Passage Summary: Some birds eat almost constantly to stay warm. The author claims that if a seed-eater and a nectar-eater need the same amount of energy, the seed-eater will be busier eating because seeds are less energy-dense than nectar.

Conclusion: Seed-eating birds likely spend more time consuming food than nectar-eating birds with identical energy needs.

Reasoning: A specific volume of nectar contains a higher concentration of energy than an equivalent volume of seeds.

Analysis: The author is making a classic jump from energy density to time spent. Just because a burger has more calories per bite than celery doesn't mean it takes longer to eat a day's worth of celery—it depends on how fast you can chew. To make this argument work, we must assume that nectar-eaters don't take significantly longer to actually consume their food than seed-eaters do. Look for an answer that ensures the speed of eating doesn't cancel out the energy advantage of the nectar.