Osprey Nests at Sperry Mill South Vallejo

by | Mar 3, 2016 | 0 comments

Osprey, the “Sea Hawk” osprey-vintage

(Pandion haliaetus) 

The Osprey, a federally protected raptor, recently began to nest in increasing numbers at the south end of Mare Island and other North Bay sites, for the first time in 150 years. No one is certain why so many raptors began nesting in the region and suspect they’d been driven to leave their former nesting grounds further north in the lakes region. Suspected causes could be changes in water quality or abundance of fish, due to drought. Water clarity has vastly increased in the Napa River / Carquinez Strait confluence, making it easier for the birds to spot prey. Another reason might be the recent appearance of bald eagles––one of the few enemies of the osprey––in the lakes region.

Prior to 2013, Photographers had been taking photos of a very active osprey nest at the Sperry Mills site and had documented the hatching and rearing of numerous chicks up to the time that Vallejo Marine Terminal (VMT) purchased the property.

Osprey feeding 3 youngIn 2013-2014, shortly after VMT bought the property (and immediately prior to beginning plant and wildlife surveys that are required by an Environmental Impact Report), an osprey nest in which observers had watched three chicks being reared that season disappeared without a trace from the top of a silo that was also removed from the Sperry Mills site.

Contractors, working on Mare Island, reported that brush and vegetation was cleared from the site as well as the silo with the osprey nest.

Not surprisingly, the biologist contracted to conduct the DEIR wildlife survey, found no evidence of a nest at the Sperry Mills site. In fact the DEIR noted, “it is unlikely that this species (the osprey) would nest in the project area.” (DEIR ES-15)

However, the DEIR does note the presence of an active nest just across the channel at Mare Island. And that ospreys were observed flying overhead, leading to questions about the status and timing of the nest’s removal. It is uncertain if the nest At Sperry Mills was still active at the time that it was removed.

It is unknown if a permit was issued to VMT/Orcem to take the nest by the US Fish and Wildlife Service, as required by law. It could be that VMT was unaware that the Migratory Bird Act––one of the oldest international treaty laws on the books that protect migratory birds––requires following a certain protocol in dealing with osprey, their eggs, nests, chicks, or feathers.

Whether or not VMT was in violation of the Migratory Bird Act would have to be determined by authorities. CA Dept. of Fish & Wildlife has been notified and an investigation has been requested.
Meanwhile, there is growing concern about another nest that was built during the 2014-15 nesting season––perhaps by the same pair that built the nest that vanished. Osprey are extremely loyal to their nest, once established. There is a mitigation measure listed in the DEIR. We and the agencies are keeping watch.


A good neighbor and responsible steward of the ecosystem would act in accordance with well-established laws to protect the ecology of the osprey. So far, VMT has not demonstrated that kind of stewardship.

California Department of Fish and Wildlife appreciates our help to protect the osprey nesting at the Old Sperry Mill site. If a disturbance of the nest of any kind is observed please call CalTIP hotline: 888-334-2258 (888-334-CalTIP) or text: TIP411 any time, day or night to report an osprey nest disturbance at 800 Derr Ave.