Collocalia unicolor (Jerd.).
The Nilghiri Swiftlet.
Collocalia nidifica (Lath), Jerd. B. Ind. i, p. 182.
Collocalia unicolor (Jerd.), Hume, Rough Draft N. & E. no. 103.
The Nilghiri Swiftlet breeds on all the hills of Southern India and Ceylon.
Mr. Davison tells me that "there are several places on the Nilghiris where the Hill Swiftlet breeds largely; one is a large rave above the main road from Coonoor to Ooty, close to the last toll-bar, before the cantonment of Ooty is reached : another is a cave below the Hooker Chinchona Estato at Pykarra, near the footpath leading from Pykarra to Musnagoodie. The birds build in company, the nests often being placed in regular tiers one above the other, and often so close that they touch each other. The nest is never composed entirely of saliva, but always consists chiefly of a long grey thread-like lichen (so common on all trees on the Nilghiris) firmly agglutinated together with the saliva. The nest is a small shallow semi-saucer-like structure glued to the rock. The normal number of the eggs appears to be two; they are quite white, very elongated, and are nearly the same thickness at both ends. They breed in April, May, and the early part of June."
Mr. A. G. Cardew, C.S., also writing of the Nilghiris, says; - " This bird breeds at several places on the Nilghiris during May and June. The nests occur in the darkest parts of caves, generally in complete darkness, and are small but compact cup-shaped structures, strongly made of lichen which is fastened together and the nest glued to the wall by the mucous secretion of the bird. They measure about 2 1/2 inches by 2 and are very shallow, the egg-cavity not exceeding l 1/2 inches in the largest, while in many the walls are less than an inch above the bottom of the nest. No lining of feathers is used, and the amount of inspissated mucus is very small, the structure being wholly of lichen. The number of eggs is invariably two. On visiting one of the most populous caves on the 6th May, I found 40 nests, among which three or four had young birds and an equal number were empty ; every one of the remainder contained two eggs. At a later visit on the 20th of June, the number of nests was about 25, and of these the majority were already empty, three having eggs and four young birds. The eggs, which are pure glossless white, are remarkable for their slightly cylindrical shape, and measure from 0.82 to 0.94 in length, and from 0.52 to 0.55 in breadth."
Dr. Jerdon makes the following remarks :- " In 1846, I paid a visit, in company with Mr. "Ward, M.S.C., to Pigeon Island, some miles out at sea to the south of Honore, which was said to be the resort of these birds. We found a large cave at one end of the island with a few of the nests, but of the second-make and inferior to the first, being mixed with feathers and extraneous matter. There were no eggs at this season (the end of December), and we did not see any of the birds to identify the species. A native who had guided us to the cave said if we waited till 8 or 9 o'clock p.m., the birds would come. We instructed him to do so and to catch some of them in a net he had with him for the purpose. It is known to have other breeding-places on the Malabar coast, vis., the Vingorla rocks, where one hundredweight of nests is said to be produced annually. If so, this must be the largest breeding-spot on the coast. Also the Sacrifice Rock, 20 miles south of Tellicherry; besides, I daresay, others. I visited Sacrifice Rock in March 1849. There is one cave here, which had perhaps fifty to hundred nests, and a few had eggs in them. Very few of the nests were of the first make, these being annually taken away by some Moplahs from the mainland. The birds were at this time flying about, feeding on the flies which abounded at the edge of the rock. About twenty couples, perhaps, were present, not more. I doubt if all the places I have enumerated on the western coast would contain the nests of a quarter of the number of these Swiftlets which I have seen at once in one locality; if so, where do the others breed'? It has been suggested that they may nestle in inland caves; but all my enquiries have failed to discover any in India."
Mr. G. Vidal gives us the following account of a colony breeding in a cave on the sea-coast. He says; - " This species, "as Jerdon says, is found at one of the group of rocks which lie between Vengorla and Malvan, some five or six miles from the mainland, and breeds there regularly every year. The right to collect the nests is annually sold by auction, and realizes on an average about Rs. 30. Two trips are made by the farmer - the first towards the end of February, and the second about the first week in April. The first harvest yields about 14 lbs., and the second from 28 to 42 lbs. Either the yield was overstated by Jerdon, or else the number of birds has greatly diminished since he wrote; half a hundredweight is now the maximum outturn.
