Caebar has an interest in learning more about Leafshade, and while the Ent is unlikely to join your crew, perhaps he will know of something that might be of use to you.
'Hrum, hoom... you have come back again, little one? Have you returned to Tumbamálë to bring me news of Nestinanessornë?'
You tell Leafshade that you are looking for crew-members to sail with you to Umbar, and you hope to rescue both Nestinanessornë and the young heir of Pinnath Gelin from the Kindred of the Coins. Leafshade exhales heavily, shaking the leaves of his grove.
'Hoooooooom...'
When the leaves finally settle, Leafshade speaks again.
'I do not like boats, hoom, toom. My friend Nestinanessornë sailed away on one such vessel, but it is not the first time I have lost a companion to the branches-that-float. Another friend of mine, Gwallang the Limlinn, built a nest here in Tumbamálë, but a wooden boat passed nearby and he flew over to it. He never, hoom, never came back. Ferien told me long ago that sailors sometimes take birds with them on their voyages. Perhaps it was the same with Gwallang.'
Leafshade slowly extends a long arm down to you. After a moment you realize he is holding a small wooden whistle.
'If you find Gwallang... blow this whistle and remind him of Tumbamálë. It may be he has, hrum, forgotten.'
Leafshade thinks an old sailor might have sailed away with his friend Gwallang, a songbird of the Limlinn species. If you could find him, Leafshade's whistle will apparently remind the bird from where he came.
The caged songbird at the far end of Sirgon's room of keepsakes may be Gwallang.
The caged songbird certainly appeared to recognize the whistle. Sirgon has given you permission to open the cage and free the bird.