Wild Neighbors: Restoration at the Berkeley Meadow: Working Around the Hawks

By Joe Eaton
Wednesday March 18, 2009 - 06:15:00 PM
This harrier's owl-like facial disc allows her to detect prey by sound.
Len Blumin
This harrier's owl-like facial disc allows her to detect prey by sound.

Corinne Greenberg has kept an eye on the Berkeley Meadow—the unit of the Eastshore State Park just east of the Marina and north of University Avenue—for a while now, paying particular attention to the northern harriers that have nested in the meadow’s northwest corner since at least 1994. No one knows for sure whether it’s been the same pair of hawks all along, or whether the territory has changed hands.  

Although part of a state park, the meadow is managed by the East Bay Regional Park District. It was during Phase 3 of their restoration project that one of the harriers’ known nest sites was cleared. Greenberg, who had seen the birds in the area earlier, feared that further work would disrupt nesting, either destroying the nest or causing the pair to desert it. She contacted the Park District and the California Department of Fish and Game (the harrier is a state species of special concern), and put out an alert on the East Bird Birding listserv. 

The Park District offered to meet with Greenberg and any other concerned individuals at the Seabreeze Market, across University from the meadow. Environmental Programs Manager Brad Olson and Acting Stewardship Manager Doug Bell represented the district. Greenberg was joined by Katie Winslow, another meadow regular; birders Dave Quady and Rusty Scalf; and a gentleman named Bill who had been passing by on his bicycle and decided to check the gathering out. Ron and I sat in as well. 

With an armful of schematics and aerial photographs, Olson described the meadow’s origin as a city landfill and the district’s plan to make it a “living meadow.” In Phase 1, covering 17 acres along University, the fill was capped, weeds like fennel and pampas grass were removed, and seasonal wetlands were planted with willows, sedges, and rushes. Phase 2, in the northeast corner by the freeway, was reconfigured as water bird habitat. The third phase, just getting underway, would clear out exotic plants in a 114-acre area and grade part of it to create salt pan habitat for shorebirds.  

By the time Greenberg discovered what was happening, a quarter-acre had already been cleared. She said the harriers had been seen mating in the area, a probable sign of intent to nest. Given that, Olson seemed open to modifying the work plan.  

“People are seeing things out here all the time we’re not aware of,” Olson said. “We don’t want to destroy high-value habitat to create restored habitat. If we know the specific location of the high-value habitat, we can establish a buffer around that area.” He added that the Park District already had two staffers out walking a transect to identify signs of nesting. 

Doug Bell, a raptor specialist who studies prairie falcons in the park system, said it was early in the season to find tangible evidence of nesting. He agreed, though, that this is when the ground-nesting harriers were most likely to desert if disturbed. “We’re looking for vegetation laid down in a systematic manner, a bowl-type depression,” Bell said. “To really nail it, it would have to be vegetation interlocked—or birds carrying nesting material. Just seeing copulation doesn’t mean they have a nest. It depends on the pair; some pairs don’t need a long courtship period.” 

The bottom line, according to Olson: “If we have harriers nesting here, then we can’t go in and clear it. That’s the law. But we manage a mosaic of habitats, and there’s no reason we can’t manage for harrier habitat.” 

The district had a short window to get the work done, with a contract expiring March 15. After that, the project will be on hold through the end of September for the recognized nesting season. Then they’ll have another two weeks before Water Board regulations shut the project down for the year. For now, Olson said weed removal would proceed on the eastern side of the Phase 3 area, and the nest search would continue. Greenberg said she’d try to get observers out at dawn and dusk when nest-building activity was most likely. Afterward, the suspected nesting area was fenced off.  

Someone—Bill the bicyclist?—asked why the northwest corner couldn’t be left in fennel for the hawks. “We don’t want this area to be a seed source for reinfesting the whole meadow,” Olson said. “Harriers evolved with native plants,” Bell added. “If you create the same vertical structure with natives, that’s OK.” Sooner or later, the weeds would have to go. The hope is that by then, the harriers would have relocated to similar habitat in the Phase 1 area. 

It’s a perennial dilemma of restoration: native wildlife that have come to rely on non-native plants for shelter or food. Even the despised eucalyptus provides nest sites for raptors and roosts for wintering monarch butterflies. An interim solution may have been reached at the meadow, but the problem isn’t going to go away.