If you look closely at the image above you’ll see that two of the Snowbirds CT-114 Tutors have their landing lights on while the other seven have their nose lights on.
Snowbird 6, Outer Right Wing Captain Maciej Hatta (Gdansk, Poland) told me that this is done when a nose light burns out on one of the jets – it and the mirror position Snowbird will switch to their landing lights to maintain visibility and symmetry within the formation.
and now you know…