NEBRASKA

GAME AND PARKS COMMISSION

TERRESTRIAL WILDLIFE DIVISION

SURVEYS AND MANAGEMENT OF ANTELOPE

W 0 R K P LAN B-7b

MAReK 1976 through FEBRUARY ]q77

PITTMANN-ROBERTSON PROJECT W·15-R-33

SURVEYS AND MANAGEMENT OF ANTELOPE

Ma rch 1 f 1976 through February 28, 1977

by Harvey Y. Suetsugu

ABSTRACT

Aerial surveys conducted in western Nebraska indicate antelope numbers were 10 percent higher than the previous year and also 10 per­cent higher than the preceding 5-year average. The productivity index of 54 young to 100 does ;s about the same as the previous year, but lower than the 20-year average of 65 young to 100 does.

Hunter success was 10 percent for 146 archers, while 1,851 rifle permittees scored 73 percent.

Table of Tables

Table 1. Comparison of 1975 and 1976 populations and sex and age ratios • . . • • . • . . . . . . • . •

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Table 2. Inventory data for new areas, 1976 . . • 2

Table 3. Archery permits, harvest, and success, 1964-76 . 3

Table 4. Applications for permits by unit . . . 4

Table 5. Permits, harvest and success by management unit. . 4

Table 6. Percent of kill by day in each unit . . .

Table 7. Days hunted by successful hunters . .

Table 8. Sex and age composition of harvest . .

Table 9. Age composition of antelope in harvest • •

Tabll of Figures

Figure 1. Rifle harvest by county and management �n;t.

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WORK PLAN 8-76 SURVEYS AND MANAGEMENT OF ANTELOPE

By Harvey Y. Suetsugu

INTRODUCTION

Since 1953, a total of 27,359 rifle permittees have harvested 21.997 antel ope for an overall succes s of 80 percent. Average success for 23 years was 78 percent , with a range of 73 to sa percent . Archery seasons have been held since 1964. A total of 1�215 bow hunters have harvested 143 antelope for a success of 12 percent . Antelope are managed on the basis of population level s . but land use and agricultural economics play major roles in management objectives.

OBJECTIVES

The objective ;s to obta i n information relative to population levels and harves t as an ai d ; t. maki ng management recommendati ons for the speci es.

TECHNIQUES

Inventory: Aerial surveys were accomplished in a manner similar to that of past years. Transects were flown at intervals of 1 1/2 miles in the Cheyenne Unit, 2 miles in the North Sioux and Box Butte. 3 miles in the Garden, and 4 miles in the Banner unit.

Transects were 1/2 mi le in width and were flown primarily in north and south directions. Observers examined a 1/4 mile area on either side of the aircraft's flight path. About 2,891 lineal miles were flown on transects, sampling approximately 1,446 of the 7,445 square miles of selected antelope range in the Panhandle. Survey areas were the same as in 1973 through 1975. Population esti mats are not for the entire manage­ment units since surveys exclude extensive areas of cropland and forested land where ante10pe densities are lower.

Two new areas within the North Sioux Managemen t Unit and one new area in the Box Butte Management Unit were surveyed.

A trial survey was conducted in a portion of the North Sioux Management Unit for the purpose of obtaining an estimate of the Wintering population.

Harvest: Biological and hunter information were collected at compu'� sory check stations manned by permanent and tempurary personne1.

FINDINGS

Inventory: Aerial surveys were con duc ted between July 12 and August 5, requiring 18 days for completion. Range conditi ons in general were 90�d, as ;n the previous year, with classifications of fair to good c :>mpared to poor in 1974. Surveys in the majo� antelope range indicate an increase of about 10 percent in antelope numbers compared to 1975. The 1976 estimate of 7,273 antelope is about 10 percent higher than the past 5-year average (1971-1975). Increases occurred in all but the Box Bu tte Management Unit (Table 1).

The productivity index of 54 young to 100 does is nearly the same as the previous year, but considerably lower than the 20-year average of 65 young to 100 does. The North Sioux and Banner units had fair productivity indices in 1976 (77 and 64 young to 100 does , respectively).

Two new areas, south of the timbered area of the North Sioux Management Unit, were surveyed at a transec t interval of 1 mile. The popul ation estimate for the areas was 620 antelope with a buck:doe:kid ratio of 24:100:68.

The area on Fort Robinson �transect interva l of 1 mile), which is in the Box Butte Management Unit, had an estimated population of 40 antelope (Tabl e 2).

Table 1. Compari son of 1975 and 1976 populations and sex and age ratios.

