What is the name of the highest instrument heard at 0:19? I first heard it at the end of a old animated Christmas cartoon.
The highest instrument in the piece, and specifically at 0:19, is the piccolo flute. The instrument is ubiquitous is wind band music.
In the late 1800s and early 20th century, the Db piccolo predominated. However, in the early 20th century, the transition was made to the C piccolo, and Db piccolos are no longer manufactured. For additional history and references, see When were the Db piccolo and the Eb horn phased out of the wind band?
The "U.S. Field Artillery March" was composed in 1917 by John Phillip Sousa while he served in the Marines during WWI. (For additional history, see the website for the recording.) The arrangement displayed in the YouTube video was orchestrated by M. L. Lake, and there are parts for both Db and C piccolo, suggesting that at the time, both were in common enough usage.
The release date of the recording in the YouTube video is unclear, but is later than the 1970s.
"The Complete Marches of John Philip Sousa" is a multi-year recording project and is the Marine Band's first comprehensive collection of Sousa's marches since the 1970s.
Based on the recording date, a C piccolo is most likely, especially since its use would not create a conflict in terms of historical performance accuracy.
For anyone who wants to hear lots of piccolo (and marches), the complete "Complete Marches" can be downloaded here.