The initiative for the launch of Tagfalter-Monitoring Deutschland (TMD) - Volkszählung für Schmetterlinge came from Helmholtz-Zentrum für Umweltforschung GmbH - UFZ, which has taken over the nationwide coordination in close cooperation with the Gesellschaft für Schmetterlingsschutz e.V. (GfS).
The recording results are visualised in the Atlas der Tagfalter und Widderchen Deutschlands - TAD. Here you can also find a map of Europe regarding the distribution of the 
Camberwell BeautyNymphalis antiopa (Linnaeus, 1758)Mourning CloakCamberwell Beauty: https://www.ufz.de/european-butterflies/index.php?en=43006
Since mid-2003, the Links has been offering Internet-based monitoring throughout 
GermanyGermany.
The Camberwell BeautyNymphalis antiopa (Linnaeus, 1758)Mourning CloakCamberwell Beauty is one of the butterflies considered there.
On the excellent pages of science4you, anyone interested can report their migratory butterfly observations and view their own entries or those posted by others in tabular or map form.
You will also find a lot of interesting information there. The pages are constantly being expanded.
Definitely take a look!
The online portal Schmetterlinge Deutschlands is a project to analyse the endangerment of Germany's butterflies on the basis of online distribution maps to compile the new Red List, funded by the Bundesamt für Naturschutz with funds from the Bundesministerium für Umwelt, Naturschutz und nukleare Sicherheit.
The NABU-Arbeitskreis TagfalterMonitoring NRW is conducting a long-term study for North Rhine-WestphaliaNorth Rhine-Westphalia. With the help of transect mapping, population trends and density values of butterflies in North Rhine-WestphaliaNorth Rhine-Westphalia are to be determined.
Anyone interested is invited to take part in the butterfly monitoring programme.
A worldwide internet-based monitoring system operates Observation.org
Their mission:
To share observational data on global biodiversity from the past and present as a source of knowledge for the future. To provide observers around the world with a multilingual global observation system, with a species register for all known species and organism groups, and to share this collection of validated field data with everyone around the world. Open data is an important starting point for us.