Which bird has crossed mandibles adapted for extracting seeds from conifer cones?

Which bird has crossed mandibles adapted for extracting seeds from conifer cones?

• A. Red crossbill
• B. European robin
• C. Cliff swallow
• D. Short-tailed pygmy tyrant

Answer: (A)

Crossed mandibles are a specialized beak arrangement that lets a bird pry apart the scales of conifer cones to reach the seeds inside. The red crossbill has this exact adaptation: the upper and lower parts of the bill cross so each mandible can grip and lever against cone scales, effectively prying open cones and extracting the seeds. This feeding niche is highly specialized and gives crossbills access to a food resource that many other birds can’t use, especially in environments where cones are abundant but hard to access. The other birds listed have more generalist or differently specialized beaks. A robin has a slender, pointed bill suited for insects and small fruits, not for prying cone scales. A cliff swallow carries a broad, short bill adapted for catching flying insects in the air. A short-tailed pygmy tyrant has a small, straight bill typical of many small tyrant flycatchers. None of these share the distinctive crossed-beak adaptation that enables efficient cone-seed extraction, so the red crossbill is the best answer.

Crossed mandibles are a specialized beak arrangement that lets a bird pry apart the scales of conifer cones to reach the seeds inside. The red crossbill has this exact adaptation: the upper and lower parts of the bill cross so each mandible can grip and lever against cone scales, effectively prying open cones and extracting the seeds. This feeding niche is highly specialized and gives crossbills access to a food resource that many other birds can’t use, especially in environments where cones are abundant but hard to access.

The other birds listed have more generalist or differently specialized beaks. A robin has a slender, pointed bill suited for insects and small fruits, not for prying cone scales. A cliff swallow carries a broad, short bill adapted for catching flying insects in the air. A short-tailed pygmy tyrant has a small, straight bill typical of many small tyrant flycatchers. None of these share the distinctive crossed-beak adaptation that enables efficient cone-seed extraction, so the red crossbill is the best answer.