The Zoologist/4th series, vol 5 (1901)/Issue 715/The Nesting Habits of Moor-hens (''Gallinula chloropus''), Pike
THE NESTING HABITS OF MOOR-HENS
By Oliver G. Pike.
During some years past there has been much discussion in 'The Zoologist' concerning the nesting habits of Moor-hens. Opinion among some ornithologists still seems to be divided as to whether these birds cover their eggs on leaving their nests. During four years I have had several pairs of Moor-hens under observation; and in the case of dozens of nests I have never seen the eggs covered. During the spring of 1900 I found a nest carefully domed over with reeds, almost perfectly hiding the contents from any egg-stealing bird that might pass over; but, with this one exception, I have never known of a Moor-hen trying to conceal her eggs.
It is not with this question, however, that I would particularly deal, but rather with an overlooked habit of this species.
On July 3rd, 1899, I roused a Moor-hen from her nest, which contained no eggs; and, thinking perhaps that the eggs might be covered, I carefully examined it. There were some flat reed-blades which had the appearance of being recently placed there, but there were no eggs underneath. A little farther up stream I found another nest built in a very exposed situation, but still containing no eggs. The next day I visited the nest first mentioned; I cautiously approached, and again saw the hen sitting, her head being tucked under one wing. She was probably asleep, but on my making a noise she instantly sat up and then jumped off the nest, when I was surprised to see three nearly full-grown young birds emerge from beneath her. The nest was an exceptionally large one, and the bird when sitting seemed to be larger than usual, the three young which she was covering of course accounting for her apparent large dimensions. About six feet from the first nest another had been commenced, but this was smaller than the other. I waited for some time, hoping the birds might return, but they did not do so. I then returned to the nest farther up stream, when I had the satisfaction of seeing one of the old birds sitting; she left the nest on my approach, but it contained neither eggs nor young. The following evening this bird was again sitting; the nest now contained one newly-hatched Moor-hen, and both this and its parent scuttled away on seeing me. In the nests first found three young birds were in possession and were all asleep, one of them being in the new nest, which was now completed.
On July 7th I again visited these two nests, but a number of people near had frightened the birds, and they were not to be seen. A curious thing, however, was that another nest, similar to the second one, had been built, the three forming a kind of triangle. After this the birds were constantly seen to leave these nests when I approached. On the same day I went to the nest which on July 5th had contained one young bird. The little black Moor-hen was still there, and its parent had left before I arrived. I heard her on the other side of the stream, however, calling to the young bird to follow, which it did with characteristic alacrity. This nest had had much material added since I last saw it, and was consequently rather high above water; it was chiefly composed of fine dry grasses. On the two following evenings the nest became visibly smaller, and careful observation proved that the Moor-hens were moving it piece by piece to the other side of the stream, where the situation was more sheltered. The nest in which the young were hatched was a few yards from this roosting-nest, being built in a bush about ten feet above water-level. I watched the Moor-hens very closely to see whether they would make another nest when the young were hatched, with the result as described. The other three roosting-nests, built close together, were about twenty-five yards from the one which was used for incubation purposes.
In the spring of 1898 a nest was built beneath the roots of a tree on the stream-side; it contained eight eggs, and incubation lasted three weeks. Immediately the young were hatched a sleeping-nest was made about three yards from the first, in the middle of the stream, supported by a submerged tree. The original was afterwards deserted, and this one alone used. As the young grew, however, another was built, evidently because the other was too small to hold the growing family. The same year I found another nest under a tree-root three hundred yards from the one just mentioned. When the young were hatched, another was made in a more exposed situation. On April 27th, 1900, I discovered a Moor-hen's nest by the side of a stream. On May 7th some of the young were hatched, and a roosting-nest was commenced—probably by the male bird—in the centre of the stream, this one also being supported by a fallen tree. For several evenings afterwards one of the adult birds was sitting in this latter with the young, and once or twice I was able to approach by day to see one or two young birds using it. As the latter grew, another nest was built under the roots of a neighbouring tree, this being a large, loose, clumsy structure, such as might have been built by the young themselves.
Near the stream-bank were a number of trees, and at the top of one of these I waited for several hours to observe more closely the habits of the Moor-hens. I had not waited long before the hen swam up stream, meanwhile calling her brood together; she entered the nest built in the stream, and turned round several times to smooth down the loose grass just recently placed there, I could hear the young birds, but could not see them on account of the foliage in the tree. At this moment the keen eye of the old bird caught sight of me; she hastily left the nest, and did not return.
This nest was of immense size, and was constantly being added to; I found freshly added green grass as late as the beginning of August. Another nest that I had under observation during this year (1900) was a repetition of those previously described; roosting-nests were added for the young in a similar way.
Although I have consulted several works for the purpose of learning something about such extra nests, they do not appear to be mentioned in any of the chief reference books. Mr. G.B. Corbin, writing in 'The Zoologist' for Feb. 1899, p. 82, says:—"With regard to the nidification of the Moor-hen, I have often found that a much larger number of nests seem to be constructed than are ever used; but for what purpose is this apparent waste of time and labour?" This is the only reference I have found relating to what I call Moor-hens' roosting-nests.
It seems to me that all Moor-hens build these extra nests for the purpose of providing resting-places for their young; I also think that the young, when sufficiently grown, make additional ones for themselves. I should like to hear from any correspondents who have observed this hitherto overlooked habit of one of our most interesting water-birds.
There is one other habit I may mention. In all of the Moorhens' nests I have found, it seems to be a general rule for the hen to commence sitting as soon as the first egg is laid, so that some of the young are hatched before others. Probably the male bird commences an extra nest for these first-comers to use; for one additional nest under my notice was commenced before the hen had finished sitting.