Little hungry warriors: Examining trade-offs between fighting and feeding in hummingbirds

Methods

Summary

We will observe the fighting behavior and dominance hierarchy of wild Sparkling violetear (Colibri coruscans) hummingbirds in Colombia. Adult territorial males have daggers and backwards serrations on the tips of their bills. We will quantify the degree of weaponry in the bill tip of each individual using macro photography.

To measure feeding efficiency, we will train wild birds to feed on modified feeders in their territories. We have already successfully trained many wild birds to feed in front of high-speed cameras, allowing us to see into their world.

Challenges

Working with free-living animals is always challenging. Even when habituated, if they feel threatened they often do not "cooperate". Training wild birds to feed comfortably in front of our cameras allows us to document natural feeding behavior. The more time we have available for field work, the more flexibility we have in training the birds and adapting to each individual's personality.

Pre Analysis Plan

Using macro lenses and high-speed cameras, we will be able to simultaneously measure the degree of bill modification and feeding efficiency in the same individual. We predict that adult territorial males will have bill weapons, and that this will translate into a decreased feeding efficiency for males when compared to females and juvenile males.

When studying museum specimens, we have already found a marked difference in the bill tips of male and female Sparkling Violetear hummingbirds. Now we want to examine these differences in living birds.