Purple martin (Progne subis arboricola), a California Species of Special Concern, nest in cavities in existing power poles at Mt Thayer, Santa Clara County. By 2008, only 100-220 pairs were estimated to live in the southern coastal section of California from Marin to Santa Barbara counties and suggested to be close to local extirpation, making this small population in Santa Clara County regionally significant. In 2021 the District constructed and installed two types of artificial habitat to support martin breeding activity - individual nest boxes and hollow cavity poles that emulate natural martin habitat. The District installed structures near the existing power poles and began a monitoring program to test the efficacy of habitat types and observation methods suitable for this unique location. In 2021, three martin nests at chick stage were observed in the existing power poles, and one fledged western bluebird nest was observed in a new artificial cavity. The District plans to monitor and adaptively manage this small martin population to assist with meeting state goals of 1) achieving a statewide species inventory, 2) reaching >2,000 martin pairs, and 3) supporting nesting in cavities rather than houses.