The hatching: Mayflies invade Saints' ballpark

The mayflies were coming. The St. Paul Saints just didn't know when.

"We’re so close to the Mississippi River, and once a year, we get one really bad day," said Erik Franke, field operations manager at the Saints' home of CHS Field. "I wish we could set it on a clock. 'Hey, this is when they'll be here.'"

Mayflies, per the Minnesota Department of Natural Resources, are "delicate insects with two or four triangular shaped wings with many veins." They spend 99 percent of their lives as aquatic nymphs, a phase that precedes an oft-synchronized hatching. It is this unpredictable event that results in a "really bad day" for the Saints' grounds crew and operations team. An innumerable horde of mayflies, attracted by the lights, swarm toward the ballpark and quickly die. An innumerable horde of mayfly corpses is the unavoidable result.

The Triple-A affiliate of the nearby Minnesota Twins isn't the only Minor League team prone to mayfly bombardment. (The Double-A Harrisburg Senators, playing in a ballpark bordered by the Susquehanna River, unveiled a mayfly alternate logo in 2007.) This time around in St. Paul, the mayflies at least had the courtesy to emerge when the Saints were on the road. It was the night of June 23, with Franke becoming aware of the situation via a tweet by broadcaster Andy Helwig ("What level of hell have we reached with all these bugs?") and a subsequent text from head groundskeeper Marcus Campbell ("You'll see how bad it is in the morning.")

"Some of the street lights were on and some of the security lights," said Franke. "Wherever a light was on inside the stadium, that’s where you could find piles of mayflies the next morning. The first thing I saw outside was the 4th Street entrance. The whole sidewalk was covered."

The Saints grounds crew and operations crew took what Franke called a "divide and conquer" cleanup approach. Among other ballpark locations, mayfly bodies were strewn across the warning track, piled up in both bullpens and layered along the concourse.

"It was, 'Hey, here’s some brooms, here’s some backpack blowers, here’s some shovels,'" said Franke. "We even got a Billy Goat, which is a long vacuum. We started at one end of the ballpark, worked our way around and got as many as we could. ... Mayflies only live about 24 hours when they reach maturity, but some were still on their last leg of life. You'd sweep a pile and hear a low buzz coming from it."

The Saints' six-legged body removal efforts were successful, with the job completed in time for CHS Field to host an American Legion doubleheader on the evening of June 24. It was altogether a less stressful -- albeit less memorable -- occasion than 2019's in-game mayfly invasion.

Were you at the game when the mayflies attacked? 😱🤢 pic.twitter.com/NZnyB8Qggk

— St. Paul Saints (@StPaulSaints) March 31, 2020

"I started [with the Saints] last summer, so I missed that one," said Franke. "There's not much you can do. The players are dealing with it. The fans are dealing with it. Hey, chalk it up to Mother Nature. Just get through the game and get out of there."

When it comes down to it, having to deal with this particular insect influx is far preferable to not having to deal with it.

"It is a good sign for our environment that there were mayflies," said Franke. "They're pretty delicate. So when they spend most of their life in water and then hatch, that's a good sign. It shows that our water's clean and that the oxygen is clean as well."