Conserving Seabirds in the Philippines’ Last Great Rookery

 

By Gregg Yan, WWF Philippines / Wildlife Extra

1‘Never look up with your mouth open,’ by Gregg Yan

The combined stench of rotting fish and guano was incredible.

Soaked and shivering, we shelter beneath a dripping grove of Argusia trees on Tubbataha’s South Islet and count birds. Chilly raindrops are the least of our concerns – more exciting things were falling from above. I wipe steaming gobs of fresh seabird guano from my hat, shoulders and writing slate then trail my partner through the dense brush.

“Nine Black Noddies in five tree nests,” observes my partner, TMO Ranger Segundo. ‘Seconds’ Conales. I strain to hear above the cacophony of over 20,000 seabirds, periodically silenced by thunderous blasts of lightning. The birds are everywhere – flitting in and out of foliage, perched atop rocks, forming a dense cloud above the island. Every few seconds, one would leave the safety of its perch to snatch a damp twig, leaf or piece of plastic from the ground.

We tread lightly, visions of Alfred Hitchcock’s The Birds flying to mind. I jot the latest numbers on my waterproof plastic slate and push on.

Conserving the birds of the Sulu Sea
It is a drizzling day in May and we are back in Tubbataha [EAAF123]. Led by Danish ornithologist Dr. Arne Erik Jensen, we are assessing the seabirds of Tubbataha North and South Islets as part of a nine-year old annual initiative by the Tubbataha Management Office (TMO) and World Wide Fund for Nature (WWF) to conserve the birds of the Sulu Sea. I had last been back in 2008 and still recall Dr. Jensen’s advice when counting his beloved birds.
“Never look up with your mouth open.”

Tale of Two Islets
At the heart of the Sulu Sea lie the twin atolls of Tubbataha, a spectacular world brimming with wealth both beneath and beyond the blue. Borne of geological action but restrained by the vicissitudes of the sea, the two isles form the Philippines’ last great seabird rookery.

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Bird Islet or North Islet provided the research team with more favourable weather. The larger of the two islands, it is home to over 20,000 breeding seabirds – most hunting by day and returning to the island at night to roost. It is also a nesting site for Green Sea Turtles. (Gregg Yan)

Islet has shrunk by 80%
In 1911, American naturalist Dean Worcester first set foot on Tubbataha North Islet, also called Bird Islet. It was then a barren sandy island of 60,000 sq m, where sea and sand danced ceaselessly. A hundred one years later the isle has shrunk to 12,435 sq m but hosts over 200 trees, the tallest shredded by a recent boom of Red-footed Boobies. At the centre lies the Plaza – a 3690 sq m open area occupied by ground-breeding birds. The scrubby landscape rises no higher than two metres above the sea.

Both islets are off limits
Parola or South Islet is much smaller, at 3140 sq m. A metre-high concrete wall, cracked and pitted by the elements, forms a protective ring against erosion, while a solar-powered lighthouse erected in 1980 by the Philippine Coast Guard stands sentinel over all. About 120 Argusia, Pisonia and coconut trees dot the grassy landscape. East of the lighthouse lies the rusting hulk of the Del San, an old log carrier. Protected as a core zone, WWF and Cebu Pacific help TMO in keeping both islands completely off-limits to outsiders.

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Parola or South Islet has heavier vegetation than its big brother. Up to 8,000 Black Noddies plus an assortment of other birds inhabit the island. (GreggYan)

“The isles vary in size each year, for the tide reclaims what geology has delivered. Tubbataha is thus constantly reborn,” says TMO Park Manager Angelique Songco. “Ecologists working in mountains or forests can wait a lifetime to see the kind of habitat change we observe monthly.” I agree, noting that since 2008, trees with back-row views now had front-row seats to the sea.

Holding Out
Prior to the Second World War, seabirds were common throughout Southeast Asia. After four years of ferocious fighting, 60 years of extensive human encroachment and marine pollution took their toll. Remnant populations have since retreated to a few isolated holdouts like Tubbataha, where the lack of freshwater bars the intrusion of predators like cats, rats and people.

Cat disaster
When cats were introduced on Ascension Island in the South Atlantic over a century ago, bird numbers dropped from 20 million to 400,000. Guam has already lost 60 % of its bird species due largely to the introduction of a slithering slayer, the Brown Tree Snake. Other threats include marine pollution, hunting, land development and climate change.

Different species have different personalities
“Six seabird species breed here, distinguished by where they nest,” whispers Seconds as we low-crawl to photograph a cackling colony of Great Crested Terns. “Ground nesters include the Brown Booby, Brown Noddy, Great Crested Tern and Sooty Tern while tree nesters include the Red-footed Booby and the endemic Black Noddy. Each has a distinct personality.”

