The nature loop trail is about 1.5 miles. You will likely see ducks and perhaps other birds enjoying the creek as you choose between the paved and dirt paths. There's also a fitness circuit. It is kind of interesting as you'll see multiple layers of trails; some dirt, some paved, some grassy, some in the creek.
Medea Creek Natural Park is managed by the Rancho Simi Recreation and Park District www.rsrpd.org/oak_park/parks/medea_creek_park.php.