Your comments and advice are most appreciated.
The birds that I (try to) photograph are stationary, although I have lucked out a few times and caught a few in-flight.
I am an old geezer, wearing tri-focals which is why I am so concerned about focusing.
My shooting is strictly for fun and usually I am not in a huge rush to press the shutter button,so
if the green dot works well, as you say, I will probably give the D 610 a try.