Undergraduate Research: An Archive - 2021 Program

Alice Egar ’21
ECOLOGY AND EVOLUTIONARY BIOLOGY
Senior Thesis Research Funding Awardee
BIODIVERSITY AND
CONSERVATION
THESIS TITLE
Responses of Broadtailed
Hummingbird
Foraging Behavior to
Climate Change Across
Multiple Temporal
Scales
ADVISER
Mary (Cassie) Stoddard,
Assistant Professor of
Ecology and
Evolutionary Biology
Each summer, broad-tailed hummingbirds
(Selasphorus platycercus) migrate from their
overwintering grounds in Central America to
their breeding grounds in the western United
States. As climate change causes the timing
of hummingbird migration and wildflower
bloom to shift at different rates, this plantpollinator
mutualism is at risk of temporal
mismatch. To determine how climate change
may affect hummingbird foraging patterns, I
analyzed time-lapse footage from Colorado of
hummingbirds visiting flowers in two years with
very different climatic conditions. Contrary to
my expectations that foraging would be more
restricted in the year of earlier snowmelt, I
found that in the year of very late snowmelt,
hummingbirds extended their daily foraging
periods and visited less favored flowers, which
is indicative of resource limitation. I also found
that networks of hummingbird-plant interactions
varied greatly across time, and that diel patterns
in hummingbird foraging varied depending on
flower species and environmental conditions. My
study highlights the flexibility of hummingbird
behavior in response to environmental variation
and points to the utility of long-term camera trap
studies of plant-pollinator interactions as a way
to better understand these networks and their
responses to climate change.
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