Fist in the series by this celebrated author.
From the back cover:
This fast-paced, sophisticated and often hilarious mystery by a distinguished historical novelist introduces Johnson Johnson, a famous but enigmatic portrait painter whose interests, it soon becomes obvious, range far beyond painting, and his sailing yacht, the Dolly. The singing bird of the title is Tina Rossi, the world's leading colorature soprano, who goes to the Edinburgh Festival largely beccause it will give her a chance to see her lover, scientist Kenneth Holmes, who is working on top-secret research on the Hebrides island of Rum. But when she goes to the secret meeting place she finds not Kenneth but an unknown corpse. The Johnson Johnson turns up; Kenneth is accused of sabotage; and Johnson and Tina sail in a race through the Hebrides on the Doll -- and it turns out that far more than sport is at stake.