Nebraska Life, Nov/Dec 2008, Vol. 12 Issue 6, p.85
Cardinals also are known for their intense parental behavior. Most feeding of fledged young is done by the males, since females typically begin a new nesting cycle very shortly after their first young fledge. I’ve seen male cardinals feed female cardinals, cowbirds and house finches. One researcher in Oklahoma reported a cardinal attempting to feed goldfish in a pond! While photographing backyard birds in Lincoln, I noticed that a male cardinal was tending to a single newly fledged cardinal chick, but also was being constantly pestered by two young house finches. Cardinals raise their young on insects while house finch parents feed their young regurgitated seeds.
Available at: http://works.bepress.com/paul_johnsgard/7/