PART IX — TERRESTRIAL ECOSYSTEMS 



3. FOREST ANIMALS 



Problems of Animal Ecology in Forested Areas 



Traditionally, the study of animal 

 ecology in forested areas of the 

 United States has been concerned 

 only with species that are either in- 

 jurious to man or to forests or are 

 game animals of interest to the 

 hunter. To these original concerns — 

 i.e., the impact of animals on the 

 forest and the availability of animals 

 for man — we should now add two 

 more: (a) the impact of man on forest 

 animals, and (b) the needs of forest 

 animals for suitable habitat. 



Large and small forest animals and 

 birds affect man's aesthetics, eco- 

 nomics, and, occasionally, his health. 

 Furthermore, the greatly increasing 

 pressure of man on the wildlife re- 

 source of the forests has created seri- 

 ous problems. Sometimes control of 

 animal populations is necessary or 

 desirable; this is true in the urban- 

 suburban fringe as well as in na- 

 tional parks and private recreation 

 areas. At other times, the need is to 

 promote the integration of forest 

 wildlife into the urban and semi- 

 urban scene, where the presence of 

 wildlife provides an antidote to some 

 of the stresses of urban living. 



The State of Animal Ecology 

 Research 



Forest animals vary greatly in their 

 adaptations, both to the type of forest 

 and to the relative amounts of forest 

 and open land that they require. 

 Many forest animals are more accu- 

 rately forest-edge animals; the white- 

 tail deer is a prime example, and any 

 consideration of white-tail habitat 

 must involve the relative proportions 

 of forest and opening. In addition, 

 year-to-year differences in environ- 

 mental conditions may have drastic 

 influences on the animals. The im- 

 pact of winter weather on the survival 



of the ruffed grouse is a case in point. 

 Low temperatures, snow depth, and 

 the conditions of the surface of the 

 snow all play a part in the survival 

 of the bird: that is, ruffed grouse can 

 survive long periods of extreme cold 

 provided that adequate snow is avail- 

 able and uncrusted, so that the bird 

 can penetrate into the snow for night 

 roosting. With deer, light snow per- 

 mits ready movement but deep snow 

 restricts it. Similarly, environmental 

 differences between locations influ- 

 ence the behavior, feeding ability, and 

 survival of an animal population. 



Data Base — A reasonably ade- 

 quate base of data on forest animals 

 already exists. This is particularly 

 true for those animals important to 

 the hunter and sportsman, such as the 

 white-tail deer, ruffed grouse, wild 

 turkey, and gray squirrel. Data are 

 gradually accumulating on the life 

 histories and behavior of various car- 

 nivores, including the black bear, 

 bobcat, coyote (in forest habitats, 

 especially), and timber wolf, as well 

 as on many smaller mammals, both 

 predators and herbivores. 



Knowledge of gross food supplies 

 for forest herbivores is readily avail- 

 able, but more important are the data 

 now being gathered pertinent to the 

 calorie content of this food and to the 

 fluctuation in mineral constituents — 

 i.e., on the quality of the animals' 

 food. Much data have been accumu- 

 lated on browse for white-tail deer, 

 lesser amounts of information on 

 fruits and nuts. 



But there are sizable gaps in our 

 understanding of the utilization of 

 food and shelter. Little is yet known 

 of the reasons why certain plant spe- 

 cies are consumed in preference to 

 others, nor are the changes in rumen 

 flora of the white-tail deer under- 



stood. Virtually no information is 

 available on forms of food materials 

 like forest herbs and aquatics. We 

 are just beginning to discover some 

 of the nuances of the summer food 

 habits of deer, the diversity of foods 

 used (particularly herbaceous mate- 

 rials), and the impact that summer 

 food selection may have on deer 

 habitat. Additionally, although we 

 know that crossbills and finches use 

 seeds of forest trees in quantity, we 

 know little of the relationship of 

 these bird populations to tree seed 

 crops. Food selection, utilization, and 

 availability are thus areas open to 

 considerable work relative to most 

 forest animals and birds. 



Instrumentation — The advent of 

 radio telemetry has done much to in- 

 crease knowledge of the home range 

 and behavior patterns of a number of 

 animals and birds. For example, 

 movement patterns of owls have been 

 studied in Minnesota and the hunting 

 pattern of barred owls delimited. 

 (The owl hunts in one area until prey 

 populations have dropped — i.e., un- 

 til hunting is unprofitable; it then 

 moves on to another location and 

 another and in time returns to the 

 original spot when mice populations 

 have again reached a suitable level.) 

 Telemetry is also producing informa- 

 tion on deer behavior as well as 

 movement patterns for such animals 

 as the grizzly bear and the timber 

 wolf. 



The impact of radio telemetry on 

 knowledge of animal behavior is al- 

 ready great, but there is ample room 

 for additional studies of movement 

 patterns and even more opportunity 

 for telemetry of physiological param- 

 eters. Improvements are presently 

 being made in the technology, and 

 much information of value will likely 

 be gained thereby. 



302 



