d7200 or d600 for bird photography upgrade

I wanna upgrade my camera D5200 to either a d7200 or D600 both are great cameras. I got my nikon 150-300mm and tamron 600mm to use. while the 7200 is faster the 600 is better quality in low light and that one is a full frame the other a dx. Who got what and how does it playout with bird photography. My 600mm tamron i can get the reach which i need.but not sure if it fits the 600 and the 7200 might just be in my favour at the moment.

I'd go with the D7200 as you'll crop less when shooting wildlife, etc. It also has a sensor that's really good at high ISOs and the 51 point AF will be better at action shooting. I've read where the D600/610's AF doesn't work well in dim light. I just wish the grip was deeper as the D7100 I had cramped my hand after awhile. Just my $0.02.

I have a D600 and a D7000 and use the D7000 mostly for wildlife. I do wish I had the D7200 with the more MP and that would give me the better reach and also have more cropping ability. I think my choice for what you want to use it for would be the D7200.

D7200 due to the 1.3x crop factor giving you a bit extra zoom. That's the main thing.

I'd go with the 7200.