OKLAHOMA CITY -- Each year thousands visit the Oklahoma City National Memorial and Museum but now some unwanted guests are refusing to leave.
Memorial officials are dealing with a major bird problem.
Each night thousands of birds migrate to the memorial and leave their droppings everywhere.
Workers are spending hours every day cleaning up the mess.
"We are trying to move them other places or move them out in a way that is fair to the birds," Kari Watkins said, Executive Director of the Oklahoma City National Memorial and Museum.
The problem started last year and officials say it is getting worse.
Wildlife experts believe the construction around the downtown area may be forcing the birds to migrate and find a new home.
"Construction is going on. That could be a part of it. Some birds could be displaced but we got a lot of birds and they are always coming through," Kevin Grant said, State Director of Oklahoma Wildlife Services.
To get rid of the birds, wildlife experts are clapping wood together to make loud noises.
Oklahoma City firefighters are also spraying the birds with water.
Officials will continue to do this until the birds find a new home.
Experts say the tactics are safe and the birds are not harmed.