Twin Brothers

These two amazing Wedge-tailed Eaglets hatched on a nest built by the parents of Wailitj - the Perth Hills' first juvenile eagle to be satellite-tracked - about a month ago. Given that Wailitj only survived for 2 months post-fledging, it was thrilling to discover his parents had doubled their 'output' this season.

At the end of September, with the help of some beautiful young boys (sons of some Perth Hills friends of mine) who have been keen to learn first hand about my eagle research, we fitted this brood of 'twins' with colour rings, weighed and measured the birds, then made ourselves scarce. With both having reached the age of 5 weeks, the odds were that they should continue growing healthily to fledging age of 3 months, but nothing is certain in the ever-changing natural world.

I was very excited to return to their eyrie this morning with my great friends Mick and Rianna and their two young sons Jarrahn and Bhodi, and find both eaglets (now juvenile eagles!) still alive and well! We fitted these birds with satellite transmitters - the second set of 'twin' WA wedgies to be sat-tagged - and I paused to photograph the partially consumed ibis on the eyrie as I placed them back 'home'. With this nest site definitely having the theme of 'two boys', I decided to give Jarrahn and Bhodi some homework: to come up with names for each eagle, with the only rule being that (as with all my Perth Hills eagles) they had to be in Noongar language.

The next day Mick rang me to let me know that the birds were to be called Naakal (= quiet) and Ngooni (= brother), two very appropriate Noongar words. It will be a privilege to follow the movements of these young brothers when they fledge and begin to wander around WA. I wonder if they will stay together on their journey?!

Naakal (left) and Ngooni sit next to a freshly killed Australian Ibis on their eyrie.

Ticking Off Eagle Nests

The time of year for Wailitj / Wedge-tailed Eagle (Aquila audax) ringing is upon us again, with most nests having quite large eaglets that are the perfect age for fitting with colour rings. Having just returned from my arid zone eagle research site at Matuwa last week, I was ready to carry on 'eagling' in the Perth Hills over the weekend and visited an amazing eyrie to ring/band the chick with my beautiful friend Dani on Sunday morning.

This eaglet 6-week old eaglet's eyrie was framed beautifully by the nest tree's limbs.

The eagle nest was located high in a live but very old and partially hollow Powderbark (Eucalyptus accedens) tree, which made the climb a nerve-racking but spectacular experience. I scaled the main trunk using ropes, then tied a safety line around the huge limb that I followed out towards the nest, inching my way along and trying not to pay too much attention to the multiple entrances to its hollow cavities, all covered in chew-marks from prospecting activities by local parrots.

This Powderbark tree has been growing in the landscape for several centuries.

I reached the young Wedge-tail and admired his view across the beautifully forested surrounds, before lifting him gently into a handling bag and lowering him safely to the ground below. Dani took him into the shade where we both worked quietly to weigh, measure and fit the two types of rings/bands. Having the bird so close allowed me to notice a small Kangaroo Tick (Amblyomma triguttatum) at the edge of its eye.

A kangaroo tick is visible just below the eaglets brow, smaller than the ever-present bush fly in the centre.

While ticks are perfectly good climbers and probably capable of ascending into the canopy on their own, I suspect this parasite may have been transported into the eagles' eyrie 'on board' a Yonga / Western Grey Kangaroo (Macropus fuliginosus) joey, common food for eagles nesting in the Perth Hills. Once the joey had been eaten, the tick probably went crawling for an alternative host, with the eagle chick being the nearest new victim. I chose not to remove this parasite as I know that these animals do drop off eventually, and risking damage to such an important part of such a young bird's body was not worth it.

Ringing and processing complete, it was great to place the eaglet back on its lofty nest and take in more off the amazing view. Now onto the next nest!

Darlyininy

In the Noongar language, the word 'Darlininy' means 'to go swiftly' ('iny' at the end of a Noongar word is the equivalent to the English suffix 'ing', but it is pronounced with a 'y' as in onion: 'in-ye'). Why is this relevant to eagles? Today, while extracting from a handling bag the young eagle who owns the fearsome-looking feet pictured above, I somehow managed to misjudge an attempted grab at one of his legs, then felt a sharp pain as a foot grabbed my hand sideways and a well-aimed talon punctured my palm (don't worry, it was just a flesh wound!). This happened in the blink of an eye, and I thought "Wow, that eagle moved swiftly!". This stuck in my brain until tonight, when I was considering a suitable Noongar word to use for the first juvenile Wailitj / Wedge-tailed Eagle to be fitted with a GPS/Satellite Tranmitter for the 2017 season. The name stuck. So where was this being carried out?

