Whirligig is one of the comparatively few features of Porcelain Basin that are active and stable enough year-to-year to have well-established, official names. This does not imply, however, that that activity is the same in every year, far from it. According to T. Scott Bryan's "The Geysers of Yellowstone," 4th edition (2009), and 3rd edition (1995), it was dormant for some time before 1974; rejuvenated in that year, to have "frequent and regular" eruptions that persisted into the 1980s; underwent a slowdown during that decade; and entered into near-dormancy around 2004, with only occasional eruptions.
Against this background, extensive observations of logger data indicate that 2017 started out as a very good year for Whirligig. Numerous intervals were measured electronically between 6 and 9 hours, with a few even shorter ones. Unfortunately, the intervals obtained during April 2017 seem definitely to be longer than in February and early March, suggesting that Whirligig is slowing down, and May intervals confirm this trend. Electronic intervals as long as 2 days, 16 hours have been recorded in April. If this trend continues, Whirligig may be heading back toward dormancy. We hope not, because it's a fun geyser to watch. It erupts from two vents, a front one in the prominent pool and a second one in a slit toward the pool's rear. Much of the fun comes from this second vent, called the "rooster-tail vent" by Bryan because of the shape of its jetting play. The observer should listen for the chugging sounds the back vent makes during the eruptions, which are synchronized with the bursting jets.
There is some evidence for an exchange of function between Whirligig and nearby Little Whirligig Geyser, which has not (yet) been observed to erupt in 2017 and indeed has been dormant for some time. If Whirligig is heading for dormancy as its increasing intervals suggest, it's possible that Little Whirligig may "turn on" some time this year -- possible, but by no means certain. This pair of geysers may reward careful scrutiny during the 2017 season.