Pronghorn Biology, Pronghorn Biology, Behavior, and ManagementBehavior, and Management

Ken CearleyKen CearleyExtension Wildlife Specialist- High Plains, Trans-PecosExtension Wildlife Specialist- High Plains, Trans-Pecos

Texas A & M UniversityTexas A & M UniversityCanyonCanyon

Objectives

Overview of pronghorn basic life history Reproduction Behavior

Pronghorn habitat requirements Management practices

Emphasis on Panhandle

Recommended ResourcesRecommended Resources

Pronghorn Ecology and ManagementPronghorn Ecology and Management. Bart . Bart W. O’Gara and Jim D. Yoakum. 2004.W. O’Gara and Jim D. Yoakum. 2004.

Common Rangeland Plants of the Texas Common Rangeland Plants of the Texas PanhandlePanhandle. NRCS. 2005. . NRCS. 2005.

A Handbook for Pronghorn Antelope A Handbook for Pronghorn Antelope Management in TexasManagement in Texas. Tommy Hailey, . Tommy Hailey, TPWD. 1986.TPWD. 1986.

Pronghorn Management GuidePronghorn Management Guide. R. E. . R. E. Autenrieth, et al. 2006.Autenrieth, et al. 2006.

Distribution of Pronghorns

TPWD 1986

Trans-Pecos Pronghorns

<12” precipitation typically Vegetation

Grama grasslands Creosote-tarbush shrublands

Tobosagrass

Lower Plains Pronghorns

~16” precipitation Vegetation

Bluestem Buffalograss Tobosagrass Mesquite Lotebush catclaw

Panhandle Pronghorns

High Plains 15-21 “ annual precipitation Mixed prairie Short-grass prairie Tall-grass prairie Vegetation

Buffalograss Blue grama Mesquite Sand sage Shin oak Yucca

Panhandle Pronghorns

Rolling Plains 22-30” precipitation Tallgrass prairie Mid-grass prairie Vegetation

Little bluestem Sand bluestem Sideoats grama Mesquite Sand sage Shin oak

Description

70-140 lbs. Adult size by 2 years Does typically breed year two Both sexes horned Males have forked horns

sheath shed annually Males have cheek/neck patch Abnormally large eyes

Placement on skull beneficial Excellent eyesight

Long legs- 45 plus mph

Physiology

Thermal regulation by counter-current blood flow to brain Cools blood supply

Maximized airflow- by design Lungs Diaphragm Esophagus

High hemoglobin concentration in blood

Other design features

Concentrated urine Water conserved by concurrent exchange of

oxygen Water intake reduced by decreasing food

intake in stressful / critical times

Reproduction

Breeding begins late summer Polygynous breeders

Few males breed all adult females Resource-defense polygyny

Resources clumped and predictable Female-defense polygyny

Resources are evenly distributed and unpredictable

Harems gathered

Reproduction

Breed as early as 16 months Breed annually until 8-10 years of age Rut onset varies with weather

Photo-period driven, basically Length breeding season

South- ~3 months North- ~ 3 weeks

Does cycle until bred

Reproduction

250 day gestation Nutrition during pregnancy and lactation

critical 112:110 males to females at birth

• Twinning common on healthy rangeland

Food Habits

Nutritional requirements Provision depends on availability

Rainfall Competition Crop depredation

Concentrate selectors Forbs- rank first in consumption, typically

more nutrients, in small package Forbs high in water content Browse ranks second ~8 % of diet is grasses Water provided from free-standing, pre-formed, and

metabolic processes

Behavior

Foraging affected by “build” Small frame Small organs Small mouth, muzzle

Foraging affected by social behavior

Behavior

Herding Tighter as move north Selfish herds

Predator avoidance Increases feeding efficiency White rump patch makes each individual highly visible

TX- nomadic Farther north- more migratory Seasonal movements in response to habitat Most move less than 10-20 miles

Restrictions to movement

Fences ~18” clearance best; net wire restricts

Highways

Disease Implications

Carriers of abortive diseases? Brucellosis? Leptosirosis? IBR?

10 years of sampling by TPWD 1060-1970 N=827

No brucellosis No lepto

N=75 IBR 5 false positives, end result- no IBR

Management

Inventory Aerial

Mid to late summer, usually Strip flying Some important parameters

Total count Doe:Fawn ratio Exceptional animals Overall range and animal condition

Management

Harvest Permit issuance determined by TPWD Surplus taken if necessary to maintain

carrying capacity Parameters

Age 4 1/3 years+ best horns

1:2 buck:doe ratio conducive 1:4 more conducive to larger number young

animals Habitat conditions Carrying capacity Objectives and goals

Aging Pronghorns

Fawns Short jaw length Molars not fully erupted

Yearling 1 yr 4 mos

TPWD

Aging Pronghorns

2 yrs 4 mos

TPWD

Aging Pronghorns

3 yrs 4 mos

TPWD

Aging Pronghorns

4 yrs 4 mos

TPWD

Aging Pronghorns

~8 yrs 4 mos

TPWD

Management

Keep watering facilities functional Maintain range condition to provide adequate

food supply Fawning cover

Thwarts predation efforts Adequate nutrition

Especially during spring and summer when peak demands from gestation, then lactation

Management

Provide unrestricted movement Pronghorn friendly fencing

Management

Deter crop depredation

Management

Supplemental feeding May be beneficial in nutritionally stressful

periods Feed not readily accepted

Summary Inventory Plan the harvest

TPWD determines permit issuance Monitor range condition and pronghorn condition to determine

carrying capacity Maintain water even when livestock not present, including

breaking ice Fencing conducive to goals

Restriction or movement Age determination of harvested animals Utilize supplemental feeding as required Manage predators when necessary (coyotes primarily) Maintain good range condition to provide physical protection

(thermal, predation) and food requirements.