A new geologic epoch is here Many believe that we have come to the end of a geologic era, a major subdivision in the earth’s history.  That era (or epoch, as specialists call it), the Holocene, ran steadily for almost twelve thousand years, with predictable seasonality, a stable climate around

Fall migration is here. Where do our birds come from?       The May issue of this column introduced National Audubon’s Bird Migration Explorer.  It’s a digital platform that shows the migration routes of most North American birds, based on repeated detections of radio-tagged individuals as they travel across

Where do our spring migrants come from?    Many of us marvel at the twice-a-year treks of migratory birds between breeding and wintering grounds.  We wonder where they came from to get here, and where they go when they depart.  Recent improvements in our ability to mark and track birds

Climate Change Reduces Nesting Success of Local Songbirds Several times this column has mentioned the chain of nest boxes along Putah Creek that the UC Davis Museum of Wildlife and Fish Biology oversees.  It is one of the best things anyone has done for songbirds in the region.  More than

Northern Birds in the South This column follows up on the situation I reported last time. In the twenty-first century, a dozen or so southern California bird species have expanded their winter ranges to include the Sacramento Valley. They appear to have taken advantage of the milder winter weather and

Looking over decades of field notes from my neighborhood in Davis recently, I was reminded of two changes in bird life in this period in the Sacramento Valley.  The first is the growing numbers of over-wintering birds here that are usually found in the milder climates of the central California

Recently I decided to use eBird, Cornell University’s public database of bird observations, to store the accumulated records from birding in my neighborhood around Slide Hill Park in Davis.  This meant reviewing all thirty-six years of written notes, and the effort produced two big surprises.  One was that many species

The Sacramento Valley population of the common raven has ridden a roller-coaster over the years, owing entirely to its interaction with people.  Three characteristics of the species have been involved.  First, ravens are highly social, and more experienced birds teach the less experienced how to make a living, including what

The Yolo Bypass Wildlife Area is in many respects the best all-around collection of birding sites in the county, drawing birders from far and near. Its attraction for water-oriented birds lies in part from its being the single largest remnant of the natural floodplain of the Sacramento River, often flooding

In recent years California has been home to all of the nesting tricolored blackbirds in the world, and almost all of the breeding birds have been in the Central Valley.  This year in Yolo County about 25,000 birds colonized Conaway Ranch at a site north of Road 25 and east