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The MANX SHEARWATER INTRODUCTION The Manx Shearwater (Puffinus puffinus) has a typical length of 30-35cm and wingspan of 71-83cm with a weight range of between 350-575g (Onley & Scofield 2007). Manxies are medium sized members of of the Procellariidae family. The species is dark above and pale below; with white under-tail coverts extending almost to the tip of the short tail. Distinguishable from other Shearwater species by a pale crescent behind the auricular. Black colouration extends from the bill covering the eye and ear openings. The species is well adapted for life at sea with long, narrow wings and legs place relatively far back on the body. The positioning of the feet aides swimming. However, on land the position prevents efficient movement and the birds can seem uncoordinated and ungainly. RANGE & DISTRIBUTION The species breeds in and around the North Atlantic in multiple colonies on islands and cliffs. The Rum Manx Shearwater colony is found at just over 400m up to the summit of the Cuillin and is the only known colony to breed at altitude. Originally named the Manks Puffin - the species was widely noted on the Isle of Man, however, a massive decline in the colony at the Calf of Man occurred following the introduction of the Brown Rat (Rattus norvegicus) in the late eighteenth century. Subsequently, the destructive rat has been eradicated and this colony is once more incline. Other colonies include: St.Kilda beyond the Outer Hebrides; Copeland in Northern Ireland; Bardsey, Skomer and Skokholm off the coast of Wales; and Lundy in the English Channel. This by no means an exhaustive list, but points the main territories around the British Isles. Additionally, since the early seventies Manxies have been recorded nesting in Newfoundland. REPRODUCTION Nesting in dense colonies Manxies begin breeding at around five years old and are typically life-long monogamous pairs. One large white egg, which is approximately 15-20% the weight of the adult is laid in a self-excavated burrow that is often over a metre long. One of the pair remains to incubate whilst the other forages for food at sea. A nocturnal changing of the pair occurs to avoid predation by gulls and raptors. Incubation occurs for approximately 51 days (Brooke 1990) and following hatching, the parents will feed the chick for around 60-65 days before abandoning it completely. The chick will then leave the nest after about a week and begin exercising it’s wings on the surface at night. Following the eventual fledging, migration occurs. MIGRATION Manx Shearwaters start migration from breeding colonies as early as late-August. However, it should be noted that multiple external factors have an influence on fledgling and migratory dates. Wintering grounds are off the coast of Brazil and as far south as Argentina - over 10,000km from summer breeding colonies. An interesting point to note is that this migration can occur in less than two weeks. Ringing recoveries have provided invaluable data supporting this. Additionally, studies have been carried out utilising Geo-locator sensors providing valuable data about migratory routes. Such a study is summarised here. FEEDING The Manx Shearwater forages by diving into water from low flight as well as making shallow dives, utilising the ability to swim underwater, from the surface. It feeds on a variety of common small fish; including herrings, sardines, and sand eels. Squid and crustaceans are also consumed. Adults are sometimes attracted to small fishing boats. Amazingly, the birds may forage up to 800km from nesting grounds. THREATS During the 1600s, Manx Shearwaters were harvested extensively throughout Europe. Young were extracted from burrows with iron hooks, killed and preserved in salt for later boiling. Historically, the bird’s oil was used in lamps and ploughed into soil as fertiliser; they were also caught for use as lobster bait. The advent of Wild Birds Protection Act of 1880 eliminated such practice. (Brooke 1990) Studies have found individuals to contain organochlorines from pesticides. Heavy metals recorded in shearwater tissue include zinc, cadmium, and mercury. (Borlakoglu et al. 1990) Manxies are highly prone to grounding by bright lights. Indeed, Rum fledglings are found in large numbers after being attracted to the lights of Mallaig. In one night in September 2009, 55 birds were found and subsequently safely released the next day. (pers. comm. Carty, 2009) It should be noted that many more were sadly not caught and subsequently predated by Great Black-backed Gulls (Larus marinus) that appear to specialise in taking Manxies in flight. Individuals are known to become entangled in sardine fishery nets in the Bay of Biscay. On some breeding islands, overgrazing and the resultant erosion has limited appropriate habitat, restricting nesting to cliffs and other inaccessible sites. Introduced species have been implicated in reducing or eliminating shearwater populations, including pigs in Bermuda, feral cats in Iceland and as previously mentioned, the brown rat. Successful rat eradication occurred on the Isle of Canna in 2005-6. As a result, Manxies have again been noted to breed on the island (Swann, 2007). Indeed, members of Team Shearwater ringed the first adult Manxie on Canna in 14 years, possibly indicating improved conditions for breeding (pers. comm. Ramsay, 2009). On Rum, rat trapping and subsequent examination of stomach contents has revealed that predation does not only occur to young and eggs but adult remains were found (Bell 2008). Burrows have been known to collapse and in few cases, flood leading to adult birds abandoning eggs. REFERENCES Bell, E (2008) Monitoring of Rat Abundance at Manx Shearwater Colony on Isle of Rum. WMIL. Borlakoglu, J.T. et al. (1990) Polychlorinated Biphenyls in Extracts of Brain from Manx Shearwaters. Springer-Verlag NY. Brooke, M (1990) The Manx Shearwater. A&C Black. Ramsay A.D.K. (2008) Rum Manx Shearwater Report. Unpublished. Onley, D & Scofield, P (2007) Albatrosses, Petrels and Shearwaters of the World. Helm. Swann, R et al. (2007) The Impact of Brown Rats on Canna’s Breeding Seabirds. 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