O N OUR CROSSBILLS.
ON OUR BY
CECIL
163
CROSSBILLS.
S . LAST, BIRDS
SUBRFCORDER.
T H A T most peculiar of British birds, the Crossbill (Loxia curvirostra, Linn.), with its tendency to be an irregulär or spasmodic colonist rather tban regulär winter visitor, usuallv arrives in November for the purpose of breeding and leaves again in April. From time to time flocks of them desert their home in the forests of Siberia to spread south and west, many reaching England. In Scotland the species has become a more permanent resident and, since the great influx of 1909, remains there. Its most striking characteristic is conveyed in the name, for the tips of its mandibles cross on one side or the other, a feature affording it remarkable power of extracting the seeds from fir-cones with comparative ease. I have watched these birds climbing along the branches of Scots pines, often Walking sideways, with head swung low to reach and wrench off a cone. When such a cone has been carefully selected it is twisted off with considerable force and carried in the bill to a firm perch, where it is held with one or sometimes both feet, the seeds are twisted out of it and then eaten, with head held w-ell erect. Although the Crossbill closely resembles a Finch in appearance, its attitudes during feeding recall, rather, those of a Parrot. T o discover its presence an examination of fallen cones is usuallv sufficient for, if the cones be dislocated and the scales forced back from their upright position revealing their seeds, it is evident this bird has been at work upon them. A close search of adjacent fir, larch or spruce trees, in that case generally discloses a nest, either high and well away from the trunk, or as low as six feet from the ground. I have seen nests sixty feet up, others ranging from fifteen to only six feet above the earth and one, observed by me on a branch overhanging a main road, was in such a precarious position that passing vehicles actually Struck the branch it was on, to the presumable detriment of the nest.
A very early but erratic nester is this bird. Its normal penod is from November to Februarv or March, and sometimes even April. This variability renders the Crossbill often unnoticed by passengers, since one hardly expects to see a nest in the very midst of winter, especially when the trees it builds m are snow-clad. A narrow belt of firs is a favourite nestingsite, invariably preferred to thick woodland, and in Suffolk our western moiety is that selected. Colonies have become well established throughout the breck district at Lakenheath iriswell, Mildenhall, Icklingham, Cavenham, Elveden^ Bamham, Euston and Fakenham ; whilst in eastern Suffolk the species is now almost if not quite extinct as a breeder, because
164
ON OUR
CROSSBILLS.
the meagre belts of pines afford insufficient food and suitable nestage. T h e eggs are greyish-white, spotted with ruddy brown, though pure white variations often occur and these sometimes bear cinereous markings. Four is the usual number in a complete clutch, five being of rare occurrence. Genuine ornithologists and more particularly commercial oologists are great menaces to Crossbills, owing to the large prices the latter can obtain for eggs. Collectors have been known to exterminate whole colonies, one of which I kept under Observation during February last in western S u f f o l k ; it suffered so extensively from their depredations that, if our sister Society of the Norfolk Naturalists had not taken action in prosecuting two wholesale pilferers, the entire assemblage would have been eventually exstirpated. Although the previous breeding season proved thus nearly futile, the Crossbills persist in returning to their former locality, a fact amply testified by the scarred cones. T h i s is a very plucky bird during the period of incubation, and considerable effort is necessary to displace her from the nest. I well remember receiving severe pecks upon the hand, while attempting to lift one of the hens from her eggs ; and, even when eventually ousted, she remained within a yard of her domain, immediately returning to the nest as I began to move out of reach. T h e male is of striking appearance, quite distinguished in his dark crimson breast and head coverings; younger males are blotched with orange and bear a yellow rump-patch. T h e female generally is greenish-yellow, more or less striped : similar striation is noticeable on the greenish grey young birds, though the pale wing-bar becomes inconspicuous when they are roosting. But a flock of Crossbills can be extremely varied in both size and plumage.
TWO DAYS AMONG THE BUTTERFLIES IN SUFFOLK. BY
D.
T.
BUTTON.
I left London July 21, and when riding from the Station to the ' Old House at Home ' I noticed a good number of Thecla W-Album on some thistles by the road side. There I had found them for several years previously : three years ago I took thirty specimens in a few minutes. T h i s time, however, my nets were as yet all packed up, so I did not disturb them. After spending a pleasant evening with old friends I arranged my nets and boxes ready for the morrow.