Pied Wagtail (Motacilla lugubris).—Fairly regular visitor on migration, but only in the early morning. I have seen them in March and December, 1898.
Yellow Wagtail (M. raii).—Very rare on migration. I saw a party of five near the round pond early on April 27th, 1898, but they had departed by 8 a.m.
Swift (Cypselus apus).—Rare visitor on migration. I saw four hawking over the pond on the afternoon of Aug. 8th, 1898, when the gardens were crowded with people.
Tawny Owl (Syrnium aluco).—A pair, I think, of genuine wild birds used to inhabit a hollow tree near the orangery, and hoot loudly at night. They disappeared in the spring of 1897, and I have heard none since.
Wood-Pigeon (Columba palumbus).—Abundant and fearless. A few pairs remain all the year, but most depart in winter. They are early breeders, and I noticed them in pairs and cooing loudly in January.
Moorhen (Gallinula chloropus).—Resident and nests at the Serpentine. I have seen sometimes half a dozen together, but often all disappear for a time, and, I suppose, visit the other London lakes.
Black-headed Gull (Larus ridibundus).—A winter visitor from October (or earlier) to April. Large parties often make their way from the Thames, but seldom stay long about the pond. Most of them are birds in immature plumage and very fearless.—Harold Russell (Kensington Palace).
Fecundity in Birds.—I have to thank Mr. Storrs Fox for his kindly notice of this subject (ante, p. 23). Perhaps he will excuse me if I in turn touch upon one or two points he brings forward. He says, "Birds cannot be conscious weeks beforehand that the time for their departure is drawing near." If Mr. Fox was in the habit of keeping caged birds he would realize, I think, that a Nightingale, for instance, feels the approach of the period of migration weeks in advance; it is vaguely restless and unsettled. That it argues logically from this feeling of unrest, I could not venture to infer: what I believe is, that the bird is influenced so that it cannot quietly attempt to nest again. I have found in the case of both winter and summer visitors, that the migratory instinct begins to work upon the bird a month or more before it actually leaves. My caged Bramblings, to give a second example, begin to fret before February is out. Mr. Fox extends my suggestion, "a hen of small size could not well lay more than five eggs," from the Finches and Warblers to the Tits. Again I was relying on cage-bird experiences. I have frequently stimulated Finches to lay more than five eggs, with the result that I have subsequently lost the hen: I have had fourteen eggs from a hen Bullfinch in about five weeks, after which she has died. From a foreign bird, neither Finch nor Warbler, I have had forty and fifty eggs in a season with no apparent resulting injury to the parents.
