Bird in sorrow first to be chucked (5)

I believe the answer is:

egret

I'm a little stuck... Click here to teach me more about this clue!

'bird' is the definition.
(egret is a kind of bird)

I cannot understand how the remainder of the clue works.

(Other definitions for egret that I've seen before include "white fish eater" , "Wader with white plumage" , "White wading-bird" , "Seabird" , "Greet (anag) -- wading bird" .)

I've seen this clue in The Sun.

Want a hint initially instead of a full solution? Install my app