Moody Weather Birding and Nest Finding

5/4/2009 The lack of evidence of nesting is, I suppose, as revealing as the contrary –though not nearly as much fun. A week ago nest building activity seemed to be going on all around me. Over the last few days there has been little to suggest that nest-building has been occurring.

Why? The first hypothesis that comes to mind is that the cold, wet storm front that hit the north-state about 5 days ago is to blame. The timing of the cessation of material gathering and the furtive activity associated with it aligns perfectly with the change in the weather. The robin’s nest that was so actively being established appears to have been abandoned. The black-headed grosbeaks who were energetically clipping twigs have now returned to more of a protracted, loose pair association (sometimes appearing to be polygynous). Male Nashville and Orange-crowned warbler continued to sing from favored perches but not much else happens.
Another possibility that would explain at least part of the slow-down is the notion that my repeated scrutiny of the nest areas has caused the birds to abandon the sites and re-build further back into the woods. While I was careful not to spend too much time near any site, certain individuals and some species are particularly sensitive to being observed during the nest building stage (per USDA Forest Service General Technical ReportPSW-GTR-144). I have also searched farther into surrounding woods and have not seen evidence suggesting that more remote birds are building nests.
So, I wait and watch, hoping that a return to normal (warm) spring weather will again stimulate nest building.

5/5/2009 I took advantage of a break in the rain and spent 3 glorious hours at the Butte Creek Ecological Preserve (BCEP) this morning. The overall variety of species was impressive and included a few nice surprises!
About ¾ of a mile before the entrance a small (5) flock of wild turkeys fed in the grass below the power-lines. The parking area at BCEP was noisy with the voices of California Towhee, House sparrow, lesser goldfinch, Nuttall’s woodpecker, house finch and bushtit. A yellow-breasted chat could be heard clearly in the distance. Walking the first hundred yards toward the north side of the preserve turkey vulture, ash-throated flycatcher, white-breasted nuthatch, northern flicker, red-shouldered hawk, Bullock’s oriole and American goldfinch were detected. Flying above the east-facing ridge were common raven and a circling speck that turned out to be a peregrine falcon gaining altitude! Four cavities arranged vertically at the top of dead gray pine held acorn woodpecker in the top hole and European starling in the bottom hole.
A soft-whistled note across the road led me past Anna’s hummingbird and black phoebe. An out-of-place green heron winged down Honeyrun road and a whistled reply by me brought a male phainopepla into view.
Another hundred yards into the north end of the reserve I was provided with good looks at the singing chat, along with the happy song of warbling vireo. In a row of live oaks mixed with willows I encountered brown-headed cowbird, orange-crowned warbler, black-headed grosbeak, mourning dove, Bewick’s wren, Hutton’s vireo, western scrub jay, oak titmouse, Wilson’s warbler and a male black-chinned hummingbird claiming a large elderberry as it’s own.
Among some tall deciduous oaks and empid gave occasional short calls, a brief look did not allow me enough time to form a guess as to whether it was Hammond’s or dusky. Near the tall alders at the north end violet-green swallows made forays into cavities and two male mallards pursued a female.
Back-tracking to the south half of the preserve I encountered my first of a handful of yellow warblers, spotted towhees (seeming to be less in numbers since the understory clearing of last year), and the first of many house-wrens (mostly where the trail meets the old haul road along the creek). Also on the creek was a lone drake common merganser. At or near the pond at the south end were red-winged blackbirds, tree swallows, California quail, Canada goose, cliff swallows, common moorhen western kingbird and downy woodpecker.
On the walk out I was happy to hear the familiar vocalization of western wood peewee.