License, verbatimPD
The National Gallery of Art: open access image with no usage restrictions under the NGA's open access policy (openaccess=1 in the Gallery's published_images dataset).
Robert Havell after John James Audubon. Chestnut-backed Titmouse, Black-capped Titmouse and Chestnut-crowned Titmouse, 1837. National Gallery of Art, Washington.