Last winter was mild enough

Answer choices

1. A

   Very Weak17% picked this

   Increases in bird populations sometimes occur following unusual

   This does fit the author's conclusion in a broad sense, but it's far too weak to have much impact. "Sometimes" means at least once, so answers on Strengthen / Weaken / Paradox that are saying "some / could / may / might / not all / not always" are almost always wrong, since they only give us one data point.

   17%
2. B

   Unclear Impact16% picked this

   When birds do not migrate south, the mating behaviors they exhibit differ from those they exhibit

   We know the mating behaviors are "different", but does that mean better or worse? Are they having more babies or fewer babies than normal? Without knowing the effect on birth rate, we don't know whether this strengthens or weakens.

   16%
3. C

   Correct62% picked this

   Birds eating at feeders are more vulnerable to predators than are

   Why this is right

   This gets at one of the comparisons we cared about. We know the mild winter led to more natural foraging, less bird feeding. Now that we're hearing that the latter is more vulnerable to predators than the former, we have reason to think that foraging will lead to a bigger bird population than eating at bird feeders.

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

   62%
4. D

   Weakens4% picked this

   Birds that remain in their summer range all winter often exhaust that range's food

   This addresses the other comparison we were wondering about: what's better for bird population -- losing some birds to migration or staying local all winter. This answer choice presents a survival-related negative about staying local all winter: the birds might exhaust the local food supply (which could lead to a smaller bird population being able to live in the area).

   4%
5. E

   Opposite / Too Weak2% picked this

   Birds sometimes visit feeders even when they are able to find sufficient food for survival

   The author was making it seem like a good thing that the birds were avoiding feeders and foraging naturally, so this answer is moving away from a good thing (so it feels more like a slight weakening / backpedaling). Furthermore, like choice (A), since this is saying "sometimes" it's giving us an incredibly weak idea -- at least one bird once visited a feeder even though it could have found food by foraging.

   2%