How Starlings Make Rational Food Choices

November 18, 2011 Updated: September 29, 2015
starling food
The starling is an ecologically rational decision-maker—its response to context improves decisions when it matters most. (Courtesy of Alejandro Kacelnik)

According to researchers from Oxford University in the U.K., starlings make optimal foraging decisions when given less information in choosing from multiple food treats.

This is known as the “less-is-more effect.” However, during sequential evaluations, that is, when starlings face sequential choices of whether to take a food item or seek better alternatives, context dependence comes into play.

Researchers Esteban Freidin and Alex Kacelnik trained eight starlings to obtain food from a hopper by pecking at colored keys that provided food treats after different time intervals. The contextual effect was incorporated by placing the colored keys in combinations, thus providing more information about each available treat.

The results showed that, when multiple choices were available, extra information interfered with the starlings’ decision-making in regard to which key to peck at to get the food the fastest.

However, this information had a positive effect when the birds were faced with sequential evaluations.

These findings are in line with the birds’ natural foraging behavior in wild settings.

In nature, foraging sites yield prey of different qualities spread over varying distances. Birds analyze the situational clues, and may decide to dig deeper or move ahead to a new opportunity.

This sequential decision-making depends on available information about the prey and the surroundings, but this could also lead to losses in terms of the amount of food gathered.

On the other hand, if birds encounter two potential prey choices simultaneously, the optimal choice depends on the prey type regardless of context, making the decision more rational and beneficial.

The research paper was published in the journal Science on Nov. 18.