Port of Long Beach Black-Crowned Night Heron Mitigation

Black-crowned night herons (Nycticorax nycticorax) nested for several years in large ornamental trees at the Long Beach Naval Station, Long Beach, California. In preparation for the proposed conversion of the Long Beach Naval Station to commercial use, the Port of Long Beach (POLB) investigated the status of the black-crowned night heron rookery in 1996. In 1997, POLB retained MBC to monitor the black-crowned night heron rookery at the Naval Station. A reconnaissance survey of the Navy Mole and the Naval Shipyard indicated that black-crowned night herons were utilizing these sites for nesting, and in 1998, these sites were included in the annual study of the nesting colony.

Due to its remoteness and previous nesting activity, Gull Park at the end of the Navy Mole was selected as the mitigation site for the Naval Station rookery. Following the 1998 nesting season, 50 trees from the Naval Station were moved to the Navy Mole. To encourage nesting, custom made black-crowned night heron decoys were installed in the relocated trees, and recordings of heron vocalizations made at the original colony were broadcast during two periods of the day.  

In 1999 over 250 active nests produced 650 young. Year 2000 surveys indicated the number of nesting birds had approximately doubled since the previous survey, and a peer-reviewed paper describing the nesting colony transplant was published in Waterbirds in 2002.  This project is unique because there is no other documented relocation of a black-crowned night heron colony of this size. The project has received wide attention due to the seemingly successful way of relocating the roosting and nesting birds and “habitat.”