Sigma Photography
Choosing a Birding lens
I have now narrowed down my choice of Camera bodies to a few ( 400D alpha 100, perhaps d80 ) and will try these out at a shop.
However I am still confused by lenses - there are so many! 
I have a rough idea of what to look out for, after reading up on all those confusing words and researching on the net, but am still stuck. What are some good models to look for ( i'm sure you know what im looking for more than i am! )? A few have been recommended - which i will keep an eye out for second hand - but i would like some more.
1 more question. With aperture, are the numbers displayed by the name the lowest aperture the lens can go to? e.g f.5 - f.6.3 
Thanks everyone!! 
If you have a look around you'll find loads of threads about lenses for birding... it's hard to know what to suggest without knowing what you budget is, if you can give some idea then I'm sure people will be able to come up with suggestions.
[QUOTE=AC/DC;908721]1 more question. With aperture, are the numbers displayed by the name the lowest aperture the lens can go to? e.g f.5 - f.6.3 [/QUOTE]
Pretty much, but just to clarify the ranges of f numbers - esp if you have a zoom lens - the apertures shown usually refer to the biggest apertures available at min and max zoom, ie, my 28-300mm has f3.5 at 28mm, and f6.3 at 300mm.
From what I can see, third party Canon lenses appear to be cheaper than, say, Nikon third party lenses, so if a BIG lens is a must, then you could (possibly) save money by going Canon and Sigma, but the D80 would be my personal choice (cuz I'm terribly biased :) ).