southern california biological services
cowbird trap
Welcome to TW Biological Services

TW Biological Services is an environmental consulting firm located in Southern California that specializes in Brown-headed Cowbird trapping, biological surveys and population monitoring of sensitive and endangered species, including the Least Bell’s Vireo, California Gnatcatcher, and Southwestern Willow Flycatcher.

In addition we also provide general wildlife species surveys, sensitive habitat assessment, habitat restoration monitoring, construction project compliance, and cowbird trap construction.

Established in 1994 by Jennifer Sexton (formerly Jennifer Turnbull) TW Biological Services has performed both subcontract and prime contract work for private companies, federal, state, and local agencies in San Diego, Riverside, Ventura, Los Angeles, and Orange Counties.

Services we Provide

brown headed cowbird trappingTW Biological Services had been operating and managing Brown-headed Cowbird contracts in Southern California since 1997. Our experience includes working on contracts for federal, state, and local agencies, as well as private companies of all sizes.

Monitoring, surveys, and banding are just a few of the services that we provide. To see a list of all the services click below.

Experienced In...

ca dept of fish and game contractorsHabitat assessments, restoration monitoring, construction compliance. We have obtained permits by the U.S. Fish and Wildlife Service and CA Department of Fish and Game to survey and monitor wildlife and perform bird and Raptor surveys. We conduct habitat assessments with an emphasis on sensitive species management.

Restoration monitoring includes working as a consulting biologist on construction projects to avoid and/or minimize impacts to sensitive natural resources.


usmc contractorOur impressive project list includes the U.S. Marine Corps Camp Pendleton, U.S. Army Corps of Engineers, U.S. Navy, U.S. Fish & Wildlife Service, U.S. Forest Service, City of San Diego, as well as many other businesses and organizations.

TW Bio is quite experienced at the government contract and bidding process. We have a great, streamlined process to get them done quickly and efficiently. There's no job too big or too small for us to handle.