These are more bird sketches done on a quick east coast trip. All were done in colored pencil in a Moleskine sketchbook - 5 1/2 x 8 1/2", taking between 20 and 40 minutes per sketch. Several are east-coast species that we don't get to see out in the Pacific Northwest that I was able to see at Heinz National Wildlife Refuge (Tinicum Marsh) very close to the Philadelphia International Airport.
These are done either using photos that I took as a reference, or referencing a field guide or magazine photo.
BLACK-THROATED BLUE WARBLER