zoo received significant improvement at the hands of the Works Progress Administration, and again from the 1970s onwards. Numerous early- and mid-20th century park attractions like the miniature railway, the enormous Whitney Young public swimming pool, the swan boats in the lagoons, and the carousel were closed, dismantled and/or discontinued in the 1970s, though a far smaller public pool was constructed in the 1990s adjacent to the site of the original Young pool. The park features sports fields and picnic facilities along the Mississippi River, in an area called Riverview Park. This riverside portion of Audubon Park is known colloquially as "The Fly", an almost-forgotten reference to the modernist, butterfly-shaped river viewing shelter constructed in the 1960s and demolished in the 1980s in the aftermath of its severe damage one foggy morning at the hands of blundering river traffic. The ring road around the park was closed to automobile traffic at the start of the 1980s and became a popular walking, jogging and biking route. A 2.2 mile dirt path located around the perimeter of the park is also popular for runners seeking a less congested route. A few of the park's old live oak trees were blown down when Hurricane Katrina hit the city in 2005, but as the park is wholly located on high ground comprising the Mississippi River's natural levee, it was spared the flooding experienced by the majority of the city after Katrina. Audubon Park was used as a makeshift helicopter port and encampment for National Guard troops and relief workers after the storm. Athletic facilities In 1898 the Audubon golf course opened within the park. In 2002, the golf course was renovated and converted to a mostly Par 3 executive course, to complaints from many non-golfing users of the park, who alleged that the original Olmsted Brothers design was being desecrated. The Heymann Memorial Conservatory, closed for many years prior, was demolished to accommodate the golf course renovation and new golf clubhouse. Also in 2002, the New Orleans city council renamed the park's "Avenger Field" to "David Berger - Avenger Field" in memory of David Mark Berger, an athlete and graduate of Tulane University who was captured and killed in the 1972 Olympic Games hostage crisis. The field was officially dedicated to Berger's memory on June 10, 2013. Wildlife Ochsner Island on the east side of the park features a rookery that is one of