Beak of the Finch

I've been reading this non-fiction book about evolution ever since I returned from my trip to Ecuador.  Jonathan Weiner writes about Peter and Rosemary Grant, scientists, who have studied the finches on Daphne major, a small Galapagos island.  The finches on this island are difficult to tell apart.  Only experts can tell the exact species of Darwin finches at a glance.  A ground finch is very much like a tree finch.  They are all LBB's (little brown birds). The beak sizes differ.  But each kind of finch can have a small, medium, or large beak.  Ground finches have smaller beaks than tree finches but a ground finch with an unusually large beak can have a bigger beak than a tree finch with an unusually small beak.  The Grants studied these finches year after year. They also studied the seed available for the finches to eat.  With the assistance of graduate students, they would lay out a grid and count every single seed.  They spent hours and hours counting seeds.  The work was grueling and boring plus the conditions were terrible.  As time went on, the Grants realized that the finches with larger beaks are better able to eat the larger seeds.  Like me, when I eat a bowl of pistachio nuts, I leave the hard to crack nuts for last.  During droughts, finches with larger beaks thrive and propagate.  Having a larger beak has disadvantages when rain and seeds are plentiful.  By paying close attention, trapping and banding finches, and measuring beaks year after year after year, the Grants eventually realized (with the aid of computer technology) that they were observing evolution.  During dry years, beaks became larger.  When rain was plentiful, the beaks were smaller.  The evolution was on a minuscule scale but very real.  When they put data into the computer on rainfall and seed availability, the computer accurately predicted the size of the beaks of the offspring born the next season.  Some of the information was fairly dry and technical but the author does a good job of keeping it real.  He throws in funny anecdotes about life on the Galapagos Islands.  Reading this book has helped me extend my vacation just a little further. 

PS Collected six cups of maple sap today - all from the east maple.