Vol 5 No 3
Colourful Migratory Birds:
Blue-tailed Bee-eater, Common Kingfisher,
BirdWatch '98: how to tell
A Year in
the Life of Waders:
migration and breeding
The Red Junglefowl
the Park: a tribute to the volunteers
Essence of the Natural Experience:
the year in 1998
Why Wader Census?
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
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.
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
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.
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.