Brian M. Jensen, Department of Biology, University of Nebraska Kearney,  Kearney, Nebraska 68849-1140, USA 

Mentor:  Dr. Joseph T.  Springer, Professor, Department of Biology, University of Nebraska at Kearney, Nebraska 68849, USA.  Email:  springerj@unk.edu) 
 

To Cite This Paper:

Jensen, B. M.  2003.  Determining the indexing possibilities of defecation rate for wild turkeys in south central Nebraska.  Research Thesis, Department of Biology, University of Nebraska at Kearney, Kearney, Nebraska.

ABSTRACT

Key Words:  defecation rate, Nebraska, population index, Meleagris gallopavo, wild turkey.
 

The return of the wild turkey (Meleagris gallopavo) to Nebraska, other states that historically had turkey population, and to states previously outside the historic range is generally considered one of the great success stories of wildlife management (Suetsugu et al. 1996).  The six subspecies were extirpated from 18 of their original 39 states by early in the twentieth century (Eaton 1992).  This included the eastern (M. g. silvestris) and perhaps the Rio Grande (M. g. intermedia) species from Nebraska by 1880 (Grier 1996).  Release of pen-raised birds began in the 1930’s but met little success (Suetsugu et al. 1996).  It was not until 1959 that transported birds were released and the true recovery began.  Turkeys currently occupy every state but Alaska and inhabit more square miles of habitat than any other gamebird (Suetsugu et al. 1996).  Current population in the U.S., Alberta, Manitoba, and Ontario was estimated at 3.5 million in 1990 although several states gave no estimate (Kennamer and Kennamer 1990).  Fig. 1 shows the approximate current range of the wild turkey.

Fig. 1.  The approximate range of the wild turkey in the United States (Stangel et al. 1992).

Because it is estimated that there is a 45% turnover in turkey population from one winter to the next, without disease outbreak, it is important to have accurate population numbers (Suetsugu et al. 1996).  In Nebraska, population monitoring is done using a variety of methods. Hunter harvest information, using a random mailed questionnaire and feathers returned by hunters, provides much information on both age and sex of the harvested birds.   Winter flock counts, primarily performed by cooperative landowners, provide information on potential breeding populations.  The Nebraska Game and Parks Commission then conducts brood surveys in July/August (Suetsugu et al. 1996).  In most states, indexing of wild turkey populations are done using only spring brood counts and flush surveys (Stevens and Porter 1998).  These methods have proven accurate but budget restraints or legislative deadlines may preclude further use of this method for setting hunting seasons (Wunz and Ross 1990).  In addition, these methods are very labor intensive when trying to get accurate estimates.  Brood/flush counts, the methods employed by most states, are only effective during the spring/early summer of the year when broods are fledging. Therefore, another index could be helpful.  Fecal pile counts and the animals corresponding defecation rate have been used to index other species, such as deer (Rogers 1987).

Unfortunately, little is currently known about the defecation rate and thus its indexing possibilities for wild turkey.  The objective of this experiment is to accurately determine the defecation rate of the wild turkey using a controlled setting.

Gray and Prince (1988) found no metabolic differences between wild and game farm animals, which would suggest that captive turkeys should have nearly equal defecation rates as wild individuals.  Further, Haroldson et al. (1998) found no difference in the field metabolic rates (FMR) between adult and juvenile hens and therefore no correlation between metabolic rate and body mass.  They did however find that metabolism increased with decreasing temperature (Haroldson et al. 1998).  It was hypothesized that there would be a difference between the defecation rate of captive and wild turkeys.
 

STUDY AREA

The captive study site was located on a captive wildlife area 1 km South of Elm Creek , Nebraska (40.72 N, 99.25 W) owned by Delos McKee.  The captive study was performed in the fall of the year (Sept.-mid Oct.), during which the weather was drier than normal.  There were two pens, each measuring 13’ wide by 70’ long, with a total of 11 turkeys.  This study area is rolling hills that in its climax would be a combination of mixed and tall grass prairie.  The ground cover is mostly bare dirt and gravel although some smooth brome (Bromus inermis) persists.  Thus, the area is an enclosed pen under full sun, which was originally thought to yield a different defecation rate than wild birds.

The Alda wild site was located on Nebraska Whooping Crane Trust land along the Platte River.  This river area, although interspersed with prairie and grain fields, was largely riparian habitat containing Eastern cottonwoods (Populus deltoides), Russian olive (Elaeagnus angustifolia), Siberian elm (Ulmus pumilla), green ash (Fraxinus pennsylvanica) and various species of willow (Salix spp.).  These trees are concentrated near the river and surrounded by smooth brome (Bromus inermis), reed canary grass (Phalaris arundinacea), and native grass plantings of big bluestem (Andropogon gerardi) and Indian grass (Sorghastrum nutans).