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Black Noddy (Anous minutus sub. worcestri) keeping its single egg warm. It is smaller, darker and has a more slender beak than the Brown Noddy. Wind and rain lashes its island home with amazing regularity. (Gregg Yan)

Black Noddy
The trip’s top priority was to monitor populations of the Black Noddy, a pigeon-like seabird whose 8,000-strong Philippine subspecies survives solely in Tubbataha. Still, we count 3,224 nests and 5,324 screeching adults on Parola alone.”Though still numerous here, Black Noddies no longer have alternate sites to breed. They are suffering from a housing crisis,” gestures WWF Tubbataha Project Manager Marivel Dygico to a Pisonia tree bursting with both Red-footed Boobies and Black Noddies. In 2001, Tubbataha saw a massive influx of Red-footed Boobies, which nest in the same trees as the Noddies.

“The problem is that large flocks of Red-footed Boobies can defoliate whole islands. They tear off leaves for nesting and burn what greens remain with their guano. In seven to ten years, all of Parola’s trees might be gone – unless we control the birds now.” Leafless, some trees on the smaller South Islet are now also lifeless.

Wings of Change
Seabirds play a crucial role in fighting climate change, particularly the threat of rising sea levels, by helping develop island ecosystems. They provide vital fertilizer for nutrient-poor sandbars, allowing the first waves of pioneer plants to survive. Drifting in from nearby islets, seeds of trees eventually take root – further binding the sand, increasing land size and trapping organic sediments – the first steps in producing soil.

Fossilized bird droppings also form Phosphorite, a type of rock used for agricultural fertilizer. Phosphorite deposits have for centuries been mined on small islands and is now of great value for food production.

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Flushed Sooty Terns (Sterna fuscata) take to the sky. Thousands of the feisty birds hid amongst Tubbataha North Islet’s scrubby knolls. (Gregg Yan)

30,000 breeding birds
After three days of research under the scorch of sun, the chill of rain and the terror of guano, we record a grand tally of 30,100 breeding birds – the highest ever recorded. In comparison, 24,300 were counted last year and 28,000 in 2010. It is estimated that from March to November, an additional 14,000 seabirds roost on Bancauan, Bancoran, Cawili and Basterra Isles – the main hub still being Tubbataha.

Ablaze with sunset hues of scarlet and crimson, Bird Islet descends into night. As the isle prepares for a fresh cycle of rebirth, I whip out my camera and snap a picture of four boobies against the red sky. One soars off and leaves behind a lone egg, bearing a world of promise.

Staring at the speckled orb, I consider what Jensen told me that morning.

Fat cats and no birds
“Tubbataha is the last refuge for many Philippine seabirds. Islands like Bancauan and Cawili once had thousands of them. When people came, they brought with them dogs, rats and cats – all of which eat both ground-breeding birds and their eggs. Today Bancauan only has eight Brown Boobies – and 25 very fat cats.”

Before it was declared a National Marine Park in 1988, Tubbataha’s residents have long suffered from exploitation, with generations of fishermen gathering not just fish, but turtles and bird eggs as well. Without continued protection, another type of sunset awaits Black Noddies, Brown Boobies and many of Tubbataha’s winged treasures.

Glancing a last time at the dying rays of the sun, I wish the unborn bird luck – and pray that its kind, which has long endured sea-storms and summers – can too weather the winds of change.

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Four Red-footed Boobies are framed by a crimson sunset on Tubbataha’s North Islet. Afterwards, the island settled into silence. (Gregg Yan)

 

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Nesting Great Crested Terns (Sterna bergii) cackle with glee. The author low-crawled for half-an-hour to sneak up to the colony. After just three clicks they flew off. (Greff Yan)

 

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Juvenile Red-footed Booby (Sula sula) gazes at author’s lens. Termed ‘pullus chicks’ or ‘cotton buds,’ they are curious and fearless. (Gregg Yan)

 

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Pisonia tree bursts with both Red-footed Boobies and Black Noddies on South Islet. (Gregg Yan)

 

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Brown Noddies (Anous stolidus) groom each other. They are larger and less Common in Tubbataha than the Black Noddy. (Gregg Yan)

 

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Lord but of a dead trunk, a Brown Booby (Sula leucogaster) looks to the sea. It thrives on denuded islands, nesting on lonely sandbars and islets. The introduction  of predators like cats has decimated its numbers in other islands: only Tubbataha’s bird islet holds a sizable population. (Gregg Yan)

Copyright © 2012 www.wildlifeextra.com and Gregg Yan of WWF Philippines