Boreal owls range over a much larger area than do other owls

Dear vnigam21,

I'm happy to respond.

First of all, I want to call your attention to a very important distinction: the official questions (in the OG, Q & V Reviews, and in GMAT Prep) vs. the explanations for the official question. These two different items are two different ages, come from two different sources, and vary tremendously in level of quality.
1) Every official question in some test prep product is a retired GMAT question. These questions were written maybe a decade or more ago, went through rigorous psychometric testing in the experimental phase, and then were on the official GMAT for many years before they were retired. Behind each official question is a mountain of data and rigorous statistical analysis. It is no exaggeration to say that these questions are some of the finest test questions in the world, some of the finest ever created. I write question for a living, and at my very best, I am lucky to come even near to the high quality of these question.
2) The official explanations are different. When the questions were retired, say, and put into a book, someone had to slap together some explanations for the book. These were written by, I don't know, maybe some poor graduate student somewhere, and it's not clear to me that these have undergone any kind of substantial quality check and probably essentially no psychometric analysis. Just about every explanation I write, for my own questions or for official questions is better than these official explanations, and I would say the same for many other experts on GMAT Club.

The difference in quality is immense. I am lucky, at my very best, to come close to the quality of the official questions. By contrast, it is almost as if I could far surpass the quality of the official explanations in my sleep!

The moral is: trust the high quality of the official questions, but don't put too much trust into the official explanations. Trust that there are deep legitimate principles governing the logic of any official question, but don't necessary expect to find that well articulate in the official explanations. Instead, come here to GMAT Club, and get better explanations from test prep experts such as myself.

Why does the second sentence of the official explanation saying what it was saying? What was the starving graduate student in the basement thinking when he wrote that? Frankly, this is not the most important question for your GMAT preparation. Rather than worry about what the official explanation was trying or not trying to say, focus on finding somebody who can elucidate the sound logic of the question itself.

Here's the prompt:
Claim: Boreal owls range over a much larger area than do other owls of similar size.
Evidence: The reason for this behavior is that the small mammals on which owls feed are especially scarce in the forests where boreal owls live, and the relative scarcity of prey requires the owls to range more extensively to find sufficient food.

That's the argument, an attempt to explain the boreal owls' behavior. Is the explanation given the best explanation?: Could there be a better explanation? Could we make this explanation more plausible? Those questions outline the fulcrum on which the evaluation of this argument pivots.

Then the prompt question says:
Which of the following ,if true, most helps to confirm the explanation above?
So, we want to strengthen this explanation.

(A) Some boreal owls range over an area eight times larger than the area over which any other owl of similar size ranges
First of all, this appears to strength the evidence. Strengthening the evidence in general is not a particularly effective way to strengthen the argument.
Also—and, who knows, this might be what the OE was trying fecklessly to say—this compares "some boreal owls" to all other birds. Group #1 is "some boreal owls" and Group #2 is every other bird on the planet. Of course, this latter group of all other birds, Group #2, includes, among many others, the rest of the boreal owls. Thus, "some boreal owls" have a particularly large range, but the others, included in Group #2, sound as if they might have small ranges. Hmm. If "some boreal owls" have gigantic ranges and the rest have relatively small ranges, then the explanation given might not be valid, because it wouldn't apply uniformly to all boreal owls.
These are the problems with (A).

(B), the OA, of course, does the job perfectly. I assume you understand that already.

Does all this make sense?
Mike