On 7 occasions, single Brant have been spotted amongst flocks of Cackling Geese:  2008-11-26, 2009-12-05, 2009-12-17, 2010-12-02 and seen again the next day, 2014-11-15, 2014-11-20.  I believe all of these sightings have been with large, pure flocks of minima Cacklers on mowed grass fields or inside baseball fields in the NE part of the park.

Brant are strongly associated with salt water (especially eel grass beds).  Marymoor is very atypical habitat for them.  They're fairly easy to find during the non-breeding season off shore from West Seattle and Vashon.