Alarm Calling in the Context of Flying Predator Stimuli: A Field Study of Carolina Chickadees (Poecile carolinensis)

This study describes chick-a-dee calling behavior of Carolina chickadees (Poecile carolinensis) in the presence of “flying” predator models. Previous experimental research with black-capped chickadees (Poecile atricapilla) as well as Mexican chickadees (Poecile sclateri) suggested a relationship between the presence of predator stimuli and the note composition of chick-a-dee calls.

Carolina chickadees were presented with two types of stimuli in field settings. These models were painted to resemble either a predatory sharp-shinned hawk (Accipiter striatus) or a blue jay (Cyanocitta cristata). Models consisted of pairs of five varying shapes, making ten models in all. A randomly chosen model was covered with a cloth and attached to a zip-line fastened to a tree about five meters high. During the procedure the cloth was removed and the model was released, causing it to “fly” to the opposite end of the zip line, which was attached at ground level. These trials were audio recorded at 20 field sites in eastern Tennessee from January - March 2010 and January - February 2011.

Chickadees produced more C notes in response to hawk models than to blue jay models. Additionally, chickadees produced more A and C notes as well as more total notes during the post-exposure period than during the pre-exposure period for both the hawk and the blue jay conditions.

The chickadees’ increased production of C notes in response to the hawk stimuli is consistent with previous research conducted on Mexican chickadees, potentially suggesting that the call structure of Carolina chickadees in threatening predator contexts is more similar to that of Mexican, rather than black-capped chickadees. Finally, chickadees increased production of A notes and C notes to the presence of both model types, providing support for the “Better Safe Than Sorry” strategy.