Heading Home and Beyond

Check out this amazing journey! Kuyurnpa never ceases to give me a surprise when I excitedly log on to download her latest satellite tracking data. This evening's map shows that in 10 days she has flown over 1000 km, heading directly south from the De Grey River area, her favoured spot of the last month, and returning all the way back HOME to Lorna Glen! Kuyurnpa spent 21st and 22nd June on the property, and on 23rd June passed less than 20 km to the north of the fenced enclosure, continuing west to roost on the neighbouring station that evening. This is the first time she has flown near her natal territory since beginning dispersal at the end of March.

Continuing to create new findings for us, she carried on south-west, roosting on Lake Way near Wiluna for the next couple of days. The last GPS fix on Kuyu shows her roosting at Lake Maitland, about 100 km north-east of Leinster, the southern-most location yet visited by our adventurous little girl!

If you live or happen to be travelling in this area over the next few weeks, please keep you eyes peeled for Kuyurnpa. She can easily be identified by the 20 cm antenna protruding from her back! If you think you've seen her or have a photo, please email me.

Lining Time

It's nest lining time at Lorna Glen!

Wedge-tailed Eagles begin their breeding cycle early in the year, timing events perfectly so the chicks hatch at a time when the surrounding ecosystem is rich with prey, maximising their chance of survival. Often this prey comes in the form of young mammals that are 'bite size' and naive enough to catch easily - especially young macropods (kangaroo family) and rabbits, which are the preferred prey items across Australia. The first stage of nesting is preparing the chosen nest, which normally begins in May and June. Eagles spend quite a few weeks lining their nest with sprays of fresh green leaves, most often using Eucalyptus, but where this species is not available, Acacia is a commonly used alternative. In the lead up to laying, the lining probably helps advertise that the nest and surrounding territory are occupied. More importantly it creates a soft bed on which the female can sit on and depress into a small cup to cradle her eggs, when eventually she is ready to lay.

The above photo shows an eagle nest that was freshly lined with Mulga (Acacia aneura) sprigs in June 2013. Here the same nest photographed at the end of the breeding, that shows the faded lining and a slight cup:

 There was no evidence of eggshell in the nest which would be expected if eggs were laid. The owners were a young, inexperienced eagle pair that didn't end up laying eggs. While we often think all birds should nest every year, it is normal for some not to, and for others to attempt but fail. Such is life in the arid outback!

Completing the Loop

Back north! Kuyurnpa completed her 10-day desert trip today after continuing north from her last position, and returning to... guess where? That favourite spot at the mouth of the De Grey River. The journey is shown in the above map - click to enlarge. It would be great to get inside her head and know what caused her to 'wander off' on a 930 km trip - searching for a mate? I think it is too early for this given she is still in her first year. And perhaps she just loves flying? I know I would.

It is more likely that Kuyu is wandering to become familiar with her surroundings, and is travelling to wherever there is food. Young eagles especially like to take advantage of carrion along roadsides, and this food source probably helps many through dry times. Although many eagles get killed while feeding on kangaroo carcasses, this cause of death has probably become a substitute for natural death caused by drought, and I suspect it has little impact to the population.

This recent trek takes Kuyu's total distance travelled since beginning dispersal to a whopping 6 800 kilometres!!! That's about 1.5 times the width of Australia. Not a bad effort for a journey that has only lasted just over 2 months.

A sub-adult female wedge-tailed eagle prepares to kick the crows off and take her share of this road-killed red kangaroo. Her bulging crop tells us she has already recently fed elsewhere.

Desert Wanderer

Kuyurnpa is becoming a real wanderer! Today's tracking data showed that she has once again ventured inland, moving another 420 km south-east of her latest Pilbara Coast hangout. She left the mouth of the De Grey River and followed this waterway upstream, roosting for the night just east of Marble Bar, before travelling a whopping 292 km the next day to spend the night at the edge of the Little Sandy Desert, just east of Newman! This seems amazing, but when you are an eagle that can cruise at 1600m above sea level doing 85 km per hour (as Kuyurnpa did that day), literally riding the wind, it's easy to put those miles behind you! Another 140 km journey northwards had Kuyu roosting between Rudall River National Park and the Newman-Marble Bar Road. Where to next?

The Pilbara Coast

Imagine being born in the middle of the desert but knowing one day you would fly so far that you would be able to reach the ocean! Kuyurnpa's lengthy day-trips during her dispersal from 'home' for a month have become shorter now as she explores the coastline between the De Grey River (east of Port Hedland) and Karratha. Here are 2 images which show her exploration of a 160 km stretch of the Pilbara coastline.

