Tuesday, 11 April 2017

Wallu Untagged


When I checked in on the most recent tracking data yesterday and found Wallu's transmitter showed no movement for 3 days, I was worried. This has in the past meant the transmitter's owner has died, and I dreaded to think of Wallu, our longest-tracked eagle, having lost his life. Given we have just moved into the 'new eagle year', and territorial behaviour will be heightening as the breeding season approaches, it would not be surprising to find a resident adult male killed by a usurper. It was at this time of year, 3 years ago, that our adult female Gidgee was ousted from her home range and later died.

Fortunately, however, this story does not have such an ending! I rang the Matuwa homestead and was delighted to talk to the current caretakers, John and Gail Grenville, who kindly offered to assist by investigating further. I later received an incomplete voice-to-text message on my phone, which said:
"Hi Simon,
We found the tracker lying on the ground but no..."
This was enough info for me to realise what had happened, and that Wallu was not dead, and I rang Matuwa back instantly for more news. When John and Gail reached the GPS coordinates shown on my tracking map, they found his PTT on its side with one part of the harness frayed, causing it to dismount. This is a very interesting discovery, as this initial harness design was a 'permanent' mount, unlike the method used now which is made with a weak link, and I expected it may have lasted much longer. It appears the heat and harsh conditions in the arid zone (along with some encouragement from big, hooked beak!), caused the harness to weaken and eventually break on one of the main straps. So after 3 years and 10 months, the end of an era has arrived, and Wallu is wild and free again! We will check on him later this year during our eagle research trip during the breeding season (Wallu is still identifiable from his leg band), and possibly even catch him to give him a health assessment. Thanks so much to John and Gail for their wonderful help! More updates soon!

Monday, 10 April 2017

Walyunga's Gone


The last satellite-tagged Wailitj is the first to leave home! Walyunga, a late-fledging juvenile wedge-tail that we fitted with a transmitter in December, has made the bold move of 'leaving home', departing his natal home range last Tuesday. After not having moved more than about 4 km during the past 4 months of the post-fledging period, he suddenly flew east and spent the night near Wundowie, 35 km away. Then Walyunga travelled inland via York, turning north to reach Goomalling, the passing Wongan Hills and Dalwallinu as he moved nearly 200 km north of Perth!

Walyunga's dispersal path into the WA Wheatbelt region (click to enlarge).

It is so exciting to have reached the stage where our Perth eagles have begun dispersal, and I'm SO grateful to all who supported the initial crowdfund to pay for 3 of their transmitters. This is the first time the dispersal path of a 'wedgie' from south-west WA has been tracked, so it is very exciting to follow Walyunga's route, and anticipate where he might end up next! Don't forget to follow my Instagram account for the most recent updates of our satellite-tracked eagles!