I  came across this little detail in an illustration that my artist father did for a Philadelphia company many, many decades ago.

Since he was not a birder as far as I know (he died when I was young), I am guessing this is a generic bird feeding its young, though I get American Robin vibes. 

Any thoughts?

(I'd like to think he'd be tickled that people are looking at one of his cartoons from so long ago.)