Evolution of Foraging Strategies in Shorebirds: An Ecomorphological Approach

We studied the relationships between bill and hindlimb morphology and foraging behavior in 17 species of shorebirds within a phylogenetic framework. The results show that the evolutionary change in bill length is related to the evolutionary change in for-aging strategies from visual hunting to tactile hunting. We also found evolutionary relationships between an increase in bill length and both plunging and sweeping foraging movements, and a decrease in bill length and "routing" behavior. No relationships were found between hindlimb morphology and movement pattern (continuous hunting species vs. pause-travel species). Examining the evolutionary rate of change in bill and hindlimb structures shows that the family Scolopacidae and the subfamily Recurvirostrinae evolved more rapidly than the species of Charadriinae. Results from our ecomorphological and evolutionary analysis support the hypothesis by Zweers and co-workers on the evolution of feeding mechanisms in shorebirds.