Prior to July, 2004, the AOU considered Cackling Goose to be subspecies of Canada Goose.  As early as 1998, however, I learned that they might gain full species status, and I began to take note of them at that time.

Cackling Geese are now commonly seen throughout the winter, with sightings beginning as early as mid-August and a few lingering through the end of March.  The peak period, however, is October through January.  Sightings of single birds on 2007-04-26 and 2010-05-02 were notably late. 

Frequency of sightings, and number of birds seen has been increasing dramatically over recent years:

In recent winters, it has been commonplace to see flocks of hundreds of Cacklers fly over the park each morning, with some of the flocks landing in the park on mowed grass fields, and others continuing to fly, perhaps up to the Sammamish valley.

By far, the majority of the birds seen are of the minima subspecies.  While sub-specific identification of "white-cheeked" geese can be difficult, minimas are relatively easy to recognize, because of their extremely small stature.  On occasion, however, we have seen Cacklers that are clearly a larger sub-species.  This is an area for future study.