Presentation Type
Presentation
Faculty Mentor’s Full Name
Chad Bishop
Faculty Mentor’s Department
Wildlife Biology
Abstract / Artist's Statement
Unpredictable food availability drives facultative migratory movements in many bird species. Irruptive finches, like pine siskins (Pinus spinus), tend to be social and flock together in large groups. Because low food availability cues pine siskin movements and these movements are unpredictable in timing and destination, I hypothesize that social information plays an important role in a flock’s assessment of food availability and/or departure timing. I studied flocks of pine siskins foraging at four discrete sunflower patches on MPG Ranch in August and September 2020 to understand the factors which influence flock size and determine whether calls share information about food availability and/or movement. To measure food availability, I walked transects through each sunflower patch throughout the season. I scored all the sunflowers in a 1 ft2 area every 5-10 m for seed maturation and seed availability. To quantify siskins’ social behavior, I collected 35 hours of audio recordings of siskin foraging flocks at four sunflower patches, using an omni-directional microphone and Roland recorder. During recordings I noted flock size, arrivals and departures from the patch, flocking behavior, and raptor presence. I used Raven Pro software to count and compare siskin calls/min during three flock behaviors: “departure,” when one or more siskins left the patch; “rising” when siskins would fly up into the air and circle the patch before landing again, often in response to raptor predation pressure; and “baseline” when there were no departures or rising events. I found that call rates during rising and departures were both significantly greater than baseline call rate and baseline call rate was significantly greater in patches with greater food availability. I also found that flock size increased with food availability and predation pressure. My results suggest that calls provide information about patch quality and are used to coordinate movement or departure from a foraging area.
Category
Life Sciences
Presentation slides
Understanding the social behavior and public information sharing of an irruptive migrant
Unpredictable food availability drives facultative migratory movements in many bird species. Irruptive finches, like pine siskins (Pinus spinus), tend to be social and flock together in large groups. Because low food availability cues pine siskin movements and these movements are unpredictable in timing and destination, I hypothesize that social information plays an important role in a flock’s assessment of food availability and/or departure timing. I studied flocks of pine siskins foraging at four discrete sunflower patches on MPG Ranch in August and September 2020 to understand the factors which influence flock size and determine whether calls share information about food availability and/or movement. To measure food availability, I walked transects through each sunflower patch throughout the season. I scored all the sunflowers in a 1 ft2 area every 5-10 m for seed maturation and seed availability. To quantify siskins’ social behavior, I collected 35 hours of audio recordings of siskin foraging flocks at four sunflower patches, using an omni-directional microphone and Roland recorder. During recordings I noted flock size, arrivals and departures from the patch, flocking behavior, and raptor presence. I used Raven Pro software to count and compare siskin calls/min during three flock behaviors: “departure,” when one or more siskins left the patch; “rising” when siskins would fly up into the air and circle the patch before landing again, often in response to raptor predation pressure; and “baseline” when there were no departures or rising events. I found that call rates during rising and departures were both significantly greater than baseline call rate and baseline call rate was significantly greater in patches with greater food availability. I also found that flock size increased with food availability and predation pressure. My results suggest that calls provide information about patch quality and are used to coordinate movement or departure from a foraging area.