring the climatic conditions are, if anything, intensified, and the ordinary food is scarcer still. Besides, it is the kea's nesting-time, and the extra work of sitting, and the feeding of the young birds, would make the parents more hungry and daring. During the late spring, when their ordinary food would be more accessible, they appear to kill less sheep, and do not become very much of a nuisance again until about the middle of summer.
The reason why the keas find this season a good time for depredations is uncertain, but may be accounted for as follows: Firstly, owing to the snow having melted, the sheep are able to roam in the kea's domain. Secondly, the sheep have favourite places for sleeping, and, if anywhere near, they make for them night after night. These spots are called “camps,” and no doubt the keas are always sure of finding a good supply of sheep in the “camps” whenever they intend to attack. Thirdly, at shearing - time the sheep are confined to small paddocks, and so have less chance of getting away from the kea. They do not, however, confine their attacks to these seasons only, but have been known to kill sheep all the year round, though autumn seems the time when they attack least: whether it is due to the quantity of their ordinary food, that would be plentiful at this season, or not, is hard to decide.
The time of day when they attack sheep is also uncertain, and, speaking generally, they have been known to attack at all hours; but the evening, night, and early morning appear to be their favourite times.
Why night-time should be their favourite time may be accounted for in several ways. Firstly, the sheep are said to make for the same sleeping-grounds or camp for several consecutive nights, and the birds would be sure of finding plenty of sheep together during the hours of darkness. Secondly, being partly nocturnal in their habits, they have an advantage over the sheep, and at night there is less chance of their being seen or disturbed.
If attacking in daylight they seem to choose dull or foggy days, but this is not always the case, as I have heard of several instances of attacks being made in bright sunshine. However, in these cases there has always been snow on the ground, and the helplessness of the sheep, or the lack of food, may have made them more daring.