Which Nikon DSLR is good for bird photography

I had been using a D300 with a AF-S 300 F4 lens for a couple of years.  I recently switched to a Nikon V1, FT-1, and the 300 F4 lens.  The new combination produces much better images from ISO 100-400.  With the V1, the 300 F4 lens is 820mm equivalent.  On the D300, it is 450mm equivalent.  Even though the V1 is only 10 MPand the D300 is 12MP, I am cropping a lot less on the V1.

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Nikon D40
Nikon D300
AF-S 18-55 f3.5-5.6 G ED II DX
AF-S 55-200 f4.0-5.6 VR DX IF-ED
AF-S 300 F4 IF-ED
Sigma 10-20 4-5.6 EX DC NIKON HSM
Nikon AF-S 35 F1.8
Series E 36-72 F3.5
Series E 75-150 F3.5
SB-400