Warbler Competition in Jamaica

I spent three winters in southwest Jamaica studying warbler competition.

To determine if the species compete, we mapped the 3D territories of both redstarts (see 3D territory of a male in gray below) and Yellow Warblers (core of territory below in yellow). We then caught the Yellow Warblers and temporarily removed them for a few hours, placing them in a "bird hotel" - a shoebox with holes punched in it. While the Yellow Warblers were removed from the system, we again 3D mapped the redstart territories. As we predicted, during the removal, the redstarts concentrated their use of space in the core of the territory vacated by the Yellow Warblers (below in blue), providing strong evidence that the two species compete for space.