When something is described as egg-shaped, the ubiquitous hen’s egg typically comes to mind. But for birds, eggs come in myriad shapes: owl eggs look like ping-pong balls, hummingbird eggs are shaped like jelly beans, swift eggs are pointed at one end like a pear.
So what’s the reason?
Biologists have been asking that question for quite some time, and their hypotheses are perhaps just as varied as the eggs themselves. Scientists in the past have concluded that cliff-dwelling birds lay