Featured Neat work - Signature help please!

I removed this beautiful painting from the professional frame under glass. I did not think it was a print and I was pleasantly surprised to the see the work without the glare from the glass. I think this work is really nicely done. I believe it to be a pastel or crayon (or both) and gouache. It is laid down on cardboard and judging from the wear on the board, not a new piece. Does anyone recognize the artist signature? Rudy? Ruth? Paul? Thank you!

 

It's striking image which made me think it's a copy of something good

Found this which has a different signature so I think it's after



https://www.mediastorehouse.com/p/164/red-ibis-4403193.jpg.webp

 

Here's a postcard.

https://www.hippostcard.com/listing...h-ibis-by-muller-vintage-art-nouveau/14055456

 

Richard Müller is the artist.

https://www.printmag.com/post/richard-muller-artist-visionary

Debora

 

This says it's gouache over heliogravure:

https://www.mutualart.com/Artwork/Der-rote-Ibis/25218A35866889E3

Looks like this is the original. Says monogrammed at the upper right:

https://www.kettererkunst.com/details-e.php?obnr=114004111&anummer=417

 

that guy could paint !!!!!

& didn't shy away from hands and feet !!!

 

Or tushies.

 

or other lady parts too !!!

 

So we did further research and the signature on this painting is that of Richard Muller. There is also a faint type of monogram upper right.