The first shows Kuyu's movements from 29th April, when she reached the coast after a 4000 km+ flight that took her (as the crow flies) 700km from Lorna Glen, until 6th May, when she had begun to follow the coast west past Port Hedland. The second map shows how, after tracking the Turner River southwards for a short distance before continuing slightly further west, she about-turned and moved back in an easterly direction, revisiting the area between the De Grey River and the Port Headland salt farm that gave her her first ever glimpses of the ocean. Her current position is about 670 km from her natal nest at Lorna Glen.

Click on the first map to view it in more detail, then hit the right arrow key to 'add' Kuyurnpa's extra journey. Where will she head to next?

Curtin University Sponsors Wedge-tailed Eagle Tracking

It's official! I'm thrilled to announce that Curtin Unversity's Department of Environment and Agriculture has made a donation to support this eagle tracking project. These funds will allow us to receive satellite tracking data for the next 12 months and follow what our three Wedge-tailed Eagles are up to. I completed my undergraduate degree at Curtin and have remained part of the Alumni family since graduating, so it's very pleasing to have their support. Thanks Curtin!

You can read more about other supporters of this project here.

Adult Eagle Update

It's been a while since you've heard anything from our adult eagles - the last update on Gidjee was nearly a month ago, and we haven't checked in on Wallu since early January. What has happened to our pioneering, PTT-bearing predators?

The above picture (click to enlarge) shows what it's like to be a few hundred metres above the ground on the border of Wallu and Wurru's home range, and that of their neighbours to the south. This photo was taken from a helicopter last year. The below screen capture shows what it's like to be Wallu at 3pm today: here, he's a mere 4000 m above sea level! I haven't written about our eagles' altitude data lately, but they are continuing to soar very high and give readings of up to 6000m asl, which provide evidence that the first seemingly unbelievable height of ~6500 m asl that Gidjee reached some months back was indeed accurate.

Spatially, Wallu is very much doing the same thing as he has for the past 11 months. Other than his walkabout in January, the beautiful breakaway country and woodland to the north and west of Lindsay Gordon Lagoon have clearly been too good to leave, and his movements have been restricted to 'prey hotspots' within this area. A wet start to the year has almost certainly helped with prey animal abundance, and it's highly likely that many waterbirds have been attracted to flooding of the two lagoons in Wallu's territory.

Interestingly, there seems to have been a shift in Wallu's key roosting sites in relation to two sections of lagoon (let's call them East Lake and West Lake - see the below maps). When we first tracked him last year, he showed a definite preference for the eastern edge of East Lake, and some scouting revealed that a well-used rabbit warren was probably the reason. Since the rain at the start of this year, Wallu has been recorded frequenting the whole northern shore of West Lake, which might well be due to an increase in rabbit numbers following rain, and the arrival of some tasty ducks and swans! A combination of both is quite likely.

Here's a map showing the large 'ring' of Wallu's favourite locations: the northern shore of West Lake (green circle), and the small cluster of points at the rabbit warren on the eastern edge of East Lake (black arrow). Click on the map to enlarge.

What about Gidjee? The sighting of her perched with Mulga about a month ago was very pleasing indeed, and you would think that not much could change in only a few weeks. However, every day is a new day, and one must never assume.

Gidjee has unfortunately gone missing. The day after her sighting, she unexpectedly left Lorna Glen and headed north-west, travelling 80 km in the three hours between 10am and 1pm. By that evening, she roosted 130 km from her territory, and I was hoping she'd return home the following day. But for the next 3 days, she wandered around this area, soaring and often spending quite some time at altitudes between 1000 and 2000 m. On the afternoon of 11th April she made another long flight north, settling to roost near a large clay-pan (which probably has water in it after such a good season).

The next day she left this roost at 8am, and flew 700 m to land, presumably to perch in a tree. This was the last time the PTT recorded movement for the next 10 days. Since then no new data has come through, and the PTT has subsequently switched off, which means it ceased to face upwards and charge properly. Here is a map showing the movements I've just described:

We still don't know what has happened to Gidjee. Unfortunately I won't have an opportunity to head out and investigate this any further until August, when I return from overseas. But currently there are two possible options: 1) she has been killed for some reason, perhaps as a result of being kicked out of her territory by another adult female eagle, or 2) the PTT has fallen off her back and landed in the desert, 195 km from Lorna Glen.

Keep watching Wedge-tailed Eagle Tracking to find out.