I've got a superzoom which I used for along time and also was considering upgrading that one. I am concerned with the slowness and not being able to take high speed shots. I may do that anyway! I have an Olympus - 26X but is real slow writing to the card and eats batteries.

I've got a superzoom which I used for along time and also was considering upgrading that one. I am concerned with the slowness and not being able to take high speed shots. I may do that anyway!

Thanks everyone! I was considering renting, but by the time I've rented one of these for 10 days, I almost could have bought one! I love my old Sigma and am leaning toward that one, but the Nikon seems to be the best choice especially with a teleconverter. I'll welcome more opinions as I ponder through my decision.

I am an amateur who has gotten the "bug" to take BoS (Bird on a Stick) photos and am planing a trip to Costa Rica in a few months for 7 days of exclusive birding. I currently have a Nikon D5100 and use a Nikon 55-300mm f4.5-5.6 and a Sigma 18-250 which is my walk-about lens. Recent experience in Ecuador with this set-up makes me want a longer reach lens for my photography. I'm retired and on a limited budget. I think my choice is one of these 3 -(1) Nikon 200-500 f5.6 ED AF-sVR (2) Sigma 150-600 mm f5-6.3 DG OS HSM (Contemporary) or the (3) Tamron 150-600 f5.6-6.3 Di VC. If anyone would like to provide their expert opinions to help me decide, I'd appreciate it. I also am considering upgrading to a Nikon 7200 and/or going the teleconverter route and keeping what I have. I have a good eye and get great results with what I have but have missed some shots. Thanks in advance for your help and opinions. I appreciate it.