Juvenile eagles are removed from their nest and lowered to the ground in a canvas bag.

Whiteman Park, a recreation and conservation reserve located 18 km north of the Perth CBD, is fortunate enough to have two breeding pairs of wild Wedge-tailed Eagles residing in bushland. I have monitored with interest the breeding behaviour and diet in one home range since the first year of my university Honours project in 2004, recording 17 juveniles fledgling in 12 years. A second pair established a breeding home range quite recently (in 2015), the result of a particularly high density of Yonga / Western Grey Kangaroos living in this area (lots of eagle food). I refer to them as the Cullacabardee pair, named after the Noongar word and nearby suburb.

In June 2016, Whiteman Park staff found an adult female Wedge-tail dead beneath powerlines, nearly 5 km from the 'nest centre' of the Whiteman pair. The discussion below a post by the Western Australian Birds of Prey Centre regarding this death contains many assumptions about individual eagle identity, pair composition and breeding chronology which paint an inaccurate picture of what was actually happening in the wild. The dead bird may well have been a female from one of the resident pairs, but we have no way of identifying individual birds without marking them with leg bands or wing tags, and there was no such proof of 'who' this bird was. It may have been a local resident, or quite possibly a 'floating' (i.e. unattached) adult female from elsewhere. While the Cullacabardee pair was present constructing a new nest, I recorded no breeding activity in any known nests belonging to the 'original' Whiteman pair, nor did I locate a new nest, but did make several observations of an adult male eagle perched alone. This meant two things: 1) 'his' female had indeed died just prior to breeding (albeit a long way from 'home') and he was alone in his breeding home range, or 2) an adult female was still present, was attending a new nest that had escaped my detection during nest surveys, and the male was seen alone while the female was busy with 'mothering duties'.

It late 2016, I was carrying out some tree-climbing work for the Park when I flushed 2 juvenile Wedge-tails from the ground about 2 km from the Whiteman pair's existing nest sites. These birds were also captured on motion-sensing cameras nearby in subsequent weeks, confirmation there was definitely a successful breeding event in this home range and the death of an unknown female had not impacted productivity in the Whiteman home range. I now knew for sure that there was a 'missing' nest, so I set out in the 2017 breeding season determined to find it.

One August afternoon I located the Whiteman pair circling high above the Banksia woodland, then watched them simultaneously plummet from the sky to disappear below the tree-line. I followed my compass to a small 'valley' in between two sand dunes and suddenly came upon the nest, built very low in a dead Marri. This nest was atypical in that it was small, low down and not visible using traditional searching methods of scanning trees from a distance, proof that even massive raptors can be hard to find! I scaled this tree and was delighted with the scene in front of me!

The second egg in this clutch failed to hatch: it was infertile.

The news of this successful hatching in their conservation area, and the preparation of a new nest by the Cullacabardee Wedge-tails, prompted the wonderful Whiteman Park staff to agree to sponsor two transmitters for my PhD research. As well as helping me answer questions about juvenile dispersal, this would allow more detailed information about the Whiteman eagles' use of various habitats at the Park to be gathered.

Six weeks after locating the nest, this tiny eaglet had transformed into a well-feathered juvenile eagle. At first glance the nest appeared empty, but soon after sorting my camera I was met with the glorious sight of the eaglet standing up and lifting his new wings into the westerly wind! It was wonderful to see him doing so well and approaching a size suitable for satellite-tagging.

An 8 week-old Darlininy stretches his new wings.

When he had reached the age of 10 weeks, I was joined by Perth bird-banding mentors and good friends Mike and Mandy Bamford (whose wonderful enthusiasm for banding allowed me to begin colour-banding Perth wedgies in 2015), Sarah Stevenson from Whiteman Park and a few university students to visit the nest and fit a transmitter to Darlyininy. He was smoothly captured on his nest, lowered to the ground in a handling bag and (after his initial aggression at my palm!) held calmly in place while I adjusted his harness and began to stitch the Teflon.

