LR Question 26 Explanation
QUESTION TEXT: Bird watcher: The decrease in the mourning-dove…
QUESTION TYPE: Strengthen
CONCLUSION: There are fewer mourning doves because there is less nesting habitat for them in the area.
REASONING: Mourning doves used to nest in orchards until sprinklers were installed.
ANALYSIS: This argument makes a causation-correlation error. True, the mourning dove decline happened at the same time that the sprinklers were installed. But that doesn’t mean that the habitat decline caused the decrease of doves in the area. There could have been other, more important reasons: less food, more predators, new food supply in a different area, etc.
The argument has also failed to show that the loss of the orchard truly was a problem for the mourning doves. If there was still much available habitat in the area, then loss of the orchard likely wasn’t the cause. Answer B addresses this by showing that the orchard was the only suitable habitat.
You might have thought “maybe the sprinklers didn’t truly ruin the orchard as habitat”. This is possible, but unlikely – sprinklers are pretty disruptive. Answer C does address this possibility by showing that the sprinklers were indeed a problem. If B didn’t exist, I would have chosen C. But B is a far stronger answer. It’s rare for there to be two answers that strengthen an argument, but this question shows that it’s possible. In such cases, you should follow the question stem’s direction: you’re choosing the answer that most strengthens the argument.
___________
- This weakens the argument by providing an alternate cause. If mourning doves can now be hunted, then maybe hunting is the cause of the decline.
- CORRECT. This strengthens the argument by increasing the impact of the sprinklers. The sprinklers affected the doves’ only habitat.
- I think this answer does slightly strengthen the argument, by confirming that the sprinklers ruined the orchard as a habitat. But it’s not much of a strengthen. It’s already pretty reasonable to assume that sprinklers ruin trees as a habitat. Further, this doesn’t show that the doves actually lacked habitat in the area. If other trees were suitable, then loss of the orchard wouldn’t have been a big deal. Only B shows that the orchard was a critical habitat.
- This doesn’t have any impact. Only a change would have reduced the number of morning doves. This answer doesn’t say that residents changed what they put in their feeders.
- This is too vague to be useful. We already knew that the doves nested in apple trees. This just tells us doves often nest in fruit trees. But it doesn’t mean that only apple trees make good habitats for doves. This actually weakens the argument slightly by showing that other fruit trees in the area might have made good replacement habitats.
More Resources for Strengthen Questions
- Intro Course lesson: This intro course lesson covers Strengthen questions.
- Mastery Seminar lesson: This LR Mastery seminar lesson covers strengthen questions.
I got this answer correct, but I find your explanation of why (E) is incorrect a bit confusing. I agree with your overall evaluation that “this [answer] actually weakens the argument slightly by showing that other fruit trees in the area might have made good replacement habitats.” In other words, if mourning doves indeed had other places to nest (in other fruit trees in a different orchard without sprinklers), then we cannot attribute their population decrease to these nearby specific sprinkler-laden orchards.
However, I do not understand why you write that “We already knew that the doves nested in apple trees. This just tells us doves often nest in fruit trees. But it doesn’t mean that only apple trees make good habitats for doves. ” I cannot find in the stimulus where it says the trees are apple trees – this is in fact never specified…The stimulus says “orchards,” but this could mean orchards of apples, peaches, olives, figs or any sort of tree-growing fruit. I’m thus uncertain why you make the distinction about “apple” trees and why this tells us (E) is therefore incorrect.
Ah thank you. This was a mistake on my part from my own cultural background. The only orchards where I grew up were apple orchards. But checking the dictionary I realize an orchard can actually be any set of fruit or nut trees. I’ve added this to a list to update.
Note: This is an old comment but I wanted to clarify the point.
Wow this question is awful. I liked B. and C. and ultimately went with C., because the sprinklers can be tied to be the common cause for mourning doves not being able to nest in orchard trees and therefore decline in population. I thought it was stronger than B. because if another type of bird was also affected in same way then the sprinklers are the common cause for the doves not being able to nest in the orchards. Could you please help me reason with B and C and how I can avoid making same mistake in future?
B says that the trees in the orchards were the only type attractive for nesting.
1) doesn’t this mean that there can be trees of this type in other places? Stimuli didn’t say that the orchard is the only place that those trees grow.
2) “most attractive” is nice, but it isn’t the same as “tge only place they can build nest”
I chose D because it eliminates an alternative explanation, that the dove are declining because of a lack of food.
Please explain? :/
1) The conclusion is referring to the decline in the mourning dove population “in this area”. If the trees in the nearby orchard are the only place “in this area” that are attractive to nesting mourning doves, it doesn’t matter if these trees exist in other areas.
2) Could you clarify what you mean here? (B) says “the only types of trees in the area attractive to nesting mourning doves”.
Re: (D), the issue here is that we’re not actually told there is a lack of food. It doesn’t say the residents of the area suddenly stopped filling their feeders, or that the area residents were starting to fill their feeders in response to some notice of a lack of natural food for mourning doves.
For (B), I meant to say that when these trees is the only type in the area suitable for nesting, that doesn’t mean that these trees are the only ones suitable for nesting. What if there are other trees of this kind that are also in the area? The stimuli does not say that the nearby orchards is the only place where these trees grow. I can’t see past this distinction. Is the reason that (B) is correct because it’s the best answer of the bunch, even though it’s not perfect?
What I mean with (D) is that, a possible weakening argument is that the doves are declining because of other reasons, such as a lack of food. By eliminating this weakener/alternative cause for the decline, (D) strengthens the argument. Thoughts?
Thanks for helping me with this question!
Ah, I see what you’re saying. That’s a bit of an obscure reading, though: the wording of (B) implies that that kind of tree is only present in the nearby orchards. For the answer choice to mean what you’ve suggested, it would need to say something like “the only type of tree that is attractive to mourning birds can be found in the nearby orchards.” The “only” in the answer choice as it is written on the test is referring to the specific group of trees in the nearby orchards. Also, note that “type” doesn’t necessarily mean species of tree, it could just mean that the trees in the nearby orchards share a certain set of positive attributes, like height.
(D) doesn’t eliminate an alternative cause, because it doesn’t tell us if/to what extent the mourning birds benefit from feeders. Sure, maybe the feeders are being filled, but we’re not told if the level of food is even remotely sufficient for the mourning bird population in the area, or if the mourning birds even use the feeders.
And no problem, am happy to help!