"You might want to check-out the weird contraption we stumbled on in the bush at Tidbinbilla Nature Reserve", urges Jack Smith of Kambah, adding "we heard it before we saw it, and initially thought the beeping sound was a bird".

Timothy DeWan of Kingston even submitted photos of the bizarre beeping installation. "A ranger we spoke to said it was actually part of a scientific experiment," he reports.

Keen to find out more, during the week we headed out to Tidbinbilla to investigate. On arrival in the main car park, it wasn't long before I heard the incessant beeping - a loud high pitch call every three seconds.

"It's amazing just how many people have asked us which bird is it that goes 'beep', 'beep', 'beep'," exclaims Heather Gow-Carey, manager of the Tidbinbilla Visitor Centre as she points me up the hill in the direction of the beeping.

Comprising a cylindrical tank-like structure tied to two large cubicles with only three sides, the beeping device looks more like a half-finished obstacle course than a high-tech scientific project.

Looks can be deceiving and on closer inspection, each component of the curious contraption is connected via a power line to a nearby shipping container, where, inside I find Dr John Taylor hunched over an old-school IBM computer which is churning out reams of data.

An Honorary Lecturer at the School of Science with the University of NSW Canberra, John reveals that his curious contraption is in fact an acoustic wind profiler designed to monitor the weather, especially the wind for the ACT Parks and Conservation Service's prescribed (hazard reduction) burning program.

"Nicknamed SODAR (Sonic Detection And Ranging), it's like a radar but uses sound rather than electromagnetic waves to measure wind speed and direction at different heights up to 900 metres above the ground", he explains.

"A special loud speaker projects sound onto a parabolic dish reflector inside an acoustic shield," he further explains, adding, "this 'tone burst' then travels up and into the atmosphere."

A tiny fraction of the sound is then scattered back to the dish and picked up by the speaker which also acts as a highly sensitive microphone. "The strength of this echo received gives information about the vertical structure of the turbulence and temperature of the atmosphere above the instrument," explains John.

"See, look here, although it's relatively calm on the ground, some 500 metres higher there are gusts of up to 50km/h," he explains, pointing to a constantly updating graph on the monitor in front of us.

This is invaluable real-time information which allows the fire authorities to make short term forecasts of when less favourable conditions might impact on a hazard reduction burn.

"Prescribed burns are usually started during benign weather conditions", explains John, adding "however strong winds up high and dry air mixing down to the ground level can rapidly change fire behaviour."

According to John, "acoustic wind profiling technology has many other uses beyond fire management, including pollution monitoring and in understanding the flight behaviour of insects such as Bogong moths". Really!

Clambering back out of the container, the sight of a couple of Tidbinbilla's resident emus wandering nonchalantly past the installation makes me wonder how the nature reserve's other critters have reacted to the constant beeping, especially the lyrebird, known for mimicking all sorts of man-made noises, from chainsaws to mobile phone rings.

"When a similar system was deployed in the Waitakere Ranges, a regional park west of Auckland in New Zealand, a bird [thought to be a Tui] started mimicking the beep," reveals John who is yet to hear any lyrebirds mimicking his SODAR's sound.

However, the ACT Parks' service has just agreed to leave the Tidbinbilla SODAR in situ for another year, so I suspect it may not be long before visitors to the reserve start hearing lyrebirds "doing the SODAR beep".

Lyrebirds are great mimics. Wildlife lover Annette Scholtz recently recorded this lyrebird in Sydney's Ku-ring-gai Chase national park mimicking a number of other birds, including a kookaburra. Can you identify the others? Video: Annette Scholtz

SODAR: The Tidbinbilla acoustic wind profiler is located a couple of hundred metres behind the Tidbinbilla Visitor Centre where it can be observed from afar, photographed and, of course, heard, but please don't touch.

Did You Know? Acoustic wind profilers were first developed at University of NSW Canberra in the late 1980s by Associate Professor Ian Bourne and have since become widely used internationally.

Giant fingers

While this column parochially highlights faces and forms in nature usually from our local region only, I couldn't resist sharing these giant fingers spotted by SODAR operator Dr John Taylor, in Western Australia. "I first noticed the fingers while looking across an inlet toward the Southern Ocean in Waychinicup National Park, east of Albany" reveals John, adding "it really caught my eye."

