( 55 ) THE MOULTS AND SEQUENCE OF PLUMAGES OF THE BRITISH WADERS. BY ANNIE C. JACKSON, HON. MEM., B.O.TJ. I. INTBODFCTORY. THE object of these notes is to give a brief account of the sequence of plumage and moults of the waders on the British List, which at the moment of writing number sixty-four species. I have endeavoured to interpret the facts correctly from the material at my disposal, but in some cases my notes are unfortunately incomplete owing to want of material; while in other cases the examination of larger series of skins may reveal new facts. I wish to express my gratitude to Lord Rothschild and Dr. Hartert for permitting me to utilize the Tring collection, also to the authorities of the Natural History Museum, South Kensington, for kind permission to work there, and to Mr. H. F. Wither by for the loan of his collection and for much valuable help. I should also like to thank Mr. W. Berry, Col. E. W. Home and others who have assisted me in obtaining material I required. Before detailing the result of my investigations, brief references to the literature already published on the moult of the waders will be of interest. The most important papers I am aware of are as follows: " On the Change of Colour in Birds through and irrespective of Moulting," from the Swedish of W. Meves, translated by H. E. Dresser (Zoologist, March, 1879). In this paper birds are divided into four groups according to the number and completeness of their moults. To the first group belong those which have a single and complete moult in autumn, and in this are included the following genera of waders : viz., Scolopax, Numenius and Becurvirostra. The second group deals with birds which have a double or spring moult and is further subdivided into those which in spring have: (a) entire, involving all or most of the body-feathers and sometimes also the two middle tail-feathers and three inner wing-quills as, for instance, Hcematopus, Charadrius, Strepsilas, Tringa, Totanus, Phalaropus, IAmosa among the waders ; (6) partial, involving only some feathers of the head and neck as, for instance, Vanellus cristatus among the waders. The third and fourth groups do not concern us. 56 BRITISH BIRDS. [VOL. xi " Notes on the Birds of Natal and adjoining parts of South Africa," by H. Seebohm, Ibis, 1887, page 338, in which it is stated that the Charadriidce moult their primaries in spring as well as in autumn. This paper will be referred to later. " The Changes of Plumage in the Dunlin and Sanderling," by Frank M. Chapman, Bull. Amer. Mus. Nat. Hist., Vol. VIII., 1896, pp. 1-8. This paper is a criticism of Herr Gatke's remarks in the Birds of Heligoland on colour- change without moult. Mr. Chapman points out that the breeding-plumage of both these species is acquired by a moult and not by a change of colour without moult as implied by Herr Gatke. " On the Annual Molt of the Sanderling." by Witmer Stone, Proc. Acad. Philad., 1897, pp. 368-372. The author of this paper confirms Mr. Chapman's remarks on the moult of the Sanderling, and gives more particulars of the autumn moult of this species. " The Moult of the North American Shore Birds" (Limicolce), by Dr. Jonathan Dwight, Junr., The Auk, 1900, Oct., pp. 368-385. In this comprehensive and important paper, Dr Dwight divides the Limicolm into two " classes " ; in the first he places those in which the young birds retain " the juvenal plumage, modified only by wear, until a mid­ winter or spring moult takes place " ; in the second he includes those which assume " a distinct first winter plumage by an early post juvenal moult, which involves only the body feathers, the tertiaries and a few of the lesser wing- coverts." In the first class he includes the following species which appear in the British List: Pectoral Sandpiper, Solitary Sandpiper, Spotted Sandpiper, Killdeer, Semi- palmated Plover and Turnstone. Except for the Pectoral Sandpiper, of which I have examined very few juveniles in autumn, I find that all these species assume their first winter plumage by a partial moult, and therefore I cannot agree with Dr. Dwight that they should be placed in his first class. Dr. Dwight then goes on to discuss other questions of moult—I will refer to his conclusions later as occasion arises. Besides the papers already referred to, the Bev. W. Whitear, Yarrell, Mr. N. Severtzoff, *Mr. J. G. Millais (" Notes on the Changes of Plumage of Calidris arenaria," Ibis, 1896, pp. 455- 457), Gatke (" Changes in the Colour of the Plumages of Birds without Moulting," in The Birds of Heligoland), Mr. P. W. Headley (in The Structure and Life of Birds) and others have written expounding the theory of a change of colour without moult and citing the assumption of certain VOL. xi.] MOULTS OF BRITISH WADERS. 