Lens advice for Nikon D3200 camera (1 Viewer)

I have recently brought a Nikon D3200 and want to buy a zoom lens, as I am new to DSLR cameras the range available is very confusing. It will mostly be for bird/ wildlife photography in the UK, any advise would be gratefully received.

You didn't mention any lenses you already have but if you just bought the camera with the 18X55 kit lens then the first thing I would do is get the Nikon 18X140. Better optics and a much better walk-around lens. For birds I just posted that Sigma is discontinuing the 150X500 (don't need that and there new 150X600) it should go on sale the Friday after Thanksgiving (US) for between $600.00 and $700.00. Beyond that I would think about upgrading the camera before spending from a thousand to several thousand on a lens. Either the D5300 or wait with most of the rest of us for a replacement for the D7100.
Steve