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Great-tailed grackles – Central and North America


  • Principal investigator: Corina Logan
  • MPI-affiliated researchers:
    • Aaron Blackwell
    • Anne Kandler
    • Richard McElreath
    • Dieter Lukas
  • Site founded: December 2013

Site Details

In 2013, I set up a great-tailed grackle field site in Santa Barbara, California as part of my SAGE Junior Research Fellowship at the University of California Santa Barbara. Grackles began colonizing the Santa Barbara area in the 1990s, so it is a relatively recent population. This species is sexually dimorphic in plumage and behavior, and their mating system is polygamous: one to a few males defend a territory, and females build nests on these territories and raise the young. Grackles are generalist foragers and highly associated with human populations: they eat our garbage, crops, and at our outdoor cafes.

With support from the Department of Human Behavior, Ecology and Culture at MPI EVA, I established a second field site in 2017 in Tempe, Arizona to begin population comparisons. Grackles have been in the Tempe area since the 1980s, so this is a slightly older population than the one in Santa Barbara. Starting in 2019, more sites will be established that span their geographic range: one site will be in the middle of their original range and will be a much older population, while the other will be on the northern edge of their range and very young. This will allow me to investigate what differences are associated with edge populations that might give them an advantage to populate new environments.


What is behavioral flexibility and is it a mechanism for surviving in new environments?

Behavioral flexibility, the ability to adapt behavior to new environments and problems, is thought to play an important role in a species' ability to successfully invade. However, behavioral flexibility is rarely directly tested in species in a way that would allow us to determine how it works and how we can make predictions about a species' ability to adapt their behavior to changing circumstances. I use great-tailed grackles (a bird species) as a model to study this question because they have rapidly expanded their range into North America in the past 120 years. I found that they are behaviorally flexible and that flexibility is independent from problem solving ability, problem solving speed (Logan 2016a), other behaviors (Logan 2016b), and innovativeness (Logan 2016c), and that grackles can solve some problems with a similar efficiency to New Caledonian crows (Logan et al. 2014). I am currently investigating how great-tailed grackles manage to survive in new environments by testing their behavior, immunity, hormones, parasites, and population genetics in three populations from the middle of their range to the expanding northern edge.

Selected Publications

Logan, C. J., MacPherson, M., Rowney, C., Bergeron, L., Seitz, B., Blaisdell, A., Johnson-Ulrich, Z., & McCune, K. (in press). Is behavioral flexibility manipulatable and, if so, does it improve flexibility and problem solving in a new context? (http://corinalogan.com/Preregistrations/g_flexmanip.html) In principle acceptance by PCI Ecology of the version on 26 Mar 2019 (https://github.com/corinalogan/grackles/blob/master/Files/Preregistrations/g_flexmanip.Rmd). 

McCune, K., McElreath, R., & Logan, C. J. (in press). Investigating the use of learning mechanisms in a species that is rapidly expanding its geographic range. (http://corinalogan.com/Preregistrations/g_sociallearning.html). In principle acceptance by PCI Ecology of the version on 11 Oct 2019 (https://github.com/corinalogan/grackles/blob/master/Files/Preregistrations/g_sociallearning.Rmd).

Logan, C. J., McCune, K., MacPherson, M., Johnson-Ulrich, Z., Bergeron, L., Rowney, C., Seitz, B., Blaisdell, A., Folsom, M.,  & Wascher, C. A. F. (in press). Are the more flexible individuals also better at inhibition? (http://corinalogan.com/Preregistrations/g_inhibition.html) In principle acceptance by PCI Ecology of the version on 6 Mar 2019 (https://github.com/corinalogan/grackles/blob/master/Files/Preregistrations/g_inhibition.Rmd).

Blaisdell A, Johnson-Ulrich Z, Bergeron L, Rowney C, Seitz B, Folsom M, McCune K, Logan CJ. (in press). Do the more flexible individuals rely more on causal cognition? Observation versus intervention in casual inference in great-tailed grackles. (http://corinalogan.com/Preregistrations/g_causal.html) In principle acceptance by PCI Ecology of the version on 31 Jan 2019 (https://github.com/corinalogan/grackles/blob/master/Files/Preregistrations/g_causal.Rmd). 

Logan CJ. 2016. Behavioral flexibility and problem solving in an invasive bird. doi:10.7717/peerj.1975

Logan CJ. 2016. Behavioral flexibility in an invasive bird is independent of other behaviors. doi: 10/c598

Logan CJ. 2016. How far will a behaviourally flexible invasive bird go to innovate? doi: 10/c599