East Lyme - Blame the birds.

The East Beach portion of Rocky Neck State Park has been closed to swimming for 14 days so far this summer and was closed for eight days last summer.

The area, east of where Bride Brook empties into Long Island Sound, often has bacteria levels that exceed state water quality standards, while the West Beach side of the swimming area tests clean and remains open.

The reason, according to Dennis Schain, spokesman for the state Department of Energy and Environmental Protection, is that the large wetland just north of the beach is a favorite spot for many waterfowl. As Bride Brook flows through the wetland and into the Sound, it carries the bird feces with it, Schain said in an email message Wednesday.

Over the last 20 years, there have been several studies in the Bride Brook watershed to determine whether human sources of bacteria from septic systems or sewers are polluting the waterway, Schain said. The most recent study, in 2011, found no human sources of bacteria.

DEEP said Wednesday a water sample will be taken at East Beach today. Test results are expected on Friday.

Rocky Neck is one of four state-owned shoreline beaches and attracts one of the highest numbers of visitors annually of any state park, after Hammonassett Beach in Madison.

The swimming area at Gay City State Park in Hebron was also closed Wednesday due to high bacteria levels, and will also be resampled today, DEEP said.

All other swimming areas at state parks open, DEEP said.

- Judy Benson