The article should answer the question: Are sparrows the most common bird worldwide?
It depends upon the definition of "most common". I wouldn't treat a bird that is common to only one part of one continent as the "most common" in the world. I would consider "most common" to be a function of both range and population -- something like "most commonly seen in most parts of the world" The Red-billed Quelea may be the most abundant bird species, but is it actually more abundant than the total population of all the species of Old World sparrow?