57 plumages in some waders as instances. Beyond saying that all the different plumages assumed by the waders are acquired by a moult and do not require the hypothesis of colour change without moult to account for them, I do not intend to enter into a discussion of this vexed theory, which the accumulation of facts I am confident will ultimately entirely disprove. I only wish here to emphasize the fact that colour change without moult, excepting of course effects due to abrasion and fading, plays no part in the sequence of plumages of the Limicoke. I would refer those interested in the literature of this subject to Mr. J. A. Allen's paper on " Alleged Changes of Color in the Feathers of Birds without Molting," Bull. Amer. Nat. Hist., 1896, Vol. VIII., pp. 13-44, which gives a most interesting summary and criticism of the papers written on this subject. Before proceeding to a detailed discussion of each species, it may be well to give the following summary of the moults which I have found to occur in the British waders:— MOULT FROM JUVENILE TO FIRST WINTER PLUMAGE. In apparently all the species of waders in the British List, the first winter plumage is acquired by a post-juvenile moult, but no first winter birds, and few or no juveniles in moult have been examined of the Stone-Curlew, American Pectoral Sandpiper, Buff-breasted Sandpiper, Red-necked Phalarope and Eskimo Curlew. In the Common and Black-winged Pratincoles, this moult involves the remiges, in the Cream- coloured Courser it would appear that in some individuals the remiges and their coverts are also renewed ; in the rest of the waders the remiges are only exceptionally renewed, the moult being confined to the body-feathers, usually some or all of the tail-feathers, some innermost secondaries and coverts, and usually some median and lesser coverts. The moult of the tail-feathers, innermost secondaries and coverts, and median and lesser coverts varies individually in many species. In the following species, however, the tail does not appear to be renewed, viz. Semi-palmated Plover (not many specimens examined), Golden Plover, American Golden Plover, Asiatic Golden Plover, Lapwing (an odd tail-feather is exceptionally renewed), Bartram's Sandpiper, Dunlin, Baird's Sandpiper, Bonaparte's Sandpiper, Purple Sandpiper, Solitary Sandpiper, and Grey Phalarope. In the Purple Sandpiper and Grey Phalarope the innermost secondaries and coverts and median and lesser coverts are also not moulted, while in the Yellowshank the median and lesser coverts do not appear to be renewed. F 58 BRITISH BIRDS. [VOL. XI. First winter birds usually resemble adults, but are dis­ tinguished by the retained juvenile wing-eoverts, except in the following species in which the first winter bird is indistinguishable from the adult, viz. Common and Black- winged Pratincole (not distinguishable unless some juvenile wing-eoverts are retained), Killdeer (difficult to distinguish with certainty), Golden Plover, American Golden Plover, Asiatic Golden Plover, Common Sandpiper, Spotted Sand­ piper, Green Sandpiper, Slender-billed Curlew (difficult to distinguish with certainty), Great Snipe (not distinguishable if all the tail-feathers are moulted), Common Snipe, Jack Snipe and Woodcock. Exceptional Instances of Moult of the Remiges in Winter in First Winter Birds. In the following species the remiges are not normally moulted in winter and occasional examples moulting their remiges must be looked upon as exceptional cases: Ringed Plover, Bonaparte's Sandpiper, Siberian Pectoral Sandpiper. MOTJLT FROM FlEST WINTER TO FlRST SUMMER PLUMAGE. This moult is usually the same as the pre-nuptial moult of the adult, though in some species, e.g. Greater Yellow- shank, Redshank, and Black-tailed Godwit, the moult is less complete, a good many winter body-feathers being retained. In the Stilt, the spring moult of the first winter bird, is more complete than in the adult and involves the tail-feathers, which are not moulted in the adult. No examples in first summer plumage of the following species have been available for examination: Oyster- catcher, Stone-Curlew, Semi-palmated Plover, Knot, Curlew- Sandpiper, American Pectoral Sandpiper, Bonaparte's Sand­ piper, Buff-breasted Sandpiper, Broad-billed Sandpiper, Red-breasted Snipe, Solitary Sandpiper, Yellowshank, Green- shank, Red-necked Phalarope and Eskimo Curlew. First summer birds are usually only to be distinguished from the adults when the retained juvenile wing-coverts are not too abraded. I have examined very few undoubted first summer specimens of any of the waders. This may to some extent be accounted for by the fact that in most waders, when the edges of the juvenile wing-coverts are completely abraded, the first summer birds are indistinguish­ able from the adults. In addition to those species in which the first winter and adult winter plumages are indistinguish­ able, first summer birds of the following species cannot be distinguished from the adult in summer: viz.