THE NEW YORKER--Wonderful sources of vintage zoo art

I have collected covers from vintage THE NEW YORKER magazines for years because I appreciate the art work of them. They would have a famous artist/illustrator depict a scene around New York, often of the zoo's each month and feature it on the cover, I have 6, and always search for others. Because you know what zoo it is that is illustrated they can often identify unknown zoos or exhibits. But you have to be careful, sometimes the artist used their "artistic license" for the illustration. I have a vintage Post cover in which the artist copied petting zoo exhibits from from the Bronx, Philadelphia, and Brookfield zoo into a "fantasy petting zoo.