Food signalling calls are commonplace in the animal kingdom.
A diverse range of organisms use some form of communication with respect to food. The general idea in several species is that if you make food signalling calls to others when a food source is found, similar generosity should find its way back to you when someone else is the food-finder.
Altruistic organisms are those that live together in groups (not necessarily related to one another) and generally behave in a manner that benefits the entire group (as opposed to behaving selfishly).
Working together provides the group members with the ability to detect and exploit a wider set of possible resources than could be located if each individual worked alone.
Food Signalling Calls Among Chickadees
Altruistic chickadees forage outside of eye contact with one another. Individuals within the group help each other to obtain adequate nutrition by singalling to other members when a food source is found.
These “come and get it” signals are deciphered from other types of signalling calls according to their note composition.
Observations of the Carolina chickadee (Poecile carolinensis) have shown that the first chickadee to arrive at a feeding station produced a call containing a large number of D notes.
Once a second chickadee arrived at the station, the number of D notes in the call of the first individual decreased. This leads to speculation that the D note serves a recruitment function.
In order to test the hypothesis that the D note is critical to the food-sharing process in the Carolina chickadee, researchers played songs containing both a high and a low number of D notes at different feeding stations in order to determine the amount of time that would elapse before birds arrived to feed.
The time between the call playback and the first individual’s arrival at the feeding station was found to be significantly shorter when the call contained a large number of D notes.
The altruistic nature of the chickadees results in a higher level of individual feeding for everyone within earshot of the food recruitment song – a concept foreign to members of other species.
This post is an adapted excerpt from my book “The Nature of Human Nature“