On a day when birdies were flying around Harbor Shores in the first round of the Senior PGA Championship, Steven Alker began soaring with an eagle.

The 50-year-old New Zealander, who already has won twice and leads the PGA Tour Champions money list with almost $1.2 million, started his round with a 25-foot downhill eagle putt on the 539-yard, par-five 10th hole after a 240-yard approach with a five-wood. He then finished his afternoon round with his sixth birdie of the day to shoot a seven-under 64, which was tied late in the day by 56-year-old Bob Estes.

Alker and Estes were a stroke ahead of Paul Claxton, a club professional from Georgia, and 52-year-old Canadian left-hander Mike Weir, the 2003 Masters champion, after the first round at the Jack Nicklaus-designed course on Lake Michigan, the site of four previous Senior PGAs since 2012.

"I'm playing with nice freedom right now," said Alker, who didn't seem fazed at all playing in the afternoon with World Golf Hall of Fame members Ernie Els and Bernhard Langer, who had rounds of 67 and 68.

"Little jitters on the first tee, but I'm making birdies and being aggressive which we could be because the greens were a bit softer and the course had softened up. It was kind of up there for the taking."

Estes took his share, recording seven birdies without a bogey, five of them after his turn on Harbor Shores' front nine. He birdied No 1, 3, 5, 6 and 9 on his march to the clubhouse.

"I love a clean card," said Estes, whose only top-10 finish this season was a solo fourth at the Rapiscan Systems Classic, which Alker won April 4.

"I made some good saves on both sides."

Like the previous four Senior PGA Championships played at Harbor Shores, this season's second major for the 50-and-older crowd is shaping into a low-scoring affair. 56 golfers in the 156-player field shot rounds of one-under or better on a cloudy day after an overnight rain softened the course. More rain and cooler temperatures are expected for Saturday's round.

On the European Tour, Kiwi Ryan Fox is in a share of 29th at the Dutch Open.

A solid finish at the tournament will likely lock in a trip to the US Open for Fox, who mixed five birdies with a bogey and a double bogey in a two-under round.

He is five shots off the lead held by Joost Luiten, with Eddie Pepperell and Rasmus Hojgaard one shot off the pace.

Fellow Kiwi Danny Lee also had a double bogey in his first round at the PGA Tour's Charles Schwab Challenge, but didn't have as many birdies as Fox.

Three bogeys, two birdies and the double saw Lee sign for a three-over round, sitting in a share of 91st, seven shots off the lead held by eight players including major winners Patrick Reed, Webb Simpson and Scottie Scheffler.

- With AP