back to start page about the 2021 MSEPF
Outlined here are the current areas of focus in the Curry Lab research program concerning hybridization in Black-capped Chickadees (BCCH) and Carolina Chickadees (CACH). Candidates for the MSEPF should consider how they could contribute in one or more of these areas. Because the position includes fairly heavy teaching responsibilities, the MSEPF should not plan on conducting research in an area that’s independent of this research program (although I would be at least willing to listen to other propositions).
Candidates need to understand funding realities, too. The Curry Lab currently has a small amount of NSF funding for the cognitive ecology component (covering supplies only, not salaries). VU’s CLAS supports the MSEPF position with $4000 of research funding per academic year, to be used at the discretion of the MSEPF and the Mentor; the Department of Biology supports the research program in other ways (e.g., routine supplies, salaries for undergraduate laboratory help, van use). I would welcome MSEPF candidates for whom seeking additional external funding would be a priority … but candidates should appreciate that opportunities for this—given time constraints and low success rates—are quite limited.
For many of the areas listed below, we have data from two decades or more that members of the laboratory can use in their research. The resources available include > 10,000 blood samples, 20+ years of demographic data from multiple field sites, and preliminary datasets for many of the topics listed.
Work on captive chickadees by Amber Rice’s group at Lehigh University showed recently that hybrid chickadees perform poorly relative to BCCH and CACH. The test included spatial memory and problem-solving. We are currently conducting fieldwork to determine whether the same cognitive deficiency is evident in wild hybrid chickadees … and if so, whether those deficiencies translate into reduced reproductive success or survival or both. This work is a collaborative supplement to ongoing NSF-funded captive work by Rice et al.
- McQuillan et al. 2018. Hybrid chickadees are deficient in learning and memory. Evolution 72:1155–1164
Our work concerning spatial memory uses the “smart feeder” system developed by Vladimir Pravosudov and colleagues in their research program involving Mountain Chickadees.
- Sonnenberg et al. 2019. Natural selection and spatial cognition in wild food-caching Mountain Chickadees. Current Biology 29:670-676.e3
The spatial memory work, as well as investigation of problem-solving, relies on Radio Frequency Identification (RFID) technology and passive integrated transponder (PIT) tags attached to the birds as an integral plastic leg band.
We have been using RFID methods also to investigate social network structure and dynamics in mixed populations of hybridizing BCCH and CACH, and in a pure population of CACH for its own sake.
This work is continuing: it provides social context for the measures of cognitive performance, while also helping us understand dominance relationships and influences of social structure on pair formation and extra-pair paternity.
In 2020, we began PIT-tagging Tufted Titmouse (TUTI) also. This part of the research program aims to determine whether TUTI asymmetrically affect BCCH, CACH, and hybrids in mixed populations in ways that could affect the dynamics of hybridization.
We have focused on personality variation between the chickadee species (and hybrids) and within genotype categories, to investigate the possibility that personality affects mating patterns in hybridizing chickadees. This work also considers genetic influences on personality by comparing phenotypes across chickadee species and their hybrids. Personality traits we have investigated include:
- Exploratory behavior using a portable “aviary” (test box)
- Anti-predator boldness in the context of nest defense
As a potential prezygotic isolating mechanism, song is an important trait to consider in hybridizing songbirds. Additionally, song production is known to affect extra-pair parentage in BCCH. However, because song is learned in chickadees, it correlates only weakly with species-level genotypes of individual males.
We have explored the role of song in chickadee hybridization—both as an influence on mating and as a product of introgressed genotypes—in BCCH and CACH. This work has combined measurement of dawn chorus participation by individual males (monitored using Autonomous Record Units, ARUs) and playback experiments.
Achromatic plumage brightness, including variation in the UV part of the spectrum, correlates with dominance and influences mating patterns in BCCH. We have investigated plumage patterns in hybridizing chickadees, using a portable field spectrometer, with the same questions in mind but have not “put this to bed.”
There is ample reason to think that dominance relationships influence both social pairing and extra-pair paternity in hybridizing chickadees … but directly measuring social dominance in our field systems has proven to be a major challenge. We are currently working to gather data on dominance interactions in conjunction with our RFID-based SNA work … but additional opportunities exist here.
Some opportunity exists for genomic approaches to questions about the behavior of hybridizing chickadees. Our publication in 2020 of work that includes a full BCCH reference genome provides a foundation. MESPF candidates should appreciate, however, that our collaborator Scott Taylor (U of Colorado) is the lead investigator for this aspect of the overall research program concerning BCCH × CACH hybridization. Further work involving genomic approaches is possible, but we would need to negotiate roles with our collaborators.
- Wagner et al. 2020. Genomic regions underlying metabolic and neuronal signaling pathways are temporally consistent in a moving avian hybrid zone. Evolution 74:1498–1513