WHEN I was a boy, I lay awake on a warm summer's night and, from behind the safety of my dark curtains, listened to the birds' final flourishes of the day in the churchyard opposite.

I thought I could hear all kinds of exotic squawkings and squeakings. I thought if I peeped out I would see fantastic birds - flamingoes and hummingbirds - cavorting on the grass, a brilliant display of colours.

When I awoke next morning and pulled the curtains, they had all vanished. So disappointing.

Perhaps I was dreaming of the Foja Mountains in Indonesia.

Scientists announced this week they had ventured for the first time into these rainforests. They were dazzled by the red-faced, smokey honeyeater. They were delighted by the dance of the golden-fronted bowerbird. They were delirious about Berlepsch's Six-Wired Bird of Paradise.

Only Berlepsch's skins had been seen before, and those were in a 19th century collection belonging to a German ornithologist called Hans von Berlepsch. But there it was in the flesh, beautiful plumage, and with six wiry feathers standing proud on its head.

What must this dawn chorus of oddities have sounded like?

The expedition found a long-beaked echidna, a spiny anteater, an egg-laying monotreme and a golden-mantled tree kangaroo.

I have no idea what any of these look or sound like. But I can imagine.

I can imagine as if I'm still a boy. In odd moments I have found myself sniggering at the thought of a tree kangaroo. God must have been having a laugh when he took a big, bouncy 'roo and told it to live in a bendy, springy tree.

But there are two types of tree kanga in Australia and now nine types in New Guinea. They look like kangaroos but have very, very long tails.

It was Captain James Cook's crew that gave the kangaroo its name. They looked at the strange, hoppy things and asked an aborigine: "What's that?" The aborigine said: "Gangurru."

One story is that the aborigine, who had never heard white man's tongue before, didn't understand the question and so said "I don't understand" in his own language. "Gangurru."

The ancestors of kangaroos descended from trees about 50 million years ago and learned to hop. Then, for some unknown reason 25 million years ago, the tree kangaroos went back up into the trees and stayed there.

Apart from the Dingiso, who came back down again. He is the only tree kangaroo who doesn't live in a tree. The natives in New Guinea call him the "mbaiso" - "the forbidden". They are not allowed to hurt him because he is their distant ancestor.

The tree kangaroos' Latin name is "dendrolagus" which means "tree hare" - another ridiculous mental image. But tree kangas do bounce up and down tree trunks and out and along bendy branches very well. They can bounce nine metres between trees, and they can jump 18 metres down to the ground without hurting themselves.

However, they can't hop very successfully on the floor and prefer to walk. But not too fast, because they cannot sweat. They lick their arms and allow the evaporation to cool them down.

More strangely, some tree kangas, when confronted by danger, will put their hands above their heads and whistle. For hunters armed with guns, this makes the standing tree kanga a sitting duck.

Not even when I was a dreamy boy did I think there would be kangaroos that lived in trees and whistled. But, even more strangely, in 2002 a tree kangaroo was believed to be in hiding in a wood near Barnard Castle.

It is a world that it is truly wonderful in its weirdness.

Published: 11/02/2006