Authors * Corina J Logan, Kelsey B McCune, Nancy Chen, Dieter LukasPlease use the format "First name initials family name" as in "Marie S. Curie, Niels H. D. Bohr, Albert Einstein, John R. R. Tolkien, Donna T. Strickland"
Abstract * <p>It is generally thought that behavioral flexibility, the ability to change behavior when circumstances change, plays an important role in the ability of a species to rapidly expand their geographic range (Chow et al., 2016; Griffin & Guez, 2014; e.g. Lefebvre et al., 1997; Sol et al., 2002, 2005, 2007; Sol & Lefebvre, 2000). However, it is an alternative non-exclusive possibility that an increase in the amount of available habitat can also facilitate a range expansion (Hanski & Gilpin, 1991; Wiens, 1997). Great-tailed grackles (Quiscalus mexicanus) are a social, polygamous species that is rapidly expanding its geographic range (Wehtje, 2003) and eats a variety of human foods in addition to foraging on insects and on the ground for other natural food items (K. Johnson & Peer, 2001). They are behaviorally flexible (Logan, 2016a) and highly associated with human-modified environments (K. Johnson & Peer, 2001), thus offering an opportunity to assess the role of behavior and habitat change over the course of their expansion. We first aim to compare behavior in wild-caught grackles from three populations across their range (core of the original range, a more recent population in the middle of the northern expansion front, a very recent population on the northern edge of the expansion front) to investigate whether: 1) certain behaviors (flexibility, innovativeness, exploration, and persistence) have higher averages and variances in some populations relative to others, and 2) individuals in a more recently established population exhibit more dispersal behavior (i.e., individuals are more likely to move away from their parents). Secondly, we aim to investigate whether habitat availability, not necessarily inherent species differences, can explain why great-tailed grackles are able to much more rapidly expand their range than their closest relative, boat-tailed grackles (Q. major) (Post et al., 1996; Wehtje, 2003). We will examine temporal habitat changes over the past few decades using existing databases on presence/absence of both grackle species and compare habitat variables to determine whether: 3) these species use different habitats, habitat suitability and connectivity (which combined determines whether habitat is available) has increased across their range, and what proportion of suitable habitat both species occupy. Finally, we will 4) determine whether changes in behavioral traits facilitate the rapid GTGR expansion by comparing their behavior with BTGR on the same tests in aim 1. Results will elucidate whether the rapid geographic range expansion of great-tailed grackles is associated with individuals differentially expressing particular behaviors and/or whether the expansion is facilitated by the alignment of their natural behaviors with an increase in suitable habitat (i.e., human-modified environments).</p>
Keywords (optional) behavioral flexibility, boat-tailed grackle, Quiscalus major, great-tailed grackle, Quiscalus mexicanus, range expansion, comparative approach
