She is a field biologist and we were privileged on Tuesday to spend some time with her on Mt Ainslie's slopes.

The slopes turn out to be a paradise for the social huntsman Delena cancerides, which means they're a paradise, too, for Rayor.

Just before we set out on Tuesday's expedition, through dry and crackling bush, she rejoices that, for a spider-investigator: ''Yesterday [also on Mt Ainslie] was a day for the record book, on many levels. Huge colonies!''

Our expedition with ANU assistants - PhD candidate Michaela Purcell and honours student Mark Wong - is an absolute ripper. An arachnoripper.

Delena cancerides, one of five huntsman species found in the ACT, is one of those also found, to the horror of arachnophobes, around our homes. The biggest individual we come across (of which more in a moment) is precisely the spider of an arachnophobe's nightmares.

Mt Ainslie is teeming with them at the moment but the lay bushwalker will never see them because they spend almost all of the time beneath the (often burnt and blackened) bark of slender Acacia saplings.

The three searchers will gingerly peel away the bark and there will be the spiders. The three will move quickly and deftly to capture them in little jars. The specimens are destined, Rayor explains, for her laboratory at Cornell ''where they'll live lives of the utmost luxury'' while she studies them.

What is it about Delena cancerides that is making them the object of her cerebral affections?

It's that they are ''social'' spiders. Overwhelmingly, the spiders of the world lead solitary lives and do little or no co-operating with other members of their species. They even eat their own species.

''I study social behaviour in spiders … and this species turned out to be magical. They are so unusual compared with other huntsman spiders, compared with other social spiders.

''There are about 80 species of social spiders worldwide, out of 44,450 species. There are 1148 species of huntsman spiders and of those just three turn out to be social spiders.''

One thing this means when you're peeling away bark on Mt Ainslie and look expertly at what you see is that you find social spiders of assorted ages.

''What I've just found,'' Rayor explains after some bark peeling and as she and the others nimbly collect the exposed spiders, ''is mom and these different clutches of youngsters with her.

''This is a social huntsman species and so they live together in colonies with multiple clutches of youngsters.

''And spiders are predators so, when living together, they're tolerant enough not to eat each other, and that's great. If you're sharing prey instead of eating each other, that's a big deal.

''The thing about Delena colonies is that you get groups of animals all the way from just out of the egg sac, right up to animals that are about the size of mom. So this is exciting!''

She hands over a vial containing about six exquisite, destined-for-Cornell youngsters, vivaciously sprinting about, in their confined space, on brilliant little whisker-thin legs.

Then we came to another highly promising blackened sapling and the bark-peeling begins. ''Yes, I think this one's going to have big animals in it,'' Rayor prophesises.

Sure enough, big animals stampede forth. ''Ouch! Shoot!'' she cries, for one of the big animals has bitten her on the thumb as she captures it.

A little later we are examining that great spider, in a vial now, agreeing how magnificent it is. Purcell muses it has an abdomen ''like a kiwi fruit''.

''She's a mom defending her colony,'' Rayor reflects, ''so she's bitten me here, and there [displaying a thumb on which there was little to see]. But they almost never bite.

''So what's so exciting about this animal is that I can tell from her colouring and her size that she's a relatively young adult female and her abdomen is full of eggs. Not to mention [here Rayor's voice rings with admiration] she's so big! So she has a long life [perhaps 2½ years] ahead of her.''

Rayor has handled thousands of huntsman spiders during her career and this is only the ninth bite she's had.

''[Huntsman spiders] are meek and mild. People say their bite is like a bee sting, but it's nothing like that bad. Look [at the ordinary-looking thumb], nothing's happening.''

Already enthusiastic about Mt Ainslie's flora and conspicuous fauna, we are left with an added respect for a richness of things there that we almost never see.

And not just spiders. On gently peeling away one long flake of bark we discover, sleeping, an exquisite little bat, immaculately folded into a tiny space.

We all coo and exclaim at its loveliness then Rayor respectfully rearranges the bark against the tree so the bat can get on with its slumber.

''This is my idea of an exciting place!'' she enthuses.