Q19 - Last winter was mild enough to allow most bird species

[mrxylophone]

I cannot for the life of me understand how answer C relates to the argument core nor do i understand how it strengthens it.

Any insight on this would be greatly appreciated.

[jolieyang]

Premises: mild winter leads to... many bird species not migrating (so limiting the usual attrition) and fewer birds visiting bird feeders

Conclusion: last year's mild winter is the reason for larger-than-usual bird population

Strategy: Find an answer that strengthens the conclusion, either an answer that rules out an alternative reason for the larger-than-usual bird population or an answer that gives an example of the effects of mild winter being the reason for the larger-than-usual bird population (in this question, it is the latter)

A) Irrelevant. This does not strengthen the conclusion in any way (nothing about the mild winter being a causal factor), just stating a phenomena that the stimulus already observed

B) Too broad. Not sure how mating behaviors affects the population and even if it does somehow increase the population in some instances, we're not entirely sure that the mating changes cannot decrease the population instead.

D) Opposite. If the birds that remain in summer range exhaust the food supply, shouldn't this have a negative impact on the population size?

E) Irrelevant. This answer just states a fact about birds visiting feeders even when there is sufficient food via foraging but this does nothing to explain how mild winters affect bird populations. When I read this answer I couldn't but think in my head "cool story bro "

C) is the correct answer because it is the only one that hints at anything relating to a causal factor between mild winters and bird populations. The premise states that because mild winters allow birds to forage naturally, so they go to bird feeders less. This would therefore result in less deaths if C) was true (since they won't be killed by predators) resulting in a larger-than-usual bird population.

Hope this helps!

[samantha.rose.shulman]

PT65, S1, Q19 (Strengthen)

This is an Assumption Family question, specifically a Strengthen question, so we not only have to identify the argument core and assess it, but also consider ways to address the issues in the argument core.

As always, we should start by finding the conclusion. This conclusion isn’t too difficult to find, since it appears at the end of the stimulus and includes "hence" to guide us there: hence, last year’s mild winter is responsible for this year’s larger-than-usual bird population.

For premise(s), we are told that the mild winter (1) allowed most bird species to forage naturally, lowering the proportion of birds visiting feeders, and (2) allowed many bird species to stay in their summer range all winter without migrating south, limiting the usual attrition accompanying migration. You might notice at this point that it is clear why (2) supports our conclusion (less attrition leads to larger-than-usual population), but less clear why (1) does.

This gives us the following argument core:

Mild Winter Allowed More Natural Foraging, So Fewer Birds Visiting Feeders + Mild Winter Allowed Less Migration, So Less Attrition -> Mild Winter Is Responsible For This Year’s Larger-Than-Usual Bird Population

What are some of the gaps in this argument? First off, why did the author mention natural foraging? Are bird feeders dangerous? You may also notice that the conclusion is very strong. Although it doesn’t use words like "always" or "all", the word "responsible" is equally strong. Couldn’t there be other factors contributing to the larger-than-usual bird population besides the mild winter?

Now that we better understand the stimulus and its flaws, we are ready to attack the answer choices. Since this is a Strengthen question we want to shrink (or close) a gap in the argument. Remember that this question type can (and often will) bring in new information. It is important to remember that the correct answer’s relation to the core may be less than obvious at first.

(A) is tempting, but incorrect. Does a mild winter constitute an unusual weather pattern? Even if we assume that it does, this answer choice just tells us what we already know. Our stimulus is proof that increases in bird populations sometimes occur following unusual weather patterns, but is it possible for an unusual weather pattern to be responsible for the increase in bird populations?

(B) is too vague. How do their mating behaviors differ? Do they mate more? If so, this would strengthen our argument. However, given the way this answer choice is worded they could also mate less, which would weaken our argument. Eliminate it!

(D) is the opposite of what we want. It weakens the argument. If birds often exhaust that range’s food supply before spring when they do not migrate then maybe the birds run out of food, which would likely decrease the bird population.

(E) doesn’t have any effect (except perhaps further confusing the test-taker). From the stimulus itself we don’t know whether visiting feeders increase, decrease, or have any effect at all on the bird population, so the fact that birds sometimes visit feeders even when they are able to find sufficient food for survival by foraging naturally doesn’t really tell us anything.

(C) answers one of the questions we were asking earlier: why does the argument mention that the mild winter allowed for more natural foraging and therefore fewer birds visiting feeders? If visiting bird feeders increases their vulnerability to predators, it explains why not visiting bird feeders would increase the bird population. This definitely strengthens our argument core!

[Joymarie.virga]

I also got this questions wrong and could not understand why. After looking up the word attrition it all made sense.

[tzyc]

I didn't realize the 1st sentence was one of the premises...just took it as background info.
Is this related because it contains "last winter was mild enough" which is related to the conclusion?
Sorry for the basic question, but really want to distinguish premise and background info...
Thank you

[ohthatpatrick]

Yes, your exactly right. The reason we know it's relevant to the conclusion is that it deals with a consequence of a 'mild winter'. Furthermore, going from the first to the second sentence we get the word "also", indicating that we should be clumping them together.

What makes it seem like background info initially is that the author really doesn't tie in how "not visiting feeders" has anything to do a larger-than-usual bird population.

This type of problem seems to get used once per test now in LR.

By "this type", I mean there are 2 premises for the conclusion. 1 of the premises CLEARLY relates to the conclusion. The other one just sits there, like, "Okay ... so what?"

Check out PT64, S3, 17.

It's the exact same template, and the correct answer similarly is just trying to make that 1 unexplained premise finally relevant to the conclusion.

Hope this helps.

[logicfiend]

I was very confused by this question, which I'm thinking is a good thing when I'm doing LSAT problems. It means I realize something is not adding up and I need to figure out how to make this argument work! I knew (C) was probably the correct AC, but in timed practice, I could not figure out how it related to the argument.

If anything, I thought it may even weaken: I THOUGHT the stim said mild winter are causing birds to forage naturally, rather than using bird feeders. I thought (C) was giving an alternate explanation for why less birds were feeding at bird feeders; not because of the mild winter, but because they're in general more vulnerable to predators. Suffice it to say, my thinking was a complete mess.

Now I realize that the stim is actually saying with the mild winter, more birds were ALLOWED to forage naturally instead of using bird feeders -->this caused an increase in bird population.

With this clarification, it is much easier to see how (C) is bolstering/explaining the relevance of this premise to the argument. Still, this is a very tricky argument to understand quickly precisely because it just doesn't make sense initially.