Same way my Lab/Rottie/whatever mix managed to snatch the neighbor's escaped iridescent bird out of the air, and leave nothing but gleaming green feathers on the back porch.
Which I quickly swept away after promising to keep an eye out for 'Peaches'.
/johnny
My 8 month old golden retriever caught a mallard drake out on our lawn, and had killed and eaten that duck before I could stop him!