Time to Fly the Coop: Varying alarm calls in Japanese Great Tit

Mammals are not the only ones who are able to think flexibly in order to survive. Birds are capable of adapting as well. Much like vervet monkeys, certain species of birds are able to make varying alarm calls according to the predator they are faced with. In this particular study, the Japanese great tit was used as a subject with two different calls, ‘jars’ which are single broadband notes and ‘chicka’ calls which are a combination of calls. However, how detailed are these variations in order to perceive the threat at hand?

The experiment was conducted in Karuizawa, Nagano, Japan.The scientist sampled 24 pairs of great tit birds in order to discover the link between alarm calls and predators. They took 3 common predators of the Japanese great tit which are Japanese rat snakes, Japanese crows, and Japanese martens. They used a nest box, where the chicks of the birds would be, and the parents would have easy access to care for them. For their experimental variable, the observer gathered snakes from the general area and created models of the other two animals. For the experiment, the model or snake (kept in a plexiglass box) was placed within a meter of the nest box. A control (turtledove) was also placed within a meter of the subjects. Once in place, the observer focused on the male birds, who frequented the nest more, as well as interacted with young more than the female counterparts. Vocalizations of the male were then recorded via a microphone after three minutes when the males were within 5 meters of the predators. The vocalizations were then sorted according to when they were emitted, and the notes analyzed to determine broadband or combinational calls. By doing this, they found that there was indeed a variation between alarm calls among the great tit males. The ‘chicka’ call was much more prevalent than that of the ‘jar’ call when crow and marten models were present, meaning the jar calls were only used when the birds recognized a snake. Likewise, there was variation in notes of the ‘chicka’ calls between crows and martens. More D notes were seen in the latter calls. Combinations were also different, showing 92 types of note combinations for crows and 128 types for martens. No responses were heard in the turtledoves.

Japanese great tits prove that mammals are not the only species of animals that do alarm calls and vary them in accordance with the threat they face. Such a feat begs the question of what other organisms are able to discern the level of danger, as well as how they should respond to said danger among their communities.

Suzuki, T. N. (2014). Communication about predator type by a bird using discrete, graded and combinatorial variation in alarm calls. Animal Behavior, 87, 59-65. Retrieved November 08, 2017, from https://www.journals.elsevier.com/animal-behaviour