The Cottonmill Park area is located within 50 yards of the Cottonmill Lake just West of Kearney, Nebraska.  The birds roost in large eastern cottonwoods (Populus deltoides) surrounded by eastern red cedars (Juniperus virginianus) and smooth brome grass.  Figs. 2 and 3 show the approximate areas of the three research areas mentioned above.
 

The research area’s habitats compares to a literature preferred habitat of white pine (Pinus strobes) and hemlock (Tsuga Canadensis) (Coup and Perkins 1999) or tall, overmature ponderosa pine (Pinus ponderosa), douglas fir (Pseudotsuga taxifolia), white fir (Abes concolor), and narrowleaf cottonwood (Populus angustifolia) (Hoffman 1968).

The recent restoration in the Midwest has shown that populations can thrive in areas with less than 50% timber, unlike the past when it was believed that large timber tracts were necessary (Ellis and Lewis 1967). This was seen by Vander Haegen et al. (1989) when they realized that turkeys used cropland, pasture, and softwood timber habitat more and hardwood, mixed wood, and abandoned fields less than expected. With relatively few woodland acres, Nebraska proves the previous point by consistently ranking in the top 20 in the nation in turkey harvest (Suetsugu et al. 1996).
 

MATERIALS AND METHODS

The defecation of wild turkeyswas measured frequently during the study period of September 1- 15 October 2002 on the captive wildlife site.  A total of 11 turkeys was placed in two pens, seven in one pen, four in another.  These were domestic black Spanish and red bourbon turkeys. All of the animals were approximately 3 _ years old, but since no metabolic difference has been shown between adult birds and juveniles (Haroldson et al. 1998) the age of the birds probably had little effect on the defecation rate. The pens were approximately 22.5 m X 4 m constructed of steel T posts surrounded by 1.75-m tall wire fencing.  The fecal piles in each pen were surveyed nearly every other day.  After the data were collected, the ground was cleared of existing fecal piles using water or shovel.  The turkeys were provided with a roost made of plastic for night roosting and for inclement weather.

The turkeys were fed a diet consisting of Dumor® chick starter/grower 20%, meaning 20% crude protein.  The feed contains cracked corn, wheat, millet, and milo in addition to about 50% more corn added by Mr. McKee.  The turkeys will be given a constant source of water.  The feedings occurred in the evening of each day (ca. 1700-1800 hours).  This was the schedule followed by Mr. McKee.  This compares to a normal diet of vegetable matter with smaller amounts of animal matter, primarily invertebrates and cold-blooded vertebrates but varies widely by area (Korschgen 1967).  In the south and west in its range primary foods include acorns and dogwood seeds (Dickson 1990) while in Texas green plant material followed by acorns, skunkberry (Rhus triloba), doveberry (Croton spp.) and Hackberry (Celtis spp.) (Korschgen 1967).

Similar methods were used for the wild turkey sites.  Roost sites, with known numbers of roosting birds, were cleared of fecal piles nearly every other day.  The data collected from each overnight period were counted as one-half day period (12 hours).  As with the captive site, data was not collected during or directly after very wet weather that may have made the fecal pile counts inaccurate.
 

RESULTS

Throughout the research period, 59 fecal pile data points were collected (Table 1) with an overall average of 5.12 fecal piles/turkey/day.  The two captive pens had a total of 17 data points collected with averages of 5.17 for the West pen and 5.13 for the East pen.  Meanwhile, the Alda site had an average of 5.21 with 11 data points.  The Cottonmill park area had an average of 4.99 with 14 data points.  The overall data are also represented in the graph that shows the change, or lack there of, in defecation rate by research area and by research date by research area (Fig. 4).

Table 1.  A list of the determined defecation rates by date and by indivual research site.  This represents an overall average of 5.12 piles/bird/day.

Fig. 4.  Defecation rates of the various research sites by collection day.  No significant differences were seen between the defecation rates of the 4 areas.

When analyzed by month using an ANOVA test, there was no significant variance between the defecation rates of September (n= 5.01), October (n= 5.26), November (n= 5.15), December (n= 5.12), January (n= 4.99), and February (n = 4.95) (P<.95).

It appears that defecation rate could provide a viable indexing tool for wild turkeys in the fall and winter of the year.
 

SIGNIFICANCE

Determination of the wild turkey defecation rate in the early fall (Sept.-Oct.) of 2002, could potentially have wide use as an indexing tool for wildlife biologists nationwide.  On a smaller scale, this tool would be very helpful for individuals who are trying to get a population estimate for their favorite turkey-hunting site by simply surveying defecation at roost sites.  One can do this without incurring much cost and virtually no space requirements. Once the defecation rate is determined, an accurate population estimate would also take very little effort or cost.

