Saturday, 27 December 2014

Staying Put

Home is where the eagle stays! Today marks the 560th consecutive day that our wonderful Wallu has spent in a fixed home range at Lorna Glen in central Western Australia. Except for a few days where he was recorded about 60 km east of his territory for part of the afternoon, Wallu hasn't left home, roosting here every night for the past 18 months. This is a relatively small area for a large eagle, especially in such an arid environment, a sign that food supply in this habitat is ample. At the beginning of this study I expected the home range to be at least 100 km2, but Wallu occupies an area less than half this size. In the future tracking more adult eagles will give us a better idea of the average home range in this landscape.

Saturday, 20 December 2014

To the Water's Edge

The last time we checked in with Jarrkanpa, he had only just fledged, making his first flight at the age of nearly 3 months. The map above shows his very limited movement from the nest, which is situated just behind a line of dense Melaleauca shrubs that border the edge of a seasonal lake.

Eleven days after his first flight, Jarrkanpa had moved to a new perch and over to the water's edge:

And by yesterday, just over 3 weeks after fledging, he had learned to move along the whole edge of the wetland, flying to roost in a patch of tall gum trees about 700m east of his nest (as shown on the far right of this below map):

You're probably wondering why I'm saying 'wetland' when these maps clearly show a white claypan which doesn't look very wet! But if you cast your mind back to the updates from earlier this year, you might remember this post from March which showed the amazing flood waters that soaked the landscape. Although not shown in these maps, the wetland has remained remarkably full for most of the year, attracting large numbers of breeding waterbirds including swans, ducks, stilts and terns. This abundance of birdlife, together with the flourishing mammals attracted to the water and surrounding green pasture, will have produced some great food for eagles, a key reason for the breeding success of nearby eagle pairs. 

Here's a picture taken just after sunset on a late October evening, showing a foreground of samphire still inundated with rare outback surface water. Although it is now dwindling as daily temperatures rise, this water is still present today, and it will no doubt be very helpful at keeping local wildlife (i.e. eagle food) alive, and building Jarrkanpa into a strong young wedge-tail well equipped for his life ahead.

In the last post I also uploaded a map predicting the size of Jarrkanpa's parents' home range. We can now look at the past 3 weeks tracking data and see how he has started to fill out my predicted home range quite nicely:

My predicted home range for Jarrkanpa prior to him fledging.

Jarrkanpa's home range 3.5 weeks after fledging. Wallu's territory is shown in the background.

You can see from this early tracking information that, as Kuyurnpa did last year, our little boy is now starting to expand his flight area to fill out what is probably his parents' home range. How far will he have moved when we next check in?

Saturday, 13 December 2014

The World Premiere!

As people piled in to the Haydn William's lecture theatre on Tuesday night, gradually changing the unform grey of the seats into a sea of colour, my nerves raced! The night had finally arrived. It was time to reveal for the first time the film I'd been working on for the past 3 years.

The world premiere of 'Where Do Eagles Dare?', the film which follows my journey to satellite track adult Wedge-tailed Eagles in Australia for the first time (i.e. the first part of the project documented on this website), saw nearly 500 people attend one of two screenings at Curtin University's Haydn Williams Lecture theatre earlier this week. Both evenings began with a fabulous Welcome to Country performed by Nyoongar elders Marie Taylor and Robyn Collard from the South West Aboriginal Land and Sea Council. These welcomes included a fantastic Dreamtime video which you can see on their website here. I then screened a short film about the successful use of a nesting box by Carnaby's Cockatoos, before I presented special gifts to all the people who I've had the fantastic assistance of in making the film. They included my partner Gill, my good friend Judy, field assistants Mick, Jeff and Mike, my bird banding supervisor Neil Hamilton, and especially the girl behind all the film's music, Storme, a singer-songwriter from the Perth hills.

Then it was time to show the film, which runs for 1 hour and 15 minutes. It was certainly a great thrill to sit back and watch the reactions of the audience to all the sequences I'd spent the past 6 months building in the edit suite. One of the highlights was having 2014 West Australian of the Year and former Chief Scientist Professor Lyn Beazley attend, who I had the pleasure of giving a guest seat.

Thanks to all the wonderful people who supported this event by attending one of the screenings, and to the people who couldn't make it but who kindly sent their words of encouragement. Keep your eyes out for the DVD, which will be available very soon in the New Year!

Professor Lyn Beazley and her husband Richard were special guests to the Friday screening.