Very possible with NEX, although I wouldn't count on getting much in focus if the birds are in flight. Overall, most nikon Ai-S lenses perform well. This is 300mm F4.5 Ai-S, @30 year old lens which can be found on eBay quite reasonably. Hint: try and find one with the JCII sticker!
All shots handheld, between f5.6-f8
great egret
gbh
gbh
gbh white morph, (mating pair), harsh backlighting, a testament to NEX sensor latitude
black crowned night heron, ISO 800, 1/250, borderline handholding sharpness
purple galinule
Higher resolution available via flickr...
Thanks for this site!
All shots handheld, between f5.6-f8
---
great egret
---
gbh
---
gbh
---
gbh white morph, (mating pair), harsh backlighting, a testament to NEX sensor latitude
---
black crowned night heron, ISO 800, 1/250, borderline handholding sharpness
---
purple galinule
Higher resolution available via flickr...
Thanks for this site!