Mallard hatching from an egg cracked by freezing
The eggs of early-nesting waterfowl in North Dakota are frequently exposed to subfreezing temperatures. Mallards ( Anas platyrhynchos ) and Pintail ( Anas acuta ), normally the first ducks to arrive in the spring, begin limited early nesting in min-April. Nighttime temperatures during this period frequently drop below freezing, and late spring blizzards are not unusual.
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