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Mr. Blyth has remarked (" Ibis," 1866, p. 336), "that the average of adult Swallows from the Indian region and China are smaller than the average of European examples, to the extent sometimes of an inch in length of wing; but some Indian are undistinguishable from European specimens."
Dr. Jerdon, in his " Birds of India," says: "On carefully comparing specimens from England and Algiers in the museum at Calcutta with Indian specimens from various parts of the country, I can detect no difference."
In a notice of the birds of the Andaman Islands which appeared in the " Ibis" some years since, Capt. Beavan remarked that the European Chimney Swallow visits these islands at certain seasons, and is not at all uncommon.
There is no evidence that it ever visits Australia; but Mr. Gould has described a Swallow from Torres Straits under the name Hirundo fretensis, which is certainly very like our well-known H. rustica, and might be a youngbird of that species in autumn plumage. It is singular that no Swallows visit New Zealand. It cannot be that the islands are too distant from Australia, where several species of Swallow abound, because, as Mr. Layard has remarked, two, if not three, species of Cuckoo (Eudynamys taitensis and Chrysococcyx lucidus) perform the journey in their annual migration twice a year.
The attachment of Swallows to the neighbourhood of water at roosting-time—which formerly led to the supposition that they actually retired under water for the winter—may be easily accounted for by the circumstance that the willow branches not only afford them most convenient perches, but enable the birds to crowd close together, and so secure greater warmth to individuals than they could possibly enjoy if each roosted upon a separate twig in trees or shrubs of different growth.
A LTHOUGH arriving in this country some.*. *. what later than the Swallow, the Martin may be said to have nearly the same geographical range. Mr. Yarrell thought that the Swallow did not go so far north as the Martin,1 but both are found in summer in Iceland and the Faroe Isles. Mr. Dann remarked that there was no want of food for them in Norway and Lapland, as the morasses in the sheltered valleys swarm with insects. During the season that it is absent from England it resides in North Africa, Egypt,
1 "History of British Birds," vol. ii. p. 251 (3rd ed.)
Nubia and Abyssinia, Palestine, Arabia, and North-west India. Capt. Irbystates (" Ibis," 1861, p. 233) that it is common in the cold season in Oudh, and Col. Tickell observed great numbers at Moulmein; but they appeared from time to time, and not constantly, likeH. tustica.'1 With regard to Palestine, it seems probable that the Martin spends the greater portion of the year there, for Canon Tristram found it breeding in colonies on the sheltered faces of cliffs in the valleys of Northern Galilee. Mr. Wright says (" Ibis," 1864, p. 57) that in Malta it is seen at the same seasons as the Swallow, but stays part of the winter, when H. rustica has departed. Dr. Giglioli observes that it arrives at Pisa at the end of March, at which time it has also been noticed at Gibraltar.
The movements of this bird and others of the genus have been concisely illustrated by Mr. Forster in a communication to the Linnaean Society, in the following table, giving the mean date of arrival:
1 Joum. As. Soc. Beng. xxiv. p. 277.
The spring tide of migration appears to set in along the entire coast-line of the Mediterranean, and in a direction almost due north. I do not remember to have seen any record of the occurrence of the Martin on the west coast of Africa, although there seems to be no reason why it should not accompany the Swallow there in winter.
Both species will rear two broods in a season; and this fact, doubtless, will account for the prolonged stay in autumn of the later fledged birds, which are not sufficiently strong on the wing to join the main body of emigrants at the usual time of their departure.