RUI: Mechanisms Regulating Facultative Migrations of the Pine Siskin

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Proposal Title: RUI: Mechanisms regulating facultative migrations of the Pine SiskinInstitutions: Loyola Marymount University, and a partnership with UC-DavisAbstract Date: 03/13/2015Migratory behavior can be characterized by regular and predictable seasonal and directional movements, or the movements may be much less predictable with respect to both timing and direction. The less predictable movements, known as facultative migration, are much more difficult to study. This project will investigate the drivers of facultative migration in a captive species of bird, the pine siskin (Spinus pinus). The goals of the project are to assess 1) What cue(s) trigger the development of a migratory stage; and 2) What endocrine hormones mediate the migratory response? Four cues (photoperiod, food availability, population density, and mate availability) and two hormones (corticosterone and testosterone) will be investigated. Understanding how animals respond to environmental variability is critical in today's changing climate. The project will train a post-graduate researcher at a primarily undergraduate institution, and will involve large numbers of undergraduates, including those from underrepresented groups. The lead investigator is a beginning investigator.The project will systematically and comprehensively investigate the mechanisms underlying facultative migration, a suite of behaviors that are taxonomically widespread. It is the captive avian model organism that enables this research. Four different hypotheses will be investigated as part of the first goal of the project: (i) an increasing photoperiod stimulates facultative migration in the spring; (ii) declining food availability stimulates the development
of migration; (iii) high local population density, prior to a decline in food availability, can trigger the transition to a migratory
 stage; and (iv) that a shortage of potential mates can stimulate migration around the time of breeding. Two additional hypotheses will be investigated as part of the second goal: (i) increased circulating corticosterone levels stimulate 
the development of a migratory stage; and (ii) the transition to a migratory stage is stimulated
 by increased circulating testosterone levels. Experiments will include manipulating the environmental triggers and tracking behavioral and physiological responses, and direct manipulation of the endocrine hormones. The combined approaches will provide significant opportunities for research training at a primarily undergraduate institution. The team will work with the Loyola Marymount University Center for Urban Resilience to develop and disseminate materials to be used in Los Angeles area schools.