Why do birds fly south?

Posted Mar 27, 2014 by Tim Sandle
This isn’t the answer to a riddle, but it is an answer to some of the remarkable abilities and interesting behaviors that different types of birds exhibit. It seems that everything comes down to a special hormone called leptin.
The tree swallow in flight
The tree swallow in flight
Callie Bowdish
Leptin, it seems, explains how the Arctic tern (a sea bird) flies more than 80,000 miles in its roundtrip North Pole-to-South Pole migration and how the Emperor penguin incubates eggs for months during the Antarctic winter without eating. There is also an answer as to how the Rufous hummingbird, which weighs less than a nickel, migrates from British Columbia to Mexico. These physiological feats are influenced by leptin, the hormone that regulates body fat storage, metabolism and appetite.
A research group made their initial discovery by comparing ancient fish and reptile leptins to predict the bird sequence. Leptin plays a key role in regulating energy intake and expenditure, including appetite and hunger, metabolism, and behavior.
By storing fat birds can do amazing things. For example, small birds can migrate over long distances without feeding, storing energy mostly as fat rather than carbohydrate. Fat is a good form of energy storage because it provides the most energy per unit mass.
The discovery may have commercial importance. It might be possible that the study of leptin in birds for the poultry industry could lead to the development of faster growing and tastier chickens.
The research was undertaken at the University of Akron. The research has been published in the journal PLOS One, in a paper titled “Discovery of the Elusive Leptin in Birds: Identification of Several 'Missing Links' in the Evolution of Leptin and its Receptor.”