Amy Holden and Brian Freyermuth have bought rubber ducks to participate in Mass Audubon's duck derby race for the past four years. Usually, the toys are themed, with names of famous bartenders or skiers.

The tradition started as Holden's birthday present her husband, with the ducks' names being kept a surprise. Freyermuth's birthday is on August 17.

This year, however, the couple decided to celebrate their 22nd anniversary, which shared the date with Mass Audubon's 14th annual festival fundraiser on August 12.

The couple's 18 rubber ducks charged alongside 5,909 other ducks toward a boon-lined finish with the incoming tide at Allens Pond.

"It's a festive week for us, and this is part of the festive week," said Freyermuth. The couple also has a dinner reservation at Little Moss in Padanaram and will tour the weekend's Art Drive, through which participating artists open their studios to visitors.

The Allens Pond Wildlife Sanctuary event brings in $44,000-58,000 for the sanctuary (between the race, food sales, and silent auction), which equates to 22-percent of its budget, said sanctuary staff person Gina Purtell.

While much planning goes into the event, the rubber duck race itself is completely dependent on the tide, Purtell said. This year, volunteers set up the course at 6:30 a.m., corresponding with low tide. The race begins when the tide starts coming in, or 10 a.m. this year.

"The current is very well defined in a channel, and we use that as the course," she said. The winner receives an all-inclusive trip to a destination of their choosing.

Purtell expected about 150 visitors to the day's event, but said duck sales were curbed by the rain. The sanctuary partners with The Bayside Restaurant — located across the street from the sanctuary's Horseneck Road location — to sell rubber ducks for $10 each. About one third of the participating ducks are sold there, but due to the rain, "no body came to The Bayside" to buy ducks the morning of the event, Purtell said.

The morning rain didn't deter everyone. Jane Freed and Jane Gasek enjoyed a luncheon on dampened chairs, while mist sprinkled their meals.

"We're not sugar babies," said Freed. "We come every year and support this gem."

Freed explained that before the sanctuary, there was a dairy farm on the site. When she bought her house across the street 31 years ago, Mass Audubon bought the property and turned it into a bird sanctuary.

Also at the event, staff members led a 14-person group to the race site to watch the ducks float for a win, and children's crafts and music were available during the following luncheon.

"It's family-oriented," said first time event-goer Angela Correia, who brought her three children and husband after seeing signs posted around town. "We missed the duck race, but this looks like a good time."

The silent auction included kids' baskets, vacation packages, and artwork. Holden and Freyermuth said they bid on the least popular items every year, and consequentially have an osprey platform named for them.