The sign is sort of mistranslated as it reads, “Beware of Kites” which I suppose would be confusing with the kids toy.

Endoshima is infested with
“tobi”–Kites, which are known for their ability to hover. Besides stealing lunches, the “tobi” nest in large groups that defecate huge piles of fishy poop.

The Kanji is 鳶 but most people just write the word in Katakana トビ . Oddly Japanese more commonly pronounce it tonbi トンビ .

Weird factiod: Kite are listed in Leviticus, 11.14, as ‘an abomination’.

Other Japanese beaches have the more solitary (and not stinky) Osprey (Pandion haliaetus), also known colloquially as seahawk, fish hawk.