Monday, April 02, 2007

Bartails Northward Migration

I paid a whistlestop visit to Five Mile Beach (close to Hobart Airport) at the weekend. I had intended to walk through the pine forest, but first scanned the bay, largely to see whether the Eastern Curlew were present. They weren't, but there were around 60 Bar-tailed Godwit, in two groups. The majority were feeding around the creek outlet, and the remainder roosting on a nearby sandy beach. Among the feeding flock were a few individuals showing a fair bit of breeding plumage, as in the upper image, but as the group shot shows, many were showing little or no colour. I wasn't able to get very close before they were spooked by passing horse riders, and although they returned later, together with 2 Eastern Curlew, I opted not to disturb them further.
There's an interesting website that's well worth a visit. This website relates to the satellite tracking of 16 Bar-tails Godwits t
hat were captured in New Zealand during February. It includes photos of the solar powered transmitters fitted to their backs. Somewhat surprisingly, some of these birds are well on their way to their breeding grounds in the Arctic Tundra. I say somewhat surprisingly, as most of the local birds appear to be still here, and many show little change in plumage. The website shows the movements of individual birds as they migrate. My son, Matthew, (Illinois Birds blog), rather more 'web savvy' than I am (who isn't), tells me that he's tracked some of the birds on Google Earth. He averaged out the speed of 3 birds. One travelled 2,318 kms in 38 hours, averaging 61km/hr, a second, 2,926kms in 42 hours, averaging 69.7 km/hr and the third, an incredible 3,762 kms in 47 hours at 79.3km/hr, no doubt with a seriously strong tail wind! The key to these significant journeys is the laying down of fat reserves. That highlights the need for these birds, and waders in general, to have access to areas of our coasts were they can do that, and roost, without constant disturbance.


Duncan said...

The word is a cliche I know Alan, but these birds are awesome. It would be very easy to specialise on them.

Duncan said...

I meant waders in general of course!

BirdingTas said...

Hi Duncan,
Yes, I agree. I've rather 'done to death' migrant waders from here, but we'll shortly lose most of them for several months, so have to make the most of them. Some of what I consider are my best photographic efforts have been of our local waders. I rarely miss a chance to photograph them.