Mahogany Glider Diaries

Mahogany Glider Diaries From the Re-introduction of Stoney and the Rehabilitation of Pan

A female Mahogany glider (Pan) spent six months in care in Far North Queensland recovering from a barbed wire injury. To increase her chances of survival after such a long period out of her territory, she was paired with a male from the captive breeding colony at David Fleay Wildlife Park prior to release. The male chosen was a feisty and fit three year old named Stoney. Their story provides valuable information about the re- introduction requirements for this species.

“I think he likes her” 19/10/2006 Photo: Daryl Dickson Mark Parsons and Daryl Dickson

16/1/2007

Three dens were installed yesterday afternoon within a diameter of 40m of each other (all three dens were present and available within the cage pen prior to release; so should still retain scent etc, and were shifted with same leaf litter lining). Both gliders were sharing the one same den (known as release den).

Conditions were light rain for an hr after midnight, with a great level of available bloodwood blossom in the release den tree and in adjoining bloodwoods. Also high

1 insect activity, particularly grey cane beetles on which both gliders were foraging prior to release.

Stoney ventured out around the den, emerging about 8pm. A position was tracked approx every 10 minutes through to 1:30am, with Stoney finishing up approx 30m from the den at the end of that tracking period. This was close to where the other two dens were installed.

He made some tentative initial jumps and short hops, spending the majority of time in the upper canopy, though he ventured on a couple of occasions down to 2 m height. He appeared to be crossing through the mid to upper canopy. Stoney was observed at one stage to go past and below the trunk where the bait station was fixed (which was immediately below the release den).

Sugar gliders and flying foxes were out and about, though Stoney not seen to make any particular interaction (spending some time though in close proximity to sugars).

Pan was not observed to emerge from the den, through to 1:30am. She was still at the same release den this morning. It did not appear that the food station was touched by either glider.

However, as of 7 to 8am this morning Stoney was located 100m NW from the release den, out in the open under foliage cover of an RF tree, about 12m off the ground. Overcast conditions; very light rain. Not in a retrievable situation. One spare den (which they recently licked clean in the cage prior to release) was installed on an adjacent tree, in hope of him utilising it.

Daryl will track mid afternoon for Stoney's last known position, and tracking to resume tonight.

17/1/07

Pan emerged from her den approx 9pm, and apparently did what gliders do; foraging within a 40m radius of the release den through to about 1:30am; returning to the release den at same stage thereafter (mod rain starting to fall at that time). Given the high level of immediately available blossom and her carrying young, this seems to possibly explain why she might not have travelled further.

Stoney spent yesterday out in the open, under the foliage of the RF tree, not apparently visiting the den or food station we installed at that site. At about 8pm he made a beeline back towards the release den, however it wasn't until about 11pm that he came in vicinity of the release den tree. We observed that his route tracked along flowering bloodwoods and that he was spending time in these, so it seems he was foraging as he returned. Foraging behaviour confirmed later by showering blossom we observed to fall from directly under where Stoney was at the time. Both gliders also noted to forage on beetles last night as well.

Stoney is having difficulty gliding, particularly the braking and gripping. We observed at least five tumbles last night down to ground level, all as he was approaching the release den. He is exhibiting a lot of effort in working out how to cross between trees through the

2 canopy, and fortunately seems to be avoiding ground level or crossing across the ground (he'll travel down to about 2m height on trunk, before returning higher).

Stoney seemed very intent on reaching the release den last night, however did not appear to make it. He spent a good hr and half in trees within 15m radius around the den tree, continually appearing to find a route to the tree and trying to cross towards that direction repeatedly. On one occasion he launched from about 9m height, flew 6m across to the den tree, but did not grip and landed heavily on the ground. From there he climbed an adjoining tree and appeared to pick up Pan's scent, particularly at a natural vertical pipe hollow that she had earlier inspected and seemed to mark. Stoney ended up entering the hollow, and sheltering from rain later at that natural den. He was still at that natural den this morning, about 30m away from the release den.

