A cool, rainy spring might have been great for the grass and garden, but it kept people away from the area’s most famous tourist attraction.

After a record-setting year in 2010, attendance is down sharply during the first five-plus months of 2011 at Brookfield Zoo. Although June has seen attendance rebound with the arrival of warmer weather and a blockbuster event mid-month, attendance is down, year over year, by 17.5 percent, or a little more than 160,000 visitors.

“It is weather dependant,” said Stuart Strahl, president and CEO of the Chicago Zoological Society, which operates Brookfield Zoo. “April and May, which are increasingly strong months for us, were down and Memorial Day weekend was pretty bad, too. Attendance was down consistently through May.”

According to zoo spokeswoman Sondra Katzen, through June 19 the zoo had 759,226 visitors. Through the same time period in 2010, a total of 920,642 visitors had come through the gates.

That strong showing early in 2010 helped Brookfield Zoo hit a record for attendance. Last year almost 2.3 million people visited the zoological park. In addition to a particularly mild spring, Brookfield Zoo opened a major new exhibit, Great Bear Wilderness, last year.

“The interesting thing is that in June the numbers are, so far, positive,” Strahl said. “I think we are still quite attractive as an institution. The weather put us in a hole, and we’ll strive the rest of the year to make it up.”

According to Strahl, attendance in June 2011 is up 12 percent compared to June 2010.

With no major exhibits opening, the marketing strategy has been a bit different in 2011. The zoo is celebrating the 10th anniversary of its Hamill Family Play Zoo and the 50th anniversary of hosting dolphin shows.

The zoo celebrated its dolphin exhibit in May, but they pulled out all the stops when they celebrated the Hamill Family Play Zoo on June 11 and 12. The highlight of that celebration was an appearance by the Kratt Brothers, stars of Wild Kratts on PBS. The appearance drew tens of thousands of people, who flooded the West Mall.

 “Between the special events and free days for kids, we were able to make up some ground,” Strahl said.

The end of June is typically when Chicago Zoological Society officials conduct a mid-year assessment, said Strahl. At that time, officials will be able to size up the numbers and suggest actions based on expectations. The zoo’s budget is crafted conservatively, Strahl said, with “what happens when the worst happens” in mind.

“Sometimes the worst comes in worse than you might predict,” Strahl said.

Among the decisions to be considered is how much operating funds to set aside for ongoing capital projects, which are legion at the zoo.

“There will be difficult decisions our management team will have to make, and the board will weigh in, too,” Strahl said.

Of course, the zoo’s fortunes have some trickle-down effect on the villages where it resides. Brookfield Zoo is one of the top four sales-tax producing businesses within the village limits of Brookfield, according to the village’s finance director, Doug Cooper.

Just how the zoo’s attendance woes will affect Brookfield’s sales tax revenues in 2011 is tough to tell. In June the village received its most recent sales tax receipts from the state of Illinois, but that money covered a period ending in March.

According to Cooper, for the period including October 2010 through March 2011, sales tax receipts are up, year over year, by 9.5 percent. Even if the zoo’s attendance is down this year, Cooper said he doesn’t expect it to have a huge impact on the village’s budget, figuring a 10-percent drop in attendance might equal about $1,500 per month in lost sales tax revenues. The village collected $652,000 in sales taxes in 2010.

Riverside Finance Director Kevin Wachtel had similar news. While the village (which includes the eastern third of the zoo) has not received any sales tax receipts for summer months yet, so far 2011 has seen a rebound in sales taxes generally.

“Our sales tax through March is as good as it’s been since 2008,” Wachtel said.