The Yelkouan Shearwater Puffinus (puffinus?) yelkouan W. R. P. Bourne, E.J. Mackrill, A. M. Paterson and P. Yesou n the classical Greek period, 2,500 years ago, two seabirds had Ialready given rise to immortal legends in the eastern Mediterranean. The Siren was reputed to lure seafarers to their doom by singing upon outlying rocks, a habit found in a variety of marine animals, but particularly characteristic of petrels on misty nights. The larger species of the area in particular, once known as the Mediterranean Shearwater and now as Cory's Shearwater, which still bears the local vernacular name Diomedee and scientific name Calonectris diomedea in memory of one of the Greeks who besieged Troy (Winthrope 1973), has a voice very like a foghorn. In contrast, the Halcyon was equally celebrated because it was never seen ashore, and thought to reproduce upon the surface of the sea in calm weather, which was named after it. This seems equally characteristic of a smaller species, long known as the Levantine Shearwater Puffinus yelkouan until it was reclassified early in this century as a race of the Manx Shearwater P. puffinus yelkouan, since it does not fly so well, and is prone to settle in flocks on the water far from its island breeding-places when the wind falls. Although the identity of these birds was forgotten over the years, and they were eventually considered to be all sorts of strange things, such as Gannets Sula bassana and Kingfishers Alcedo atthis (Yapp 1987), Win­ thrope (1973) reported that the name Halcyon is still used for the 'Levantine Shearwater' in its area of origin. There, it appears to have given rise via the modern Turkish 'Yelkouan' or 'Yelkovan', also used for the souls of the dead (Vian 1877, cited by Mayaud 1936), or 'spirit of the wind', and hence weathercock (Pierre Loti, cited in an annotation by J. Vielliard to Kumerloeve 1972), to the species' scientific name. In the last century, it was thought to wander to British seas, until N. F. Ticehurst (1908) noticed that one collected in Kent about 1865 and identified by John Gould as a new species was originally reported to be pink, and remained unusually dark, below. Witherby (1921) eventually showed that all the British specimens belonged to this form, which was described as a third race of the Manx Shearwater, P. p. mauretanicus, by Lowe (1921). A discussion between leading British ornithologists and some distinguished visitors, including Alexander Wetmore, Ernst Mayr and Sir Charles Fleming, under the chairmanship of Lowe, when C. B. 306 [Brit. Hints 81: :«)B-S19.July 1988] The Yelkouan Shearwater 307 Ticehurst eventually located the breeding-place in the Balearic Islands, was summarised as follows (Anon. 1930): 'Mr Witherby called attention to the fact that he had personally examined almost every example of this petrel which had been recorded as P. yelkouan in the British Isles. Practically every one turned out to be P. mauretanicus (Witherby 1921). He also stated that he was inclined to think P. mauretanicus would prove to be a separate species. The Chairman said he thought Mr Witherby was right, and he himself had been in doubt as to the position of P. mauretanicus as a subspecies of P. puffinus. He thought that in considering the question of its specific rank it was necessary to bear in mind that not long ago, geologically speaking, the Mediterranean consisted of two land-locked seas divided by a causeway whose remains were now represented by Italy, Sicily, Malta, Corsica and Sardinia. It seems possible P. mauretanicus originated in the western basin.' The structural differences between the European shearwaters were then studied by Mayaud (1932), who found that, -while puffinus,yelkouan and mauretanicus are all very similar, the last two resemble each other, and differ from the first, in having a longer, lower skull with more powerful jaw muscles, and a long sternum, but proportionately short wing and tail adapted for more aquatic habits, while they differ from each other only in their average size and amount of marking below. He also remarked how the extreme forms, puffinus and mauretanicus, occur next to each other rather than at opposite extremities of the range of the group, as might be expected as the result of convergence in a similar environment and hybridisation if they were all conspecific, though he continued to treat them as the same species. In the next definitive check-list of the petrels, one of the two greatest authorities of the day, Mathews (1934), added three more very similar North Pacific races to P. puffinus. He was initially followed by the other main authority, Murphy (1952), who first went on to add two more Fig. 1. Distribution of the Manx group of shearwaters Puffinus. Continuous arrows show direction of movement of the black-backed forms: A Manx Shearwater