We installed a 'branch bridge' this morning at the point where Stoney seemed to want to cross over to the release den tree, so hopefully he'll discover and utilise this tonight.

We don't know if Pan and Stoney actually interacted with each other last night, but they were in close proximity at one stage when Stoney was foraging. Not observed to be in the same tree at the same time. Stoney was also vocal, a single bark, thereafter and later inspected sites where Pan was previously, so seems they should at least be aware that each other is close by.

Stoney's lack of gliding ability clearly is logical given his captive background, but he does seem to demonstrate that he's attempting to understand the puzzle and challenges of crossing, particularly by exploring all branch options along the tree trunk. His behaviour at present, of sometimes crossing through thicker vegetation (ferns, vines, RF trees) is clearly not what wild origin gliders would appear to do in normal circumstances (and certainly not what Pan is doing at present), but he is also scaling to the top of open canopy trees (bloodwoods, acacias). Again, his landings are awkward, but hopefully something that should improve with experience and gaining confidence.

It certainly seems that the incentive, of having a partner carrying young, does contribute towards Stoney's return to the release den site, plus his dogged behaviour in attempting to reach the den tree but failing repeatedly. Hopefully tonight this will be ok.

18/1/07

Stoney made it back to the release den with Pan, and both were there this morning. Mod rainfall most of last night, so all the slurry and fruit at station was eaten. We relocated the dens outside the cage pen, about 60m away. That put them right inside the candy store, re the bloodwood blossom. TJ's work certainly paid off. Certainly would pay to consider vertical challenges for gliding and landing within a cage pen, but two things?

Stoney's short jumps and hops till about 3 - 4m seems fine. It's the longer launch involving the landing and braking at speed. I'm not sure (given that gliders lose most of their height from the launch), that we could replicate this without access to a larger enclosure. It may not just be the braking manoeuvre either, haven't had the opportunity (and Stoney may not either) to observe his steering ability. This is unfortunately maybe

3 a hard learning curve that Stoney has to go through via trial and error. But certainly pay if gliders had to land on a vertical surface.

Part of Stoney's behaviour, of moving through thicker veg is part of the difficulty. Part of the tumbling is because a vine, fern etc seems to give way under him. He also seems to have difficulty with smooth barks (Poplar, Blue Gum), mainly with the ribbon bark strands that hang off the tree, again that these give way. It might pay to replicate this aspect, of loose ribbon or stringy bark, smooth branches?

I wasn't really happy about the idea of releasing from the cage pen (i.e. leaving the door open for the night, I thought it could be a potential predator trap. The three dens in the forest really launches the gliders into having to acclimatise almost immediately, which perhaps has been a bit rough on Stoney but then again challenging him at the moment seems to be the only way to do it. Pan seems to have acclimatised straight away.

Didn't want to take flash photos of either glider at night to minimise disturbance, but I'll leave you with three mental images.

Sitting under a bloodwood tree, as it is snowing blossom due to Stoney busily tucking in.

Stoney crossing a long palm frond, of a palm tree you'd find in any established garden, the frond giving way to his weight as it leans over to touch a Melaleuca trunk.

Stoney tumbling out onto the ground, climbing onto a star picket with a water sprinkler head at the top of the picket, then sitting on the water sprinkler glaring at Daryl, Geoff and me for putting him through all this...

25/1/07

Stoney's behaviour and foraging patterns seems much more settled, though he's not happy with the neighbours. It seems last night he encountered a foreign MG; in the same tree as himself and Pan shortly after emerging from the den.

I only had a quick observation in the spotlight, so can only be 90% sure it was an MG, but Stoney gave three distinct gurgles within my hearing and chased the glider up the trunk. Both appeared to be the same body size and were immediately adjacent to each other when first spotted, and though Stoney has demonstrated prior behaviour of chasing away a Sugar Glider from his feed station, this was done without any gurgles nor the same intensity to chase away the offending glider. Pan, higher in the same tree, seemed largely oblivious to the disturbance.

