If a cowbird female fails to lay in a warbler nest in time for her egg to hatch with those of the host, she can reset the clock in her favour by killing the first clutch.

ECONOMIST: How cowbirds run protection rackets

All leftover funds roll over into the next year, allowing employees to build a nice nest egg over time.

FORBES: Uncommon Sense

This gives your nest egg more time to grow and shortens the time you'll need to support yourself on savings alone.

WSJ: How to Get to Retirement? Practice!