Colonel Montagu remarks that "there are a variety of instances of the Swallow and Martin having been seen flying in the months of November and December, roused probably from a state of torpidity by an unusual warmth of the air;"[129] and Captain H. W. Hadfield, commenting on this, affirms that he has "more than once had ocular proof of their presence during the winter months."[130] Yarrell gives examples of the late appearance of the Swift. One was seen by Mr Blackwall on the 20th of October 1815; a second in Perthshire on the 8th of November 1834; and a third in Devonshire, by the Rev. Mr Cornish, on the 27th November 1835.[131] In considering these cases, it is needful to bear in mind that the Swift migrates from this country annually from the 1st to the 15th of August. Mr C. R. Bree mentions the following case, which I record, not because it was particularly late, but because the state of the season, and some other circumstances which he remarks on are interesting:--"On the 25th of October 1848, some workmen being engaged on the roof of my house, I was surprised by the appearance of three Swallows flying about the men. I had not seen one since the beginning of the month. By the side of the edge of the gable-end of the house the plaster was broken away, forming a hole, which led under the roof. While watching the birds, which came occasionally quite close to my face, I saw first one, then another, alight upon the ledge of the gable-end, near the hole. Now, I thought, I am to settle the question of hybernation: but I was disappointed. Though I watched them for several hours--though I sent the workmen to another part of the house, yet, although they frequently settled about the hole, they never entered it. They were evidently young birds, and had been disturbed. One of them rested upon the chimney, and appeared weak and dull. I lost sight of them during the day; but the following morning, the weather being warm, I saw several flying about high up in the air. There is some mystery about these things. Why have these late appearances been more remarked this year than other years? How did the birds obtain food during the three weeks of bitter cold weather when they were not seen in October?"[132]