Last winter was mild enough to allow most bird species to forage naturally, which explains why the proportion of bird...

MichelleRod on August 16, 2018

Thanks for your question, @EmilyMarieMenendez

You are correct that the passage never mentions predators. There are some cases where new information can be introduced by an answer choice. In this case, we are strengthening the argument by adding new information that supports the conclusions.

MichelleRod on August 16, 2018

@EmilyMarieMenendez

We already know from the stimulus that migration contributes to attrition, so the fact that there was less migration contributes to large burg populations.

We also know that birds were not eating at feeders as much. But how does that contribute to the large bird population? Answer choice C gives is that answer: if birds were at feeders less often, they were less vulnerable to predators and fewer birds died as prey.