Where does “дрозду” come from?

дрозду (Russian) comes from Russian дрозд, from Proto-Slavic drozdъ, from Proto-Balto-Slavic trozdós, from Proto-Indo-European trósdos.

дрозду (Russian): dative singular of дрозд

Definitions

Step	Language	Word	Meaning
1	Russian	дрозд	thrush
2	Proto-Slavic	drozdъ	thrush
3	Proto-Balto-Slavic	trozdós	—
4	Proto-Indo-European	trósdos	—

дрозду — Etymology, Origin & Word History | Etymology Explorer