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To meet thermoregulatory demands associated with northern winters, turkeys must
increase food consumption, reduce energy expenditure, or use energy reserves (Pekins 2007).
When snow limits availability of ground forage (e.g., corn and acorns) or agricultural foods are
unavailable, turkeys are forced to use foods of lower nutritional value and energy content (Pekins
2007). In diet characterized by negative energy balance, juvenile hens are the first to succumb
(because they have the smallest energy reserves), followed by adult hens (Porter et al. 1983,
Roberts and Porter 1996, Pekins 2007).
In this study, I will evaluate wild turkey food habits during winter on the northern fringe
of their range in Minnesota. I will specifically investigate the association of agriculture and
snow conditions with food habits and body condition.
Objectives
1. Determine winter foods used by wild turkeys on the northern fringe of their range in Minnesota.
2. Describe diet as a function of agriculture and snow conditions.
3. Compare body condition of wild turkeys with access to high-energy diets to those without.
Study Areas
This study will be conducted north of Minnesota‟s ancestral wild turkey range (Leopold 1931)
where wild turkey populations have been recently established (Minnesota Department of Natural
Resources 2006). This region is located within the Western Superior Uplands (WSU) and Northern
Minnesota Drift and Lake Plain (MDL) Ecological Sections of the Laurentian Mixed Forest Ecological
Province (Minnesota Department of Natural Resources 2003). The 25,959 km 2 study area is comprised of
35% upland deciduous forest, 31% crop/grass, 16% aquatic environment, 10% shrubland, 4% upland
conifer forest, 2% lowland conifer forest, 2% lowland deciduous forest, 1% non-vegetated (GAP Land
Cover Minnesota Department of Natural Resources 2008). This area includes the following counties;
Becker, Clearwater, Mahnomen, Hubbard, Ottertail, Wadena, Cass, Crow Wing, Morrison, Todd, Benton,
Aitkin, Mille Lacs, Kanabec, Isanti, Carlton, Pine, and Chisago.
The mean annual snowfall for this region from 1971-2000 ranged from 100 to 127 cm per year,
and averaged 40 days per year with snowfall accumulations of 30 cm or greater. The mean winter
temperature (December – February) from 1971 – 2000 was –12 C (Minnesota Climatology Working
Group 2008).
Methods
I will evaluate food habits in relation to snow condition and habitat type by examining crop and
gizzard contents of wild turkeys collected during 2 winters (December 2008 – March 2009 and December
2009 – March 2010). Using a fixed wing aircraft, I will locate wild turkey flocks using a random
sampling strategy that will be stratified by presence/absence of agricultural foods and presence/absence of
snow conditions that limit mobility. A small number of birds (e.g., 1 – 5 turkeys) from each flock will be
collected in late afternoon or early evening, when crops are most likely to be full (Hillerman et al. 1953),
by shooting. Date, snow depth, snow condition (e.g., crusted vs. powder snow), temperature, habitat
class, and geographic coordinates will be recorded at each collection site.
2009 Conservation Program Report
Page 218