The Secret Garden

This simile is likening the hunger Martha's siblings with hawks and foxes.

"Eh!" said Martha. "I can't abide to see good victuals go to waste. If our children was at this table they'd clean it bare in five minutes."

"Why?" said Mary coldly. "Why!" echoed Martha. "Because they scarce ever had their stomachs full in their lives. They're as hungry as young hawks an' foxes."