Birds on small islands have smaller flight muscles and longer legs than their close relatives on larger islands. How do these differences affect function? Birds on small islands might experience less predation, and do not need to take off as rapidly. They are able to save energy by reducing the size of flight muscles, and the longer legs could compensate for smaller muscles during takeoff. This might lead to a slower overall takeoff for birds on small islands. This study aims to test these hypotheses about how differences among island populations affect takeoff. The take-off mechanics of five bird species on the islands of Trinidad and Tobago will be studied. A perch instrumented with strain gauges and a high-speed video camera will be used to measure force generated by the leg thrust as well as flight velocity, acceleration, and wing movements. These data will be used to calculate: (1) the timings of leg thrust, wingbeat, and peak acceleration; (2) total forces produced by the leg thrust; (3) velocities at the end of the leg thrust and of take-off; and (4) percent leg contribution to take-off velocity. This study aims to assess the functional consequences of island evolution and to test how small-island species differ functionally from their close relatives in ways that directly affect their abilities to compete and escape predators. These functional biomechanical differences might help explain why island species are so vulnerable to human disturbance and introduced species. This project will involve training undergraduate biology students in research skills.
