What does the black-headed gull symbolize or mean to the japanese?

i'm making a brochure for school, and i would like to know what type of meaning the black-headed gull has to japanese people. or actually the people of tokyo. because the black-headed gull is the perfecture bird of tokyo.What does the black-headed gull symbolize or mean to the japanese?
I'm Japanese and lives in Tokyo. it's the first time I've heard the black-headed gull is the prefecture bird of Tokyo. and I came to know that's true.


it's Yurikamome in Japanese. I'm sure it reminds most of us of the elevated train in Odaiba.


http://www.yurikamome.co.jp/en/


this is a little off the track, but it's head is not black at all.


http://ja.wikipedia.org/wiki/%E3%83%95%E鈥?/a>What does the black-headed gull symbolize or mean to the japanese?
I was born and raised in Tokyo but never thought of or heard of black-headed gull. It means nothing to me. Of course, I've been in U.S. for a long time. Seagulls are called ';kamome.';