Logical Reasoning

PT102 · S4 · Q26 At night, a flock of crows will

A free, expert breakdown of this official LSAT Logical Reasoning question.

  • Save & drill this skill — build targeted practice sets from questions like this one

  • Video walkthroughs — watch every question solved step by step

  • 81 official LSATs — as questions, timed sections & full-length tests

Start practicing free

At night, a flock of crows will generally perch close together in a small place—often a piece of wooded land—called a roost.

Statements

At night, the crows bunch up into a roost. By day, they fan out, like radii shooting from the center of a circle, going out about 100km. Then they come back again to roost. After a few years, they find a new roosting spot. It's not that far away from the old one (only about 8km).

Evaluate

On Must Be False (or this more softly worded version), the correct answer usually contradicts a conditional idea or contradicts a possible inference.

There weren't any conditionals in this paragraph, but there does seem to be a bit a math-y inference we can make by considering the two math facts: - they fan out about 100km in all directions - they move to a new roosting site within 8km of the previous one

What can we say by combining those two facts?

- their scavenging territory hasn't changed much. - they've moved somewhere within their current scavenging territory - their new roost was on some crow's old scavenging route

Goal

Since we want something to essentially contradict our possible inferences, maybe we'll see a correct answer like - their scavenging territory has completely changed - their new roost is somewhere they had never been / in a place none of the flock had been before

26.

Of the following claims, which one can most justifiably be rejected on the basis of the statements above?

  1. Crows will abandon their roost

    Out of Scope

    Out of Scope: in response to (cause) There is no information about why they eventually abandon a roost, so we have no means to contradict anything in that department.

    16% picked this

  2. When there is a shortage

    Out of Scope: food shortage

    We never discuss this hypothetical. There isn't any conditional that restricts us from believing this could happen. So, sure, maybe when food is scarce, some scavengers take an exploratory mission elsewhere.

    6% picked this

  3. Most of the hunting and

    Unknown Quantity: most

    We don't have any idea what proportion of hunting and scavenging is done within the first 8km vs. within the next 92 to 122 km. To contradict this answer, we'd be saying that most of their hunting is done within the first 8km of their 100-130km trip.

    8% picked this

  4. Once a flock of crows

    Out of Scope: ease of relocating

    We never delve into how easy or hard it is for a flock to move to a new roost and then up and move again. If anything, the passage supports the idea that when they find a new roost they stay for several consecutive years, so maybe it is very hard to move them soon after they've just moved.

    10% picked this

  5. Correct

    When a flock of crows

    Why this is right

    Here we get the "Most Supported" spin on Must Be False. This is going against one of the inferences we made. We realized that since they had a giant 100-130km radius circle before, scooting the center of that circle 8km from where it was isn't moving that huge circle much. If you saw an overhead satellite view of a circle that was 200-260 km in diameter, and then someone shifted it 8km in any direction, you'd still be looking at more than 90% the same land. Since we know that when they change roosts, they usually move very little, relative to how big a local area they explore each day, then it makes no sense to say, as (E) does, that they're moving because their hunting area has run out of food. It'd be like if your city had terrible unemployment, and your solution was to move eight blocks south, to improve your job prospects.

    Skill tested: Must be False · how this choice captures the argument's function is the move to repeat next time.

    59% picked this

Continue the review in LSAT Lab

Save this question, watch the video walkthrough, and drill similar questions in your LSAT Lab account.

Save and practice this skill
LSAT Lab

Turn this review into a targeted study plan.

Save this question, drill more like it, watch the video walkthrough, and track your progress in your LSAT Lab account.

Start practicing free