Survey Estimated Area

Management Unit

North Sioux Box Butte Garden Cheyenne Banner

TOTAL

Po�u1ation 1975 1976

2,512 2,904 2,616 2,240

618 918 138 147 704 1,064

6,588 7,273

Percent Change

+16 -14 +49 + 7 +51

+10

Table 2. I nventory data for new areas, 1976.

Management Unit

North S10ux (l) (2)

Box Butte (Fort Robinson)

fOTAL

Population Estimate

562 58

40

660

BuciqDoe:Kid 1976 1975

40: 100: 75 37:100:37 28:100: 50 17 :100: 75 45:100:75

37: 100 :55

32:100:77 20: 100: 34 37: 100:45

6: 100:38 26:100:64

26: 100: 54

Ratio Buck:Doe:Kid

27:100:70 6:100:56

43:100:00

26: 100: 63

(1) West of Harri son , south of Pine Ridge, north of Highway 20 (2) East of Harrison, south of Pine Ridge, north of Highway 20

A winter survey of the North Sioux Management Unit was flown to obtain information on trends and locations of herds and concentrations. The total number of antelope observed was 685 in 31 g roups, averaging 2 2 animals in a group (range: 3-69).

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Square Miles

653 1,988 2,904

305 1,595

7,445

Harvest (Archery) : Oates for the archery season were August 20 through September 24 and October 4 through October 3 1 . During the 64-day season, 146 bow-hunters bagged 14 antelope for a 10 percent success. Success has ranged from 4 to 26 percent during the previ ous 12 years , with an average of 14.7 percent (Table 3). Bow-hunter numbers for the previous 5-year averaged 129 ( range 95 to 156) and hunter success averaged 9.4 percent (range 4 to 11 percent) .

The harvest consisted of 7 adult bucks, 6 adult d�es . and one fawn buck. Kill by counti es was 11 in Sioux, 1 in Dawes , 1 in Cherry, and 1 in Custer.

Table 3.

Year

1964 1965 1 966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976

TOtAL

Archery permits, harvest,

Perm; ts Issued

29 35 47 49 76 85

104 95

122 148 123 156 146

1 ,215

*Average of perc�nt success.

and success, 1964-76.

Harvest Percent Success

6 21 9 26 9 19

11 22 9 12

�? L ... 15 14 14 10 11 13 1 1 16 11 12 10

7 4 14 10

143 14*

Harvest (Rifle): Application for permits have for several years exceeded

the number that were available, thus necessitating a more equitable system for allocation. Beginning in 1973 restrictions were placed upon applicants. In 1974, 1975� and 1976 . those persons who held permits dur i ng the previou s two years , except those who held limited landowner permits only. could not app1y for a firearm permit during the ini t i al application peri od .

Demand for permits was over twice the number authori zed (Table 4). All units required a d rawing d�ring the initial application period� el iminating chances for residents who had permits the previous two seasons and for non­residents.

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Table 4. Applications for permits by unit.

Percent Excess Percent Chance of Unit Permi ts Ae�lications A2�lications Obtaining a Permit

Banne r 125 231 85 54 Box Butte 500 952 90 53 Brown 50 113 126 44 Cherry 150 278 85 54 Cheyenne 50 55 10 91 Dismal 100 185 85 54 Dundy 10 35 250 29 Garden 200 269 35 74 North Sioux 600 1,679 180 36 Rock 25 62 148 40

TOTAL 1,810 3,859 113 51*

*Weighted by unit

Forty-one limited landowner permits were i ssued as follows: Banner-4 ; Box Butte-9; Brown-5; Cherry-4; Dismal-7; Garden-6; and North Sioux-6.

Hunter success during the 1976 rifle season was 73 percent, with 1,352 antelope harvested by 1,851 permi ttees (Table 5). Succes:; was the lowest on record, with the previ ous low of 74 percent in 1957. Season dates were September 25 through Oc tober 3. Hunt1ng conditions were poor in most of the western ante l ope range during the opening weekend due to high winds and rain but generally improved as the seaSOfi progressed.

Eighty-three percent of the harvest occurred during the first three days of the season ( Table 6). During the previous season 83 percent of the harvest occurred during two days. The average number of days hunted was 1.50 (Table 7) comp ared to 1.40 ;n 1975.

Adult males comprised from 49 to 100 percent of the harvest in various unit�� while averaging 59 percent fc� all units combined (Table 8). °an­handle units show about 56 percent of the harvest was adult males, wh;�e the surrrnerinventories show about 14 percent adult males in the populati�n. Biologists' data, using the mandibular dentition eruption and wear metho� of aging, show 54 percent of the harvest was adult males (Table 9).

