VCS-1: Zum KUCKUCK noch eins ... [DE/EN]

Preface:
The Bird Cache Series (BCS) is about birds and proverbs in which they appear.
For the 1st cache in the series no additional tools are needed.
Please take care and don’t do it by night!

The Cuckoo:
Ah, how lovely it is to hear the Cuckoo (Lat. Cuculus canorus) singing, which
happens actually quite seldom around these parts!
It is only here part of the year, being a migratory bird, which winters in Africa,
South of the equator.
From mid-April to the beginning of May, the distinct call of the male looking to
find a mate can be heard in our Northern latitude.
Because the female Cuckoo tricks other birds into hatching its eggs and raising
its own young, the Cuckoo has earned a special reputation in our tradition.
For instance, sometimes the term, “Cuckoo-Child” refers to a child being raised
by a man who is actually not the biological father, even if both father and child
believe they are related!
The world famous Cuckoo Clock, hailing from the Black Forest region, is another
well-known use of the bird’s name.
There are indeed other diverse uses of the bird’s name.

So, now on to the cache:
In order to get into the Cuckoo’s nest one must figure out the right combination!
Do not get confused by the information you find on-site. This information has
been planted to confuse the Muggles who might stumble upon the nest by
accident.
The correct order is C, B, D, A
I would be very pleased if the serious Geo-Cachers appreciate and figure out the
code based upon the clues I have given.
So, Happy Hunting!

Links to other caches of the BCSeries:

VCS-2: Ich glaub du hast 'ne MEISE ... [DE/EN]
VCS-3: Wo EULE und Kauz ...* [DE/EN]
VCS-4: Lieber die Taube in der Hand als ... [DE/EN]