The Israeli reintroduction program started in 1978 with the arrival of eight individuals of White oryx to Hai Bar Yotvata in the south Arava, Israel. The Hai Bar is a dedicated site created to rear breeding cores for reintroduction. The majority of the reintroduced population was released from 1997-2007 in seven soft-releases of 10-21 individuals. In these releases the animals were transferred from the breeding core to the habituation enclosure at the release area for a period of a few weeks or months and were provided food, water and protection from predators and hunting. After 2007, the soft-release program was discontinued mainly due to the high cost of providing 24/7 security on site.
In 2017, the Israeli Nature and Parks Authority (INPA) decided to conduct a pilot and test hard-release in the Arabian Oryx reintroduction program. In hard-release the animals are transferred from the breeding core directly to the release site and are set free immediately. The pilot had two main purposes, first was to test the survival rate of hard-released individuals and second was to connect the released individuals to wild herds. We selected young but sexually mature females and males for hard-release to allow them to connect with the herd but not to threaten the dominant female and male, increasing their acceptance to the herd. Each release consisted of three oryx released together at the same site, all were marked and two were fitted with Vectronic Aerospace Vertex Lite GPS collars.
To date 42 oryx were released in 15 hard release events in three locations known for high oryx presence in the hyper arid ecosystem in south of Israel: Zihor Wady, Paran Wady and Ashush stream, dry rivers replenished by annual floods. Due to large areas of unreachable habitat we were unable to track released individual hence survival rate was calculated only for collard individuals. Out of 31collard individuals 16 survived the first month of release making survival rate 52% (survival rate was not calculated for five collard oryx due to collar malfunctions). Eleven out of the 16 oryx with known survival connected with wild herds, one female created a herd with a lone male and produced a young.
Even with only 52% survival rate the hard-release method had proven to be fast, flexible and cost-efficient in reintroducing a large number of oryx individuals in multiple sites. This compared to soft-release which is more time and funds consuming and with a limited number of potential release sites. The collared individuals integrated into the local herds provide vital information on the home range and roaming behavior of the Arabian oryx reintroduced population in Israel. This information is crucial for the establishment of the monitoring program for the Arabian Oryx in Israel.
