Arguably the most-studied animal in the park, the tortoise was placed on both the California and Federal Endangered Species Lists in 1989 and 1990, respectively. Its status is 'threatened,' just one notch below 'endangered.' Several factors conspired to diminish the population of the desert tortoise. As more people moved into the western deserts, the resultant loss of habitat made a serious dent in the number of tortoises. With more people came more ravens, large black birds with a keen appetite for hatchling tortoises. The number of ravens has exploded in recent years, due in large part to their ability to thrive in developed areas. The factors contributing to their dramatic increase include more roads, thus more roadkill; landfills; powerline poles, an ideal lookout post for hungry ravens; and littering. Litter in the park attracts ravens, so please dispose of your garbage responsibly.