Wailitj Satellite-tagged

I felt quite nervous ascending my climbing rope 20 metres into the canopy of this glorious Marri tree to reach the huge Wailitj / Wedge-tailed Eagle (Aquila audax) eyrie today. It was the first time I'd climbed this particular nest, and the first time I was going to attempt to catch a chick belonging to this particular pair. It was also the first time I would be fitting a juvenile wedgie from the south-west of WA with a satellite tag, so a big part of the nervous feeling was related to excitement! The rope swayed as I neared the nest and clipped my safety line around a large branch. I wiped my brow. I could just see the top of the eaglet's head.

The nest seemed large from the ground, but its sheer size really became apparent as I stood up and peered across to examine its contents. The eaglet was a male, about 10 weeks old, and almost fully feathered with beautiful rich-brown plumage. It stood firmly, lifted its wings, and in reaction to my presence, shuffled over to the opposite side of the nest. Jill Shepherd (my PhD supervisor) and Bill Brown (an eagle scientist from Tasmania who has been helping me ring/band and satellite-tag juvenile Wedge-tails this month) kept a watchful eye on the bird from one side of the nest as I adjusted my climbing ropes, while Stuart Rae (a Scottish pal currently visiting from Canberra and also helping with eagle ringing/banding and tagging) watched the chick from the other side of the nest. Even with my go-go-gadget arms, I was unable to reach the eaglet from a standing position, so I climbed onto the eyrie and quickly grabbed its legs in a secure grip, then tucked the wings under my arms, to ensure the bird could not flap around and injure itself (or me!).

Once securely inside a handling bag, the juvenile wedgie was safely lowered to the ground. Bill's expertise in handling eagles was a wonderful help, and he held the bird firmly but gently while we took measurements and fitted the metal- and colour-rings to its legs. It was then ready to be satellite-tagged. As Jill filmed some of the procedure from close-range, I attached a 70 gram solar/Argos GPS/Satellite transmitter with a Teflon harness, which goes on like a backpack and is stitched up at the front to create a 'weak link', designed to fall off after a year or so of tracking. This method is used widely on eagles worldwide, does not cause the birds any harm, and has been approved by the relevant Australian Animal Welfare and Wildlife Licensing authorities. The eagle could obviously tell something was going on, but it remained remarkably calm during the attachment procedure.

A hood is used to keep the eagle calm during handling.

With satellite transmitter attached, the eagle is ready to go back on the nest.

With the processing complete and the tag attached, the eagle was ready to be returned to its nest. I scaled the tree as quickly as possible, sat carefully on the eyrie, and hoisted the bird back up to its arboreal home. Even after being off its nest for just under an hour, this magnificent young eagle was amazingly calm as I lifted it out of the handling bag and placed it down on the flat bed of Eucalypt leaves lining its nest. Wailitj, the ancient Noongar name for the Wedge-tailed Eagle, had been echoing inside my mind during the whole morning, and now it was time to extract it from my thoughts and speak it to the bird in front of me. To honour the First Australians and importance of keeping traditional language alive, Wailitj was the perfect name for the first South-west Australian Wedge-tail to be satellite-tagged. At that moment, I was overcome with a thrilling feeling that the GPS/Satellite transmitter was ON, and we would finally be able to follow the movements of this majestic creature from the moment it takes its first flight, throughout the post-fledging period, and (like our desert-born Kuyurnpa), on a dispersal journey across this vast continent!

I am indebted to the wonderful people who have supported me in the tracking research, particularly Jill, Bill and Stuart for their help today, and the amazing selection of crowd-funding supporters who jumped on board this 'maiden flight' earlier this year! You can see a quick video of my personal thanks, taken just before Wailitj went back on his nest, here. I can't wait to glimpse the first set of tracking data!

Flying with Matuwa Eagles

I am very privileged to have just returned from Martu Country where it's been a busy few weeks conducting the annual Wedge-tailed Eagle breeding survey on Matuwa. This recent research trip produced some really interesting findings - please visit the Wedge-tailed Eagle Tracking website where you can read more about them.

The trip ended with a bit of a disaster (my car broke down and we needed to be towed back to Perth!!), but the images of some fantastic experiences flying with eagles during the aerial nest surveys are etched into my mind, and these remind me that any pitfalls that arose during the trip were worth it to have been able to see these magnificent birds from such a unique perspective! The above photo was taken when this adult launched off a perch and flew below the helicopter.

Owlet Trio

When Mike Lohr rang me with the good news that he'd found a Googamit / Southern Boobook (Ninox boobook) breeding in one of the owl nest-boxes we installed earlier this year, I nearly jumped out of my skin! I could hardly contain my excitement as I tied the ladder onto my roof-rack and packed some camera gear into the car. Bill Brown, a friend from Tasmania who had just arrived to help me with eagle research at Matuwa, was also excited to come along and we chatted about our past experiences with owls during the drive down to meet Mike at a bush reserve in the Perth suburbs.

As we approached the nest tree, an adult boobook peered out from inside the nest-box, keeping a half-closed but watchful eye on us. Leaning the ladder against the tree trunk was enough to cause her to launch from the box and swoop in a silent glide to perch in a nearby Banksia. As I slowly scaled the rungs, I was very excited about what I might find, and still tingling with excitement that the target species had nested in a box designed especially for it! This was the first record of owls using one of my nest-boxes, and it is always interesting to be able to have a intimate insight into the nesting habits of a less-common, nocturnal species.

