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Verbal·Information and Ideas·Inferences

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From larks to buzzards, many birds fly in flocks. But starlings uniquely form murmurations, large flocks that swirl in changing shapes before the birds roost together overnight. The two leading explanations for this behavior are the “warmer together” hypothesis, which holds that the goal is to attract more starlings to increase body heat in cold roosts, and the “safer together” hypothesis, which centers on defenses like crowding to make it hard for peregrine falcons and other predators to target a single bird. A study of over 3,000 murmurations across a range of climates found that local temperature was not associated with size, but the presence of a predator correlated with increases in both size and duration. Thus, researchers suggest that       

Which choice most logically completes the text?

A

starlings’ flocking behavior likely evolved as a response to predation from birds such as peregrine falcons rather than as a response to cold overnight temperatures.

B

starlings are unlikely to form murmurations in climates where overnight temperatures tend to be warm, regardless of the prevalence of local predators.

C

starlings’ movements are likely less predictable when a peregrine falcon poses an imminent threat to the flock than when other types of avian predators do.

D

starlings differ from both smaller birds like larks and larger birds like buzzards in that starlings engage in flocking behaviors primarily when predators are present.