Which bird is known for nests of mud on cliffs and under bridges?

Which bird is known for nests of mud on cliffs and under bridges?

• A. Common raven
• B. Red crossbill
• C. Japanese white-eye
• D. Cliff swallow

Answer: (D)

This question tests knowledge of nesting behavior—specifically the materials birds use and where they build their nests. Cliff swallows are famous for shaping nests out of mud and attaching them to vertical surfaces, especially cliff faces and under bridges. They gather mud pellets, mound them into a gourd-like, cup-shaped nest with a single entrance, and often build in large colonies on natural ledges or human-made structures. That combination of mud construction and attachment to cliffs or bridges is distinctive, which is why this species is the best match. The other birds nest with different materials and in different places (for example, ravens build bulky stick nests in trees or on cliffs, crossbills nest in conifers with twigs and plant material, and the Japanese white-eye uses plant fibers in shrubs), so they don’t fit the description of mud nests on cliffs and under bridges.

This question tests knowledge of nesting behavior—specifically the materials birds use and where they build their nests. Cliff swallows are famous for shaping nests out of mud and attaching them to vertical surfaces, especially cliff faces and under bridges. They gather mud pellets, mound them into a gourd-like, cup-shaped nest with a single entrance, and often build in large colonies on natural ledges or human-made structures. That combination of mud construction and attachment to cliffs or bridges is distinctive, which is why this species is the best match. The other birds nest with different materials and in different places (for example, ravens build bulky stick nests in trees or on cliffs, crossbills nest in conifers with twigs and plant material, and the Japanese white-eye uses plant fibers in shrubs), so they don’t fit the description of mud nests on cliffs and under bridges.