However, as several readers were quick to point out, swinging bridges aren't the only hair-raising man-made structures which span some of our waterways. The Canberra region also boasts a number of purpose-built flying foxes which have been designed to transport a range of goods, from essential supplies to residents stranded by flood waters near Tharwa to construction equipment at Burrinjuck Dam. However, without doubt, my favourite three were engineered to ferry cargo of a much more precious kind – people!

Until the recent construction of a sturdy foot bridge, unless you were prepared to get soaked, this heritage-listed flying fox was the only way to cross Farm Creek near Guthega in the NSW Snowy Mountains.

Originally built by the Illawong Ski Tourers in 1961 to a design by John Turner and replaced in 1979, using a design by Tim Lamble which followed the original concept, many walkers and skiers have negotiated their way across the creek on this swinging apparatus while on their way to nearby Illawong Lodge, or up higher into the snowy back country.

Unfortunately (or fortunately?!) I never had an opportunity to attempt a crossing on this ingenious apparatus before it was decommissioned in 2011, but I'd love to see photos, especially winter ones, of courageous cross country skiers edging across it, being careful not to tumble into the icy waters below. Brrr!

Near Oaks Estate are the remains of a flying fox which was used to suspend hydrologists over the middle of the Molonglo River when it was in flood, to measure the flow rates.

Karen Williams, president of the Molonglo Catchment Group, reports: "There is often a white faced heron perched on the flying fox cable. I think it must like the view."

Flow rates are now measured by more high-tech means, however, the ACT Heritage Library holds an historic 1989 photo, which clearly shows workers from ACTEW checking flood flow rates.

"I seldom use it now as it's hard to use," reveals Heyer. "The pull rope needs replacement and the cable needs more tension and in a big flood the seat touches the water."

Heyer also questions whether it is a true flying fox. "Technically a flying fox implies a sloping cable, but this cable is horizontal," explains Heyer who instead likes to refer to it as "a rope pull".

Whatever you want to call this daredevil device, it looks like an exhilarating way to travel.

"We absolutely loved them," exclaims Cross, who walked to the gnarly old inland scribbly gums trees last Sunday with two friends, and "enjoyed a nice cuppa at the Crace shops afterwards".

Sounds like a perfect morning.

Bill Coote of Campbell may have solved the mystery of the naming of Brown Mountain (It's all in a name, April 29).

Coote reports that in 1879 the editor of The Bega Standard and General Advertiser visited the Brown Mountain region (the area around the present Bemboka) and on Saturday September 6, 1879, on page 2 of the paper he wrote the following summary of his trip.

"Brown Mountain district is so named from a brown looking hill, called in courtesy a mountain, which although overshadowed by the looming heights of the Great Dividing range and its offshoot known as Bemboka Peak, still maintains a distinctive feature of brown against 'the calm proud purple of the purple hills' that hedge it to the north, east and west. There has been a popular delusion that the appellation is derived from the strong muster of Browns that cluster under the shadow of these heights."

Coote explains that "the editor is referring to what modern maps call Little Brown Mountain, a prominence a few kilometres north of Bemboka" which on his Google Satellite view "certainly looks brown against the green of the surrounding hills."

I'll be sure to pay more attention to the different shades of green (or brown) on the mountains which ring the Bega Valley on my next trip to the coast.

"They measure from 10 to 15 centimetres long and I guess that a large moth has emerged and flown off to a brief life above ground," hypothesises Gralton, who wants to know "more on the mystery creature's life cycle".

Ted Edwards, this column's moth man, reports that "Gralton's photo shows the pupal shell of one of the ghost moths or Hepialidae," but that he would "need to see the moth itself to determine the exact species".

Edwards explains why Gralton often sees them at this time of year. "The moths emerge from their tunnel and the pupal shell usually on a wet night in autumn and there is sometimes a mass emergence when conditions are just right," reveals Edwards. "The female moths scatter thousands of little round eggs over the ground.

"Depending on which type of ghost moth it is, the food of the caterpillar will be either dead leaf litter under a wattle tree or the roots of a eucalypt.

"The larva of the eucalypt ones probably stays underground for one or two years feeding externally on the roots and then prepares a tunnel to the surface leaving a little bit at the surface undisturbed.

"The pupa has rows of blunt spines on its back and by wriggling can move up the tunnel and break through to the surface and the moth emerges,

the ones that feed on leaf litter already have a feeding tunnel to the surface.

"These wonderful moths emerge with rains in autumn presumably because this moistens the litter and the ground for the tiny larvae. Because it is often cold at night then the moths by shivering can warm their flight muscles and once flying create enough heat to stay warm."

Amazing.

With the river, steep mountains and poplar trees the only clues to go by, the Cox's think "the scene may be near Canberra".

Your Akubra-clad columnist does see a resemblance to the area around Wee Jasper, but a number of long-time locals in the pretty valley carved by the Goodradigbee River, including Ian Cathles are not so convinced. "No, it's definitely not in Wee Jasper, but it does look reminiscent of some of the mountains and scenery heading south from Tumut," suggests Cathles.

According to the Cox's, "Robert Parsons was a pseudonym used by Leon William Hanson (1918-2011) on some of his early landscape paintings, mainly for tax reasons and during hard times trying to sell more works under different name to survive."

Can anyone identify the location, or even rule out the Canberra region?

In Gungahlin's Goorooyarroo Nature Reserve, avid geocacher Daniel Newton recently stumbled upon this shapely burl at the base of a tree which he reckons is a dead ringer for an "alien face". Lucky he wasn't out walking at night or it would have given him a real fright.

Clue: Tony was recently here.

Degree of difficulty: Medium-Hard

Last week: Congratulations to Sep Westerhuis, of Harrison, who was first to correctly identify last week's photo as a sculpture at the Watson (hence the clue, "It's elementary") shops. Westerhuis, who "regularly enjoys coffee at the shops", just beat observant Watson locals Jack Palmer and Ali Dunn to the coveted prize.

How to enter: Email your guess along with your name and address to timtheyowieman@bigpond.com. The first email sent after 10am, Saturday May 20, 2017 with the correct answer wins a double pass to Dendy cinemas.

CONTACT TIM: Email: timtheyowieman@bigpond.com or Twitter: @TimYowie or write c/- The Canberra Times, 9 Pirie Street, Fyshwick. You can see a selection of past columns online.