Ethnic Notions is a film about the disturbing, racist caricatures and stereotypes that were developed through minstrel shows and other media in the Jim Crow period in the US. Many Americans know about caricatures such as the Sambo or Mammy, but not everyone knows the sinister, calculated reasons for them. People who owned slaves, and then wanted to keep their descendants in a cycle of oppression utilized these caricatures to create ideas that would subtly inform racism for generations to come. A chilling example of this is the depictions of black children as animalistic, clumsy, and often in violent situations. This image shows barely clothed or naked children unsupervised and in peril, literally labeling them as subhuman bait.
Images like this suggest that black children are expendable and unprotected by parents, maybe even not worth protecting. It draws the mind to the scraps of meat usually used to bait alligators: scraps and bits not fit for human consumption. The fact that this was printed on a post card shows that the joke was popular at the time, and people were desensitized to the horrific implications that black children were as expendable as spoilt meat saved for a hunting trip.