Fr:  Prion bleu
    Ang:  Blue Petrel
    All: Blausturmvogel
    Esp: Petrel  Azulado
    Ita: Petrello  azzurro
    Nd: Blauwe  Stormvogel
    Sd: Blåpetrell
Photographers:
Otto  Plantema 
  Trips around the world 
Alan  & Ann Tate
  AA  Bird Photography 
Text by Nicole Bouglouan
Sources:
HANDBOOK OF THE BIRDS OF THE WORLD vol 1 by Josep del Hoyo-Andrew Elliot-Jordi Sargatal - Lynx Edicions - ISBN: 8487334105
A Complete Guide to Antarctic Wildlife by Hadoram Shirihai and Illustrated by Brett Jarrett - Edited by Guy M. Kirwan - ALUL.A Press Oy, Finland - ISBN 9519894705
BirdLife International (BirdLife International)
Department of Sustainability, Environment, Water, Population and Communities
New Zealand birds and birding (Narena Olliver)
Wikipedia, the free encyclopaedia
Blue Petrel 
      Halobaena caerulea
Procellariiformes Order – Procellariidae Family
INTRODUCTION:
    The Blue  Petrel is the sole member of genus Halobaena. Its plumage pattern is very  similar to that of prions of genus Pachyptila, but it differs from prions in  some ecological aspects and morphological features. 
    The Blue  Petrel is found in Antarctic and subantarctic waters. Its global population  appears to be stable. The main threat is the predation by rats and cats on some  breeding islands. 
DESCRIPTION OF THE BIRD:
      Biometrics:
    Length:  26-32 cm
    Wingspan:  58-71 cm
    Weight:  150-250 g
The adult  has grey-blue upperparts with conspicuous blackish M across the upperwing, well  visible in flight. The three outermost primaries are blacker. The rearmost  scapulars and the tertials are dark grey with white tips. The tail is grey-blue  with dark indistinct subterminal band and broad white tip, slightly narrower on  the outermost rectrices. 
    The underparts,  including wings and tail, are white. 
On the  head, a blackish cap extends to and around the eye and onto the neck sides,  forming a dark partial or sometimes complete collar. It contrasts strongly with  the white forehead and throat. 
    The bill  is blackish-grey to bluish-black. The eyes are blackish-brown. Legs and webbed  feet are blue-grey with pink webs. 
Male and  female have similar plumage, but the female is smaller with shorter wings. 
    The juvenile  is browner on the upperparts, and it has greyer forehead.    

RANGE:
    The Blue  Petrel is circumpolar in Southern Ocean. It breeds on South Georgia, Prince  Edward, Marion, Crozet (east), Kerguelen and Macquarie Islands and in Cape  Horn. 
    Outside the  breeding season, it may reach S Australia, New Zealand, S South America and  South Africa, although some birds may remain year-round close to their breeding  colonies.   
HABITAT: 
    The Blue  Petrel is pelagic. It occurs in the cold Antarctic and subantarctic waters. On  the breeding islands, the colonies are established on tussock-covered coastal  slopes. It nests in self-excavated burrow. 
CALLS ANS SONGS: SOUNDS BY XENO-CANTO 
    The Blue  Petrel is usually silent at sea but it is more vocal at colonies. The adults  produce pigeon-like cooing “kuk-kuk-kuk coo-coo” fairly similar to prions of  genus Pachyptila. These calls are given mainly from the ground at night, but  also in flight. They also give cackling calls. 
    The calls  vary between the different islands within the same group or archipelago. The heaviest  males usually give faster calls. 

BEHAVIOUR IN THE WILD: 
    The Blue  Petrel feeds on crustaceans, especially krill of genus Euphausia, small fish  and squid caught by dipping while flying or swimming.
    It uses  several fishing techniques such as surface-dipping, surface-seizing and  surface-diving. It may occasionally perform pursuit-diving. 
    It often  associates with prions, and forages sometimes around the large cetaceans which lead  the preys close to the surface. It may fly alongside the large vessels. 

The Blue Petrel breeds in colonies in self-excavated burrow on grassy slopes. They are monogamous. They are nocturnal at colonies, in order to avoid predation from skuas. The colonies are dense with two nests/square metre. Both parents share all the nesting duties. Most courtship and sexual activities take place inside the burrow.
The Blue  Petrel adult may be largely sedentary. They disperse first to adjacent waters. They  leave the breeding colonies between late January and early March. 
    Non-breeding  birds and young of the year may reach SE Australian waters between September  and November. 
    It returns  to the colonies in late August/early September. 
The Blue Petrel flies mainly close to the sea surface and soars more than other prions. Its flight is less erratic and more buoyant.

REPRODUCTION OF THIS SPECIES: 
    The breeding  season starts in August-September and lasts until February, with peak of laying  in October, after a pre-laying exodus by the breeding adults. 
    They breed  in dense colonies in self-excavated burrows. The breeding colonies are established  on coastal slopes covered with tussock grass. The burrow is sometimes lined  with twigs and leaves. 
The female lays a single white egg. Both adults share the incubation during 45-49 days. At hatching, the chick is covered with bluish-grey down. It is brooded for three days. Both parents feed it by regurgitation. It fledges between 43 and 60 days after hatching, usually in February.
PROTECTION / THREATS / STATUS: 
    The Blue  Petrel has stable populations in spite of predation by cats and rats on some islands,  and skuas in Kerguelen Archipelago. 
    The global  population was estimated at least at 3,000,000 individuals in 2004. 
    The Blue  Petrel is currently evaluated as Least Concern. 
