The Eastham edition of the Cape Codder has a more detailed article on the plans for poisoning crows to protect piping plovers at the Cape Cod National Seashore. It does mention that it takes three days for the crows to die but doesn't address the issue of where the dead crows will end up. An editorial in the the Truro/Provincetown edition today raises that issue. They mention the gull-poisoning fiasco that happened in 1997.
The way the Cape Code National Seashore is pitching the crow poisoning bothers me a little. They're not just concerned about the survival rate of the piping plovers. They are concerned about beach access. They are promoting this as a way to keep the beach closure from extending into late July or August because of second clutches. If the crows get the first egg or eggs, the pair will lay another clutch. The same thing happens if a storm washes over the first clutch, some other predator gets the first clutch, or there's simply an unusually high tide. I'm afraid the biologists are overselling the idea that poisoning the crows will get the beach open earlier.
I wish there were a simple answer, but there isn't.