Surprisingly, the genesis of the jumbo-sized message painted on the flat roof of his family's Bindel Place home has absolutely no connection with any unhealthy obsession of alien lifeforms.

The quirky missive actually stems from the location of Clayton's family home, which is often under the flight path of hot air balloons. According to Clayton, back in 2015, his son, Ethan, aged nine at the time, "would often run out at dawn in his onesie and holler 'greetings from Earth' at the top of his voice to passing balloons".

Later that year his older brother, Samuel, hatched a plot to write the message on the roof, explains Clayton.

"You can't see our roof from anywhere above, like a hill or the neighbour's house, so we thought we'd spray paint it on the roof in big black letters and see how long it took for someone to find it," says Clayton. "Even the boys kept it to themselves."

Despite a steady stream of balloons flying over Aranda in the interim, Clayton wasn't contacted about the out-of-this-world message until this column was tipped-off earlier this week by fair tax advocate Peter Bradbury of Holt.

Peter was using the ACT government's map-based information system for research and noticed the giant lettering.

"If there are other messages to aliens elsewhere in Canberra, I've never seen them," attests Peter.

After almost five years exposed to the elements, "the words are still in pretty good condition" explains Clayton who checks on them every time he cleans out the gutters.

However, rather than touching it up, Clayton thinks his next move might be to remove the writing. "If we decide to sell the house, it might not be everyone's cup of tea," he muses. "I might have to get the boys up there to scrub them off."

In fact, Clayton suspects a few bemused real estate agents may already be aware of his rooftop antics. "In aerial photos of the street published to promote nearby homes, the writing on our roof always seems to have mysteriously disappeared, sometimes the agents have somewhat conveniently placed their logo over our roof."

Rooftop messages, usually station names, are much more commonplace on outback homesteads, so I wonder if this is the only secret message on a Canberra roof.

Did You Know? In the 1970s, a large model spaceship stood proudly in a front yard of a house on Belconnen Way in Weetangera. Apparently the National Capital Development Commission demanded the suburban spaceship be removed as it resulted in a number of crashes from rubbernecking motorists. Does anyone remember the spaceship, or even better have a photo of it?

Further insight has emerged regarding those logs laying end to end beneath some Gungahlin Drive pedestrian underpasses (Curious Crossings, May 16).

Constructed as a feature to encourage native wildlife to cross, a former worker involved with the project advises that after the wildlife crossings were first installed in 2008, "they were initially a cause for amusement to all and sundry".

"The logs were sourced from material cleared during stripping and grubbing and had to be replaced several times due to the weekend wood fire gatherers who would come in and remove them," reports my anonymous correspondent. "They must have thought we were just keeping them dry for them," he muses, adding "it was not until the site was fully fenced off to vehicles that the problem stopped".

Meanwhile, despite a lack of published data regarding the efficacy of the crossings, a number of readers including Mike of Hackett believe "rather than helping animals, they are a trap where dogs and feral cats lie in waiting for native animals to cross".

Oh dear, I hope that isn't the case.

Nominations for Canberra's Top 100 'objects' (The 100 Objects that Define Canberra, March 14) keep rolling in. While many Canberrans who have been the victim of a spring-time swoop might think otherwise, David Jenkins has "long thought one of the most charming and almost defining features of Canberra is the (many) magpies that inhabit Garema Place and City Walk".

"Of course, magpies are quintessentially Australian but I also don't know of an urban space anywhere else where they're such a dominant presence, with the added bonus that they seem to keep the feral pests (such as mynas and pigeons) largely at bay, at least in daylight hours," explains David, adding "and then there's the warbling".

While many lap swimmers around the region are champing at the bit to get back into heated pools, Barbara Keng of Sutton reminisces about winter at the Goulburn Pool in the 1960s (The Day I swam across Lake George, April 4).

As a nine-year-old member of the Goulburn Swimming Club, Barbara remembers "in 1961 the pool didn't have a filtration system so the water was drained and the pool refilled every week".

"This meant on Monday mornings when we turned up for training at 6.30, the pool was often only half-full so we swam in it as it filled," recalls Barbara, adding "it was kinda fun".

Less enjoyable for Barbara, but equally as memorable, was the chilly water temperature. "As there was no heating in those days, the water in the pool was always cold but on Monday mornings it was super cold", she recalls, adding "and the showers were even colder".

And to think many of us now complain if the water temperature in pools isn't above 25 degrees.

Reports of Canberrans enamoured by the antics of Yellow-tailed Black Cockatoos (Cocky Capers, May 23) continue to fill my inbox.

"We had two of them in our backyard this week," reports Maureen and Andy Marshall of Nicholls. "There were a pair of them, we think they were both female as they had light-coloured beaks, having a good feed on our Hakea."

"They must have been there for at least two hours having a good chew on the nuts that are so plentiful in the Hakea," explains the duo, who add "we have never seen them land before, normally they just fly over". It was so lovely to see.

"As well as excavating larvae from tree trunks they are very keen on pine cones," reports Mike Sim, who explains "Isaacs Pines is a good place to see them sometimes in small groups but also in flocks of fifty.

"They eat all the seeds and just leave a core," he reports. "You can hear the pitter patter of pieces falling from the trees and sometimes they picnic on tree stumps and leave the shreds behind."

Meanwhile, a number of times in recent weeks Lorraine W. Ovington of Fisher "has been distracted by these wonderful birds flying gracefully over the tennis courts at Weston Creek".

"They seem to be flying north-east - possibly from Mt Stromlo or perhaps the Molonglo Valley," reports Lorraine, who has also witnessed their penchant for pine cones. "Their distinctive cry "Wee-ah" reminds me of my childhood in southern Tasmania when these distinctive cockatoos arrived every autumn to feast on a row of pine trees in our neighbour's property."

Lorraine has also put paid to the myth that the arrival of black cockatoos means bad weather. "Ornithologists recently discovered it is merely 'coincidence' that black cockatoos are seen before bad weather," she says.

Clue: almost 92

Degree of difficulty: Medium - Hard

Last week: Congratulations to Margot McGinness of Weston who was first to correctly identify the location of last week's photo as the 'message rock' on the side of the Kings Highway about 10km the Canberra-side of Braidwood. "I've driven this road for the last 40 years and always looked to see who and what is being celebrated on the rock," reports Margot, who, like many, wonders "if there is a booking sheet in Braidwood which determines what gets put on the rock". General consensus amont readers is that 'hi' was written on the rock in the late 1970s and only in the late 1980s did it become a message board for birthday and other celebratory wishes.

How to enter: Email your guess along with your name and suburb to timtheyowieman@bigpond.com. The first email sent after 10am, Saturday June 13, 2020, wins bragging rights. Tickets to Dendy Cinemas will once again be given as a prize when the cinemas reopen.

Several months ago this column (Lost Natural Treasures, January 18) queried the post-fire condition of the giant tree ferns in Penance Grove in the Monga National Park, near the top of Clyde Mountain.

While the area remains off-limits to the public, one reader who recently had permission to visit the forest reports encouraging news. "I can vouch that the ferns are well on their way to recovering," reports my insider, who also spotted "six lyrebirds and a number of wallabies and eastern grey kangaroos scuttling through the bush". Good news indeed.

No word yet whether the wheelchair-accessible 250-metre boardwalk, that led nature lovers through the area featured in this photo, will be rebuilt.