:eek: How did you get access to my porn collection?!
Yeah, sapience is the better word in this instance. I got my definitions muddled - blame Star Trek 
This seems to have moved more into an argument of “how will we know they are sapient?” rather than “what would happen if there was another sapient species?”
I know it’s important side area for the debate, but i’m presuming in the OP that, in this hypothetical situation, we are certain that this new species is sapient. I’d like to know what people would think would happen if, say, a corvid flew down to City Hall with a pen and a Corvid Bill of Rights and asked you to sign - would most people be happy to think, and have in law, that this second species is equal to humans?
It’s probably that the species would not yet be as “highly” sapient as us, so some people might argue that they deserve a lesser prescence in the law, too. Where do we draw the line, legally, between pet and equal? Would it be right to “keep” one of these animals as a pet, seeing as how it’s higher level of sapience than a dog would effectively make it a slave? Should a person forcing sex on one of these animals be charged with beastiality, or rape? Would the murder punishment for killing one of these animals be lesser?
I don’t believe that we would ever consider any other species on earth as our equal even if they did, for example, pen their own Corvid “Bill” of Rights (bird “Bill”, nice pun 
). The majority of our society would, however, treat them with much more respect than we do now. I say this only from the perspective of understanding past trends in this area. When an animal is re-assessed as being more advanced intellectually than was once believed, we quickly afford it more protection and respect. The enlightenment typically originates from the scientific community, is embraced by the animal rights people and eventually trickles down to the masses. Take the porpoise as an example: when scientists confirmed that they are much brighter than once believed, they shot to the top of the animals-to-be-revered list. While this is certainly good for the cause of the porpoise, one can’t but feel sorry for those animals that are still perceived as being too stupid to make the list. It’s really just a case of elitism.
The more anything is perceived as being more like us, the better we treat them. Unfortunately, the opposite is also true, and you don’t even have to look to the animal world for examples. Our history is fraught with examples of acts of barbarism committed by one subset of human population toward another. In most cases the barbarism is deemed justified by viewing the other races/cultures/ethnic groups etc. as being 1) different than them, and 2) inferior to them. Once the veil of ignorance is lifted, it becomes much harder to sustain the butchery and repression.
So, in the case of the writing Corvidae, they would shoot to the #1 spot in the non-human animal kingdom with respect to how well we treat them, but they would never approach equality. Think of worst-case scenarios of human repression and denigration toward other humans (WWII – Aryans vs. Jews, Americansvs. Japanese; Colonial times -whites vs. slaves; Inquisition – Christians vs. Jews and Muslims; Ancient times- Romans vs. Christians…the list is long and exhaustive), then figure that the scenario for an animal would be a bit worse than those (they don’t even look like us).
I believe that this human elitism is reprehensible, but not necessarily aberrant or curable imagine a super-sapient species teleporting down to earth saying, “We were here first, we’ve simply been on a multi-millennium jaunt around the galaxy. Now that we’re back, why don’t you silly humans get back into your cages and entertain us.”
The current standard used is self-awareness which is not measureable. I think the fact that they managed to teach a gorilla basic sign language should qualify.
“The gorillas themselves are too shrewd to talk to anybody but another anarchist. They’re all anarchists themselves, you know, and they have a very healthy wariness about people in general and government people in particular. As one of them told me once, ‘If it got out that we can talk, the conservatives would exterminate most of us and make the rest pay rent to live on our own land; and the liberals would try to train us to be engine-lathe operators. Who the fuck wants to operate an engine lathe?’”
—Illuminatus!