There is a good walk along the River Nidd from Old Bilton, quite a lot of which is managed by the Woodland Trust. I regularly see a kingfisher there, along with grey wagtails and goosanders.
The link below should take you to a map of the walk
http://www.getamap.ordnancesurveyleisure.co.uk/?key=IynuGObu5Eqoc76Vc2HNVw2
Its a brilliant walk with birds and wildlife to see all the time every season.
Haven’t yet managed to get a photo of the Grey Wagtails.