Size and Weight:
As is often the case in the dinosaur business, even though Alverexsaurus has bestowed its name on an important family of bird-like dinosaurs (the "alvarezsaurids"), this genus itself isn't very well know. Judging by its fragmentary fossil remains, Alvarezsaurus appears to have been a fast, agile runner, and it probably subsisted on insects rather than other dinosaurs. Much better known and understood are two of its closest relatives, Shuvuuia and Mononykus, the former of which is considered by some to have been more bird than dinosaur.
By the way, it's widely believed that Alvarezsaurus was named in honor of the famous paleontologist Luis Alvarez, but in fact it was named (by another famous paleontologist, Jose F. Bonaparte) after the historian Don Gregorio Alvarez.