Who we study:

Mountain chickadee

Mountain chickadees are most easily distinguished by their discrete white eyebrow. These industrious birds are easily spotted flitting through Ponderosas on Flagstaff Mountain (or anywhere mixed conifer stands predominate), on the hunt for seeds and insects. From the western fringes of the City of Boulder to tree line, mountain chickadees deliver a near-constant chorus of 'chick-a-dee's that is overall raspier than their black-capped cousins. 

Black-capped chickadee

Black-capped chickadees abound in Boulder. Their all-black cap is the clearest difference between them and the closely-related mountain chickadee. Their inquisitive nature and boldness make them an endearing bird to all naturalists. Their simple whistle song is a morning staple in nearly every corner of Boulder, but especially along creeks. 

What we study:

Black-capped and mountain chickadees are closely-related species that co-occur in Boulder County but occupy different habitats based on elevation. The Boulder Chickadee Study leverages an extensive network of nest boxes from Boulder up to the Mountain Research Station to examine how cities are changing interactions between these two species from both genomic and field-based perspectives. We pair field studies with cutting-edge genomic tools to understand interactions between these inquisitive & industrious birds.

We are broadly interested in understanding how human-modified spaces are impacting the interactions between these two species. We currently have the following on-going projects:

  • Assessing the degree of hybridization between the two species
  • Quantifying nest parasites along mountain slopes
  • Characterizing the feather patterning of the two species.



Theodosopoulos AN, Grabenstein KC, Larrieu M, Arnold V, Taylor SA. Accepted. Similar parasite communities but dissimilar infection patterns in two closely related chickadee species. Ornithology.

Grabenstein KC, Burg T, Otter K, Taylor SA. Hybridization between closely related songbirds is related to human habitat disturbance. Global Change Biology. 29:955-968. https://doi.org/10.1111/gcb.16476

Grabenstein KC, Burg T, Otter K, Taylor SA. Sympatry leads to reduced body condition in chickadees that occasionally hybridize. Ecology and Evolution. Accepted. 

Grabenstein KC, Taylor SA. 2018. Breaking Barriers: Causes, Consequences, and Experimental Utility of Human-Mediated Hybridization. Trends in Ecology and Evolution, 33(3), 198–212. doi.org/10.1016/J.TREE.2017.12.008 

In the Press

Daily Camera Article "Boulder Chickadee Study explores hybrid trends" by Jeff Mitton

Radio 1190 Interview with Kathryn and Scott!