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Together with Tony Pym and María San- which is now known to be widespread in Román, Hadoram visited Réunion in De- the south-west Indian Ocean. The Mas- cember 2012, and managed to see more carene has a stout bill, a large, squar- than 30 Mascarene during three ish head, a long hind body tapering into a days at sea, 30 to 45 kilometres off the is- graduated tail, and very long, slender wings land’s south coast. They attracted the petrels with rounded tips. The dark brown plum- with massive, 25-kilogram blocks of frozen age offers few characters to aid identifica- chum, which slowly release a fragrant cock- tion, but at very close range it shows fine tail of fish oils as they melt. All sightings yellowish streaks on the sides of the neck. were made in the late afternoon and even- A full discussion of the identification of ing, as the petrels presumably returned to the is presented in the the island. One of the photographed Bulletin of the British Ornithologists’ Club on 22 December showed a distinct bulge in (Shirihai et al. 2014, 134: 194‒223). This its lower abdomen, which is thought to be paper is essential reading for any birders caused by an egg about to be laid. If cor- visiting the tropical Indian Ocean, and rect, this provides the first strong evidence will allow us to gain a much better idea of of the laying date for the . Until now the species’ at-sea distribution. Although baby on the breeding season was only inferred from it is currently only known from waters the timing of fledglings crashing into the east of Madagascar, there’s a small chance island’s lights. that the might stray into southern Af- Despite being considerably smaller, the rican waters. Mascarene Petrel proved hard to tell apart PETER RYAN board from the Great-winged Petrel Pterodroma macroptera. Close attention to the bill Compared to a Great-winged Petrel, the The Tubenose Project © Hadoram Shirihai (3) shape as well as the body and wing struc- Mascarene Petrel has a heavier bill base, ture is essential to differentiate the two spe- longer neck and straight, narrow wings Mascarene Petrel unveiled cies. Care is also needed to separate it from with rounded tips (but beware Great-wings the smaller Jouanin’s Petrel Bulweria fallax, completing primary moult). espite comprising only about three (Near Threatened) can be regarded as re- per cent of all birds, hold motely easy to see. The other three species a special allure for many birders. are all Critically Endangered. Beck’s Petrel AndD for some, these birds can become an ob- P. b e cki resembles a diminutive Tahiti Pet- SCALING... Up & down session. Hadoram Shirihai is one such fan- rel and is thought to breed on New Ireland. t is widely accepted that birds evolved from theropod dinosaurs, complex set of traits associated with miniaturisation it’s unlikely atic. For more than a decade his Tubenose Hadoram visited the Bismarck Sea in 2007 but there has been considerable debate as to how and why we’ll be able to deduce what drove the trend towards reduced body Project has attempted to document all al- and managed to get the first good images I predominantly small-bodied birds evolved from their massive size, but that together this set of characters ultimately contributed batrosses and petrels worldwide. This has of the bird at sea. Even more challenging dinosaur ancestors. to the long-term success of the avian lineage. taken him to some of the most remote is- was the P. macgillivrayi, a vir- A recent paper (Lee et al. 2014, Science 345: 562–566) uses novel At the same time, another paper (Hospitaleche and Reguero lands, where he arranges dedicated pelagic tually mythical species known from only analytical approaches to infer the rate of change in body size 2014, Geobios 47: 77–85) reports the discovery of the largest known trips to photograph the world’s most elu- a handful of specimens. Hadoram visited and other structural characters in the evolution of modern birds. penguin. Fossil remains of the giant penguin dubbed Palaeeudyp- sive seabirds as they gather offshore at their Gau Island twice in 2009, where he man- It suggests that the evolution of small body size resulted from tes klekowskii were found on Seymour Island, off the east coast of breeding sites. aged to obtain stunning images of this tiny, sustained selection for smaller body size lasting about 50 million the Antarctic Peninsula. Dating back 37 to 40 million years ago, the Some of his greatest successes have been all-dark petrel, which could be confused years, from ancestors weighing in excess of 160 kilograms around giant penguin is estimated to have stood almost two metres tall with the Pseudobulweria. Of the four with a Bulweria petrel. 200 million years ago to bird-like forms weighing less than one and weighed over 100 kilograms, more than double the weight species, only the P. rostrata The final species in the genus is the Mas- kilogram around 160 million years ago. of the Emperor Penguin, the largest living species. At that time, carene Petrel P. aterrima, which has a tiny The decrease in body size was most rapid during a 10-million- the climate was sub-Antarctic, and fossil remains indicate that at above A Mascarene Petrel, photographed on remnant population on Réunion in the year period from 175 to 165 million years ago, when body size de- least 10 species of penguin lived in the region. 22 December 2012, showing a distinct bulge tropical Indian Ocean. It is best known creased from around 50 kilograms to one kilogram. Interestingly, Large size enhances dive depth and endurance, and it is possible in its lower abdomen, thought to be from an from the occasional bird that crashes into the rate of morphological evolution in the lineage of dinosaurs the giant bird could have dived for as long as 40 minutes. It lived egg about to be laid. buildings after becoming disoriented by leading to birds is estimated to have been about four times well before the ancestors of seals moved back into the sea, at a the island’s many lights. Although there greater than in other lineages at this time. time when whales and dolphins were just starting to evolve. It right The Mascarene Petrel is one of several have been several sightings from the wa- Lee and his colleagues argue that traits favoured by miniaturisa- is possible that competition from marine mammals contributed all-brown petrels found in the tropical Indian ters around the island, its identification tion, such as reduced teeth, short snouts and relatively large brains to the demise of the large penguins and other flightless marine Ocean. Separation from the larger Great- has been handicapped by the lack of well- and eyes, all predisposed birds to take to the air. The enhanced birds. It is striking that currently there is virtually no overlap in winged Petrel and smaller Jouanin’s Petrel documented records, resulting in limited insulation provided by feather-like structures also contributed to the body size between marine mammals and birds. requires careful attention to body proportions understanding of how it differs from other ability to evolve small body size. They conclude that because of the PETER RYAN and structure. Note the long uppertail coverts. all-dark gadfly petrels at sea.

10 african birdlife november/december 2014 news & views 11