
This photo shows pelicans skimming the waves off shore on Seabrook Island. A little googling finds articles that indicate “Skimming permits the birds to take advantage of an aerodynamic phenomenon known as ground effect”.
Following is an article, from Stanford University which explains skimming, why birds fly low over water. Also, a link has been included for today’s photo saved on Flickr with the caption Pelicans looking for fish offshore from Seabrook Island in South Carolina.