Characterization of a Local Population of Black-capped Chickadees (P.
carolinensis), Carolina Chickadees (P. atricapillus), and their hybrids – a
preliminary genetic analysis.
Eric Zluhan, Corbin Salthouse & Gabriel Colbeck
Introduction
Methods
 We set out bird feeders to attract chickadees
 22 Chickadees were captured 1. in mistnets
at bird feeders and 2. using song playback
 50 microliter blood samples were taken from
the brachial vein
 Measurements were taken of the birds’
wings, nares, and legs
 The birds were each tagged with a unique
plastic color band combination and a unique
Fish & Wildlife aluminum band
 Mitochondrial DNA was extracted from the
chickadee blood samples
 PCR protocol was ran using forward primer
0
HBCCHCR (5 -AATAGCGCGGTTTAACG30) and reverse primer LBCCHCR (50CATGCTTTAYAGGGTATGC-30)
 Sequencing of the mtDNA is forthcoming
 Song characterization of marked individuals
is forthcoming
Black-capped Chickadees and Carolina
Chickadees come into contact and ‘hybridize’
within a narrow zone in the eastern region of the
United States. Hybrids can possess physical
traits of either purebred species, making
identification of the chickadees in the zone
difficult for field observations. Our project
sought to establish a marked population of
chickadees around the Maryville campus. We
sought to use 1. mtDNA genetic analysis; and 2.
song attributes to identify potential hybrids and
potential pure breeds. Here, we outline our
preliminary field and lab work, and discuss the
long term goals of the project.
Discussion/Further
Research
Map of eastern United States
illustrating the hybrid zone
(green) of the Chickadee species.
http://goo.gl/27IfN
Current Objectives
 Catch and color-mark ~40 individual
chickadees breeding on the Maryville campus
 Record and measure song characteristics from
all marked males
 Analyze DNA samples from captured
individuals – determine if their mtDNA is
‘Black-capped’ or ‘Carolina’
 Look for mismatches between song and
mtDNA that could indicate potential hybrids
 Determine ratio of Blackcapped/Carolina/potential hybrids in local
population.
A. A recently banded
chickadee
B. Setting up a mistnet to catch
chickadees
C. Corbin Salthouse taking
morphological
measurements of a
chickadee
D. Eric Zluhan working with
chickadee DNA
E. A gel showing preliminary
mtDNA PCR product
Previous studies (in Pennsylvania) have shown
that the Black-capped/Carolina hybrid zone is
moving northward. The dynamics of the local
hybrid zone remain unstudied. After
characterizing the local population via song and
mtDNA, we would like to study the causes and
consequences of hybridization in the local
population. Our long term project would like to:
 Analyze nuclear DNA of the local population
 Establish ~40 bird houses and a marked
population of breeding individuals
 Determine mating patterns, and infer if
hybrids have lower fitness
 Look for correlations between song
characteristics and reproductive success (e.g.
do males who sing Carolina songs have
higher reproductive success?)
 Compare our current results with historical
records to infer if the hybrid zone is moving
Reference: Reudink*, M. W., S. G. Mech, S. P. Mullen*, and R. L. Curry. 2007. Structure and dynamics of the
Black-capped Chickadee (Poecile atricapillus) and Carolina Chickadee (P. carolinensis) hybrid zone in
southeastern Pennsylvania. Auk 124:463-478