In the middle of May (sunrise 4:00 CET) this bird alarm clock would work as follows:
3.00 - Song Thrush (drozd spiewak, sings from the tops of tall trees)
3.10 - Robin (rudzik, sings hidden in the thicket of forest undergrowth)
3.15 - Blackbird (kos, sings from tree tops and high branches)
3.20 - Tree Pipit (swiergotek, sings from tree tops and in flight)
3.30 - Cuckoo (kukulka, sings in crowns of trees)
3.40 - Great Tit ( bogatka, sings in lower parts of the forest)
3.50 - Chiffchaff (pierwiosnek, sings in lower parts of the forest)
4.00 - Chaffinch (zieba, sings in lower parts of the forest)
4.20 - Golden Oriole (wilga, sings in crowns of tall trees)
4.40 - Starling (szpak, sings in different places)
All above mentioned birds are common dwellers of Polish woods. The majority of them is easily distinguishable and they all sing in a loud, characteristic way.