Natural History Journal

Winter is the season for raptors in California's Great Central Valley, as a number of species move south in latitude and down slope from the Sierra Nevada mountains to spend the coldest months in the Valley's mild climate.  On a really good day birding across the Valley's wetland and grassland habitats, it is possible to encounter an astounding FIFTEEN species of diurnal raptors (also known as birds of prey.)  And that's not even including at least an additional FIVE species of nocturnal raptors: the owls! The Valley's diverse mosaic of habitats, which includes wetland, grassland, farmland, oak woodland, riparian forests, and even suburban neighborhoods provides an abundance of specialized niches and prey to support this wide array of species.   Around open bodies of water, look for Osprey and Bald Eagles .   On open grasslands, keep an eye on the sky for Golden Eagles , Prairie Falcons , Rough-legged Hawks and Ferruginous Hawks .   While also...

With the sun well below the horizon and the late autumn dusk rapidly falling, the chorus of Great-horned Owl calls rose from the cottonwoods, seeming to emanate from all directions at once.  Surrounded by the hauntingly beautiful sound of owls, we slowly made our way along the road toward home.  We had just left behind a pair of Short-eared Owls , after watching them hunt over the grassland for nearly an hour.  Rounding the bend, I spotted our third owl species of the evening, a small round-headed gnome, hunched in the grasses. Burrowing Owls inhabit grasslands and other open areas across the western United States, where they are found in association with high densities of burrowing animals like ground squirrels and prairie dogs.  Since most Burrowing Owls don't actually excavate their own burrows, they rely on other species to do the bulk of the digging for them.  When moving into an existing burrow, however, the small owls do make some renovations, enlarging o...

Some birds show astounding site fidelity, the same individuals or populations returning year after year to the same small patch of habitat to breed or overwinter, sometimes even showing up within a few days of the same date every year.  As territorial animals, birds are likely to defend and return to a favorable site that offers the things they need: food, water, shelter, and, seasonally, suitable breeding habitat.   Last year, on our annual day-after-Thanksgiving adventure, Eric and I were privileged enough to watch two Short-eared Owls hunting over the grasslands south of the wetlands at Merced National Wildlife Refuge.  This year, we repeated the outing, spending the day exploring the vast grassland and wetland habitats at San Luis and Merced National Wildlife Refuge.   As the sun began to sink toward the western horizon, we found ourselves along the same stretch of road that we traveled on the same day last year, at the same time of late afternoon...

Despite the recent lack of rain, we are still entering into what is perhaps my favorite time of year to explore the grasslands and wetlands of California's Great Central Valley.  The weather is mild, and the end of winter is in sight.  Life rejoices!  Grasses are green, wildflowers are blooming, and new growth abounds in the tule beds.  And most importantly, bird activity is ramping up for the spring migration and breeding season. If you venture out into one of our precious preserved open spaces this spring ( use this tool  to locate a National Wildlife Refuge near you), you are likely to come across a bird, medium in size and brown or gray in color, flying low, coursing back and forth across wetlands and adjacent fields and grasslands.  This marsh hunter is one of our most beautiful and unique diurnal raptors, the Northern Harrier ( Circus hudsoniu s). A female Northern Harrier, perched in the tules at Merced NWR  Northern Harriers are amon...

While we're  on the subject of owls , perhaps my favorite group of birds, I'd like to introduce you to a common little owl found across much of California and the west: the Western Screech-owl ( Megascops kennicottii ). While I've heard and even seen these little nocturnal hunters right here in our Central Valley neighborhood, the following photographs were taken this past summer while Eric and I were birding in Southeastern Arizona at the fabulous  San Pedro House  near Sierra Vista. Western Screech-owls inhabit open woodlands and forested areas below 6,000 feet in elevation, particularly favoring deciduous trees along rivers and canyon bottoms.  But they are not uncommonly found in parks and suburban areas as well, where a reliable food source and suitable nesting habitat are to be found. Screech-owls nest and roost in natural cavities, such as those excavated by woodpeckers or formed where branches break off of the trunk (as pictured here).  They als...

A few days ago, I mentioned that I recently encountered a species that took my breath away and left me shaking with excitement!  If you know me, or are anything like me, you know that this kind of reaction is typically caused by an encounter with a member of my favorite group of birds: the owls! Driving around Merced National Wildlife Refuge's auto tour loop in the early dusk of an overcast day, I casually remarked to Eric that it's funny how everyone pays attention to the wetland ponds on the left side of the road, all but ignoring the grasslands on the right.  With heads turned the opposite direction, there could be all kinds of neat birds in the grasslands that would never be seen!  To prove my point, car after car rolled slowly by with massive telephoto lenses pointing out the windows, trained on the wetlands and waterfowl, completely obliviously to the grasslands. It was just a few minutes after I made this observation that I glimpsed a flicker of movement over t...

"I'm so glad we live in a world where there are Octobers." L.M. Montgomery, Anne of Green Gable s Like Anne Shirley, I adore the season of autumn and the month of October, but, it must be said, I loathe Halloween.  America's fastest growing consumer holiday, I could probably write for days about why I despise it so much... but suffice it to say much of my reasoning is bound up in that one word, "consumer." This year, Americans are expected to spend  over $8 billion  on Halloween paraphernalia.  That is a disgusting amount of [largely plastic] costumes, masks, decorations, candy wrappers and other stuff which will, mostly, end up in the garbage. But since I do enjoy colorful fall foliage, old-timey barn dances, pumpkins and apples, harvest celebrations and that piece of classic literature, The Legend of Sleepy Hollow ( read it here ), the season still holds its charms.  (It would hold more of its charms if Halloween hadn't become  an ecologi...

Riparian forests are invaluable in all regions and climates around the world, but as one might imagine, they are especially critical in arid regions like southeastern Arizona.  While a plethora of bird species cluster along the rivers, breeding in the complex, multi-level gallery forests, even more incorporate these riparian corridors into their migratory pathways.  With this in mind, I knew that a good portion of our time birding in southeastern Arizona would need to be spent along such rivers, and we found a few locations that lived up to their reputations as particularly good spots to find neat birds. (In case you missed it, in Part I of this series, we visited  Madera Canyon .) The San Pedro River, near Sierra Vista The Santa Cruz River, which we visited near Tubac, has its headwaters in high grasslands to the east of the town of Patagonia.  From there, it flows south into Mexico before changing its course to flow north past Tucson where it eventually ...