Booby come back!


Up to the early 20th century Bird Island, Seychelles, was almost entirely, as its name implies, an island full of birds. Most of them were Sooty Terns nesting on the ground but early accounts also mention “gannets”. The kind of Gannet we are familiar with in Britain does not occur in the tropical Indian Ocean but some of its relatives do – the boobies.

Masked Booby family, Desnoeufs 1972
Masked Booby family, Desnoeufs 1972

Descriptions of these “gannets” were very basic but there appeared to be two species nesting on the ground. A “large brown bird” incubating an egg in a nest made of “a few twigs and pieces of withered grass” was certainly a Brown Booby discovered by Richard Coppinger on his visit in 1882. He said that there were many Gannets and, although he did not describe them, most are likely to have been Masked Boobies, which are larger, nest on the ground and more closely resemble the European Gannet. When John Fryer, a member of the Percy Sladen Expedition to Seychelles in the early 1900s, landed on Bird Island in 1908, Masked Boobies nested in small colonies around the periphery of the Sooty Tern colony.

Brown Booby, Desnoeufs 2972
Brown Booby, Desnoeufs 2972

By 1940 the boobies had all gone, probably eaten by the island workers employed to manage the coconut plantation, harvest the nuts and also to dig guano for export.  In addition, the island had been transformed into a coconut plantation, leaving little room for ground-nesting birds.

These two species of ground-nesting boobies have suffered from human predation and habitat loss on many of their former homes in Seychelles.  In 1972, on my first visit to Desnoeufs Island in the south of the Amirantes, 200 pairs of Masked and 4 pairs of Brown Boobies were nesting. My most recent visit in 1996 revealed only one Masked Booby nest and the Brown Boobies had all gone. They formerly nested on several islands in the Amirantes and Seychelles and in the latter one tiny island is even named after them – “Booby Islet”. Most of these colonies have been lost but Boudeuse, northwest of Desnoeufs, still has a surviving colony. When I visited in 1976 around 3000 pairs of Masked Boobies were nesting – but there was also a large pile of booby heads and wings, indicating that fishermen sometimes visited and took their toll.

On the southernmost atolls of Seychelles Masked Boobies are faring better with thriving colonies on some of Cosmoledo Atoll’s islets, but Brown Boobies less so, and since 1976 the latter have disappeared from Farquhar Atoll.

Even more serious losses of booby colonies pre-dated my own observations. Guano removal from St Pierre, to the north-west of Farquahar Atoll, and Assumption Island in the Aldabra group led to the demise of formerly major colonies. Red-footed Boobies, the arboreal member of the family in Seychelles, and Masked Boobies both nested on Assumption prior to and during the early stages of guano extraction. Guano harvesting involved vegetation removal and enormous ground disturbance in order to remove the phosphate-rich soils. The former would have removed the nesting habitat of the Red-footed Boobies while soil removal would have destroyed the nesting sites of the Masked Boobies; in addition, adults and young of both species are likely to have been regarded a free food service for the labourers! On St Pierre the whole island was formerly covered in woodland and an early description mentioned every tree housing booby nests. All of the woodland was removed to allow access to the guano, leaving the island devoid of vegetation and also devoid of soils to allow any vegetation recovery. What must have been a huge colony of Red-footed Boobies was rapidly eliminated and when I visited in 1976, just a few years after the last shipment of guano had been taken off, the island resembled a moonscape, cluttered with the rusting remains of a miniature railway system and its trolleys, used to transport guano to an equally rusting gantry for loading ships, dilapidated buildings and a large cemetery.

Young Red-footed Boobieis roosting cheek by jowl on Bird island, August 2015
Young Red-footed Boobies roosting cheek by jowl on Bird island, August 2015

Large numbers of Red-footed Boobies still nest on Aldabra and Cosmoledo Atolls, in bushes or mangroves. On Farquhar atoll, on the other hand, it nests in tall Casuarina trees. When I visited in October 1976, 24 pairs were nesting on South Island but over the last few decades the number of nesting birds there has increased dramatically. Aurélie Duhec, currently working with Island Conservation Society on Farquhar, reports that over 4000 active nests were counted in June 2015, most on South Island but they have additionally spread north, colonising the small Manahas Islets and now also nesting on North Island. Red-footed Boobies have spread even further north, having colonised Marie Louise in the Amirantes at some stage during the last 30 years, again nesting in tall Casuarina trees. Red-footed Boobies are clearly faring better in Seychelles than the other species and increasing numbers, especially of young birds, are being seen on Bird Island. Here they roost in Casuarina trees among large numbers of roosting frigatebirds, but in August 2015 a group of 30 Red-footed Boobies established a roost on a group of Casuarinas at the northern end of the island, not used by roosting frigatebirds. The island’s conservation officer, Roby Bresson, has recorded Red-footed Boobies sometimes in the hundreds in the last few years. Perhaps it is wishful thinking, but it would be wonderful to see these birds establish a nesting colony on Bird Island. Encouragement of some birds to settle might be achieved by constructing artificial nests in the Casuarinas, with plastic models of adult birds as an attraction, possibly augmented by broadcasts of territorial and copulatory calls, especially at night, from loudspeakers placed in the trees. Adventurous tree surgeon needed!

 

 

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