Bert Spiegel does not look 90. He hardly looks 80 with snakeskin boots and long grey rock star hair. Number aside, Windward Bay residents threw him a party May 22 in the clubhouse. It just so happened that Rosalyne Weiner was celebrating a birthday, too. And Spiegel insisted on sharing his day with all of the May birthdays. Birthday songs were sung, candles were blown, wishes were made and plenty of cake was eaten. Happy Birthday, Mr. Spiegel.