Besides laying eggs in her own nest, any female wood duck will lay an

Answer choice (C) says that the actual size of the wood boxes are smaller than the natural nesting sites. We don't know how big the natural nesting sites are, nor do we know the size of the wood boxes. So we can't choose (C).

Answer choice (D) says that the wood boxes are less effective now than they would be if they were hidden. We know that the boxes "actually undercut the ducks' reproductive efforts." Also, we know that when nesting sites are hidden "this parasitic behavior is rare." Hiding the nesting sites would improve the situation, so we can infer answer choice (D).

Besides laying eggs in her own nest, any female wood duck will lay an egg in the nest of another female wood duck if she sees the other duck leaving her nest. Under natural nesting conditions, this parasitic behavior is relatively rare because the ducks' nests are well hidden. However, when people put up nesting boxes to help the ducks breed, they actually undercut the ducks' reproductive efforts. These nesting boxes become so crowded with extra eggs that few, if any of the eggs in those boxes hatch.

The statements above, if true, most strongly support which one of the following?


(A) Female wood ducks will establish nests in nest boxes only when natural nesting sites are not available. X

(B) Nesting female wood ducks who often see other female wood ducks are the most successful in their breeding efforts. X

(C) The nesting boxes for wood ducks have less space for eggs than do natural nesting sites. X

(D) The nesting boxes would be more effective in helping wood ducks breed if they were less visible to other wood ducks than they currently are. CORRECT. If the female wood ducks that aren't supposed to be laying their eggs in those makeshift nesting boxes, then the ducks that those boxes are made specifically for would indeed be more effective.

(E) Nesting boxes are needed to supplement the natural nesting sites of wood ducks because of the destruction of much of the ducks' habitat. X

The argument is that female wood ducks have a tendency to breed in other female wood ducks nest IF the other nest is visible. In reality, they are quite well hidden. When people put up nesting boxes (presumably in open), it undermines the reproduction efforts because the parasitic behaviour comes to fore and female wood ducks lay their eggs in it and the nest becomes crowded, leading to no hatch and hence "undermining" reproductive efforts.

Notice what i wrote in bracket is of utmost importance because if some people hid that nest to aid a particular duck, then, the "undermining reproductive efforts" may not happen.

(A) Female wood ducks will establish nests in nest boxes only when natural nesting sites are not available. -- The argument does not bring that out. Eliminate.

(B) Nesting female wood ducks who often see other female wood ducks are the most successful in their breeding efforts. -- The argument gives no info on comparative results of breeding efforts. Eliminate.

(C) The nesting boxes for wood ducks have less space for eggs than do natural nesting sites -- We do not know that and the argument does not suggest anything like that. Eliminate.

(D) The nesting boxes would be more effective in helping wood ducks breed if they were less visible to other wood ducks than they currently are. -- The argument does suggest that when it says "this parasitic behavior is relatively rare because the ducks' nests are well hidden.". Therefore, it is reasonable to conclude that if nesting boxes are well hidden (less visible) from other ducks, they may aid reproductive efforts since overcrowding may be avoided.

(E) Nesting boxes are needed to supplement the natural nesting sites of wood ducks because of the destruction of much of the ducks' habitat. -- Again, the argument does not provide us with any such information. Eliminate.


Hi AndrewN - could you please look at my reasoning process? Much appreciated!

I agree with your reasoning, Ravi, and I can see why you arrived at the correct conclusion. I felt as though only when was too strong in (A); the superlative most successful was too strong in (B); the comparative less space was purely speculative in (C); and the entire because clause was, again, purely speculative in (E). Well done.

- Andrew

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