" None of the nests I have ever got from the Vengorla rocks are pure white. In April 1878 I sent my shikaree, to bring nests, eggs, and birds, and he returned with specimens of all three. The birds were all Collocalia, and the nests all mixed with grass and feathers, the saliva being pure only where the nest is attached to the rock, and on the rim of the saucer. The nests vary a good deal in size and shape. They are very shallow, seldom deeper than half an inch, and have a diameter of about two inches. Externally the saliva, freely mixed with grass and feathers, is smooth and coagulated. Inside the cup it forms a network of fine shreds. They look at a little distance exactly like deep oyster-shells with one side flattened, the saliva, where it is smoothed down, having a pearly appearance. As this batch of nests was collected about a week after the farmer bad paid his last visit to the rocks for the season, and had presumably left no nests worth taking, and as the natives, who ought to have known, persisted in saying that pure white nests were to be had at the first take, I could come to no definite conclusion about the matter. However, in February 1880, I sent my man again to the rocks, with the farmer's people. They were there for three days, and returned on the 28th with about 12 or 14 lbs. of nests, which I examined. These nests were undoubtedly first nests, as not a single egg had been laid. All were quite as impure and mixed with grass and feathers as those I had got in the preceding April, when there were eggs or young birds in every nest. The farmer still held out that white nests are sometimes got. Of course it is possible that a few pairs of C. spodiopygia may breed in the same cave, but none of the specimens got were of this species, and I think it is highly improbable that they occur. Determined to sift the matter as closely as possible, I sent my shikaree again with the farmer's people for the April take. He spent three days on the rocks, from the 7th to 9th of April, and returned with about two dozen of the purest and comparatively whitest nests that were found on this occasion, as well as eggs and specimens of Collocalia. The nests were all mixed with grass and feathers precisely as before.
" The evidence, therefore, is now pretty complete, and shows conclusively that Collocalia does not make pure white nests in this locality. The Vengorla nests are all despatched to Goa in the first instance, but I have not yet ascertained their ultimate destination. Commercially, they must rank as a very third sort commodity. The nests I got in February were literally swarming with common bugs."
Captain Horace Terry writes :- " One day, while I was in the Pulney Hills (June 1883), a native whom I employed to collect for me brought me word that he had found some Swifts breeding in a cave. I went with him the next day, and close to the Pillar Rocks my guide showed me a large sort of hole, and intimated I was to go down it. I did not quite like the look of it; it was the sort of place where one might meet anything and with no room to pass. However, as the man absolutely refused to go first (which was odd, as he assured me he had been there the day before), I had no choice, so I went. After going through a sort of tunnel for some few yards in a downhill direction in the dark, I found myself in a good-sized cave with a high roof, and an opening (quite inaccessible from the outside) on to the face of the cliff. Here were the Swifts safe enough, but what puzzled me was how on earth the man knew they were there, as I am quite convinced he had never been down that hole before ; there were no signs of footmarks in the sand, his description of the cave was quite inaccurate, and he could not possibly have seen anything of it from the outside. The cave was occupied by a large number of Swifts (C. unicolor) flying in and out, who had their nests near the roof of the cave, quite out of reach, and it was impossible to get at all near to any of them.'
Mr. Bourdillon, writing from Travancore, says:- "The cave in which the Edible-nest Swiftlets breed is on the opposite side of the valley to this bungalow, at an elevation of about 2600 feet. It is formed by the displacement of a huge mass of rock, which, sliding from its original bed, has left a slit in the side of the hill, blocked at one end, some 40 yards long, 30 feet high, and of an average width of about 3 feet. The mouth of the cave is much darkened with stones and shrubs, so that 10 yards from the entrance, without a light of some sort, one gets a very hazy idea of the surroundings. We had a candle, and after going the whole length of the cave we set to work counting the nests of the Swifts. This was no easy job; however, with a little trouble we made out that there were fully '250 nests in the cave, of which two in every three were occupied by eggs or young. While all this was going on, the old birds were in a great state of excitement, and occasionally one, more courageous than the rest, would dash at the candle and, putting it out, leave us to grope about for the matches. We took three or four nests, and altogether a dozen eggs. Of these two only were hard-set, the rest being perfectly fresh ; and as we took only solitary eggs, it would appear that this Swift occasionally lays but one egg, though far more frequently two, and never, 1 believe, more. As I hope my brother will send you specimens of eggs and nests, I need only say in passing that the nests are pretty solid cups with a shallow cavity, composed principally of moss and the feathers of the bird, cemented to the rock and neatly lined with threads of the peculiar isinglass-like substance excreted by the bird. The eggs are pure white, smooth, and slightly glossy ; and of those taken the measurements ranged from 0.81 to 0.91 in length, and from 0.52 to 0.59 inch in breadth, averaging 0.85 by 0.55.
" This accomplished, we had to secure some of the old birds. After expending all our small stock of cartridges we had only two birds to show, and these on dissection proved to be males. One bird was evidently in the breeding-stage and the other not; and I may here note that the breeding one had a very highly-developed gland beneath the chin, containing a sticky creamy substance, which was no doubt the same as that used to fasten the nest to the rock; this bird also, when shot, had a piece of moss in its claws, so that one may fairly conjecture it was still building. The other bird had no trace of the gland, at least so far as I could make out without the aid of a microscope. My brother will also send you with the nests and eggs a sample of the guano which was thickly spread over the floor and walls of the cave. This appears to be composed principally of the undigested portions of the birds' food, with some proportion of soluble ammoniacal matter, which has a rather disagreeable smell."
