Although a regular summer visitant to England, the Tree Pipit, like the Nightingale, from some unexplained cause, is distributed over a very limited area. It never reaches Ireland, and is considered rare in Scotland, although the nest has been found as far north as Dumbarton, Aberdeen, Banff, and East Inverness.[43] Even in Wales and Cornwall it is a scarce bird, so that England may be said to be the western limit of its geographical range. Mr. Wheelwright never met with it in Lapland, but Messrs. Godman found it in June as far north as BodÖ, in Norway, and from this latitude southwards to the Mediterranean it seems to be well known in summer. Mr. Howard Saunders says that it is generally distributed in Spain from autumn to spring, and he suspects that some remain to breed on the high plateaux. In Portugal, according to the Rev. A. C. Smith, it is rare. Mr. Wright, of Malta, states that it is very common in the island in spring and autumn, departing in May northwards, and returning in September and October. He adds that a few remain the winter. According to the observations of Lord Lilford, it is now and then seen at Corfu in winter, throughout which season it is found in small flocks, apparently on passage to North Africa. Mr. Layard does not include it in his “Birds of South Africa,” but, according to Professor Sundevall (“Svenska Foglarna,” p. 41), a specimen was killed by Wahlberg on the Limpopo, in Kaffirland, between lat. 25 deg. and 26 deg. S. Canon Tristram found it sparingly distributed in Palestine in winter, and in spring in the Jordan valley. It is recognised by naturalists in north-west India, and there can be little doubt that the Pipit which has been described from that country, and from China and Japan, under the name of Anthus agilis, Sykes, is only our old friend A. arboreus in a different plumage from that which it assumes here in summer. Herr von Pelzeln says[44] that agilis only differs from arboreus in having a stouter bill, and he does not think that it can be specifically distinct, notwithstanding that Dr. Jerdon gives both species as inhabitants of India. On this point Mr. Hume says (“Ibis,” 1870, p. 287): “I took nine specimens of arboreus from England and France, and compared them with our Indian birds. There was no single one of them to which an exact duplicate could not be selected from amongst my Indian series. That all our Indian Pipits known as agilis, maculatus, and arboreus ought to be united as one species under the latter, or possibly some older, name, I can now scarcely doubt.”