Wailitj birds have a strong Aboriginal background!

Haemostats hold the Teflon in place in preparation for stitching the week-link harness.

The above image shows how a cardboard template is used to position all four straps of the transmitter harness evenly across the eagle's breast-bone. Once adjusted, the Teflon straps are crimped in place with haemostats, then a single 'weak link' is stitched through all four pieces where they meet in the centre. I am most grateful to Ewan and Jenny Weston from the Scottish Raptor Study Group, with whom I have been privileged to spend time learning raptor ringing and tagging techniques in Scotland, for teaching me this method.

It was fantastic to finally band an eagle with Mike and Mandy.

With metal and colour-rings/bands and a GPS/Satellite tag fitted, it was time to return Darlyininy to his nest. He posed for a quick image of his amazingly beautiful set of new wing feathers before being placed back in the handling bag and hoisted back up the tree.

Juvenile eagles' have conspicuously banded primary and secondary feathers.

Darlyininy assumes the threat posture typical of nestling wedgies.

It was wonderful to see Darlyininy back on his eyrie with a transmitter safely attached, and know we will be able to follow his first movements when he takes to the sky! For more information on satellite-tagging and to follow this and other eagles' progress, check out the Wedge-tailed Eagle Tracking website here.

Eaglets Growing Fast

It's now the season of Djilba and the beautiful wildlife in the forests surrounding my home in the Perth Hills, including our magnificent Wailitj / Wedge-tailed Eagles, are busy rearing their offspring. This means I'm out and about a lot lately, checking eagle nests and aging eaglets in preparation for the satellite-tagging season, which is almost upon us! Here is a beautiful brood of 'twin' eagles which I photographed earlier this week. Keep your eyes on the sky folks - these birds will be in the air really soon!

Eaglets & ABC Afternoons

It's the time of year again in this beautiful season of Djilba when our marvellous Wailitj / Wedge-tailed Eagles are welcoming their new eaglets into the world. Yesterday I was thrilled to come across a wedge-tail 'suspiciously' gliding into the trees and a few minutes later, locate a new nest, one of those 'rare' ones in which both eaglets had hatched successfully and survived their first ~5 weeks.

On most nests I monitor, the larger eaglet kills the smaller one during the first fortnight, so it was very exciting to find both chicks looking fat and healthy.

The arrival of 2017's first eaglets has recently inspired me to post a few images on my Instagram and Twitter accounts, which prompted 720 ABC Perth to get in touch. Last week I was very fortunate to be given the opportunity by Gillian O'Shaughnessy to talk on her WA Afternoons program, so I had the idea of arranging this to be done live from the canopy of a tall Marri tree in the Perth Hills! The interview was booked for 2 pm on Thursday, and just beforehand, I was thrilled to climb another of this year's new nests, peer over the edge, and be greeted by this magical sight...

This eaglet is almost 4 weeks old, and as you can see in the below photo, still has a tiny egg-tooth, something which, after helping the chick break out from within its calcified prison, remains present on the end of its new bill for about 5 weeks. His first amazing primary feathers were emerging too, just visible as tiny feather pins in the above photo.

This egg tooth has a trail of dried salt which extends along the bill, the result of 'gaping' behaviour - the bird equivalent of panting - which helps lose heat in warm conditions.

It was very exciting to share this sight with ABC listeners, talk about my ongoing eagle research, and also mention the 'Where's Wailitj' Crowdfunding campaign that I'm currently running via the awesome team at Pozible. This publicity, and the fantastic article published by the Hills Gazette the following day (which talked about some of the threats to juvenile wedgies like drones that may have killed Walyunga earlier this year), created some nice media attention and helped the crowdfund climb even closer to its target! I am so grateful to all those who helped publicise my research!

If you missed the interview you can listen to it now on the ABC WA Afternoons blog here.

And if you haven't pledged to the crowdfunding campaign yet, watch this video and then visit the Pozible campaign website to make your pledge!


*POZIBLE 2017 from Simon Cherriman on Vimeo.

