Live Trapping Texas Antelopes

Abstract

The credit for the first successful livetrapping and transplanting of pronghorned antelopes (Antilocapra americana) belongs to Elliot S. Barker, State Game Warden, and Paul Russell, District Deputy Game Warden, New Mexico Department of Game and Fish. The antelope trap and shipping crate now used by the Texas Game Department are modified from those employed by the State of New Mexico. The Texas method of drifting the antelopes into the trap and of removing the animals for shipment differs from the New Mexico live-trapping technique. An airplane replaces horsemen and antelopes removed from the crowding pen in a group. There are two main purposes of livetrapping and transplanting antelopes. The first is to remove antelopes from sheep to cattle range, the incompatibility of domestic sheep and antelope having been convincingly demonstrated by management and habitat studies. The second objective is to reduce the population on enclosed areas where there is a surplus and to distribute them over former and present suitable ranges from which they are now absent. Antelopes are unable to escape from sheep-wired enclosures but can crawl under or through ordinary barbed wire fences; by transporting them to favorable cattle ranges they may increase in number, spread, and become more firmly established in the fauna of the state. The first attempt to transplant antelopes in Texas was made in Sterling County during 1939, when 257 head were trapped and liberated in twentyone new localities. Trapping operations were resumed in the Davis Mountain Range in Brewster and Presidio Counties during October, 1940. Because of the mountainous terrain of this section of western Texas and also the large pastures (10,240 to 22,400 acres) in which the antelopes were to be trapped, it was soon learned that the method of employing horsemen for drifting the animals into a trap was too costly. While the writer was taking a census of antelopes by airplane near Alpine, Texas, it was observed that the animals tended to flee from the drone of the airplane motor. This tendency was found to increase in proportion to the nearness of the plane. Following up this lead, it was learned that scattered herds of antelope could be assembled into one and drifted in any desired direction, provided the airplane was maneuvered so that the drone of the motor issued from a position behind or to one side of the antelopes and at altitudes of 50 to 500 feet. Further experiments showed that a modification of the trap would be necessary before this species could be captured by airplane driving. Numerous variations in trap construction were tried before success was achieved. Since the adoption of this method of herding ant lope by airplane, 467 animals have been trapped, sexed, aged, weighed, eartagged, and released in suitable habitats. The trapping operations covered 43 days. Only three animals died, a mortality of but 0.64 per cent. Releases were made at distanceE of from 25 to