P. p. puffinus, B Townsend's Shearwater P. (p.?) auricularis, C NewelPs P. (p.?) newelli, H Hutton's Shearwater P. huttoni. Dashes show movements of the brown-backed forms: D Levantine Shearwater P. (y.?)yelkouan, E Balearic Shearwater/3, (y.?) mauretanicus, F Black-vented Shearwater/5, (y.?) opisthomelas, G Fluttering Shearwater P. gavia. (Derived from Bourne 1982) All forms are illustrated by Harrison (1987), and mauretanicus and yelkouan will be dealt with in detail by Yesou et al. (in press) 308 The Yelkouan Shearwater races from New Zealand, but remarked that the group appeared to be divisible into contrasting black-backed and brown-backed forms every­ where that it occurred, but, when the New Zealand forms were shown by Harrow (1965) to differ markedly in their ecology, eventually concluded that yelkouan and mauretanicus are also 'more distinct from the Manx Shearwater than present nomenclature indicates' (Murphy 1967). When Bourne (in Ash & Rooke 1954) saw his first mauretanicus alongside nominate puffinus in 1953, he immediately thought that they differed in their 'jizz' as well as their markings. On reviewing the petrels for Palmer (1962), he soon developed growing doubts whether they should be considered conspecific when he observed how inconsis­ tently Murphy (1927, 1952) treated the very similar geographical variation of the smallest shearwaters, divided into two species, the Little Shearwater P. assimilis and Audubon's Shearwater P. therminieri, and the Manx group, combined into one, P. puffinus. After examining both the European and the Australasian forms at sea and considering Murphy's (1967) terminal change of opinion, he eventually decided to reopen the matter (Bourne 1982), whereupon it emerged that the other three authors had arrived independently at similar conclusions. Fluttering and Hutton's Shearwaters At this point, it may be useful to describe the extreme situation found in Australasia. The existence of local allies of the Manx Shearwater with more marked adaptations for diving, which include a reduction of the wings for use in swimming under water, resulting in a more fluttering type of flight similar to that of the auks (Brown et at. 1978), was noticed very early, in 1773-74 during Cook's second expedition. For a long time, only one form was recognised, the Fluttering Shearwater P. gavia, which has a brown back prone to fade and white underparts. It tends to feed socially inshore on shoaling fish, breeds early in the southern spring on islets around northern New Zealand, and later disperses as far as southeast Australia to moult (Serventy et at. 1971). The existence of a second, larger, dark-backed form with more markings on the sides of the body and underwing, and a very long, slender bill, Hutton's Shearwater P. huttoni, was noticed only in 1912, possibly because it disperses out to sea to feed. Even then, its status remained doubtful for over half a century, until eventually it was found to breed two months later in the spring, above the tree-line in the mountains of the South Island of New Zealand (Harrow 1965, 1976), and then migrate to moult during the winter in an area of upwelling which occurs off the northwest coast of Australia during the southeast monsoon (Shuntov 1968; Halse 1981). These are such dramatic differences that, clearly, the two forms must be treated as distinct species. Indeed, once their marks were worked out, they proved quite easy to tell apart at sea (personal observation, WRPB). A comparable situation appears to occur on a larger scale The Yelkouan Shearwater 309 among the similar but longer-winged shearwaters of the northern hemisphere. This has been obscured by their greater geographical variation, so that each type is represented by three forms spread across two oceans, where they have traditionally been classified in different ways: as one species in Europe, but as two or three in the Pacific. The resulting confusion has been increased by the fact that, here, it is the brown-backed forms which are the more heavily marked below. Northern black-backed (Manx, Townsend's and Newell's) shear­ waters The Manx Shearwater P. p. piiffinus has acquired a misleading image in Europe as an inhabitant of northern seas, where it appears very 'lithe' {Cramp & Simmons 1977) and black-and-white, owing to the compara­ tively sharp division between the dark upperparts and white underparts as it swoops over stormy waters among stouter Fulmars Fulmarus glacialis. If, however, we consider the rest of its range, where it has been seriously affected everywhere by introduced predators, a different picture emerges. Thus, some still breed in the mountains of the Canaries, Madeira and the Azores, and formerly bred in the consolidated coral sand-dunes of Bermuda, as far south as 30°N in the Atlantic; and two close allies, Townsend's Shearwater P.