This piece was written in memory of Claude Debussy. In the last decade of his life the older composer warmly and graciously befriended the young Stravinsky.
The last part of the piece could be called mournful (or sad). There definitely is an elegiac character to the piece. With Stravinsky an elegy would never be weepy or sentimental, but rather ceremonial and solemn.
This video has beautiful and sensitive camera work. I think it would be very useful with children. It shows the embouchures, the breath control, and the spirit of playing each of the different instruments. Stravinsky's writing for wind instruments was distinctive during the entire course of his career - in fact it's hard to think of another composer who wrote so remarkably for winds.