6 September 2010

With a shape like a Scottie dog, Christmas Island lies in the Indian Ocean some 2,600km northwest of Perth, Western Australia. An Australian Territory, its nearest neighbour is Java, Indonesia about 360km away.

Christmas Island has 63% (over 85 sq. km.) of its area declared as national park and holds many species of endemic flora & fauna!

Christmas Island Frigatebird. Photo Geoff Jones, Barra Imaging.

From a birding perspective the island is home to a number of endemic species and sub-species including probably one of the most beautiful birds in the world known here as Golden Bosunbird. This race of White-tailed Tropicbird is found only on the island and fortunately is visible everywhere. Red-tailed Tropicbird or Silver Bosun to give its local name is also here and can be seen from the gardens of a favourite café on the north shore.

Particularly important from a seabird perspective, as indeed are most islands around the world, Christmas Island is the only home of the unique and endangered Abbott’s Booby, which nests in the tall emergent trees of the western and southern plateau rainforest. This forest is the only remaining nesting habitat of the surreal Abbott’s Booby in the world.

Christmas Island is also home to an endemic frigatebird – Christmas Island Frigatebird now nests in only three small and discrete areas on the island and is deserving of its endangered status! Great Frigatebird is here too, in good numbers while Lesser Frigatebird may be seen occasionally and has recently been found breeding here.

Red-footed Booby and Brown Booby complete the avian booby triumvirate to match the frigatebird trio, while land birds include Linchi Swiftlet, Christmas Island Imperial Pigeon, Emerald Dove, Christmas Island Hawk-Owl, Variable (or Christmas Island) Goshawk, Christmas Island White-eye and Island Thrush. All are island endemics or sub-specific endemics.

White-breasted Waterhen is a recent colonist from Southeast Asia and the island is a veritable twitchers’ paradise with a growing number of avian vagrant visitors each year.

Notable amongst other endemic life is the Red Crab with over 100 million of these vivid red creatures living on the island’s forest floor amongst the leaf litter. It is the most abundant of the land crabs, though massive numbers are only visible in November / December when the spectacular migration to lay eggs and breed takes place. Christmas Island displays tremendous diversity in the crab department with over 21 species including huge Robber Crabs, elegant Blue Crabs and many others easily seen scurrying about on forest and shoreline walks.

Surrounded by coral reef, this remnant volcanic island’s 80-kilometre coastline boasts magnificent cliffs and sheltered bays. Evidence of volcanic origins can be seen at The Dales and Dolly Beach where the basalt rock is exposed, forming the beds of freshwater streams. With virtually no coastal shelf the sea plummets to a depth of about 500 metres within 200 metres of the shore.

Atop the cliffs lies the island plateau; reaching a height of 361 metres, it is dominated by stands of rainforest that sit on mainly limestone and layers of volcanic rock. This is where the Red Crabs spend the majority of their lives, migrating to the ocean shores to breed and release eggs into the sea in one of the greatest wildlife spectacles known. Breeding is usually synchronized island wide and is seemingly linked to the phases of the moon. The eggs are released into the sea at the turn of the high tide during the last quarter of the moon after the onset of the wet season. It’s fortunate there are so many of them as introduced Yellow Crazy Ants are wreaking havoc amongst the population. Studies show the ant has displaced an estimated 15-20 million crabs by occupying their burrows, killing and eating resident crabs, using their burrows as nest sites and just being generally downright nasty! Work continues on the Yellow Crazy Ant issue.

Christmas Island has a tropical equatorial climate with wet and dry seasons. The wet season is from December to April when the island comes under the influence of the northwest monsoons. During the rest of the year, the southeast trade winds bring slightly lower temperatures and humidity with much less rain. Tropical cyclones occasionally pass close to the island during the monsoon season, bringing strong winds, rain and rough seas and the prospect of some excellent avian visitors. The mean annual rainfall is 1,930 millimetres with most of this falling between November and May while February and March are usually the wettest months.