Spatial vs. Colour cues
In some species, males use spatial cues (distance and direction) and feature cues (a colour or a landmark) to relocate a reward while females only use a feature cues. Maria tested whether female hummingbirds of three species use either a spatial cue (location within an array) or a feature cue (colour of the flower) to relocate a rewarded flower. First, the hummingbird had to find the single rewarded flower amongst four flowers of different colours. Upon return the spatial and feature cues were put in conflict. Male rufous hummingbirds first return to the flower at the previous correct location, but what would the females do?