As a result of its isolation in the midst of a sprawling and seemingly barren desert, Siwa is a haven for threatened species and an island of biodiversity with a variety of endemic flora and fauna. 
Date palm and olive groves grow wherever water is available at or near the surface.  In the lower parts of Siwa, wetlands, salt marshes and a range of sand formations have emerged.  To the south, the dunes of the Great Sand Sea stretch endlessly in a landscape of otherworldly beauty. 
Siwa supports a distinct and wide-ranging collection of animal species, including at least two amphibians, 28 mammals, 32 reptiles, 52 insects, 92 soil fauna and 164 birds.  Among these, several species appear to be unique to the Siwa region, and several more are endangered or threatened.
Rodents, gerbils and fat sand rats are the most common species of mammal in the oasis, but it also home to two Saharan desert foxes, the Sand Fox and the Fennec Fox. 
The oasis contains a number of resident and migratory birds, including the lesser flamingo, sooty falcon, thick-billed lark, lesser short-toed lark, red-rumped wheatear and the desert wheatear, as well as the European quail. The Al Qasr desert has been recently discovered to be the breeding ground for all these bird species.

Slender-horned Gazelle
The endangered slender-horned gazelle, a nomadic species that wanders the Saharan dunes in search of scarce vegetation, was once the most common of all gazelle living in the Saharan desert.
Perfectly adapted to its desert habitat, the slender-horned gazelle rarely needs to drink water.  Instead, it draws hydration from the dew that forms on leaves and the higher water content plants.  Its reflective white coat and specially adapted nasal passages keep it cool in the hot desert. 
In the early 1970s the slender-horned gazelle fell into serious decline due to over-hunting, and populations became scarce and isolated.  The population, in fact, has all but disappeared from the Eastern Sahara in Egypt, though many slender-horned gazelle trophies can be found decorating the walls of El Manial Palace in Cairo, the former home of Egyptian Prince Mohamed Ali Tewfik.  Due to its status as a protected area, Siwa is the last domain in Egypt where slender-horned gazelle still dwell. 

Fennec Fox (vulpes zerda)
The Fennec Fox is the smallest canine specie (males weighing 1.5 kg and females 0.8 kg) and is found throughout the Sahara and along the Mediterranean Coast from Morocco to Kuwait. The fox lives only in desert environments, for which its excellent hearing, small size, and omnivorous diet are well adapted. The Fennec inhabits areas in close proximity to light grass or scrub vegetation cover as it uses the plant matter to line and shelter its den.
The animal is noted for its large, bat-like ears and bushy tail, which comprise approximately 60 percent of its body length. Despite its often-remote habitat range, the Fennec has recently suffered from sport hunting, accidental ingestion of chemical fertilizers, and human encroachment, problems that fortunately do not exist in Siwa due to its protected status. Though not a Red Book-listed specie, due to insufficient data, the Fennec has been Appendix II listed by Austria and Appendix III listed by Denmark and Tunisia.

Sooty Falcon
Sooty Falcons are distinguished by their pale gray color, slim wings, and long, thin tail, though young falcons are a darker charcoal color.  This medium-sized migratory falcon breeds mainly on the coast and islands of Northeastern Africa, but has breeding colonies in the Siwa Oasis, one of which is partially located on the grounds of the Adrère Amellal eco-resort. Siwa is, therefore, a unique place to witness the breeding season of this falcon that usually only lays its eggs on coastal cliffs and Mediterranean islands. After breeding, the falcon migrates south to Madagascar, returning to its birthplace at the beginning of winter.
The Sooty Falcon is believed to have a stable population and has been placed on the "Least Concerned" index by the IUCN Red Book.