The population of songbirds

Answer choices

1. A

   No Impact1% picked this

   Official records of the population of birds in England have been kept for only the

   While the duration of official records may matter for long-term trends, it doesn't impact the explanation regarding magpies affecting songbirds' recent decline. The argument doesn't rely on the historical depth of records but on the correlation between recent increases in magpies and decreases in songbirds.

   1%
2. B

   Unclear Impact9% picked this

   The number of eggs laid yearly by a female songbird varies widely according to

   The variation among different species of songbirds in their egg production doesn't directly affect the argument about magpies being the reason for the decline. In recent years, has songbird egg production been higher or lower in England? And what does the rate of egg production have to do with whether or not magpies are a causal factor?

   9%
3. C

   Correct75% picked this

   Although the overall population of magpies has increased, in most areas of England in which the songbird population has decreased, the number

   Why this is right

   This impugns the plausibility of the author's hypothesis that an increase in magpies is causing a decrease in songbirds. The answer has the classic Effect w/o Cause form. There are places where we observe a decrease in songbirds, even though we don't have an increase in magpies. That suggests that something besides "more magpies" is apparently causing the songbird decreases in most areas.

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

   75%
4. D

   No Impact6% picked this

   The population of magpies has increased because farmers no longer shoot or trap magpies to any great extent, though farmers still

   While this gives a reason for the magpie population increase, it doesn't directly argue against the magpie effect on songbirds. Understanding why magpies increased doesn’t necessarily impact whether magpies are causing a reduction in songbird populations.

   6%
5. E

   No Impact10% picked this

   Although magpies eat the eggs and chicks of songbirds, magpies’ diets consist of a wide variety of

   Magpies can have varied diets, but this doesn't weaken the causal link that their predation on songbird eggs and chicks could still impact songbird populations. Eating other foods doesn't mean they can't still negatively impact songbird populations through predation. We can't say, "it's plausible that an increase in magpies could lead to a decrease in songbirds, since songbird eggs aren't the only thing that magpies eat."

   10%