* [[Jellyfish]] in [[Hawaii]], which swarm to the beaches precisely 9 to 10 days after each full [[moon]]<ref>http://www.aloha.com/~lifeguards/jelyfish.html</ref>
* [[Jellyfish]] in [[Hawaii]], which swarm to the beaches precisely 9 to 10 days after each full [[moon]]<ref>http://www.aloha.com/~lifeguards/jelyfish.html</ref>
* [[cicada]] that appear like clockwork every 13 years for some species, and every 17 years for others<ref>http://inside.msj.edu/academics/faculty/kritskg/cicada/faq.html</ref>
* [[cicada]] that appear like clockwork every 13 years for some species, and every 17 years for others<ref>http://inside.msj.edu/academics/faculty/kritskg/cicada/faq.html</ref>
* migratory powers of butterflies and birds<ref>[[migration]]</ref>
* migratory powers of butterflies and birds<ref>[[migration]]</ref>