WETlands
a publication of Sungei Buloh Nature Park
Vol 5 No 3
Nov 98

Colourful Migratory Birds:
Blue-tailed Bee-eater, Common Kingfisher,
Black-capped Kingfisher

BirdWatch '98: how to tell
waders apart

A Year in
the Life of Waders:
migration and breeding

Birds of
Pulau Ubin:
The Red Junglefowl
(Gallus gallus)

Butterfly Appreciation

Friends of
the Park: a tribute to the volunteers

Essence of the Natural Experience:
the year in 1998

Why Wader Census?
Counting shorebirds
at Sungei Buloh		 A Year in the Life of Waders

How far can the migratory birds travel?
When do they know it is time to migrate?

Find out more as Lim Haw Chuan reveals some intimate details of our "fair weather" feathered friends.


Many shorebirds (Order Charadriiformes) are marathoners of the animal kingdom. The many brown birds you see on the mudflats in Sungei Buloh Nature Park during September to March breed in places like Siberia, Northern China and Alaska. Some species are known to be able to travel at least 4,000-5,000 km on a single non-stop flight. Some species breeding at high arctic may travel up to 24,000km per year from the breeding ground to non-breeding ground and back. We will be taking a glimpse at some aspects of the biology of these birds, the magnificent travellers.

>Breeding Ground
A typical wader would probably arrive at its breeding ground in the arctic tundra or taiga in May, as soon as the snow covering is melting away. The next 1 or 2 weeks will be spent on establishing a territory, courtship and mating. Eggs, usually a clutch of 4, are soon laid and the next 3 weeks are spent on incubating the eggs.

As different species practise different mating system, either both parents or just one of them will incubate the eggs. The hatched nestlings are quite independent soon after hatching. The parents or parent will then spend the next 3 weeks caring for the young. As soon as the duties of the parents are discharged, they will fly south again, followed by the juveniles separately. If all these sound hectic to you, it is. Northern summer is short and particularly precious; food supplies decline very fast.

The Journey
To travel thousands of kilometres with largely inhospitable habitats or barriers in between is not an easy feat. There are several things to be taken care of. The first thing will be timing the move. Like many other animals, migrant birds possess an internal clock that corresponds to the annual cycle. This clock and the general shortening of the day length will prompt the birds to get ready by accumulating fat as a source of energy and enlarging their flight muscles.

When flying, waders like other birds, may have a repertoire of navigational skills. The obvious one is the use of the sun as a directional guide. But since the sun is always moving across the sky, its use must be co-ordinated by an internal clock that tracks the time of the day. At night, the moon or the night sky may be used. When using stars, the birds will judge direction using the axis of rotation of the sky (at the polar star in northern hemisphere). Other cues for navigation used by birds are the earth's magnetic field, the landscape below and sound waves. The fact that some waders from the continents arrive at tiny islands in the middle of the Pacific Ocean yearly is testament of their ability.

En route to non-breeding ground, some waders will utilise a tapestry of coastal or inland wetlands or other suitable habitats as stopovers, particularly when the weather condition is not favourable. Others will cover the journey in a few very long flights.

Non-breeding Ground
After arriving at the non-breeding ground in the south, the waders will replace their flight and contour feathers that have been well used in the last few months. This time of the year can become comparatively relaxing for them since all they have to do is basic survival, feeding and roosting. It is when February is approaching that they have to start preparing for northward migration and repeat the magnificent feat.
 
© Sungei Buloh Nature Park