Kathleen O. is from the second crop of Upstart (by the A.P. Indy horse Flatter), who won the 2015 Lambholm South Holy Bull Stakes (USA-G2) but was one of those frustrating horses who always seem to find one or two better than they when the biggest prizes are on the line, placing in six Grade 1 events. She is the first foal of of stakes-placed Quaver, whose sire Blame was the American champion older male of 2010 after defeating the great mare Zenyatta in that year's Breeders' Cup Classic (USA-G1).
Quaver was the only black-type runner from the four foals produced from her dam Skipper Tale (by Tale of the Cat), but the picture improves considerably at that point. A nice allowance-level filly, Skipper Tale is a full sister to 2007 Railbird Stakes (USA-G3) winner Ashley's Kitty and a three-quarters sister to multiple Grade 3 winner Heart Ashley (by Tale of the Cat's Grade 1-winning son Lion Heart), dam of multiple Japanese Group 3 winner Fiano Romano (by Fastnet Rock) and second dam of last year's Chandelier Stakes (USA-G2) winner, Ain't Easy (by Into Mischief). Skipper Tale is also a half sister to Gold Cup at Santa Anita (USA-G1) winner Cupid (by Tapit), who also collected three Grade 2 wins as a 3-year-old, and to listed stakes winner Indianapolis (by Medaglia d'Oro).
Skipper Tale and her siblings were produced from 2001 Railbird Stakes (USA-G2) runner-up Pretty 'n Smart, whose sire Beau Genius started 42 times and won a dozen stakes races---including the 1990 Philip H. Iselin Handicap (USA-G1)---before becoming a useful stallion. A half sister to multiple Grade 3 winner Hostess (by Chester House), Pretty 'n Smart is out of the Vice Regent mare Charge d'Affaires, whose female line traces back to the great handicap mare Gallorette.
Like many top American pedigrees nowadays, Kathleen O's background is steeped in line breeding to the great Native Dancer through his son Raise a Native (5x6x6x6x7) and his maternal grandson Northern Dancer (5x6x6x6x6x6). More immediately, she carries crosses of 4x5x5 to Raise a Native's son Mr. Prospector and 5x5 to Northern Dancer's son Vice Regent.
A leggy, gangly filly who still has some filling out to do, Kathleen O. has a long stride and lacks early speed. These characteristics force her into an off-the-pace running style that will leave her vulnerable to traffic jams. Nonetheless, she has so far had more than enough closing punch to dominate her opposition once in the clear and has proven a bit handier than her appearance might suggest, and heavy traffic is generally less of an issue in the Oaks than in the Kentucky Derby. The big filly will probably race in one more prep prior to the Oaks---McGaughey has indicated that he is leaning toward the Gulfstream Park Oaks (USA-G2) on April 2, though the Central Bank Ashland Stakes (USA-G1) on April 8 is also under consideration---and if she continues her winning ways, she will likely be among the favorites to wear the lilies on May 6.