Some birds, such as phoebes, hermit thrush, palm warblers, are known to frequently pump their tails while sitting on a branch. There are a number of theories trying to explain this behavior but no one knows for sure.
A recent study on Eastern Phoebes dispelled some theories. They don’t pump their tails to maintain balance. Or to signal aggression toward other phoebes. Or to aid in finding food by flushing or disturbing insects.
One finding from the study revealed that phoebes do pump their tails more often and at a faster rate when potential predators are around. It is thought that rapid tail movements notify the predators that the phoebe is aware that danger is nearby. If the predator knows the element of surprise has been removed, it may be less likely to pursue the phoebe.
Even though we do not know the reason behind tail pumping, it can still be a clue in identifying certain species.
birdsoup 
Leave a Reply