Crozet Shag Leucocarbo melanogenis Scientific name definitions

70 cm; 1700–2700 g; wingspan 125 cm. Has an erectile crest of upcurved feathers on crown  ; crown to gape or just below it black with greenish-blue gloss, hindneck and rest of upperparts  including outer sides of thighs black glossed blue (bronzy green on scapulars and wings), can have some hair-like white filoplumes on head and upperparts often forming noticeable tufts on rear superciliary, some outer scapulars can be white, usually has comparatively small white bar over variable number of lesser wing-coverts; underwing blackish, with coverts except greater coverts blacker and can have some white at base of leading edge; tail duller blackish with whitish shafts at base; white on throat and rest of underparts, broader on lower head and sides of upper neck; crest much reduced or lost as breeding season progresses, white filoplumes are lost and plumage is less glossy. Iris dark brown; prominent buffy-yellow to orange-buff warty caruncles  on sides of forehead, facial skin blackish except blue eyering, bare skin below gape and gular pouch blackish with tiny yellowish tubercules, eyering duller in non-breeding season; bill blackish grey tinged horn-brown, usually paler at tip of mandible; legs pink with some grey tones. Sexes similar. Juvenile has dark brown instead of glossy black upperparts, wing-coverts and remiges pointed, coverts with pale tips, forming more complete pale fringes on some lesser coverts, iris brown, lacks caruncles, eyering dark, gular puch violet with black posterior border, legs brownish; immature resembles juvenile but new feathers darker, has variable sandy patch on upperwing, underparts can have a few brown spots or blotches, and bare parts intermediate. Very like other “blue-eyed” pied shags, from which should be carefully separated by overall size, amount of black on head-sides and white on upperparts, bill length and often more subtle variation in caruncles and colour of bare facial skin. Head pattern much like that of P. verrucosus and P. purpurascens, both of which have more yellowish skin in gape region, while first-named is marginally smaller, often with some black reaching malar region, usually lacks white on upperwing and has duller legs and brighter large caruncles, whereas second-name appears almost identical in face pattern, but black usually does not reach below gape, and tends to have more white on upperwing. P. atriceps albiventer distinguished only by usually longer bill and larger and brighter caruncles, with yellower (less blackish) skin in gape region; P. bransfieldensis and P. georgianus have more white on head-sides.

Sometimes placed in genus Notocarbo. Often treated as conspecific with P. verrucosus and P. purpurascens, and all three, along with P. bransfieldensis, P. georgianus and P. nivalis, frequently considered conspecific with P. atriceps. Monotypic.

Prince Edward Is (Marion and Prince Edward) and Crozet Is, in S Indian Ocean.

Marine. Forages close inshore, at Marion I no more than 400 m from coast, at Crozet Is occasionally up to 6 km offshore over continental shelf. At Marion I, normally forages near fringe of thick beds of kelp (Macrocystis pyrifera), occurring within fringe in Dec. Breeds along coast, generally in areas sheltered from prevailing wind; occupies cliffs, slopes with or without vegetation, flat ground, rocky outcrops and sometimes boulder beaches. Roosts on cliff tops, headlands and stacks.

Sedentary; not recorded far from respective island groups. At Crozet Is, some local movement over short distances by juveniles and by adults outwith breeding season, birds turning up at different colonies and roosts.

Bottom feeder, taking benthic prey: mainly fish, particularly nototheniids, and around Marion I particularly Notothenia squamifrons; also crustaceans, especially the shrimp Nauticaris marionis, octopus, squid, polychaetes and holothurians. Fish most important in Feb–Mar, far less so in Apr–May. Feeds mainly by pursuit-diving. Forages generally alone, or sometimes co-operatively in small flocks.

Male gives repeated “heh-heh-heh” or “egh-egh-egh” during display, protracted "whaaah" in threat; also loud barks and roar-like calls. Female emits hissing sounds during gape display.

Season varies between colonies, with egg-laying Oct–Feb at Marion I and Crozets, but on Prince Edward I in 1984 some laying in Jun. Breeds alone or in small groups of up to c. 50 pairs (54 pairs recorded); sometimes associates with penguins. Nest a truncated cone of Cotula plumosa and other plant matter, cemented together with mud and excreta, placed on bare ground or in vegetation, often in or near patches of Cotula plumosa; reused in successive years, but new pair each year (on Crozet Is, at least). Clutch 1–5 eggs, normally 2–3; incubation priod 27–32 days; chicks naked, grow greyish-brown down; fledging period 50–63 days, exceptionally 75–80 days; post-fledging care c. 1 month. Hatching success 45–62% (Marion), 56–65% (Crozet); overall breeding success 31–39% (Crozet).

Not globally threatened. Has relatively small global range and small population size. Total population c. 1200 pairs, variable. In survey of Prince Edward I in Dec 2001, found breeding at six (possibly seven) sites, all on offshore stacks or inaccessible cliffs, with total of c. 39 pairs recorded and c. 50 pairs estimated; although some nests on island’s sheer cliffs possibly overlooked, this represents a decrease of probably more than 50% since Sept 1984, when 120 pairs estimated (1 Ryan, P.G., Cooper, J., Dyer, B.M., Underhill, L.G., Crawford, R.J.M. and Bester, M.N. (2003). Counts of surface-nesting seabirds breeding at Prince Edward Island, summer 284841/842. Afr. Journal Mar. Sci. 25(1): 441–451. Close ). On Marion I, 589 breeding pairs noted in 1980s, 841 in 1994–1995, 672 in 1995–1996, with respectively 537, 388, 505 and 490 in following four seasons, and dropping to 443 pairs in 2000–2001, 344 in next year and only 272 in 2002–2003 (2 Crawford, R.J.M., Cooper, J., Dyer, B.M., and others (2003). [Full list of authors: Crawford, R.J.M., Cooper, J., Dyer, B.M., Greyling, M.D., Klages, N.T.W., Ryan, P.G., Petersen, S.L., Underhill, L.G., Upfold, L., Wilkinson, W., De Villiers, M.S., Du Plessis, S., Du Toit, M., Leshoro, T.M., Makhado, A.B., Mason, M.S., Merkle, D., Tshingana, D., Ward, V.L. & Whittington, P.A.] Populations of surface-nesting seabirds at Marion Island, 1994/95–23973972/3973. Afr. Journal Mar. Sci. 25(1): 427–440. Close ). Common in Crozet Is, c. 810 pairs (3 Duriez, O., Jornvall, H. and Shirihai, H. (2005). Birds and wildlife of the French subantarctic islands: Crozet, Kerguelen and Amsterdam & St Paul. Dutch Birding 27(2):87–115. Close ). Some natural predation of eggs, but breeding failure apparently due mostly to rough sea conditions. At Crozet Is and Marion I some colonies deserted probably as a result of disturbance by humans; at present, populations seem to be reasonably stable. Prince Edward I is a restricted nature reserve.