Cramond Island, Cramond, Edinburgh EH4 6NU 

Cramond Island is one of many along the Firth of Forth; it can be reached on low tide following a bridge, the Cramond Causeway. The island houses many old fortifications from the WW2 era, and it is also a great place to observe coastal birds and seabirds crossing the Firth of Forth, such as the Eider duck. Particularly during low tide, many waders, such as the Oystercatcher, the Dunlin or the Redshank, can be seen stirring sandy mud looking for seaweed, small invertebrate, and shells.  

Sources:

Individual Researcher Walk; RSPB (Edinburgh Area Local Group)