Hot off the press from eNature.com:

Putting Your Eggs in Someone Else's Basket


Cliff Swallow
© Anthony Mercieca/Root Resources
Cliff Swallows are colonial -- that is, they nest in colonies, sometimes numbering in the thousands of birds. In many ways the members of a colony appear to display remarkable social cohesiveness. They work together to mob predators and will even learn from each other where the good food sources are. But if you look closely at a Cliff Swallow colony, you'll see that this seemingly cooperative community also harbors its share of dastardly misbehavior.

In every colony there are a few swallows (you might call them bad eggs) that parasitize their neighbors. They do this not by sucking other swallows' blood or stealing food, but by putting their eggs in nests other than their own. Sometimes the sneaky swallow will even toss out one of the nest owner's eggs before laying her egg in its place! This behavior is known as brood parasitism. The extra eggs go undetected, and the surrogate parents end up doing the work of raising the slacker's young.

These parasitic egg-laying visits are clandestine and quick, but some Cliff Sparrows have been spotted launching an even faster, more remarkable sneak attack: carrying eggs in their very small beaks (adapted for catching tiny insects on the wing) and quickly dropping them into a neighbor's nest. Incoming!

Did I miss something, or was the first method--the less sneaky, quick one--simply laying the egg in the to-be parent's nest?

Nest regards,
Wordwondering

From what I recall of my vast absorption of PBS Nature specials, this isn't too uncommon... there's some large bird that adds its egg to the nest of a small, unsuspecting bird with a trusting nature ~ she incubates them all, and when they hatch, the interloping egg has produced a big, ugly, squawky monstrosity that strongwings its way to the front of the line every time the mother brings back any food. Her own brood perishes, and adding insult to injury, I think I recall the big mean one eating its nestmates. No recollection whatsoever, of course, as to which bird this is. It's called *selective memory.

EDIT: This may be it... google criteria were "bird egg nest surrogate" (it was the best I could come up with in free association): http://members.aol.com/WHobbs7491/web/cbird.htm It's called the Brown-Headed Cowbird, and apparently I made up the part about eating the other young. It's evidently a major threat to songbirds.