Comparing lenses

Blipmate and I have been drooling over a bigger lens to capture those birds that are just out of reach. So today I did some comparing.
You need to see the extras to see what I was trying to compare. All lenses at full length.
This is the Canon EOS 700D with Tamron 16 to 300mm lens. Weight ok, not too heavy.
The first extra is with the Canon SX 50. Light as a feather.
The second extra is the Tamron 150-600mm lens that I had a trial with at Hanafins shop the other day. It has plenty of zoom but so heavy I couldn't lift it comfortably just standing, I had to sit down. It is just hand held and still quite sharp. I would be two blocks away from the cathedral.
If it wasn't so heavy I might be tempted.