Tubenoses in Trouble

Here’s a good question for a pub- or lockdown-quiz: Where is Macaronesia? And yes, the word is Macaronesia, not Macronesia. Well, it’s the name given to four island archipelagos that lie off the west coast of the Iberian Peninsula and Africa, namely the Azores, the Canary Islands, Madeira and Selvagen Islands, and the Cape Verde islands. All have volcanic origins and are as significant to the Atlantic in terms of island biodiversity and evolution in isolation as the Galápagos and Hawaii islands are to the Pacific. Sadly, and inevitably of course, human colonisation has had a terrible impact on Macaronesia’s native and endemic flora and fauna with a tragic tally of extinctions including many birds. But devastating though human impact has been on the region’s avian fauna, the minor miracle is that some of the rarest of the rare have clung on to survival.

In birding circles, Macaronesia is famed for its tubenose seabirds (order Procellariiformes): petrels, shearwaters and storm-petrels, whose mouth-watering allure is enhanced by the extreme rarity of some. Relatives of albatrosses (which are absent from the North Atlantic as breeders) they are named for their tubular nostrils, used for salt excretion and to facilitate their sense of smell and help them locate food in the open ocean. Tubenoses evolved to nest on remote islands, and in the absence of mammalian ground predators. Predictably, humans have upset the balance through the introduction of cats and rats to many locations. And in some instances, historically people added to tubenose woes more directly through habitat destruction and by killing the birds for food.

Among Macaronesia’s tubenoses, its Pterodroma petrels are particularly noteworthy. Traditionally, they were considered to be subspecies of Soft-plumaged Petrel P. mollis, an otherwise southern hemisphere seabird. Subsequently they were regarded as subspecies of a bird named Fea’s Petrel P. feae. However, more recently, detailed studies have revealed this to be a false assumption and DNA analysis confirms the existence of three species: Zino’s Petrel P. madeira, which breeds only on six cliff ledges in one mountain range in Madeira, with a world population of perhaps 160 individuals; Desertas Petrel P. deserta, which breeds on Madeira’s Desertas islands and numbers just a few hundred individuals; and Cape Verde Petrel P. feae with a world population of fewer than 2,000 individuals. More facts and information about these and other birds can be found on the Birdlife International website.

Above: At one time Zino’s Petrel was feared extinct but it was saved from that fate by the pioneering work of ornithologists including two (father and son, Paul and Frank Zino) after whom the species is named. To this day, conservationists do their best to prevent predation by rats and cats and the birds have also had to contend with a devastating fire in August 2010, which killed many individuals. However, maybe there are grounds for cautious optimism that numbers are growing: on 20 July 2020 one was recorded by seabirding legend Bob Flood and a band of pelagic enthusiasts off the Isles of Scilly, the first time the species had been seen in British waters. Photo ©Paul Sterry/Nature Photographers Ltd.

As a group, Pterodroma petrels are superlative seabirds, capable of effortless, speedy flight as they wander the open ocean. Satellite tagging has revealed that during feeding forays, which can last as long as a couple of weeks in the breeding season, Macaronesian species travel as much as 10,000km. Their wanderings take them right across the Atlantic to waters as far away as the east coast of North America.

Above: Most tubenoses, Zino’s Petrels in particular, shun land by day and only return to their nest burrows under cover of darkness. Their ability to locate their breeding grounds, high in the mountains of Madeira and at night is an extraordinary feat. Photo ©Paul Sterry/Nature Photographers Ltd.

Above: Faring rather better than its Pterodroma cousins, Cory’s Shearwater Calonectris borealis is a tubenose species that is present in good numbers in Macaronesian waters. Photo ©Paul Sterry/Nature Photographers Ltd.

Above: Tubenose seabirds such as this Bulwer’s Petrel Bulweria bulwerii present perhaps the ultimate challenge for photographers wanting to capture them in their element – at sea and in flight. On a rolling sea, everything is moving erratically, unpredictably and independently of one another – not just the bird, but the photographer and the boat itself. Thank goodness for modern autofocus technology. Photo ©Paul Sterry/Nature Photographers Ltd.

In addition to the larger tubenoses, Macaronesian islands are home to diminutive storm-petrels. Scientific advances have revealed a hitherto unknown complexity amongst the Band-rumped/Madeiran Storm-petrel group. It turns out they comprise not one but potentially three separate species, each of which breeds at a different time of year. Birds on the Brink advisor Dr Mark Bolton has played a part in these revelations but that’s a subject for another blog…

Birds on the Brink (BOTB) receives funding and support from the international competition Bird Photographer of the Year (BPOTY) and it was thrilling to spot that among the 2020 entries were several photos of Macaronesian tubenoses. It was particularly heart-warming to see Erik Wahlgren’s amazing image of Zino’s Petrel, which was commended and appears in the most recent BPOTY book – Collection 5. Buy the book and you will begin to appreciate the ethos of both BPOTY and BOTB – ‘Inspiring people to care about the Environment through World Class imagery’. Zino’s Petrel Photo ©Erik Wahlgren/BPOTY.

Order your copy of BPOTY Collection 5 here