Bird Migration Card - 1937

Image scan of a historical bird migration card. This is just an example of the more than 6 million handwritten cards stored in government files, in the North American Bird Phenology Progam, with more than a century of information about bird migration, a veritable treasure trove for climate-change researchers because they will help them unravel the effects of climate change on bird behavior.

This card: Ruby-Throated Hummingbird