BRITISH BIRDS NUMBER 12, VOL. XLV, DECEMBER, 1952. THE BIRDS OF INNER LONDON, 1900-1950. BY S. CRAMP AND W. G. TF.AGLE. IN 1929 A. Holte Macpherson published A List of the Birds of Inner London (antea, vol. xxii, 222-44) outlining the history and status of the birds occurring in an oblong area with boundaries running 4 miles east and west and z\ miles north and south ot Charing Cross. Since then an account, necessarily restricted, has been given annually in this magazine (A. Holte Macpherson 1930-41, G. Carmichael Low and Miss M. S. van Oostveen 1942 and 1946, G. Carmichael Low 1943-45, Miss M. S. van Oostveen 1947, C. B. Ashby 1948-49 and W. G. Teagle 1950). This paper summarizes the information available on the birds of this major urban area for the period 1900-50, paying particular attention to the changes in numbers and distribution of the more important species, many of which are striking. The boundaries of Inner London, although purely artificial, enclose an area of ecological significance, including most of the densely populated core of the capital, all the central parks (except for a small portion of Victoria Park) and some districts in the west and north containing houses with large gardens. It is rich in water, with a long stretch of the Thames, and lakes in many of the parks. The reservoirs and the larger, wilder open spaces, such as Hampstead Heath and Wimbledon Common, are excluded. To survive in such an area a species must be able to adapt itself to living in close proximity with man. Some of the birds which had done so before 1900 were a surprise to many ornithologists, and a number of the newer arrivals have been equally unexpected. There is no sign that the changes are at an end, and in the present state of our knowledge it would be rash to guess what may happen in the next fifty years. Between 1900 and 1950 there have been a number of develop­ ments affecting the bird-life of Inner London. Although the process of demolishing and replacing the buildings will never cease, the main areas of built-up land were fixed by 1900 and the few changes since are of minor importance. There is one major exception, though presumably only temporary. In the last war many acres of buildings were destroyed by enemy action, leaving derelict areas, most noticeable in the City, but occurring in all parts, which have had a vital effect on birds in the last ten years. Both wars caused changes of a less enduring character, e.g. the draining of the lake in St. James's Park in the first, the massacre of Wood- Pigeons during the second and, in both, the closing of some 434 BRITISH BIRDS. [VOL. XLV. sections of the parks and the conversion of others into allotments. During the last fifty years the streets have become increasingly congested and the horse traffic has greatly declined, so that there is less food available for those birds which scavenge in the road­ way, and less chance of their picking up what food is present. The trees in the parks and gardens, many of which were planted in the last century or before, are ageing steadily, providing more food and nesting holes for some species of birds. An important factor has been the virtual disappearance of the Grey Squirrel (Sciurus carolinensis) from the area, following the campaign for its destruction which began about 1930. The Grey Squirrel eats both eggs and young birds, and, although its influence on bird life may be less serious than some have suggested, the elimination of this predator has almost certainly been a factor in the increase of some species, such as the Blackbird and Mistle-Thrush. Finally, during the last fifty years the growth of London has continued at a striking rate, halted only temporarily during the two wars. The small area of Inner London has been separated from the open country by an ever-growing zone of built-up land, and it might reasonably have been expected that the bird-life would be steadily impoverished as a result. The disappearance of the Rook after 1916 must have seemed a clear sign of things to come. The Committee on Bird Sanctuaries in the Royal Parks in their 1928 Report said—"In the matter of bird-life the inner Parks generally have suffered most from the rapid expansion of London in latter years, and will do so increasingly as long as that process con­ tinues. It is feared that, in their case, as London goes on spreading, the number of species to be seen will decrease, and that all that can be done is to retard their diminution." The opposite happened. In the last fifty years the number of breeding species has increased and so also, though to a lesser extent, has the number of species regularly