Overread
Hunting birds with a canon
Well the canon 300mm f2.8 is often heralded as one of their sharpest and best lenses - it works very well with the 1.4TC with almost no loss of quality at all - and works very well with the 2*TC.
Its possibly a little short without TCs for general birding around the countryside - but a a great wildlife in general lens 0 and the ability to go up to 600mm on a good day is a good bonus.
The sigma 500mm (whilst I can't comment on quality) might be a better aim if you primarily do only wild birding - since it is giving you the focal range that you will most find yourself using.
Its possibly a little short without TCs for general birding around the countryside - but a a great wildlife in general lens 0 and the ability to go up to 600mm on a good day is a good bonus.
The sigma 500mm (whilst I can't comment on quality) might be a better aim if you primarily do only wild birding - since it is giving you the focal range that you will most find yourself using.