Friday, June 23, 2017

Bird Eggs and Wings

A NY Times article caught my attention. Why Do Bird Eggs Have Different Shapes? Look to the Wings. The article relates egg shape to "flight ability," but doesn't explain what that means. Speed? Stamina? Maneuverability? Efficiency?

Having recently returned from New Zealand, it made me wonder about kiwis. Kiwis can't fly and have tiny stubby wings. The article suggested to me a kiwi egg would be more spherical, less elongated, and not pointy. It isn't pointy as I expected, but it is elongated similar to an egg of a wondering albatross, which has great flying ability and huge wings, at least in length, relative to their body size.

By the way, while in New Zealand I was surprised when I saw an x-ray image that showed egg size relative to the mother's body size. Why Is the Kiwi’s Egg So Big?

We also saw an albatross breeding ground on the Otago Peninsula near Dunedin. About the only time they spend on land is for breeding. The rest is in air or on water. They migrate eastward encircling Antarctica in the process. They fly long distances expending very little energy by soaring (using the wind with minimal wing movement).


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