Resources

Photo attributed to Wingchi Poon. This file is licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license. No endorsement implied. 

Photo attributed to Gerald Vicker, U.S. Fish and Wildlife Service. This photo is in the public domain. No endorsement implied. 

Photo attributed to Irvin Parco Sto. Tomas. This file is licensed under the Creative Commons Attribution-Share Alike 4.0 International license. No endorsement implied. 

Photo attributed to Hannahlongole. This file is licensed under the Creative Commons Attribution-Share Alike 4.0 International license. No endorsement implied. 

This image is in the public domain because it contains materials that originally came from the U.S. National Oceanic and Atmospheric Administration, taken or made as part of an employee's official duties.

This work has been released into the public domain by its author, Binter at the Wikipedia project. This applies worldwide.

Photo attributed to Colin Mutchler. This file is licensed under the Creative Commons Attribution 2.0 Generic license. No endorsement implied.