Petrels
Barau’s Petrels, Pterodroma baraui, are a medium-sized gadfly petrel from the family Procellariidae. Its main breeding site is the island of Réunion in the Indian Ocean.
Behaviour
Barau’s Petrels spend the majority of their life far from land, in the vast pelagic zone of the ocean. These seabirds have mastered the art of flying, using wind currents and gliding over waves with great skill. Barau’s Petrels can be quite agile and active when it comes to hunting. The Barau’s Petrels use surface-seizing, a technique that allows them to grab small fish or squid just below the surface of the water. They are also known for performing shallow dives. They will often feed with other seabirds, using the schools of fish that are driven to the surface.
Birdwatchers who are lucky enough to be on the sea at the right time can enjoy this social feeding behaviour. Barau’s petrels are cleverly able to avoid predators by returning to land in the darkness during the breeding season on the cliffs that surround volcanic islands such as Reunion, located in the Indian Ocean. Barau’s Petrels are a fascinating seabird that attracts admiration and study from enthusiasts around the world.
Etymology
The name commemorates Armand Barau, an agricultural engineer and ornithologist from the French territory of Réunion in the Indian Ocean. It is one of the most recently discovered species of seabird and was only described in 1964, although it was known to local people before that.
Description
Barau’s Petrel has a unique and elegant appearance. This medium-sized petrel measures around 40 centimetres. Once you know where to look, it is easy to identify. The bright white underparts and the forehead of this petrel contrast beautifully with its darker upper part. The soft, grey-black ‘M’ pattern that gracefully stretches across the upper wings and back is one of its most distinguishing features.
Birders use this natural marking to identify birds in flight. A sleek black bill is also a feature of the bird, which suits its lifestyle in the ocean. Barau’s Petrel, which is found primarily in the tropical waters of the Indian Ocean, is a seabird that is best observed at sea. It is rare to see it close to the shore. This petrel is a treat for bird watchers in Australia and elsewhere. These birds spend their days soaring over the ocean. According to BirdLife International, this species is well documented.
Distribution and habitat
Barau’s Petrel ranges across the Indian Ocean from Réunion to Western Australia and Indonesia. Except a single nest found on the island of Rodrigues, the bulk of the population is thought to nest on Réunion. According to Audubon Society, this species is well documented.
Feeding
The petrels are highly pelagic at sea, preying on small fish (10cm) by surface-seizing and plunge diving. They will associate with other species while feeding.
Breeding
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.
Conservation Status
Barau’s Petrel is considered to be an endangered species. It has a highly restricted breeding range and has suffered from hunting pressure in the past.
While the shooting of the species has now been stopped, and the population seems to have recovered, it is currently threatened by introduced species and light pollution. Young birds, particularly fledglings, are disoriented by artificial lights such as streetlights or the floodlights of sporting venues, which they mistake for bioluminescent squid, and lead them to fail to reach the sea. It is estimated that as many as 40% of each breeding season’s fledglings get confused in this fashion.
Conservation organisations work with local people to catch disorientated chicks and release them back at sea, a program that is thought to rescue most of the lost chicks. Measures are also underway to reduce light pollution by shielding light sources so that they don’t attract young birds, a method that has been used to help Newell’s Shearwaters in Hawaii.
References
- BirdLife International (2008). In: IUCN Red List 2008. IUCN Red List of Threatened Species. Downloaded on 2009-04-18.
- Brooke, M. (2004). Albatrosses And Petrels Across The World Oxford University Press, Oxford, UK ISBN 0-19-850125-0
- Le Correa, M., Ollivier, A., Ribesc S., Jouventin, P., (2002) “Light-induced mortality of petrels: a 4-year study from Réunion Island (Indian Ocean)” Biological Conservation 105: 93–102
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