Colonel Legge thus describes the breeding-habits of this Swift in Ceylon ; - " The breeding-season of this little Swiftlet in Ceylon lasts from March until June. It nests in large colonies in various caves in the hills and mountains of the central and southern parts of the island. Many of these are known from seeing the birds haunt the vicinity of certain precipitous hills ; but few have been visited and examined on account of the general inaccessibility of these resorts. Among those which are known are two situated on the rocky hills of Diagallagoolawa, near Pittegalla, on the banks of the Bemtota river, and which are referred to by Layard; several "occupied by large and small colonies on the Dambetenne and Piteratmalie estates on the south face of the Haputale range; one on Pedrotallagalla, spoken of by Kelaart; and another which I am informed of in a hill called Maha-ellagala, near the 'Haycock' Mountain, as also another in the Nitre-cave district. Besides these there are, I believe, colonies in the ' Friars-Hood' or some of the surrounding rock-hills and in Rittagalla, the above-mentioned mountain, situated between the Central and Trincomalie Roads. The celebrated cave in the Haputale range, and the only one which I have had the good fortune to visit, is situated on a bold peak standing out above and towering over the Dambatenne and adjoining estates, which form one of the finest sweeps of coffee-ground in Ceylon. ... At a point where the great gorge suddenly commenced by a sheer precipice drooping down about 1000 feet into the lower estate, stood the fine bungalow occupied by the gentleman, Mr. Imray, who was to be our kind host for the night; and at the back of this, at the top of a rich slope of coffee, towered up a rocky buttress, iu which the Swiftlets of Haputale propagate their species. In this precipice a vast boulder, about 70 feet in height and 50 in breadth, has at some period slipped away from the face of the mountain, and leans against it at an angle of about 30°, forming a lofty narrow cavern. Here about 300 pairs of birds have their nests built against the inner side of the boulder, which is convex and corresponds with the concave face of the main mass. There are no nests on this latter, down which there is doubtless a considerable amount of drainage, and the instinct of the little birds is here wonderfully displayed in rejecting the wet side of the cavern, which would seriously impair the stability of their gelatinous nests. These are placed in tiers, one above the other, about 15 feet from the guano at the bottom of the cave; in places three or four were joined together, the back part of the under nest being prolonged up to the bottom of the one above it. The little structures .were by no means edible, being constructed of moss and fine tendrils, arranged in layers and cemented with the inspissated saliva of the bird, the back part attaching the nest to the rock, as well as the interior of the cu]3, being, however, entirely of this material. I have seen one or two nests from Pittegalla almost wholly made of this substance; but even these were mixed to a certain extent with foreign or vegetable material. The interior of these Dambetenne nests was in most cases oval, the longest diameter, which varied from 2 to 2 1/2 inches, being parallel to the rock. In depth the egg-cup was, on the average, about 1 inch. At the date of my visit, the 22nd of May, nearly all the nests contained young, two being the average number. A series of eggs procured at another time, and which I have examined, were of various shapes, long ovals being the predominant; they were pure white, and varied from 0.81 to 0.83 inch in length by 0.51 to 0.54 in breadth. It is noteworthy that the partially-fledged young which were procured for me on this occasion, and which I kept for the night, scrambled out on to the exterior of the nests and slept in an upright position with the bill pointing straight up. This is evidently the normal mode of roosting resorted to by this species.
" The interior of this cave, with its numbers of active tenants, presented a singular appearance. The bottom was filled with a vast deposit of liquid guano, reaching, I was informed, to a depth of 30 feet, and composed of droppings, old nests, and dead young fallen from above, the whole mingled into a loathsome mass with the water lodged in the crevice, and causing an awful stench, which would have been intolerable for a moment even, had not the hundreds of frightened little birds, as they screamed and whirred in and out of the gloomy cave with a hum like a storm in a ship's rigging, powerfully excited my interest and produced a long examination of the colony. This guano-deposit is a source of considerable profit to the estate, the hospital-manager of which informed us that he had manured 100 acres of coffee with it during that season. Besides this colony there are two smaller off-shoots on the adjoining estate, in one of which, Mr. Bligh tells me, the birds have to pass through a cloud of spray in order to gain access to their nests."
The eggs that I possess of this species, all sent from the Nilghiris, are a dull, almost wholly glossless white; as a rule slender elongated ovals, almost cylindrical, and sometimes absolutely cylindrical; at times slightly pyriform, and typically, I think, somewhat compressed just beyond the middle. They vary in length from 0.79 to 0.9 inch, and in breadth from 0.53 to 0.58 inch; but they average 0'83 by 0.54 inch.
