Cran is a decoration used on the Uilleann Pipes.
Typical use is on the first or second note on the Chanter - D or E.

It is written as a 1/8, 1/4, 1/8,1/8,1/8,1/8. The notes used in a D cran are a D g d f# d. That said it does not sound like the little notes are 1/8 notes but very very tiny. The Piper's description is very accurate 'snap out the small notes'.