What an amazing sight! THREE juvenile boobooks sat low in the nest chamber. As I snapped a few photos, the owlets gave me occasional winks and made clicking noises with their bills, warning me to keep back. It was interesting to note several regurgitated pellets on the floor of the nest-box's hollow entrance, which mostly contained insect exoskeletons, and also, to my surprise, a scatter of green, orange, yellow and blue body feathers belonging to a Rainbow Lorikeet (Tachyglossus haematodus). Several bright green and yellow tail-feathers, also belong to this species, lay on the floor of the nest box chamber.

Bill Brown lends a hand to Mike Lohr as he prepares to band one of the owlets.

After lowing the owlets down in a calico bag to Mike, I watched while he weighed, measured and banded them, took a blood sample for health analysis and collected parasites. This work is part of Mike's PhD research investigating the impacts of fragmentation on the Southern Boobook, which has been recorded as declining for the past decade or so. I was very fortunate to be given the opportunity to supply and install nest-boxes for a part Mike's project testing whether nest sites are limiting their presence in urban and agricultural areas. Breeding records inside easily accessible boxes like this one allow broods of owlets to be given health checks and marked to help collect information on factors affecting their survival - and they also allow an up-close look at some of the most beautiful young birds one can find in the bush!

Mike takes a head-bill measurement from one of the Boobook owlets.

When all the data had been collected, it was time to return the owlets to their nest. I scaled the ladder, hauled the calico bag and its precious contents back into the canopy, and gently lifted each bird out, one at a time, and lowed it inside. As I leaned inside the box, a pungent odour of ammonia filled my lungs, a result of the bed of decaying regurgitated pellets which had accumulated during the past few weeks. Seemingly oblivious to the smell, the owlet trio peered up at me and continued to blink their wonderful, wide eyes. It would only be a week or so before they would begin putting these to use, making their first flight from the nest box into the nocturnal world.

Three Little Pigs

 

Many people don't realise that feral Pigs (Sus scrofa) are an environmental issue in parts of the Perth Hills. In fact, there is a sector of the community who actively hunt pigs and in recent times people have been caught and fined for illegally breeding and releasing them into several catchment areas to ensure they have a constant supply of 'hunting game'. Waterways such as the Avon and Helena Rivers, and Wooroloo and Gidgegannup Brooks, are particularly attractive to pigs as they are remote, and at this time of year offer a reliable water supply and lots of food. Land management authorities such as Parks and Wildlife and the Australian Wildlife Conservancy go to great lengths to remove pigs, but as with any feral control, its a labour-intensive and ongoing battle.

While at a Wedge-tailed Eagle nest yesterday, I was delighted to find one pair were doing 'their bit' for removing pigs from the ecosystem surrounding their eyrie. I decided to write a little story about my discovery, which goes like this...

One day a small & weak Wailitj (Wedge-tailed Eagle) chick was suffering head injuries after attacks from its larger sibling, when mama eagle flew in with a sudden delivery of fresh prey: pork! One little piglet had wanted to build a house of straw, one a house of bricks, & the third couldn't decide WHAT house he wanted to build... when suddenly, a large bird of prey decided they should ALL move into a biiiiig house of sticks. So it dived down, lifted them up with its powerful talons, & carried them high over the Wandoo woodland.

"My eaglet is weak", thought mama Wedgie.

"But this food might just help save its bacon!!"

Many people had been worried about the damage feral pigs cause to the precious Perth Hills bushland, but now they knew of an amazing house of sticks where Three Little Pigs (and hopefully many more) had died happily ever after. And that is the end of the story!!

As part of my current research project on Wedge-tailed Eagle movements, I am fitting colour-rings to eagles to help identify individuals and find more information about their dispersal. This involves lowering eaglets from their nest to the ground in a handling bag for ringing/banding. Mike Lohr, an experienced bird-bander currently doing a PhD research project on Googamits (Southern Boobook owls), assisted with ringing the larger chick. At only 3 weeks of age, the smaller one was too small to be banded, and its chance of surviving sibling attacks currently seemed slim... but we decided that if it is still on the nest when we return to check this site in a month or so, we might be able to colour-ring it then.

It was interesting to note the difference between the two eaglets - the weaker chick had damage to its crown, a result of sibling attacks, and normally chicks in this condition gradually decline in condition and eventually die. However, this one's wounds seemed to be healing well and the chick's full crop suggested it had recently been fed, so perhaps some sudden 'intensive care' from its parents will help it against the odds.

The smaller eaglet had many feathers missing from its brows, but this seemed not to be related to sibling damage, as there were no scars or evidence of bleeding.

The larger chick had well developed pin-feathers on the wings, and its wing length suggested it was just under 4 weeks of age. You can see the differences in physical development clearly in the below photo (note that the size difference is accentuated by the proximity of the more dominant chick to the camera):

 After ringing/banding and measuring were complete, we hoisted the eaglets back into the canopy and I placed them back in the centre of their massive eyrie, about 18 m above the ground. The dominant chick sat up and gazed back at me, and I was thrilled to see a hint of the yellow colour-ring on its leg, which will hopefully give a good chance of this bird being resighted at a later date.

I wonder what will be for dinner tomorrow? Maybe a nocturnal bird, like a Boobook, or perhaps more pork?!?