Stoney has avoided the area where he was having so much difficulty previously re the tumbling, and though still seems adept at hopping we still have not witnessed a glide attempt this week. It seems he may be still utilising the feed station irregularly, though very late at night, so he may be sourcing suitable quantities of wild food. Heavy rain at times possibly cutting down his foraging time, but some nights not all food consumed.

The feed station has been moved, aiming to set up a remote camera next week to see if we can id who and when visiting station.

4 Pan is gradually foraging further from the den, and two glides witnessed with no apparent difficulty or hindrance.

31/1/07

It appears that Pan has been able to remove her collar, or more likely chewed the antenna wire, judging by Daryl's most recent report.

Daryl's getting conflicting movement on that signal over Monday and Tuesday both at separate dens each day and within the canopy at night. She sighted a large female glider which had a distinctive V notch on the patagium (matching Pan's description) at the feed station and at close quarters; but could not sight a collar or more importantly the antenna.

Due to the extremely wet weather I don't anticipate being able to get to Kennedy in near future to confirm.

On past experience we've had both a collar thrown off after five weeks; and two antennas chewed off at the stub. I suggested modifications to Sirtrack to attempt to resolve both issues (pre drilled holes and longer angled sheath protection for the antenna) which were adopted for these collars, and both Pan's and Stoney's antennas were dipped in peri peri sauce just prior to placement as per SOP, but not really a surprise if that hadn't worked. Had observed Pan flicking her front limbs at the collar last week, so wouldn't be a great leap (or glide??) to find that the collar's been tampered with...

We need to ask ourselves if there is any value in attempting to re-collar Pan? She seems to have a settled foraging pattern, seems to have stuck to the artificial dens that we've provided, and Daryl seems so far to still be able to id and track Pan indirectly. I'm happy with the data we've got to show so far at least in the short term that wild origin gliders can be re-introduced (according to the measures we've provided to assist that re- settling in period). Longer term survivability perhaps unknown, but judging by how Pan's progressed so far don't expect too many difficulties there.

The only value in tracking Pan really is if she were to disperse off site, which is what she doesn't appear to have attempted yet. Given that Pan has young I wouldn't expect her to disperse till after the Wet anyway if she were to attempt it, so really wouldn't anticipate that till late Apr? The imperative seems to be tracking Stoney anyway.

2/3/07

Stoney is doing reasonably well, Daryl just reported last night an odd new scenario of him co-habiting with a third foreign glider, not sure if Pan is denning at that same site either.

This is in a very small box designed and used previously by sugar gliders until a goanna got into the box. We'll cover the base of tree with tin to prevent re-occurrence should goanna reappear.

5 Apparently Stoney gurgled on top of the box when he emerged, which Daryl thought was unusual but I've seen and heard similar with wild MGs. We think the 3rd MG could be a juvenile (male or female?), which might explain the ruckus Stoney made a few weeks earlier when they first encountered if same foreign glider, but seems odd if now all three part of a family group.

Stoney is foraging out further, but I don't think any glides greater than 10 m observed. Both gliders still using feed station, but so are a lot of sugar gliders so reliance/ dependence on feed station is probably more the fact that it is just there to utilise, rather than being necessary. Daryl has cut back amount provided anyway.

5/3/2007

Stoney has joined the big boys club. Saw Stoney glide last Friday night, approx 15 - 20m.

The glide was right into the top of the canopy of the land tree so a tricky launch and landing, and looked like the work of a polished glider. So only took him six weeks to adjust, but he is moving freely which is in stark contrast to his earlier efforts.

He's foraging really well, still accessing the feed station but this seems again the fact that it is there to access.

Putting on protective behaviour (mostly calls) above the den box where pouch young present. No sign of foreign glider though I heard a separate glider landing adjacent to den site approx 20m away, and I strongly suspect that Daryl had sighted the face of a pouch young at the den site, not a foreign glider within the den which would have just been just unbelievable.

