White-throated Needletails Are still in Eastern Australia

Morning Birdos

While it will only be 2-3 weeks before most of the WTNT depart from the Eastern coast of Australia they are still visible. You may need to use your binoculars because they tend to spend more time out of normal vision range just prior to their departure. On Friday I watched quite a few flocks feeding between 80 and 600m but yesterday even though they were right overhead, I could only see them without my bins for about a minute. They ranged from 800m to 1,400m above me. Food does reach these heights particularly above ridges where the wind is bounced upwards taking the flying insects skyward and at the same time enabling the swifts to fly without beating their wings. I recall that in my last year at Massey University we were provided with data from the NZ & Aus BOM departments that traced the air Australian butterflies were in when they arrived in NZ. I think they did this on three occasions and each time the air carrying the insect was traced at quite some height to Central Gippsland in Vic.

A Japanese paper to be released soon in Pacific Science shows that 3 WTNT with geo-locators on them that came to Australia last year did what I had predicted some years ago when departing for the Northern Hemisphere. Two of the birds were in Qld when they recived the call to return to Hokkaido, so they headed off too high to be seen from the ground, through the NT, one leaving our shores near Darwin, the other from the Kimberley. The third bird had just reached Tassie when it recieved the call to return home, so it went high back to Melbourne then west through Vic, S.A. and W.A. departing our island near Port Headland. The fact that sightings of WTNT in central SA, N.T, and W.A. are extremely rare demonstrate that they are flying too high to be seen from the ground.

SO Now, before they get too high is a good time to look out for them and watch their high speed flight, their complicated pair-bonding display flights. Please count how many in the flock and report it some place that I can find it so I can continue to monitor their decline.

So if you live down the east coast of Australia, enjoy one of our greatest birds before they depart.

Cheers

Mike Tarburton.