Researchers at Binghamton University, New York have found that baby crows in the suburbs are smaller than those in the country. In this New Scientist story they talk about whether junk food is to blame.
It makes me think of an experiment John Marzluff mentions in his book "In the company of crows and ravens." A child did an experiment seeing what kind of paper bag Seattle crows would investigate first: a brown paper bag, or a white McDonald's bag. The McDonald's bag was the clear winner.