Otmoor RSPB nature reserve is only about 15-20 minutes away from Oxford, hosting mainly wildfowl, ducks & waders, on a wetland & reedbed habitat. You may also see several different types of birds of prey, such as Red Kites, and is host to large number of starlings in the winter.
I recommend both obtaining directions before setting off to the reserve as it is not signposted, and taking food & drink supplies if you plan to be there some time as there are no catering facilities on site. The reserve does have easy accessible paths, although some are not so easily navigable in winter or after heavy rain, and offers several bird screens and 1 large bird hide for views across the wetlands and reedbeds. Also certain areas may not be accessible depending on the season that you visit.
OS Map Reference – SP570126