Tail Pumping Behavior in the Black Phoebe
by Bryce W. Robinson
The Black Phoebe – Sayornis nigricans in it’s simple suit of black and white, catches the eye of anyone remotely keen on the goings on of the natural world. This phoebe demands attention, even in a guild of flashy desert denizens. In doing so it provides some quality behavior birding that never disappoints.
One behavior I have noted while watching the bird forage is the methodic tail flick, not uncommon in the family Tyrannidae, but somehow unique in the Black Phoebe. I’ve wondered about the habit, but never sought to satisfy the wonder until now. The illustration above came about in preparation for the coming San Diego Bird Festival that I will be attending. In practice, I decided to couple the illustration with looking into any insights in the literature regarding the tail pumping habits of the Black Phoebe.
In little time I found a paper (Avellis 2011). The study addressed four hypotheses explaining the behavior, the Balance Hypothesis where the phoebe tail pumps to maintain balance atop unstable perches, the Foraging Enhancement Hypothesis where tail pumping increases foraging success, the Signal to Territorial Intruders Hypothesis where the tail pumping signals conspecifics of the birds fitness and establishment on a territory, and the Signal to Predators Hypothesis where the tail pumps exhibit the birds vigilance amidst predators.
The results of the study indicated the following:
Balance Hypothesis – Not supported
Foraging Enhancement Hypothesis – Not supported
Signal to Territorial Intruders Hypothesis – Not supported
Signal to Predators Hypothesis – Supported
The paper reports that the Black Phoebe increased tail pumping rates significantly when a predator was detected either visually or audibly. The suggested purpose of tail pumping then is to advertise the birds awareness to the predators presence. Tail pumping communicates the phoebe’s health, and that it in turn will be a more difficult prey to capture.
So, when asked why the Black Phoebe pumps its tail, I’ll answer that the behavior is to exhibit the birds vigilance, acting as a deterrent for predators looking for the path of least resistance for procuring food. Another day, another bit of knowledge gained.
Avellis, G. F. 2011. Tail Pumping by the Black Phoebe. The Wilson Journal of Ornithology 123:766-771
We have a lot of those cuties here. Beautiful image and information!
Thanks Laura. I’m glad you get to enjoy them regularly.
I love them. They are so cute. You’re welcome Bryce. 🙂
Hey B, was any consideration given to the possibility of tail pumping being employed as a signal to other phoebes (mate, offspring, etc) about the existence or non existence of a predator? What the heck is “forage enhancement”?
Hey Mike. The author looked into the change in frequency of tail bobs when conspecifics were present, but did not look into the interaction between presence of conspecifics and presence of predators. The signal to territorial intruders hypothesis addressed whether the birds tail flick to signal a males quality and vigilance against usurpers. It would definitely be important to look at the interaction though. Forage enhancement was investigated to look into a correlation between the ability to obtain food and rate of tail bobbing. The hypothesis is that tail bobbing aids in foraging efficiency where birds that are more successful at obtaining prey will tail bob at higher rates. It wasn’t supported