That smaller egg is definitely a Cowbird egg. I got in a HEAP of trouble a few weeks back when I was trying to get some advice on this subject (see the reg. birding forum under "Cowbird Egg in Finch Nest - probably on about pg. 3 by now, for the fracas...), so tread very carefully. I - how shall I say - "took care of" the egg in question. Only you can choose what to do with your interloper egg, but be ready to get flamed by most of the GW birding world for your "illegal, unethical, criminal, (et al)" behavior if you mention it here.

Interesting. I knew Brown headed cowbirds could not be raised by Goldfinches because they feed their young seeds, but I didn't know House Finches did also. I looked it up at Cornell's lab of ornithology, and they confirm what you have read. I guess that means you don't have to worry about the young House Finches. I've also read about retaliation from the Cowbirds, so I guess just leaving it there should protect the baby House Finches best.

Well these barn swallows have been re-furbishing this same nest on our porch year after year. There really is no other location on the porch or nearby that would be practical or safe for the swallows to nest. This southwestern corner is under the eaves above our steep staircase, high up and inaccessible to predators. I don't know for sure they are the *same* two swallows year after year, but there is only the one nest. Meanwhile Mrs Finch is sitting on the nest and occasionally perching on the edge to turn her eggs. I imagine Mr Finch takes over nest sitting duties, although I haven't witnessed the changing of the guards. I do see him sometimes land on the ledge and sometimes in the little crabapple tree nearby. It is totally strange to see the pair of barn swallows arriving at dusk to spend each night perched next to the nest. I wonder if one or both could be last year's barn swallow babies.

House finches are delightful. I don't blame you for wanting them to stay. They are pretty good at getting used to people. A friend of mine has them build nests on her front porch every year, even on the light fixture that is right next to the front door. We sometimes sit on the porch with our dogs, and it doesn't even bother them anymore. I would try not to slam the door or spook them excessively. But my guess is they will settle down and get used to you coming and going. I have watched them nest up to three times per season, though the last clutch tends to be the smallest.