canberrabirds

Gull

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Subject: Gull
From: "Tim Jones" <>
Date: Tue, 21 Nov 2006 09:38:34 +0000
Dear All

I don't have much to say about plumage and other characteristics, but a point of order on size. It depends what you mean by 'twice the size'. It's clearly not 'twice the length'. But by the measurements given, it is roughly 15.4% bigger in length, which may imply that it's also 15.4% wider and 15.4% taller - which in three dimensions means it's 1.154 x 1.154 x 1.154 times the volume, which is 54% 'bigger' - maybe a bit off 'twice the size' but not that far out and probably within tolerance to the naked eye. In fact, it would only need to be 25% longer in each direction to be 'twice the size', so that extra 6cm would only need to be just about 10cm.

Just to reinforce the point, my 50L esky doesn't look all that much bigger than my 25L one!

Cheers

Tim

From: "Philip Veerman" <>
To: "Simon Mustoe" <>,<>, <>
CC:  
Subject: [Birding-Aus] Gull
Date: Tue, 21 Nov 2006 17:56:01 +1100

Simon,

If by Black-tailed Gull we are referring to Larus crassirostris, then not only is it in the same family (Laridae) as the Silver Gull Larus novaehollandiae, but it is in the same genus (Larus). So, sorry but you have your wires crossed in suggesting they are in different families. They don't look that much different in shape either and I suspect just by a quick look at Geoffrey's, picture and description that it is probably not a Silver Gull.

Philip



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