Table 5� Permits, harvest, and success by management unit.

Penni ts Harvest �ercent Success Unit 1975 1976 1915 1 976 1975 1976

Banner 152 129 122 100 80 78 Box Butte 606 510 481 318 79 62 Brown 25 55 19 30 76 55 Cherry 129 154 105 117 81 76 Cheyenne 50 50 38 38 76 76 Dismal 105 107 75 76 71 71 Dundy 11 10 9 8 82 80 Garden 152 205 133 159 88 78 North Sioux 506 606 449 494 89 82 Rock 27 25 18 12 67 48

TOT�L 1,789 1 ,851 1,463 1 ,352 82 73

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Table 6. Percent of kill by day in each unit.

Management Unit 2 3 4 5 6 7 8 9

Banner 70 10 6 3 2 2 3 4 Box Butte 55 17 8 5 2 2 2 8 3 Brown 47 33 7 3 3 3 3 Cherry 65 11 3 3 1 3 3 4 8 Cheyenne 74 16 3 5 3 Dismal 34 33 5 7 1 1 8 9 1 Dundy 88 12 Garden 51 23 7 4 3 1 1 6 6 North Sioux 70 11 6 1 1 4 2 3 1 Rock 58 25 17

Total 61 16 6 3 2 2 2 5 3

Table 7 Days hunted by successful hunters.

Number of Average Successful Daas Hunted Number Days

Hunters 2 3 5 6 7 8 Hunted

Banner 100 75 14 3 3 4 1 1.52 Box Butte 318 193 74 33 10 5 2 1 1.66 Brown 30 16 10 2 1 1 1.73 Cherry 117 89 19 4 2 2 1 1.39 Cheyenne 38 32 4 1 1 1.24 Dismal 76 37 26 8 4 1 1. 78 Ound}' 8 7 1 1. 13 Garden 159 94 39 17 6 3 1.65 North S10UX 494 386 70 24 11 1 1 , 1.34 j

Rock 12 9 2 1 1.42

Totals i t352 938 259 92 39 15 4 3 2 1.50 ---------�-----------------------------��-----------------------------------

Percent 69 19 7 3 1 Tr� Tr. Tr.

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Tab1e 8 . Sex and age compositio� of harvest.

�.anagement A GE Unit Ad, Male Ad Femare---�oung-

Banner 71 26 3 Box Butte 176 119 2" Brown 19 9 2

Cherry 91 21 5 Cheyenne 20 16 2 O'i �ma' 48 25 3 Oundy 8

8 Ga""den 110 45 4 North SiOUX 242 150 94 Rock 9 2 1

Unknown Total Buck;[)oe:Fawn

100 273: 100: 12 318 148: 100: 19

30 211 : 100: 22

117 433:100:24

38 125: 1 00: 13 76 192: 1 00: 12

8 100

159 244: 100:9

8 494 161 � 1 00: 63 12 450: 1 00: 50

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Total 794 413 137 8 1,352 191 : 1 00: 33

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Table 9 Age ccmpcs't�on of antelope tn har�e;t (b'olo91st data).

Managem€nt ----------------,-------------

Percent Adult Males

71 55 63

78 53 63

100

69

50 75

59

___ �n' t _____ . __ £��� ___ l ___ � ___ l _____ � _____ � ____ �.L:) Unaged Adul t rota 1

Male

Sanner 80)' Butte­Ga"der'l NO<th Sioux

Bant"ler Bo ... Butte Gal""oer: North SiOU);

9 70 8

52 122

6 22 1

30 34

2 27

6 45

11 2

17

1 15

1 13

5 1

21

2 10

i 7

14

10

1

1 9

4

2

12

6 _ .. -------------_._----------*"

1

5 132

18 242

1 80

6 142

Harvest by county and management unit is presented in Figure 1. Sioux County provided 551 antelope, which was 41 percent of the total harvest.

SUMMARY

Summer aer�a1 surveys in the major antelope range indicate a 10 percent increase in antelope numbers compared to 1915. The 1976 estimated population was also 10 percent higher than the past 5-year average (1971-1975). The productivity index of 54 young to 100 does is about the same as the previous year, but �s considerably lower than the 20-year average of 65 young to 100 does

Hunter succ�ss for 146 a�chers was 10 percent with 14 antelope harvested while 1,851 ftreaJ"m hunters scored 73 percent. Successful firearm hunters required an average of 1 5 d ays afield. and 88 percent of the antelope harvested took 2 days or less

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Figure 1. Rifle harvest hy county and management unit.

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