p.s. I have not had much time to devote to the Sirin-Zhar ptitsa path recently (not that anyone on the List has shown the slightest interest in the subject), however those who recall the image of the Kalmakov painting I posted may also recall the Smert'/subMarina Princess's swanee arms and might be intrigued to think about a possible link between Lebedinoe Ozero [Swan Lake] and the vanishing city of Kitezh, both Dangleleaf productions, as it happens ...
There's a swan/subMarina theme in Ada of course - does it appear anywhere else in Nabokovian seas or ozeros [lakes]?
Is Ada itself a Dangleleaf production?