Durham Bridge Professional Review and Guide
"Durham Bridge and attached causeway provide foot access to Sebasticook Lake, a productive waterfowl site. While birding can be done from either side of the causeway, it’s probably not a good idea to stand on the bridge itself. The bridge is slightly narrower than the causeway, leaving scant room for both pedestrians and motor vehicles. Riprap (stones) on either side of the bridge, though, provides good places to sit and watch.
Durham Bridge is part of a causeway spanning a narrow finger of Sebasticook Lake. Ducks and shorebirds are key here, but other interesting birds include Common Loon, Canada Goose, and Belted Kingfisher. American Bittern and Virginia Rail sometimes frequent the marshy section to the east side of the causeway. Shorebirds here include both Greater and Lesser Yellowlegs, Semipalmated Sandpiper, Least Sandpiper, and Common Snipe. Expect to see Mallard, Hooded Merganser, Common Merganser, and Greenwinged Teal."