#19 - Last winter was mild enough to allow most bird

[Administrator]

Complete Question Explanation

Strengthen—CE. The correct answer choice is (C)

Your task in this Strengthen question is to select the answer choice that best supports the conclusion
that last year’s mild winter is responsible for this year’s larger-than-usual bird population.

Premise: that most bird species were able to forage naturally last winter due to the mild
weather explains why the proportions of birds visiting feeders was much lower
than usual

Premise: the mild winter also allowed many species to stay in their summer range all
winter without migrating south, limiting the usual attrition accompanying
migration

Conclusion: thus, last year’s mild winter is responsible for this year’s larger-than-usual bird
population

The correct answer choice in this Strengthen question will support the conclusion. The support for
the conclusion provided by the stimulus explained why the lack of migration would result in an
increased bird population. However, the argument did not explain why the bird’s ability to forage
naturally, rather than at feeders, would impact this year’s bird population. Your prephrase for the
correct answer is that it will likely explain how bird’s feeding naturally would contribute to an
increase in the bird population.

The incorrect answers will not support the conclusion. Instead, they will either have no effect on the
conclusion or will weaken it.

Answer choice (A): While this choice provides some support for a correlation between an unusually
mild winter and an increase in bird population, it does nothing to support the conclusion that the
mild winter and the increase in bird population are causally related.

Answer choice (B): This choice has no effect on the conclusion, because it does not explain how the
mating behaviors differ. From this information, it is just as likely that the failure to migrate south
might result in a decreased bird population.

Answer choice (C): This is the correct answer choice. This choice is correct because it explains
the causal relationship between natural feeding and the higher population. Feeding naturally, rather
than at bird feeders, reduces the bird’s vulnerability to predators, meaning fewer birds will be killed
by predators, and may instead survive to be counted among the bird population.

Answer choice (D): This choice does not support the conclusion, because it describes an effect of an
increased population in the summer range during the winter months, rather than providing support
for the conclusion that the unusually mild winter caused the larger-than-usual bird population.

Answer choice (E): This choice is incorrect because it does not explain why the birds feeding at
feeders rather than foraging naturally has any effect on the bird population.

[karlaurrea]

Correct me if I am wrong, but through the books, and in class lesson the number one thing that was constantly stressed upon and ultimate the key to identifying the correct answer choice was finding the conclusion, especially when it came to strengthen and weaken question, because that is the bases for the correct answer choice is it not?

So, for this strengthen question, the conclusion (correct me if I am wrong) it is the last sentence: "Hence, last year's mild winter is responsible for this year's larger than usual bird population"

For me, finding a strengthening answer choice would have been A, but the answer key says it is C; which I do not understand because what do the birds eating at feeders being vulnerable have anything to do with the conclusion and strengthening the argument in general?

[Steve Stein]

Hi karlaurrea,

You're right that it is always valuable to focus on the conclusion, but I wouldn't suggest focusing exclusively on the conclusion; the other components of the argument can be vital as well.

The author does conclude that last years warm winter led to this year's bird increase. This is based on the fact that birds were able to forage naturally, didn't have to visit bird feeders, and didn't migrate south.

The correct answer choice will somehow support this reasoning. Correct answer choice C provides support for the idea that the mild winter led to the increase in bird population, because this choice provides that the mild winter allowed them to avoid the predators that they would normally encounter in bird feeders.

I hope that's helpful--let me know--thanks!

~Steve

[cls]

I too was thrown by this question. I identified the weather as the cause and the increase as an effect (which it sound like you might have also been saying "...the author does conclude that last yrs warm winter led to this year's bird increase.") I do see how how answer choice C adds to that argument, but I'm not sure why it's better than answer choice A. Is it because A reiterates what we already know? Likewise the use of "sometimes" changes the relationships little?

Thank you.

[Steve Stein]

Hi,

That's a good follow-up. Let' s quickly review the author's reasoning:

Last year's mild winter allowed birds to forage rather than visit bird feeders and allowed many to stay put rather than migrating.

Conclusion: Last year's mild winter is responsible for this years larger-than-normal bird population.

Correct answer choice (C) provides that visiting bird feeders makes birds more vulnerable. Since the stimulus provided that the mild winter led to less birds at feeders (and more foraging), this would strengthen the author's conclusion : the mild winter was responsible for this year's larger-than-usual bird population.

Choice (A) provides that bird population increases sometimes occur after unusual whether patterns.

First, "Sometimes" is a very vague term; it actually just means more than never--so another way to phrase this would be as follows:

"Bird population increases have occurred after unusual weather patterns at least once."

Additionally, beyond the use of the term "sometimes," this choice also doesn't create a chain of causation--the fact that bird populations sometimes increase after strange weather patterns does not mean that the weather patterns were responsible for any such increases.

(Incidentally, I'm not entirely sure that a mild winter qualifies as a strange weather pattern either, but that's a side point...)

I hope that's helpful! Please let me know whether this is clear--thanks!

~Steve

[cls]

Hi Steve,

That certainly clarifies things.

Thank you!

CLS

[Jkjones3789]

Hello, I got this strengthen question wrong I went with A could u please tell me why its C. I guess I got it wrong because I didnt clearly understand the stimulus. Thank You

[David Boyle]

Hello, I got this strengthen question wrong I went with A could u please tell me why its C. I guess I got it wrong because I didnt clearly understand the stimulus. Thank You

Hello Jkjones3789,

Answer A is not all bad: "Increases in bird populations sometimes occur following unusual weather patterns." might *slightly* strengthen the stimulus, but in a weak way. (And assuming that a mild winter is even an unusual weather pattern to begin with.)
Answer C is much better because we know that bird feeders were used little, so that, since answer C tells us that bird feeders are actually dangerous to birds (the predator problem), therefore, that predator problem was lowered, since bird feeders were used less. Thus, fewer predators, so more birds, and the stimulus is big on having more birds, of course.

Hope this helps,
David

[15veries]

Hi,

I thought A is kind of re-statement of the conclusion or just make sure what is told in conclusion is true...but it just does not explain "why" it happens.
Is this another reason A wrong?

[Claire Horan]

The explanations above state the best reasons why answer choice (A) is wrong, so I won't rehash them here.

I do want to point out, though, that answer choice (A) is not a restatement of the conclusion. (If it were just a restatement, this question wouldn't really make sense because it would fully support the conclusion without at all strengthening the argumentation that makes the conclusion valid.)

One difference is that answer choice (A) notes unusual weather patterns, which may not include mild winters, as other instructors have pointed out. Answer (A) is also general ("sometimes" = "at least once"), whereas the conclusion is specific to "last year." Lastly, answer choice (A) does not specify causation. It merely says that B sometimes follows A. But B happening after A does not imply that A caused B.