A Study of Two Chickadees

A female Black-capped Chickadee sits near her brood of freshly banded and measured chicks. Photo: M. Larrieu

Mia Larrieu, one of four recipients of the 2022 WFO research grants, describes the results of her work in the field as part of a long-term study of chickadees in Boulder County.

Quantifying the effects of urbanization and hybridization on chickadee nestling development rates along the Colorado Front Range

The focus for the 2022 field season was to study the nesting period of breeding Black-capped Chickadees (Poecile atricapillus) and Mountain Chickadees (Poecile gambeli) in Colorado. This work is an essential aspect of the Boulder Chickadee Study, a long-term study system that leverages a network of over 370 wooden nest boxes placed throughout Boulder County. It was established in the Taylor Lab at the University of Colorado Boulder and continues to expand in research scope.

In summer of 2022, my field crew and I put USGS bands on adults and chicks and kept track of the nest-building process throughout the breeding season. I was most interested in nestling growth and development, so in addition to collecting morphological data such as body mass, wing length, and tarsus length, I made note of when nestlings fledged from the nest. Overall, we banded over 300 chickadees and monitored over 70 nests—a very productive field season indeed!

This was also my first year as a field crew leader supervising a team of five crew members. I got to practice my leadership skills in a meaningful way while managing the day-to-day logistics so the field season could run as smoothly as possible. It was rewarding to train my crew on how to safely band birds and to see their field ornithology skillset improve as the season went on. Currently, I’m using our collected data to determine if there are any interesting social mating patterns that exist in our population across location and between the two chickadee species.

The funding I received was used for transportation, and without it, I would not have been able to travel to field sites that spanned over three major areas in Boulder County. I am very appreciative to WFO as well as all the donors who supported me and my research through this grant.

—Mia Larrieu, University of Colorado Boulder

Mia Larrieu

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