Eurasian treecreeper / Waldbaumläufer (Certhia familiaris)

As seen creeping up a tree trunk Source: WIKIPEDIA Wikimedia - European Treecreeper - Certhia_familiaris_-climbing_tree-8_(cropped_version).jpg
Classification: Genus Certhia; Subfamily Certhiinae; Family Certhiidae
General: The Eurasian treecreeper or common treecreeper (Certhia familiaris) is a small passerine bird also known in the British Isles, where it is the only living member of its genus, simply as treecreeper. It is similar to other treecreepers, and has a curved bill, patterned brown upperparts, whitish underparts, and long stiff tail feathers which help it creep up tree trunks. It can be most easily distinguished from the similar short-toed treecreeper, which shares much of its European range, by its different song. [more]
Song: Lang u. klar! (Waldwege sind lang). Tonreihe im Ganzen absinkend, nur letzter Ton höher. [Link]
Song a short, continuous three-part phrase. [Link]
Calls: weniger scharf, „srih,“ weniger eindringlich als oben [Link]
Contact call a drawn, high-pitched "tzreeee". Similar to Goldcrest in timbre, but of longer duration with a vibrating and slightly rolling tone. Generally repeated in evenly paced, slow series (unlike Goldcrest). Each phrase starts with a few contact call-like notes followed by a Willow Warbler-like descending part, which then jumps to a few descending high notes to form a marked conclusion. Note that "mixed singers" are not uncommon in areas where both species of treecreepers occur. [Link]
Physical details: length=12 cm, wingspan=17-21 cm, weight=8-11 g
Habitats: Forest
Looks similar to: Short-toed treecreeper.
Song: I say: it sounds like a faster higher chaffinch song. Wikipedia says: The male's song begins with srrih, srrih followed in turn by a few twittering notes, a longer descending ripple, and a whistle that falls and then rises.
Song attributes: Mnemnoic: Sagging tree branch Melody: stereotype melodic, slow, Frequency: medium (1-5 KHz)
Call: General: Wikipedia says: The contact call is a very quiet, thin and high-pitched sit, but the most distinctive call is a penetrating tsree, with a vibrato quality, sometimes repeated as a series of notes.
Fairly regularly spaced single tseep at 7-9KHz.
Call: Contact call a drawn, high-pitched "tzreeee". Similar to Goldcrest in timbre, but of longer duration with a vibrating and slightly rolling tone. Generally repeated in evenly paced, slow series (unlike Goldcrest). [Link]
Call attributes: Call melody: one note, slow, Frequency: 7-9 KHz,
First documented observation : 2020-04-25 in Luppmen.