Would be very useful to continue tracking to see interaction with pouch young as they venture out of the den, so hopefully Dan can pick this up.

13/3/07

Both gliders were radio collared, however it took Pan two weeks to remove her collar, and the antenna on Stoney’s collar has been chewed down to the stub. Fortunately we’re still able to monitor, as both gliders have remained paired and continue to use the release dens we provided.

Both gliders are well, and are raising pouch young that should soon be independent and able to forage by themselves within three weeks or so. Judging by age it appears that Stoney and Pan mated within two weeks of being introduced in the captive pen.

Key observations for the release trial are as follows:

 On the first night of release Stoney immediately headed away from the release site, and was found the following morning 200m approx exposed in the open under the canopy of a rainforest tree. He spent the remainder of that day in the open, though we installed a temporary den on an adjoining tree to provide cover.

6 This is highly atypical behaviour, and naturally very risky. Fortunately Stoney returned to the release site the following night, and has remained within the area.

 Basically Stoney is only now just demonstrating a gliding behaviour and ability that would be comparable to a wild origin glider. Pan in contrast has demonstrated natural glider behaviour and glides of 20m plus immediately from the first release night onwards.

 It took six weeks for Stoney to achieve a level of competency in gliding that could be called comparable to wild gliders, in the early period it was very apparent that Stoney had major difficulty in gliding, particularly in the braking manoeuvre to land on a target tree. We witnessed numerous tumbles where Stoney could not land onto the target tree at even relatively small glide distances of 6m. Stoney’s choice of land targets also was highly atypical (rainforest vines, palms etc) and potentially exposing him to greater risk of predation then more typical open forest canopy glides of wild origin gliders.

 Stoney’s tumbles were often to the point where he would bounce off the tree and land on the ground at speed. Such events could be considered to have the potential for trauma to occur such as a broken tail (witnessed in other wild origin gliders), as Stoney’s launch point was 10m above ground.

 Stoney’s glides are approaching 20m. Given the thicker vegetation aspect of the release site than more open typical mahogany glider habitat, we have not been able to witness any longer glides to judge whether Stoney could be able to glide up to 30 – 60m range, which is the average distance we would expect wild origin gliders to be capable of.

 Pan and Stoney are still utilising the feed station provided, though selectively grazing and quite often not always consuming all food supplied. The amount and type of food has been reduced over the release period. Both Pan and Stoney are sourcing native food (blossom, insects etc); the fantastic work by Traza-Jade to supply blossom to the Fleays gliders I believe has assisted Stoney to adjust to sourcing native food resources immediately on release.

 The installation of artificial dens was I believe I key ingredient to the success of the trial to date. Though we’ve observed that Pan and Stoney have shifted between the three dens we installed on an irregular basis, the key thing here is that both gliders continue to use these den sites in preference to natural hollows that are available in the release area (we’ve observed both gliders inspect these alternatives, but for an unknown reason these don’t seem suitable).

 Another key aspect is the paired release nature of the trial. Stoney’s behaviour on the first night of his release to the wild was certainly atypical. At this stage I could only suggest that without a den partner, it could be conceivable that Stoney or other captive reared gliders introduced into the wild individually would demonstrate similar behaviour, and likely to continue to disperse further away from the release area without a suitable reason to return. Given that collars don’t seem to last for more than 4 – 6 weeks in terms of effective range, I suspect we

7 would lose our ability to track any released gliders in this scenario, if they did not return to utilise the den sites.

 Even though the release site is not typical mahogany glider habitat, it still contains at least one pair of ‘foreign’ resident mahogany gliders. We have observed several territorial confrontations between Stoney and a resident glider, most likely a male. This has obviously been of benefit for Stoney’s adjustment, but part of the consideration here relates to the den partner scenario, in that on release Stoney and Pan had pouch young to rear, hence a purpose to establish and defend territory. Again, if Stoney had have been released individually I suspect he may have found territorial confrontations more challenging, and probable reason to disperse from the release site.

