• Ravens are the largest passerines.
• Adults are wary of approaching novel kinds of carrion and new situations and will often only approach after the presence of blue jays and American crows makes it clear that no danger is near. 
• A flock of Ravens is called an “unkindness”
• Ravens have been impacting the recovery of the endangered Mojave Desert tortoise, who roamed their namesake desert in the American Southwest for tens of thousands of years, but have declined due to habitat loss.
• Ravens, alternatively, have seen their population grow in this region, due to new man-made food sources, like garbage dumps or habitat changes, like power lines for nesting, golf courses, or more trees and shade. The birds make fast food of young, vulnerable tortoises, whose shells are not yet hard enough to protect them. Some recovery efforts have utilized green laser beams to deter Ravens from tortoise release sites. They also eat imperiled sage grouse and fringe-toed lizards.
THREATS & CONSERVATION
Common Ravens tend to do well around people, profiting from the garbage, crops, irrigation, and roadkill that accompany us. In fact, they have benefitted from people so much that Raven population increases in the US Southwest are now a threat to California desert tortoises (they eat tortoises and their hatchlings), and Ravens have become a menace to reestablishment efforts for this endangered reptile. As eastern forests were cut down in the nineteenth and twentieth centuries ravens disappeared from most of eastern North America, but they are beginning to return to the Northeast as forest cover regenerates. In many situations ravens are unwelcome: they have been shot at, poisoned, or harassed in attempts to preserve crops (and occasionally livestock such as lambs).