Cormorants have a reputation as prodigious eaters, and for setting up large colonies that reek of guano and vomit. This reputation brings their colonies into conflict with local fishermen, who believe that cormorants reduce fish stocks and threaten their livelihood. A graduate student at Queens College in New York is studying cormorant vomit to learn what they eat and why they vomit so readily.
The thumps he hears are exciting for him: In gobs of vomit, to be referred to in his thesis as boli, he has identified eels, mud snails, oyster toadfish and menhaden. Sometimes he will hear a thump so loud it can only be a whole fish, or close to it. This, he says, is particularly interesting.The study site is Swinburne Island in Lower New York Bay, which is home to 264 cormorant nests.
“I’ve been hit on occasion,” he said. “In some ways it’s almost this great personal experience between you and the birds.”
Mr. Grubel got down on his hands and knees, picking up about a dozen samples for what Professor Waldman describes as frantic ichthyology — a search for ear bones or other fragments that could identify a certain species. The fish he found were nothing unusual: cunner and tautog, small fish generally found around pilings or rocky shores, and one weakfish.