Audubon's Shearwater - exact location?, Massachusetts waters, August 26th, 2012. One of two Audubon's giving excellent views on the return journey towards Nantucket shoals. Compared to the Barolo Shearwater (below) seen earlier in the day, the Audubon's appears much darker below, especially on the underside of the longish tail, the wing margins and the neck sides. The Barolo appears much whiter below in all aspects with the white undertail coverts almost reaching the tip of the tail. Although difficult to see in this poor record shot, the bill of the Barolo Shearwater is also smaller and finer than Audubon's. What a rare treat to have wonderful views of both of these species in the same day!