 The above situation, of resident foreign gliders, I believe reinforces my concern that wherever any relocated wild glider, or captive reared glider be considered for release into a site, it should be expected that this will involve resident, territorial gliders. Measures to ameliorate this impact, such as pairing, provision of artificial dens etc I believe are vital to any consideration for a release effort.

 Given Stoney’s behaviour and long time to settle into a comparable level of behaviour and ability as a wild origin glider, monitoring is also vital to judge whether a captive reared glider is able to settle and defend a new territory, and to adjust to challenging tasks such as gliding.

11/4/07

The feed station has been removed for over a week, though the structure is still in place.

It appears Pan is foraging off site, in an adjoining gully, but is still being sighted regularly.

The two young have not been sighted recently.

Stoney disappeared for six nights. His collar signal was coming from one stationary location, within the canopy of a medium sized Acacia where there was no den.

The Rufous Owl has been continually returning to the site, with vocal interaction witnessed by Daryl between the owl and Pan, from the gully.

Stoney was observed last night at 7pm, within the canopy of the release tree. It appears he's managed to chew off the transmitter, but still has the plastic collar loop in place which helps to confirm id. Stoney was observed in close quarters at the feed station where he returned, and appears in great health.

Both Pan and Stoney's behaviour suggests that they may have shifted into a natural hollow adjoining the site, as all four artificial dens appear quiet and possibly unused. It seems that Pan and Stoney may be rotating parenting roles, particularly if one glider isn't being seen for any length of time.

8 Given Stoney's re-appearance and behaviour and seems likely to suggest that he is now adapted to his release site, and capable of gliding, foraging, finding dens, avoiding predators etc to a self sufficient level.

5/12/07

Stoney is still very much alive and kicking; in recent times he's been entering Daryl and Geoff house maybe once or a few times a week after not being sighted for a few months earlier. Stoney is still appearing on the veranda...I might put a feeding station up again temporarily to see if I can site Pan...can't quite work out why he is suddenly doing this...he is not desperate for food, seems to want to interact for short periods then leaves...very odd after such a long time. He shows no interest in Teddy's enclosure. His arrival and departures are quite graceful these days...quite the wild glider....

31/1/08

Stoney turned himself in on Monday 29th Jan 10pm, I thought it was one of his usual visits but it soon became apparent that he had problems. I can only guess that it has been an owl attack. He has injury to his hind leg, head, eye and a lost claw on a front paw. He weighed in at 330g and looked distressed. We had seen him the previous Wednesday 23 Jan and all was OK. The injuries appeared to be several days old and his hind leg has an established infection.

We decided that he had to come back in and go to the vet. He was fed and settled for the night and I telephoned Graham Lauridsen at 7.30 on Tuesday morning. Graham was on a day off but arranged to come into the surgery in Tully to see him at 9.30. His eye was checked before he was put under. The iris was responsive so Graham thinks that his vision is OK. The wound on his head is healing. He was X-rayed - no breaks but the hind leg has a well established infection that is causing swelling more than half way up his leg and it is obviously very painful and difficult to move.

He is on a course of antibiotics, I have kept him in a restricted hospital box for 2 days and I have just moved him out to the small veranda enclosure. He has one more dose of antibiotics to go. Weight this morning 352g. Will see how he is moving tonight but will not re-release until I am sure that we have the infection under control, the swelling is down and he is moving properly. He is not too keen on being captive again but seems a little less distressed today. Am still amazed that an animal that has been in captivity all his life is more stressed when handled than a wild one.....he's getting better though and let me apply cream to his eye, check his teeth and give him his antibiotics this morning with out any great fuss.....poor little soul....not sure how many lives MG's have. Still have not sighted Pan, it will be interesting tonight if she is out there she may hear him in the enclosure and come to investigate...

14/05/08

Stoney turned himself in again last night with injuries to his front leg and paw and around the eye again, poss also an injury to his side. Won't have all the details until we have had a good look... He spent the night in the small enclosure on a heat mat and settled after his pain medication took effect. At this stage it doesn't look life threatening.