Ian Poulter and ex-US Open victor Webb Simpson are among a group three shots adrift of Cauley at five under. Webb Simpson (eight-under), Jason Dufner (seven-under), Brandt Snedeker (five-under) and Martin Kaymer (five-under) are among the golfers within five shots of the top spot. Instead, it hopped in the cup to put DeLaet out front. He previously missed two cuts at the Heritage and tied for 37th in 2012.
The former world number one, now ranked 96th, is searching for his first win since 2013 and has finished second four times and third twice in his eight starts at the PGA Tour event. He held off a spate of wild drives after the turn - Donald drove way right on No. 10, played a provisional, found his first ball and made par - before chipping in for birdie on the closing, lighthouse hole at No. 18.
Ogilvy made a promising start with birdies at the second and fourth holes but he faltered with successive double bogeys at the 11th and 12th.
"This place has been kind to me and it's nice to get off to a great start again", said Donald, who has tumbled to 96th in the world rankings.More news: North Korean missile test fails, United States and South Korea say
Donald was one of the early starters, and he took advantage of excellent scoring conditions as he began at the 10th and birdied two of his first three, although he did drop a stroke at the 11th.
Poulter is still playing on a medical extension and needs a tie for 12th to retain his full PGA Tour privileges, and he recovered from a bogey at the opening hole with six birdies to join Lowry and Shell Houston Open champion Russell Henley on five under. I have to clear my mind.
Bud Cauley boasts a two-shot lead at the RBC Heritage after the American produced a near record-breaking round in SC.
"You never go out thinking you're going to shoot that", Cauley said. Taylor was 7 under while Hadwin was 5 under. Those going home included Jim Furyk, Ernie Els, 2016 Masters champion Danny Willett and Charley Hoffman, who contended at Augusta National for much of the week before falling off the pace.