Chicago Animal Care and Control will be closing the east half of Humboldt Park starting Sunday night in an effort to humanely capture the alligator discovered July 9 in the lagoon.

“It is likely that residents who have been watching from the lagoon banks and paths in the park have been influencing the animal’s behavior,” Kelley Gandurski, executive director of Chicago Animal Care and Control said in a statement. “We are taking these steps to in an attempt to create an environment that lends to the animal’s safe capture so we can quickly reopen the entire park to activity.”

Parking closures at the east half of the park were set to start Sunday at 9 p.m., when the boathouse parking lot closes, CACC said. Walking path and street closures are expected to begin at 11 p.m.

Access to North Luis Munoz Marin Drive and all walking paths bounded by Humboldt Park Drive, Division Street, California Avenue and North Avenue will be closed until further notice, CACC said.

Humboldt Drive will close to traffic between North Avenue and Division Street, CACC said.

In addition to the closure, CACC has hired Frank Robb, an alligator expert and owner of Crocodilian Specialist Services in St. Augustine, Florida, the agency said. Robb arrived in Chicago July 14 and immediately began assessing the park and lagoon. Robb, CACC, The Chicago Park District, Chicago police as well as other participating agencies are taking steps to ensure the park is as calm and quiet as possible, which will increase the chances of capturing the alligator.

The west half of Humboldt Park, including the swimming area and field house, will remain open, CACC said. Parents can drop their children off at camp at the field house but will need to enter and exit the park from North Avenue.