Our daily look at what happened at Ray Nitschke Field:

Thumbs up: Sam Shields may be green as grass and have only played cornerback for one year at the University of Miami (Fla.), but the kid knows how to make an impression. During 7-on-7 drills, the speedy Shields undercut receivers’ routes to break up passes. Then, he registered the first interception of camp when he stepped in front of a Matt Flynn pass intended for Chastain West to end a team period. Shields’ perfectly timed break on the ball left him in the open field for what would have been a pick-six interception for a touchdown.

Thumbs down: While coach Mike McCarthy lauded the Ray Nitschke Field drainage system for how well it handled the previous night’s rain and the day-long, off-and-on showers that lingered around Green Bay, two players said after practice that they had serious concerns about the wet, slippery field conditions. While the 2-hour, 31-minute practice didn’t have to endure any major downpours, there were several drizzles that kept the field wet throughout. McCarthy’s decision to stay outside rather than move inside the Don Hutson Center – he said he had “zero intention” of practicing inside – was understandable given the 4,000 or so fans cramming the stands, but when the coach said the field was “great” and “excellent,” he would have found a few players in the locker room who would’ve disagreed.

Play of the day: It was only one practice, but both punters Tim Masthay and Chris Bryan impressed. McCarthy had two extended punting periods, and according to the Green Bay Press-Gazette’s Rob Demovsky, who has turned covering the punting sessions into an art form, Bryan performed better in the first one, averaging 47.8 yards and 4.28 seconds of hang time compared to 44.4 yards and 4.34 seconds of hang time by Masthay, who had one shank that nearly landed in the stands. In the second session, though, Masthay had the better hang-time numbers on Demovsky’s stopwatch, averaging 51.3 yards and 4.56 seconds of hang time compared to 45.7 yards and 4.34 second of hang time by Bryan.

Camp confidential: With just over half an hour left in practice, a bird – some believed it was a crane, others thought it was a loon – flew smack-dab into the wall of the Hutson Center and tumbled to the ground below. After regaining its bearings, the bird flew across the field – past general manager Ted Thompson, who was standing alone at that end of the field – and over the stands. In my 14 training camps, it was one of the oddest sights I’ve seen.

Injury report: The three players on the physically unable to perform list – cornerback Al Harris (knee), safety Atari Bigby (ankle) and running back James Starks (hamstring) – were the only three players who did not participate in practice. Starting left outside linebacker Brad Jones left practice after taking a helmet to the lower back but said afterward that the injury was “minor.”

Practice schedule: The Packers practice twice Sunday, at 8:45 a.m. and 6:30 p.m.