Wildlife Initiatives

Located in the San Joaquin River Delta, the Port of Stockton plays host to a wide array of plant and animal life, and, while commerce and trade are the primary objectives of the Port, the need to be good stewards of the environment is taken very seriously. To this end, the Port is engaged in several ongoing initiatives aimed at achieving a healthy balance between being good stewards of the environment and keeping the wheels of commerce rolling.

Owl Nest Boxes

From time to time, it becomes necessary to tear down old and dilapidated buildings at the Port and occasionally these structures serve as nesting sites for barn owls. Great care is taken not to disturb active nests and in the summer of 2006 the Port launched its Barn Owl Nest Box Program. The goal of the program is to enhance the barn owl population by providing suitable nesting locations. Thus far the Port has installed 20 barn owl nest boxes at various locations around the East and West Complexes to replace lost nesting sites and create new ones. The Port has found the nest boxes to be a very effective, environmentally friendly and cost-efficient method to control the rodent population.

Thus far, results from the program have been outstanding. Since the inception of the program the boxes continue to be used year after year and we estimate that collectively the boxes have housed over 1,960 new baby owls! If you consider that, over the course of one breeding season, two adults and five young can consume as many as 2,000 rodents, you get the picture of what an efficient method of rodent control this can be without the need for toxic bait or other environmentally unfriendly controls. With 20 active boxes we estimate that the owls are consuming over 40,000 rodents annually.  We have installed cameras at three of the nesting boxes that can be seen by clicking on the photo above.  Nesting season is January – June.


Antioch Dunes Project

The Antioch Dunes, located in the San Francisco Bay-Delta area, is the only place left on the planet where the endangered Lange’s Metalmark Butterflies can be found. In the early 1900s, their habitat went through dramatic changes as human development expanded.

The Antioch dunes project, sponsored by the Port of Stockton, involves dredging part of the San Joaquin River just east of Antioch’s downtown. This area is dredged annually to clear the path for large cargo ships traveling through the Central Valley. Some of the leftover sand is then pumped to the nearby Antioch Dunes National Wildlife Refuge to help stimulate population growth for the near-extinct Lange’s Metalmark Butterfly.

Bat Boxes

In addition to the Port’s very successful Owl Nest Box Program, the Port established its Bat Roosting Box Program in 2012. All bats in California are protected. The goal of the program is to provide suitable roosting sites and encourage the bats to raise young and establish themselves in the area. Bats are the number-one predator of insects that fly at night, and they can reduce mosquito problems substantially. According to the U.S. Fish and Wildlife Service, a colony of bats with approximately 100 members will consume more than 600 million insects in a 200-day feeding season. It is easy to see that bats provide a benefit to humans, including insect control and plant pollination.

Arundo Eradication and Habitat Restoration Program

Arundo donax (Arundo) is an invasive plant species that has infested many parts of the Sacramento-San Joaquin Delta. Its ability to survive and grow at almost any time under a wide variety of environmental conditions makes it extremely difficult to eradicate. Arundo, a member of the grass family that resembles bamboo, is an extremely fast-growing plant that can grow up to 4 inches per day and reach 30 feet in height. It forms dense clumps that spread from thick roots that grow horizontally. Problems associated with Arundo include riparian habitat loss, erosion of stream banks and levees, fire danger because it is highly flammable, and high water consumption (1 square yard of Arundo can consume up to 500 gallons of water per day).

The goal of the program is to remove the Arundo so that native vegetation can reestablish and provide suitable habitat for fish and wildlife. The Port has begun an eradication program using a somewhat experimental method of treatment. Previously known methods include chemical treatment, mechanical removal, and prescribed burning, all of which have drawbacks and limitations. The method being tested by the Port is based on work by researchers at the University of the Pacific and includes cutting the Arundo down to ground level, then securely covering the area with thick black tarp. The tarp serves two purposes—it inhibits new growth by preventing sunlight from reaching the plant, and it traps heat during the hot summer months, effectively “cooking” the roots and killing them. Although the effectiveness of this method has yet to be determined, it offers an environmentally friendly alternative to other methods that can have negative impacts on the surrounding environment and are often prohibitively expensive.

Ballast Water Management Program

The Port of Stockton, in consultation with the California State Lands Commission, is implementing a pilot Ballast Water Management Program. The purpose of this program is to slow the spread of invasive species by providing ballast water management information prior to a vessel’s entry into the San Francisco Bay or at least 24 hours in advance of the vessel’s arrival at the Port of Stockton. The Port also requires ship operators to fill out a ballast water inspection log in order to verify that open ocean exchanges of ballast water are made.