The Noctule seems to prefer for its resting place the hollows of old trees, and generally to avoid buildings, although instances of its taking up its abode in or about the latter are not wanting. It is gregarious in its habits, considerable numbers often retiring together to the same hiding-place. Thus, in the second edition of Bell’s “British Quadrupeds,” a good many Noctules are said to have been “dislodged from a hole made by the Green Woodpecker in an elm by the insertion of a flexible stick;” and at Rugby, in Warwickshire, in a grove of old oaks, their excrement has been observed to form so thick a layer as to darken the ground under some of the oldest trees. Pennant states, on the authority of Dr. Buckworth (Buckhouse?), that one hundred and eighty-five of these Bats were taken in one night from under the eaves of Queen’s College, Cambridge, followed by sixty-three on the second night, when the supply seems to have been nearly exhausted, as only two were captured on the ensuing evening.
The natural food of the Noctule consists of insects, and its jaws are sufficiently powerful to enable it to devour even such large and horny Beetles as Cockchafers, which, indeed, seem to constitute its favourite food. It is, in fact, most active during the period of the year when these insects abound, for White, who first noticed its occurrence in Britain, states that he never saw it at Selborne before the end of April, or later than the end of July. In Warwickshire, however, it has been observed as early as the 12th of March, and as late as the 18th of September. It flies very high, and on this account was named by White Vespertilio altivolans. Its course through the air is rapid and straight, and accompanied by a continual sharp and shrill cry, which ceases only during the capture and consumption of its insect prey. It is described by White as emitting a rancid and offensive odour.
Mr. George Daniell, in a paper communicated to the Zoological Society in 1834, published some notes on the behaviour of this Bat in captivity, which are particularly interesting from the description they contain of the birth of a young Noctule. Mr. Daniell obtained four females and one male of this species on the 16th of May, 1834. The male was very savage, biting the females, and breaking his teeth upon the wires of the cage in his attempts to escape. He refused to feed, and died on the 18th of May. The females, although at first sulky, fed after a time upon small pieces of raw beef, which they seemed to prefer to insect food. One of them died on the 20th, and two others on the 22nd; the survivor, which fed by preference upon the breasts and livers of fowls, lived on for rather more than a month. It passed the day suspended by the hind feet at the top of the cage, and came down in the evening to feed, which it did sometimes most voraciously; the quantity eaten exceeding half an ounce, although the weight of the animal itself was only two drachms. It rejected flies, but ate parts of some Cockchafers that were given to it. The animal was rather careful in cleaning itself, using the posterior extremities as combs, with which the hairs were parted on either side from head to tail, forming a straight line down the middle of the back. The membrane of the wing was cleaned by passing the nose through its folds. On the 23rd of June Mr. Daniell observed his Bat to be very restless, and this condition lasted for about an hour, the animal remaining as usual suspended by the hinder extremities. Suddenly “she reversed her position, and attached herself by her anterior limbs to a cross wire of the cage, stretching her hind limbs to their utmost extent, curving the tail upwards, and expanding the interfemoral membrane, so as to form a perfect nest-like cavity for the reception of the young, ... which was born on its back, perfectly destitute of hair, and blind. The mother then cleaned it, turning it over in its nest; and afterwards, resuming her usual position, placed the young in the membrane of her wing. She next cleaned herself, and wrapped up the young one so closely as to prevent any observation of the process of suckling. At the time of its birth the young was larger than a new-born Mouse; and its hind legs and claws were remarkably strong and serviceable, enabling it not only to cling to its dam, but also to the deal sides of the cage. On the 24th the animal took her food in the morning, and appeared very careful of her young, shifting it occasionally from side to side to suckle it, and folding it in the membranes of the tail and wings. On these occasions her usual position was reversed. In the evening she was found dead; but the young was still alive, and attached to the nipple, from which it was with some difficulty removed. It took milk from a sponge, was kept carefully wrapped up in flannel, and survived eight days; at the end of which period its eyes were not opened, and it had acquired very little hair.”
From these observations of Mr. Daniell it appears that the period of gestation in the Noctule exceeds thirty-eight days, and they are of very considerable interest with respect to the general history of the Chiroptera, at any rate of the present family, for it is most probable that the conduct of this female Noctule on this interesting occasion is closely followed by other maternal Vespertilionidæ at the arrival of their “little strangers.” Moreover, the fact of the production of only a single young one, and the finding of only a single embryo in each of the three females which died soon after they came into Mr. Daniell’s possession, taken in conjunction with observations to the same effect which have been made upon the female of the Pipistrelle, and of several other species of Bats, would seem to show that the Bats in general produce only one at a birth.
THE SEROTINE.[190]
Three other species of Vesperugo occur in Britain. One of these, the Serotine (V. serotinus), is nearly as large as the Noctule, and closely resembles that species in some respects in its habits. The head and body in the Serotine are about two inches and two-thirds in length; the ears are ovate-triangular, and a little shorter than the head; the tragus is a little more than one-third the length of the ear; and the extremity of the tail projects nearly a quarter of an inch from the membrane. The fur, which is soft and silky, is usually chestnut-brown above, and yellowish-grey beneath, but it is liable to vary more or less; British specimens being sometimes of a greyish tinge, whilst some from the Asiatic side of the Ural Mountains are described as having the upper parts yellowish cream-colour, and the lower surface yellowish-white. Like the preceding species, the Serotine is widely distributed, being found apparently over a great part of Europe, and throughout the temperate regions of Asia, at least as far east as the Himalayas; whilst specimens have been identified with it, which were brought from the northern parts of Africa, as far south as the mountains near the Gaboon. In England it is found only in the South-eastern counties, and is said to occur in the neighbourhood of London. Folkestone and the Isle of Wight are other recorded localities. In France it is not uncommon, frequenting the forests, and flying amongst the lofty trees; it is also found in the timber yards of Paris. Like the Noctule it is late in making its appearance in the spring, and it also flies late at night, whence its specific name. In France it bears one young one about the end of May.
THE PARTI-COLOURED BAT.[191]
Of the Parti-coloured Bat (Vesperugo discolor) only a single specimen has been taken in England, and it was obtained by Dr. Leach many years ago at Plymouth. The probability is, as indicated by Mr. Bell, that this individual must have been conveyed to Plymouth in the rigging of some vessel. On the continent of Europe it is found chiefly in Russia and Germany, but does not extend into Belgium, Holland, and France. It has also been obtained from Central Asia and from the Himalayas. This Bat is of the same size as the Serotine, and is perhaps the handsomest of the European species, the fur of the upper surface being of a fine chestnut or deep brown colour, with the extreme tips of the hairs pale, or even sometimes white, giving the fur a finely-marbled appearance, while that of the lower parts is grey at the base and white at the tips, with a reddish-brown patch on the middle of the chest and belly. The ears are about two-thirds the length of the head, oval, and directed outwards (see [figure]), their outer margin produced nearly to the angles of the mouth, and their inner margin with a projecting lobe at the base. The Parti-coloured Bat is said to haunt towns, and to come abroad early in the evening.
HEAD OF PARTI-COLOURED BAT.