How Do Birds Know When to Fly South? | A2 ESL Science Reading Passage

Use this A2-B1 ESL science reading passage to learn how birds know when to fly south. It includes key vocabulary, reading comprehension questions, and answers for English learners.Reading LevelA2-B1Word Count286 wordsReading PassageMany birds fly south before winter arrives. But how do they know when it is time to leave? Birds do not use calendars. Instead, they notice natural signs around them ..