Conversation so far:
what was birdsong and the 1960s by oliver messiaen?
While he had long been fascinated by birdsong, and birds had made appearances in several of his earlier works.
did he make any pieces based on birds?
Messiaen incorporated birdsong into all of his compositions and composed several works for which birds provide both the title and subject.
which one of them was most known?
He took this development to a new level with his 1953 orchestral work Reveil des oiseaux--its material consists almost entirely of the birdsong.
what instruments were used in the work?
for example the collection of thirteen pieces for piano Catalogue d'oiseaux completed in 1958.
did he travel or have tours in the 1960s?
He began to travel widely, to attend musical events and to seek out and transcribe the songs of more exotic birds in the wild.

Question: when did he begin to travel?
Self-contained rewrite: When did Olivier Messiaen begin to travel?