Hawk-Owl Boxes for Christmas

This fabulous nest-box is one of 30 that were recently constructed by a fantastic bunch of school students from the Christmas Island District High School, under the supervision of their teachers Brad and James, a project initiated by Range to Reef Environmental and supported by Christmas Island Phosphate. These artificial tree-hollows were made for a unique, endemic and Vulnerable species of nocturnal bird of prey, the Christmas Island Hawk Owl (Ninox natalis). Range to Reef engaged me to become involved in the work, and after having closely related Southern Boobook Owls successfully use nest-boxes I installed in Perth and the WA Wheatbelt region early last year, I recommended that Range to Reef supply the same design to the school. I very privileged to be asked to assist with installation and have just returned from the island (which is one of the most amazing, unique places I've ever been!) where I worked with Range to Reef to find an arboreal home for all 30 boxes. I'll write more on this soon, but for now, here are a few snaps from the trip!

Boxes were installed using the tree-friendly 'Re-Cyc-Ology method with wire and hose-pipe.

Spot the Hawk-Owl nest-box! This one was hung about 20 m up in a beautiful Sysigium tree.

The awesome team from Range to Reef: Roget, Sophie and Andrew!

Despite spending over a week 'hanging out' in the rainforest, most of work was conducted during the day when Hawk Owls are roosting, and I was a little sad to climb on the plane and leave the island without having seen one! However, I know that one day I'll be back - hopefully to find owls nesting inside one of their new homes! In the meantime, I know the island's beautiful Frigatebirds will be soaring above the rainforest and keeping an eye out.

Kala & Aus Geo

You might remember a few weeks ago when I was thrilled to find Kala, our sat-tagged juvenile Wailitj hanging out with his parents, and be lucky enough to take some close-up photos of him perched in the morning sun. Today Australian Geographic reported on a recently published journal article about Wedge-tailed Eagle movement ecology (as studied by DNA), and one of these photos of Kala featured as the headline image! You can read the article, which contains some very interesting findings about the ecology of wedgies in Tasmania, at the Aus Geo blog here.

Armadale Kaaraks

Early last year the City of Armadale gave me the wonderful opportunity of installing a variety of nest-boxes for wildlife throughout several bushland reserves, many of which were designed for Black Cockatoos. I was extremely excited when Tony Kirkby, a cockatoo biologist, who, along with Ron Johnstone from the WA Museum's Cockatoo Care Project, has studied Kaarak's (Forest Red-tailed Black Cockatoos Calyptorhynchus banksii naso) for many years, emailed me through the above photo. This was a fantastic sign that less than a year after installation, one box was being used for breeding!

Fresh chew-marks on the sacrificial chew-posts provide convincing evidence of cockatoo occupancy.

Today I was installing more nest-boxes (this time for microbats) in the area and took the opportunity to visit the active cocky box. Under Tony's guidance on the phone, I walked quietly through the bushland to the nest tree, and after observing for a few minutes then 'raking' (knocking on) the nest tree, discovered the female did not emerge. This was a good sign that a chick had hatched because adult Kaaraks are known to only brood their nestling for a week or so, then leave it on its own for most of the day while away foraging. Tony was happy for me to scale the tree and confirm there was a chick present, and also to photograph in order for its age to be estimated. When I reached the rim of the nest-box, I was met with this absolutely remarkable view!

A tiny ball of yellow natal down-feathers huddled in one corner of the nest-box, swaying ever so gently from side to side. This beautiful new gift to the world was only the second Kaarak chick I had seen in real life, and appeared a lot smaller than I expected. I lowered my camera inside the box to snap a few closer photos from a side angle, then film a few short video clips (watch a short one of this beautiful young bird on my Facebook feed here), just as a large flock of Baudin's Cockatoos flew noisily over the treetops. The nestling made a few soft rasping noises and swayed from side to side, but otherwise showed no reaction to the goings on in the outside world. Keen to keep disturbance to a minimum, I snapped some descending gear onto my rope and left the canopy behind, then walked away from the nest tree as quietly as I had come. The only sign of adult red-tails was a single, distant 'kreeee'.

After seeing these photos, Ron and Tony tell me this young Kaarak is just under a week old, and is quite young to be left alone by itself, but it does happen. I am most grateful to Tony and Ron, who mentored me during the successful use by Carnaby's Cockatoo of a nest-box in the Mundaring Shire just over a year ago, and who continue to offer guidance with various ornithological projects I am involved in. What a lucky find - and an awesome way to end the week!