Friday, 27 June 2014

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.

Monday, 16 June 2014

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!

Sunday, 1 June 2014

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.