They break the hard-shelled insects and swallow them rapidly.
Their long-oval, hard-shelled eggs are deposited in the ground.
But if I were to express a preference it would be for the hard-shelled suitors.
I heard one crunching a hard-shelled bit in his strong beak.
The eggs are hard-shelled, and the males are usually smaller than their mates.
Boil the desired number ...