Related Clues:

• "One Flew Over the Cuckoo's ---"
• Fit one inside the other
• Fit one inside another
• Roost
• Fit well together
• Brooding place
• Treetop retreat
• Hotbed
• Place for fresh eggs
• Fit snuggly
• Digs in a tree
• Arboreal home
• Cozy retreat
• It takes a lot of eggs
• Clutch