Gray Noddy Anous albivitta Scientific name definitions

28–31 cm; wingspan 46–60 cm. Small, relatively long-legged noddy, with grey back , darker grey wings and tail, and pale greyish to whitish head and underparts  ; white or pale underwing-coverts; eye with narrow black semicircle at front, white behind; iris brown, bill  black; legs and feet blackish brown, with pinkish yellow webs  ; mouth-lining yellow. Distinguished from slightly smaller A. ceruleus by paler plumage, with much whiter head and underparts. Juvenile tinged brownish above, but uniform, without scaling or barring. Races differ mainly in plumage tone; underparts whitest on skottsbergii and imitatrix.

Editor's Note: This article requires further editing work to merge existing content into the appropriate Subspecies sections. Please bear with us while this update takes place.

Genetic data suggest that both species formerly placed in Procelsterna should be included in genus Anous (1 Cibois, A., Thibault, J.-C., Rocamora, G. and Pasquet, E. (2016). Molecular phylogeny and systematics of Blue and Grey Noddies (Procelsterna). Ibis. 158(2): 433–438. Close ). Temperate and subtropical counterpart of tropical A. ceruleus, to which it is closely related; sometimes considered conspecific, but has white vs grey head, hindneck, underwing and underparts (3); paler grey upperparts (1); longer bill, toes and notably wings (effect size 4.02, score 2). Although this score reaches only 6, the near-”parapatric” arrangement of populations across the Pacific Ocean roughly at the Tropic of Capricorn, in combination with the different size, is highly suggestive of a distinct ecology (putative score 1), and species status is considered appropriate. Some authors have claimed that races of SE Pacific belong to A. ceruleus, but specimen evidence refutes this. Three subspecies recognized.

Editor's Note: Additional distribution information for this taxon can be found in the 'Subspecies' article above. In the future we will develop a range-wide distribution article.

Temperate and subtropical oceanic islands. Breeding birds occur around coasts of rocky islands, nesting on cliffs  up to 600 m high, or on ground. Forages in inshore waters.

Around breeding colonies, utters noisy plaintive screams, “kraarr”, which are quite low-pitched, both in flight and on the ground. Elsewhere mainly silent.

Aug–Nov in SW Pacific (nominate race). At Easter I race skottsbergii reported present during Dec–Apr and in Aug, and found nesting there in Jun (3 Marín, M., and P. Cáceres (2010). Sobre las aves de Isla de Pascua. Boletín del Museo Nacional de Historia Natural (Chile) 59:75–95. Close ); the same race found breeding on Pitcairn I in Oct and a well-grown chick was found then (4 Williams, G.R. (1960). The birds of Pitcairn Islands, central South Pacific Ocean. Ibis 102: 58-70. Close ). Eggs and recently hatched chicks of race imitatrix found on San Ambrosio I in Oct (5 Millie, W. R. (1963). Brief notes on the birds of San Ambrosio and San Felix islands, Chile. Ibis 105(4):563–566. Close ). Reported to be only passively colonial. Nest  in cliff crevice or ledge, or on ground under rocks, on bare rock, or under vegetation such as tussock grass (Kermadecs). Single egg  ; incubation period unknown; chick  uniform smoky grey or chocolate-brown, unspeckled  , with dark felted forecrown, and paler belly, nape and face; pin feathers appear c. day 17; fledging 32–45 days. Some may be double-brooded.

Not globally threatened (Least Concern). Its status is not at all well known and the species is possibly rare. The total population is not known but is probably under 25,000 pairs, the great majority of the nominate race in the SW Pacific . Of these, Norfolk I holds several thousand pairs, possibly up to 10,000; fewer than 10,000 pairs in the Kermadecs, where said to be common, with several thousand pairs on Herald Islets; fewer than 1000 pairs on Lord Howe I. The two SE Pacific subspecies are probably endangered: the Easter I population (race skottsbergii) is threatened by cats and recent visits (2009) have found only a few individuals (3 Marín, M., and P. Cáceres (2010). Sobre las aves de Isla de Pascua. Boletín del Museo Nacional de Historia Natural (Chile) 59:75–95. Close ). Only about 40 birds documented on the Desaventuradas (race imitatrix) (5 Millie, W. R. (1963). Brief notes on the birds of San Ambrosio and San Felix islands, Chile. Ibis 105(4):563–566. Close ), but no recent data available. Cliff-nesting assists survival, even on predator-infested islands.