Although not a known landmark, aware of this column's somewhat unhealthy passion for simulacrum, John devotedly pulled out his camera and zoomed in on the hand.

At first glance I couldn't quite make out the fingers in John's photo, but when you finally "see" them (look for four prominent fingers, complete with thumb to the side, clinging to the boulder in centre of the photo), it's quite impressive.

"If that's the size of his hand, imagine how big the rest of the giant must be", jokes John, who confesses that when he first visited the location in 1988 he never noticed it.

"Maybe the creature hadn't emerged from the water at that stage," he laughs.

A sword sticking out of a rock is one of the last spectacles you'd expect to see while driving along the lonely Cullerin Road near Gunning.

"What next, a castle of Camelot proportions," muses Gary Poile of Collector, one of several readers bewildered by the sudden arrival of the sword which bears an uncanny resemblance to Excalibur, the legendary sword of King Arthur.

Searching for an explanation of the sword's sudden appearance, during the week, your Akubra-clad columnist tracked down Peter Foley, owner of the property.

"There's no magic, I simply made the sword," reveals Peter, who has farmed the surrounding land his entire life, and who explains "all the other paddocks have names and I didn't know what to call this one until I noticed the blue granite boulder in the middle of the paddock had a small crack in it".

"I knew immediately the paddock had to be named Excalibur," reveals Peter who promptly crafted the sword from scrap metal and jammed it (with the help of some quick setting concrete) into the crevice.

"From a distance you can't see the concrete and the sword looks like it's sticking out of the rock, just like in the Arthurian legend," asserts Peter.

Are there any other Arthurian motifs on our region? I'd love to know.

One reader familiar with the exterior, but not the confined interior of the relic World War 2 bomb shelter at Calthorpes' House (A look into a suburban treasure, June 15) is Jessica Kirsopp.

In the early 2000s when Jessica worked as a volunteer at the much-loved museum, she reports "she was never game enough to venture into the shelter".

No, she isn't claustrophobic, rather, she somewhat alarmingly reveals, "a giant brown snake used to live in it."

Heck, I'm glad I didn't know that before I crawled into it for last week's column.

Meanwhile, a number of readers, including Richard Somers wonder if there are any other relic air raid shelters in Canberra's suburbs.

If you know of any, with or preferably without a resident snake, please let me know.

Clue: The bike gives it away. Be as precise as possible.

Degree of difficulty: Medium

Last week: Last week's photo stumped many readers, with over a dozen different playgrounds across the ACT nominated as the location of the resting kangaroo. However, the first reader to correctly identify the location as the Caldwell St playground in Hackett was Sophie Lewis. It turned out to be an easy win for Sophie who lives "just around the corner" from the playground and who "often goes there for swings" (presumably with someone younger in tow!).

The photo features on the back cover of Hackett - 50 years plus: Story of a North Canberra suburb, published by the Hackett Community Association. The book which details many interesting stories about the inner north suburb, proved so popular when it was released late last year that it quickly sold out, however a reprint ($20) is now available at IGA Hackett. "An e-version is also available for $15 at hackettcommunity.com.au", reports Christopher Mobbs, chairman of the association.

The book is a must-have for anyone with an association with Hackett, which incidentally isn't named after the Olympic swimmer of same name (as per last week's clue), rather after Sir John Winthrop Hackett (1848-1916), who was a newspaper editor, politician and university chancellor.

How to enter: Email your guess along with your name and address to timtheyowieman@bigpond.com. The first email sent after 10am, Saturday 22 June, 2019 will win a double pass to Dendy - The Home of Quality Cinema.

Graeme Shields of Fraser couldn't resist snapping a photo of this Transport Canberra bus as it turned from Ginninderra Drive into William Slim Drive in McKellar. "Is this finally proof that our local government is evil," he muses.

While Graeme ponders "if the bus route is Woden Cemetery to Norwood Park", I'm more interested whether or not ABC Canberra radio (frequency 666AM) plays through its speakers.