visiting the area in winter. Before attempting a rough balance-sheet it is well to point out that even for this small area of forty square miles, perhaps the most watched in the world, the record is far from complete. This is particularly true of the early years of the century when we lack precise information on the status of even some of the commoner breeding species. By 1929 the position -was more satisfactory, but Holte Macpherson pointed out that there were comparatively few records from open spaces other than Hyde Park and Kensington Gardens. Since then there has been a steady increase in the number of observers and most of the parks are watched regularly, whilst particular attention has been paid to the City bombed sites. We have visited all parts of the area, mainly in the breeding season. Yet the south bank of the Thames (apart from Battersea Park), the East End and the docks are still inadequately covered and would repay closer study. Still more important, the grounds of Holland House, whose superb woodland VOL. XLV] THE BIRDS OF INNER LONDON. 435 has for long served as a vital sanctuary in the heart of the central zone and acted as a base from which species such as the Jay, Great Spotted Woodpecker and Stock-Dove have been able to spread into less favourable parts, were only rarely visited during the last ten years of the period. Bearing these limitations in mind it appears that there are some twenty species which have probably bred or attempted to breed throughout the period 1900-50. These are Carrion-Crow, Starling, Greenfinch, Chaffinch, House-Sparrow, Great Tit, Blue Tit, Spotted Flycatcher, Mistle-Thrush, Song-Thrush, Blackbird, Robin, Hedge-Sparrow, Swift, Tawny Owl, Mute Swan, Mallard, Wood-Pigeon, domestic pigeon and Moorhen. In addition, there are the Jackdaw and Wren, which appear to have been con­ tinuously resident but in such small numbers that breeding may not have been regular; the Great Spotted Woodpecker, whose status in the early years of the period is uncertain, but which has been probably resident and breeding throughout, and the Little Grebe, for which regular information is not available as its main breeding stronghold in recent years has been the grounds of Buckingham Palace. There has been one certain loss in the period (the Rook), and two species which may have ceased to nest (the Willow-Warbler and Blackcap, both of which formerly bred regularly in the grounds of Holland House, but whose status there in the last ten years is not known). Against this may be set seven definite additions to the list of regular breeding birds— Jay, Goldfinch, Pied Wagtail (which formerly nested inter­ mittently in various parks, and now does so regularly in the bombed areas of the City), Black Redstart, Kestrel, Tufted Duck and Coot. The Stock-Dove is a probable gain, for it now breeds every year in small numbers, whereas there is no clear evidence that it nested at the beginning of the century, though W. H. Hudson in 1898 (Birds in London) considered it a possible resident. The Tree-Creeper may probably be regarded as now established as a resident in Kensington Gardens, though its numbers are still small. The Coal-Tit may become a regular nesting bird in the same area, but as, so far, it has only once been proved to breed it is better classified with several other species (Yellow Wagtail, Lesser Whitethroat, Chiffchaff, Swallow, Cuckoo and, probably, Linnet) which have bred occasionally in the period. It is interesting to note that, of the additions to the list of breeding species mentioned above, the great majority (Jay, Goldfinch, Pied Wagtail, Tree-Creeper, Black Redstart, Kestrel and Coot) have been known as nesting birds only within the last twenty-five years. Lack of definite information makes it more difficult to assess changes in numbers of species which have been present through­ out, but it is safe to say that the Mistle-Thrush, Blackbird and 436 BRITISH BIRDS. [VOL. XLV. Great Spotted Woodpecker have both increased and extended their range in the last fifty years, whilst there is some evidence that the House-Sparrow may have declined in numbers. Amongst the non-breeding- species the gulls show the most remarkable changes in status. The Black-headed Gull may now be seen during most of the year, perhaps because of the establish­ ment of a breeding colony in Middlesex. The Lesser Black-back, at one time a scarce visitor, is now a common passage-migrant and a winter resident in small numbers. The Great Black-back, formerly a somewhat uncommon winter visitor, has become numerous on the Thames in recent winters and is also seen at other times of the year.