Baraus Petrel (Pterodroma baraui)

Baraus Petrel

Subspecies

Genus	Species	subspecies	Region	Range
Pterodroma	baraui		IO	sw

Genus

Genus Pterodroma, Pseudobulweria and Aphrodroma are also knwon as the Gadfly Petrels. They vary in size from rather small birds such as the Cookilaria-species, measuring about 26 cm, to the much larger and robust representatives of this group like the White-headed Petrel with an overall length of about 43 cm. Their plumages also vary a great deal from species to species; from completely black to light grey mantles and pure white bellies, and with different color phases within species. One feature shared by all of them is the black bill of which the shape also shows much variation. Some species are extremely rare and restricted to a very limited area, other are abundant and wander widely or have unknown pelagic ranges.
The group of the Gadfly Petrels counts over 35 species, mainly from the Southern Hemisphere. There are three genera: Pterodroma with about 30 species, Pseudobulweria counting four and Aphrodroma with only one. Many authors have tried to classify the large number of species of this group and to determine their relationships. This has resulted in a division in several subgenera and the grouping of several species which are considered to have a more or less close relationship. The taxonomic discussion has not come to an end yet: new species have been added or split recently and probably will be in the near future.

Physical charateristics

Medium-sized, grey-and-white gadfly petrel. White forehead, black cap merging to greyish-brown back and upperwing. Paler wing-tips give scaled appearance. Slightly darker tail. Moderately defined “M” mark across wings. White chin, throat and rest of underparts, except for some grey mottling on sides of breast and flanks. White underwing with dark trailing edge, dark tip, narrow black edge to leading edge distal to carpal joint. Black thickens at joint. Then clear black bar extending from joint towards centre of wing.

wingspan min.:	88	cm	wingspan max.:	92	cm
size min.:	36	cm	size max.:	40	cm
incubation min.:	52	days	incubation max.:	57	days
fledging min.:	100	days	fledging max.:	120	days
broods:	1		eggs min.:	1
			eggs max.:	1

Range

Indian Ocean : Southwest. Pterodroma baraui nests on the Massif of Piton des Neiges, Reunion (to France).

Habitat

It nests on cliff-ledges in volcanic ash soils beneath sparse, heathy vegetation such as Philippia montana associated with upland elfin forest

Reproduction

Their colonies are unusual in being far inland and at high elevations; they dig burrows under the forest at around 2400-2700m above sea level. The breeding biology of the species has not been studied but it is inferred that they have a 55-day incubation period and take around 100-120 days to fledge a chick. Unlike most burrow nesting procellariids, Barau’s Petrels begin to return to their colonies diurnally, returning in the late afternoon and riding the thermal updrafts to conserve energy. The chicks fledge between November and February.

Feeding habits

It fishes over a wide area, sometimes associated with flocks of feeding seabirds, and occasionally near fishing boats. A study of grounded birds in 2005 suggested that most juveniles left their colonies over a period of eight days, beginning four days after the new moon in early April

Video Baraus Petrel

httpv://www.youtube.com/watch?v=95m0p73AROw

Conservation

This species may have undergone a rapid population decline owing to illegal shooting in the 1990s, but has apparently recovered. However, it has a very small range when breeding (probably at fewer than five locations) and a small population, both of which are thought to be declining. It is therefore classified as Endangered.
Pterodroma baraui nests on the Massif of Piton des Neiges, Reunion (to France). In 1987, the population was estimated at 3,000 breeding pairs based on colony and coastal counts, and 15,000 individuals based on transects at sea11. More recently, improved knowledge of the colonies indicates that 4,000-5,000 pairs may be a more accurate estimate of breeding numbers, although this could be optimistic. In 1992, it was estimated that up to half the breeding population may have been killed by illegal shooting. Although this may have been an overestimate, the population appears to have recovered to former levels (because of large numbers of non-breeders) following the cessation of shooting4. It has been observed at sea north of Reunion, from the Oman Sea as far as Sumatra and around the Cocos Keeling Islands, and south-east towards Australia.

Migration

Little known, but seems to disperse N then E, following S Equatorial Current, reaching area of Cocos (Keeling) Is and Christmas I; recorded S to Amsterdam I, and E to Australia. Forages in zone of Subtropcial Convergence to S of Reunion.

Distribution map

Baraus Petrel distribution range map

Planet of Birds