One could simply walk a 1-m wide transect for a pre-determined distance (probably about 200 m) while looking for turkey feces.  This area (200 square meters) divided by the total area of the given habitat, would give the percentage of habitat covered by the transect.  This area would then be multiplied by the determined defecation rate to give an accurate population index for the habitat.  The given example would likely take no more than an hour.  Longer transects and slightly more time could be used to yield more sensitive index estimates.
 

FUTURE RESEARCH

It would be helpful if this research were further quantified with more results over a wider time frame to include the spring and summer seasons when no data were collected for this project.  It would be interesting to see if the defecation rate remains the same throughout the “growing” seasons when the birds’ diets undoubtedly change to one of more protein from insects, etc.

Further, it would be helpful if similar studies were conducted in different parts of the country and thus in different habitats.  If this were done, and a conclusive average defecation rate for turkeys was found, then turkey population sizes could be determined  throughout North America.
 

LITERATURE CITED

Bailey, E. W.  1956.  Sex determination of adult wild turkeys by means of dropping configuration.  Journal of Wildlife Management 20:220.

Coup, R. N., and P. J. Perkins.  1999.  Field metabolic rate of wild turkeys in winter.  Canadian Journal of Zoology 77(7):1075-1082.

Dickson, J. D.  1990.  Oak and flowering dogwood fruit production for eastern wild turkeys.  Proclamation at National Wild Turkey Symposium 6:90-95.

Eaton, S. W.  1992.  Wild Turkey.  Birds of North American 22:1-27.

Ellis J. E., and J. B. Lewis.  1967.  Mobility and annual range of wild turkeys in Missouri.  Journal of Wildlife Management 31(3):568-581.

Gray, B. T.  1986.  Bioenergetics of the wild turkey in Michigan.  Thesis, Michigan State University, East Lansing.

Gray, B. T., and H. H. Prince.  1988.  Basal metabolism and energetic cost of thermoregulation in wild turkeys.  Journal of Wildlife Management 52:133-137.

Grier, B.  1996.  The wild turkey’s return.  Nebraskaland Magazine 74(8):35.

Haroldson, K. J., M. L. Svihel, and R. O. Kimmel.  1998.  Effect of winter temperature on wild turkey metabolism.  Journal of Wildlife Management 62(1):299-305.

Hoffman, D. M.  1968.  Roosting sites and habit of Merriam’s turkeys in Colorado.  Journal of Wildlife Management 32(4):859-866.

Kennamer, J. E. and M. C. Kennamer.  1990.  Current status and distribution of the wild turkey 1989.  Proclamation of National Wild Turkey Symposium 6:1-12.

Korschgen, L. J.  1967.  Feeding habits and food. Pages 137-198 in J. G. Dickson (ed.) The Wild Turkey:  Biology and Management. Stackpole Books, Harrisburg, Pennsylvania.

Oberlag, D. F., P. J. Perkins, and W. W. Mautz.  1990.  Influence of seasonal temperatures on wild turkey metabolism.  Journal of Wildlife Management 54:663-667.

Rolley, R. E., J. F. Kubisiak, and R. N. Paisley.  1998.  Wild turkey population dynamics in southwestern Wisconsin.  Journal of Wildlife Management 62(3):917-924.

Rogers, L. L.  1987.  Seasonal changes in defecation rates of free-ranging white-tailed deer.  Journal of Wildlife Management 51:330-333.

Suetsugu, H., K. Menzel, and B. Grier.  1996.  The wild turkey in Nebraska.  Nebraskaland magazine 74(8):N1-N15.

Stangel, P. W., J. I. Smith, and P. L. Leberg.  1992.  Systematics and population genetics.  Pages 18-28 in J. G. Dickson (ed.) The Wild Turkey:  Biology and Management. Stackpole Books, Harrisburg, PA.

Vander Haegen, W. M., W. E. Dodge, and M. W. Sayre.  1989.  Winter use of agricultural habitats by wild turkeys in Massachusetts.  Journal of Wildlife Management 53:30-33.

Wunz, G. A., and A. S. Ross.  1990.  Wild turkey production, fall and spring harvest interaction, and responses to harvest management in Pennsylvania.  Proceedings of the National Wild Turkey Symposium 6:205-207.

Jensen, B. M.  2003.  Determining the indexing possibilities of defecation rate for wild turkeys in south central Nebraska.  Research Thesis, Department of Biology, University of Nebraska at Kearney, Kearney, Nebraska.