350 in 1961, a winter of only moderate snow depth. 

 However, as south-facing slopes — with the best 

 winter browse — open up because, of snow melt and 

 evaporation, the deer dispei'se in response to food 

 demand. During years of hea\^ snowfall, forced 

 concentration of deer for long periods on re- 

 stricted areas of the winter range sets the stage for 

 above-normal dieoff due to starvation and malnu- 

 trition. 



According to an Idaho Unit study, tlie age struc- 

 ture of the Middle Fork (Salmon River) mule- 

 deer herd has all the cliaracteristics of a herd 

 grossly underliarvested. Animals 8 years old or 

 older constituted 25 percent of tlie population as 

 compared with about 12 percent in liiglily produc- 

 tive lierds sustaining continued good hunting. In 

 1961, the Middle Fork doe: fawn ratio was 

 100: 159. By late fall the ratio was 100: (;.\ and 

 by spring it was down to 100 : 19. For years two 

 deer per hunter have been allowed ; now, in 

 response to this information, three deer may be 

 taken during the ;3-montli Inuiting season, one of 

 which must be a doe. 



Estimated birth dates of 1,137 mule-deer fetuses 

 measured in Utah by Denver Center biologists re- 

 vealed a fawning peak of June 19 and extremes 

 of May 16 and August 22. However, 86 percent 

 of the estimated fawning dates fell within the 30- 

 day period of June 4-July 3, and two-thirds 

 within the 20-day period of June 9-28. 



Returns from mule deer fawn tagging research 

 in Utah have emphasized the desirability of plac- 

 ing a tag in each ear. Of 117 bucks, from 4 

 months to 8 years of age and for which tag-loss 

 records are available, 17, or 14.5 percent, had lost 

 one tag. For 71 does 4 months to 7 years of age, 

 7, or 10 percent, had lost one tag. These records 

 provide a mathematical means for determining 

 the probable number that had lost botJi tags. 

 Such an estimate is not possible when a single 

 tag per animal is used. Computations indicate 

 that, for the number of tagged deer returns re- 

 ceived to date, one could expect one buck and no 

 does to have lost both tags. 



Records and observations of deer, ear-tagged 

 as fawns in Utah, indicate a rather liigh disjjersal 

 rate of young from the area of birth. These 

 observations provide fairly good evidence that 

 most dispersals take place during the second sum- 

 mer of life. The movi^nients ajjpear to be !;;rgely 

 initiated b}' antagonism of the mothers, induced 

 by the approach of the fawning season. Apjiroxi- 



mately 60 percent of the bucks and 45 percent of 

 the does seemingly wander for varying distances 

 from the plac« of birth, the records showing from 

 1 to 42 miles for bucks and 1 to 20 miles for does. 

 The mean distance between the summer-range tag- 

 ging and kill sites for 78 males, yearlings and 

 older, was 4.3 miles, as compared with 2.3 miles 

 for 35 females of similar age, again indicating 

 greater movements by bucks. A practical aspect 

 of dispereal is the mechanism it provides the herd 

 for more equitable distribution over the range 

 soon after decimations due to hunting or disaster, 

 or in response to localized food contingency. 



Sprayed plots remain attractive to ivhitetail 

 deer. — In 1958, on the Tamarack Refuge in Minne- 

 sota, 16 plots in four vegetative types (aspen, 

 oak, jack pine, and upland brush) were sprayed 

 with 2,4-D. Four years later it was unmistakably 

 evident from pellet-grouj) counts tliat both brows- 

 ing and bedding use had increased on the 2-acre 

 plots in contrast to the unsprayed controls. 



Grizzly bear investigation. — The Montana Unit, 

 in studies carried on for 3 years, lias revealed 

 definite .social stratification among members of 

 grizzly-bear populations. Males were most pug- 

 nacious during the breeding season. A distinct 

 hierarchy existed among large, older males, 

 vfherein the same males retained the dominant 

 positions for all 3 years. Fights were observed be- 

 tween males in breeding condition, but none re- 

 sulted in serious injury to any of the combatants. 

 Sows with cubs were extremely hostile toward 

 males and shared status with many of the large 

 bears. The breeding season extended from about 

 June 10 to July 10, reaching its highest intensity 

 in late June. 



In another phase of the Montana study, a radio 

 tracking system was completed and tested during 

 the sununer of 1962. This system lias the capabil- 

 ity of picking up a radio signal .so that an instru- 

 mented bear can be located by triangidation and 

 approached to within sighting distance by means 

 of portable direction finders. It was possible to 

 follow an instrumented bear constantly for 48 

 hours, and some bears were under ob.serxation 

 intermittently for as long as 3 weeks. 



CoUared peccary and pricMy pear. — In an Ari- 

 zona Unit study, penned peccaries remained 

 healthy for 3 months on a diet of prickly-pear 

 cactus pads with no free water, cactus being tlie 

 only source of moisture. Peccai-ies can live for 5 

 months on the cactus witliout undue loss of weight. 



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