strong shift towards smaller beak size among the medium ground finch. The birds' feeding patterns changed too: they went for the large seeds only half as often as in previous years.

Seen, not inferred

This kind of evolution, in which a characteristic of two similar species diverges due to competition over resources, is called character displacement. The idea has become widely accepted thanks to a number of well-detailed studies, says Jonathan Losos, a biologist at Washington University, St Louis.

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"People have inferred character displacement," says Jeffrey Podos, an associate professor of biology at the University of Massachusetts, Amherst. "But to actually see it as it happens is quite a triumph. To be in the right place at the right time to observe something like this is really just incredible."

Peter and RosemaryTraining camp is winding down for the Indianapolis Colts as the team now has just one more practice at Anderson University. The biggest news of the day happened a few hours before practice when the Colts signed T.Y. Hilton to a five-year extension worth $65 million.

The deal keeps Hilton with the team through the 2020 season and, more importantly, keeps Andrew Luck‘s favorite target where he belongs. The Colts have a number of other players from the 2012 class to consider re-signing (including Luck himself) as the season progresses.

Today’s practice was shorter than most but the team was in full pads for the afternoon. The offensive and defensive lines were a bit more aggressive but the rest of the players were essentially playing two-hand touch.

The Colts have just