Question 58·Easy·Inferences
Wildlife biologist Nora Singh has documented the spring arrival dates of the red-tailed warbler in the northern state of Pinecrest for fifteen consecutive years. From 2000 through 2012, the birds consistently arrived between April 10 and April 20. In 2013 and 2014, however, Singh recorded their arrival between March 28 and April 2. During those two years, the average winter temperature in Pinecrest was about 5 °C warmer than the long-term average.
Based on Singh’s observations, it is most reasonable to infer that the earlier arrival of the warblers in 2013 and 2014 was due to ______.
Which choice most logically completes the text?
For SAT Reading & Writing inference questions, first restate what changed or what outcome you must explain, then underline or note any specific details (dates, conditions, measurements) linked to that change. Look for answer choices that directly connect to those details, and be very skeptical of options that introduce new concepts, places, or causes the passage never mentions. Choose the option that stays closest to the given evidence and explains the pattern or shift without adding unsupported ideas.
Hints
Locate the key time period
Focus on what is different about the years 2013 and 2014 compared with 2000–2012. What major change does the passage describe for those two years?
Connect the change in bird behavior to the passage details
The birds arrive earlier in 2013 and 2014. Which detail in the passage occurs in those exact same years that could logically be related to bird migration timing?
Watch out for new, unsupported ideas
Eliminate any answer choices that introduce information the passage never mentions, such as changes in population, technology, or conditions in other locations.
Check for direct alignment with the evidence
Ask yourself: Which option directly uses the specific environmental detail the passage provides and could sensibly explain why the birds arrived sooner?
Step-by-step Explanation
Clarify what the question is asking
The question asks what it is most reasonable to infer caused the warblers to arrive earlier in 2013 and 2014. That means we must find the cause that is best supported by the information stated in the passage, not something we make up or guess from outside knowledge.
Identify the key change in the passage
From 2000–2012, the birds arrived between April 10 and April 20. In 2013 and 2014, they arrived much earlier, between March 28 and April 2. The passage also tells you that in those same two years, the average winter temperature in Pinecrest was about 5 °C warmer than the long-term average. So the only explicit change the passage mentions is that the winters in Pinecrest were warmer in the years when the birds arrived earlier.
Use the passage’s cause-and-effect clue
When a passage mentions a big change (earlier arrival) and pairs it with another big change during the same period (warmer winters), it is usually hinting at a cause-and-effect relationship. So the best answer will connect the earlier arrival directly to the warmer winter conditions in Pinecrest.
Test each answer against the passage
Now quickly check each choice:
- Choice A talks about food in the birds’ tropical wintering grounds, which the passage never mentions.
- Choice B mentions a decline in the warbler population, which is also not in the passage.
- Choice C suggests a change in Singh’s equipment, but the passage does not say anything changed about how she observed the birds.
- Choice D ties the earlier arrival to an unusually mild winter in Pinecrest, matching the detail that winters were about 5 °C warmer in the years of early arrival.
The only answer that uses the actual information given in the passage and explains the timing change is choice D: an unusually mild winter in Pinecrest that signaled the birds to begin migrating sooner.