"Outside The Lines" Plein Air Painting Documentary, Plein Air Force
https://www.youtube.com/watch?v=F86HvkQaz-o

How to set up a French easel for outdoor painting
https://www.youtube.com/watch?v=NAHXCZaD5nw

Jose Salvaggio (lovely paintings)
https://www.youtube.com/watch?v=ssRDh4dbtVc

LibraryThing offers wonderful nature painting recommendations here
https://www.librarything.com/work/209554/recommendations

Animal drawing book list from Marshall Vandruff
https://www.marshallart.com/HOME/reviews/animal-anatomy/

More nature drawing books + book review video of the artist's favourite top 5 books
https://samuelearp.com/blog/best-art-books-for-painting-landscapes/