I have to say that I have a new found respect for Q and his bird photos. There's a lot to learn and remember when shooting birds in flight. I definitely need more practice. Tracking the birds and keeping them in the right position for spot metering and spot focusing isn't as easy as you would think it would be. That little square in the viewfinder gets really tiny when you're trying to keep it on the face of a bird, especially when they don't fly in a straight line.
These were all shot with the Nikon 1.4x teleconverter on the 600mm f4 lens. I cropped each photo about 10%.