Common raven / Kolkrabe (Corvus corax)

Kolkrabe am Aabach, Wetzikon. 2021-03-10 09.49.56 Wetzikon
Classification: Genus Crows (Corvus); Family Corvidae
This bird appears across the great seas in the following continents: Europe, North America, Africa.
The raven is often mentioned in word puzzles as the largest songbird.
Good to know: Other: A flock of ravens may be called an unkindness [Literary names of groups and flocks]
Etymology: Kolk, die erste Silbe seines seit dem 16. Jahrhundert bezeugten deutschen Namens, ist vermutlich lautmalerischen Ursprungs, ahmt also den Ruf des Vogels nach. [Link]
Appearance and identification: It is one of the two largest corvids, alongside the thick-billed raven, and is possibly the heaviest passerine bird [Link]
Ravens are larger, the size of a Red-tailed Hawk [in Switzerland a red kite, similar 'length' but only 2/3 of the huge kite wingspan]. Ravens often travel in pairs, while crows are seen in larger groups. Also, watch the bird’s tail as it flies overhead. The crow’s tail feathers are basically the same length, so when the bird spreads its tail, it opens like a fan. Ravens, however, have longer middle feathers in their tails, so their tail appears wedge-shaped when open. Listen closely to the birds’ calls. Crows give a cawing sound. But ravens produce a lower croaking sound. [How to Tell a Raven From a Crow]
Vocalization: Quite varied repertoire. Most heard sound a short, coarse, but resonant "korrk. Other sounds may be surprisingly resonant and pure, like a ringing "clong" etc. Shows even more variation when courting. [Link]
Physical details: length=64 cm, wingspan=120-150 cm, weight=800-1560 g
Habitats: Mountain

Call: Graak!
Call attributes: Call melody: non-musical, slow, Frequency: low (1-3 KHz), Special sounds: cawing.
First documented observation : 2021-03-10 in Pfäffikersee.