As a host site for the Smithsonian's Neighborhood Nestwatch, I take notes on the bird activity in my yard, particularly their target species of Robin, Catbird, Cardinal, Song Sparrow, Carolina Wren, House Wren, and Carolina Chickadee.  

Any insights on the behavior of a female cardinal with a limp nestling, presumably dead, as she prepared to fly away with it in her beak?  Did she find it already disabled?  Did she kill it? Was she dumping a cowbird?  Rescuing a baby cardinal? Bringing food to her fledglings? I'll include the transcript of my mid-May notes below for context.  

Cardinals--I see a few around the neighborhood, males and females.
Male with only the alum band (he had green and purple plastic bands when he was banded a few years ago, but had chipped them off within that first year)--was feeding good-sized fledglings last week in the evergreens in 56 Court.  I hear the youngsters and adults chipping in the trees and hedges this week.
Female--very surprising behavior!--about May 18, a female was on the top surface of the wooden fence opposite my backyard, and she had something leaf-sized that she carried there.  Through the binoculars, I saw that it was the limp body of a baby bird.  The body mass may have fit into a walnut shell or a pingpong ball.  I could see skin and thin dark fluff about a quarter of an inch long.  Ms. Cardinal took hold of a light colored part--leg or entrail?--and stretched it above the baby bird's body.  She didn't seem to be eating it on the spot, more like testing for a good grip.  She moved it a few inches along the fence by flying, and set it down again.  Soon she picked it up in her bill and flew beyond my sightlines.  I didn't go looking for a raided nest, since I was going to work, etc.

What kind of nestling?  I couldn't see.  the books describe the colors of the gape, but don't say much about foot and leg colors.  Are they helpful in nestling IDs?  For size and coloration, I'm thinking robin or catbird, or maybe starling.  There are plenty of them around.  By this time, grackles are probably out and about.

Thanks for any light you can shed on this unexpected behavior.

Carolyn Sturtevant

Greenbelt, MD