Hi David,
Sorry about the slow reply, not sure if anyone has replied to you offline in the meantime. Firstly, I would suggest your large all brown bird with the very pale bill was a young Giant-Petrel sp. There are often still a few Giant-Petrel around well into October and later. The vast majority of Giant-Petrel occuring off the East coast are immature birds which are prone to hanging around longer into the spring. On the Wollongong and Ulladulla pelagics over the weekend we saw several Northern and Southern Giant-Petrel (typically, all immatures).
As for the shearwaters, at the moment rafts of 200 or more are most likely to be Short-tailed Shearwater. There were large numbers observed during the weekend trips but they are not reaching the peak migration volumes just yet. There are also good numbers of Wedge-tailed Shearwater around inshore and both species should be readily identifiable in flight (even at a distance). The Short-tailed Shearwaters are likely to be moving south in much tighter flocks - often in rolling, arching groups with relatively rapid wingbeats. Short-tailed Shearwaters hold their wings straight-out from the body, whilst Wedge-tailed Shearwater hold their wings well forward at the wrist and have a more relaxed, low flight.
The Short-tailed Shearwaters also have greyish underwing panels - a variable feature, although only rarely as white/silvery or as extensive as in Sooty Shearwater. Furthermore, at this time of year the STShearwater upperwing secondaries can also appear contrastingly pale to the darker wing coverts and primaries. Short-tailed Shearwaters can have much darker brown heads which contrast with the paler brown (?tan) mantle, belly, breast and upperwings. This, along with the contrastingly pale upperwing secondaries, may be what you described as the tan coloration on the wing and mantle.
The other all dark shearwater that should be arriving back in our waters during October is the Flesh-footed Shearwater but we saw none at the weekend and it is rare to see flocks of 200 off the East Coast. They also tend to be further offshore with only much small numbers along the coast.
I attached some photos - the STShearwater are from this weekend, so their plumage should be similar to the birds you saw, but the others are last summer's birds.
Cheers Dan
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Date: Mon, 19 Oct 2009 23:48:03 +1100
Subject: [canberrabirds] Pelagic problems
A lovely morning whale watching in Jervis Bay. But my poor skills at IDing seabirds was evident.
There were many shearwaters, sometims in rafts of 200 or more. They all appeared the same species and I assumed they were short-tailed because I know they are abundant in the area. However, they displayed characteristics that the books don't describe - even HANZAB. They were dark brown in colour but their wings had a tan colouration in the mid parts and their mantles were also tan. Does this description fit the STSW?
Also an albatross (??) flew by very close to the boat. It was all brown on the back and wings with a very pale bill and did not seem a very big albatross. I thought Giant Petrel, but the season is wrong, and it doesn't seem to fit the description of a juvenile albatross of any of the common species in the area.
Anyone got any helpful suggestions? (Keep them clean!)
David Rosalky
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