Influence of Light and Weather on Observability of Iowa Deer

Abstract

The individual and combined effects of light intensity and various weather phenomena on numbers of white-tailed deer (Odocoileus virginianus) seen per observation were correlated by multipleregression analysis using the model with deer sighted (adults, juveniles, anterless, antlered, and unknown) versus sunset or sunrise time, time of sighting, location, lunar phase, minimum daily temperature, maximum daily temperature, wind direction, wind velocity, nebulosity, type of precipitation, amount of precipitation, type of ground cover, and amount of snow on the ground. Observations were made from a blind during crepuscular periods from September through May. A significant relationship (P < 0.05) to the number of deer sighted per sighting existed with the effects of: time of sunrise, time of sunset, maximum temperature, minimum temperature, wind direction, wind velocity, and ground cover. These effects were not the same for all age and sex classes, and in some instances, different effects were observed for the dawn and dusk periods. J. WILDL. MANAGE. 38(2):220-228 The influence of daily light intensity and various weather phenomena on deer movement has been cited by several authors (Darling 1937, red deer; Linsdale and Tomich 1953, mule deer; Loveless 1964, mule deer; Dasmann 1954, black-tailed deer; Moen 1968, white-tailed deer; Buss and Harbert 1950, black-tailed deer). Because of the current emphasis on the esthetic aspect of wildlife and on the intensive management of white-tailed deer in many states it is appropriate to investigate what environmental factors influence the chances of one observing deer in their natural habitat. To obtain this information, various light and weather criteria thought to influence deer activity were considered as one aspect of a general study (Zagata 1972) of deer movement in the intensively farmed region of north-central Iowa. Deer were observed from December 1969 through May 1972 to provide basic information for deer management in north-central Iowa. The objectives were to: (1) determine if light intensity and various selected weather parameters were related to the number of deer sighted during crepuscular periods, (2) secure data useful for effective deer management. Thanks are due the Iowa State Conservation Commission and the U.S. Bureau of Sport Fisheries and Wildlife for funding the study and to J. Anderson of the Iowa State Conservation Commission for his field assistance. Special acknowledgment is given to H. Clausen and L. Yerxa for their help in preparation of this manuscript.