2016 Oct black vulture in Sonoma Co!!
black vulture (top right), turkey vulture (bottom right, slightly in the distance), and kestrel / Bodega Bay * Sonoma County CA
Black vultures are a rare visitor here on the West Coast, more typically found in the American Southeast and South, and in Mexico. We are in the middle of the migration right now, so you never know what might show up. Though this bird must have taken a wrong turn around Tennessee. We spotted it in a small kettle that had a couple turkey vultures and an American kestrel (small falcon).
Research at this time indicates that this type of vulture finds its food by site (similar to many African vultures), as opposed to the turkey vulture, more common here in CA, which uses its sense of smell to find food. Though they are both considered vultures with dark bodies and bald heads, but you can see that the black vulture has a distinctive wing shape and short tail, combined with a dark head and dark flight feathers that make it easy to differentiate from a turkey vulture. Turkey vultures also have a silvery hue to the underside of their flight feathers, the adults have red heads, and they have slightly different flight styles as well. Very different builds on these birds, and it’s reflected in the way they soar and fly (turkey vulture has a slight “v” when it flies as viewed from head-on, and it tends to rock back and forth more – a less steady looking soar). Often it’s easiest to ID a bird at a distance based on a sillhouette and how it flies.
20161013 calm before the storm
juvenile Great-Horned Owl / Wildcat Canyon Regional Park * Richmond, CA
almost-full-Moon and Red-Tailed Hawk hunting late / Wildcat Canyon Regional Park * Richmond, CA
Probably the last of this waxing moon we’ll see this month, due to the coming storm. Beautiful night.
20160926 elk
It’s that time of year again – the elk rut is in full effect. The bulls are gathering their harems and bugling, it’s always an impress sight and amazing to hear!
20160922 backyard boyds
bushtit (yes, that’s it’s name) – one of my favorites, and not just because of their name; when these tiny little birds come through in their flocks, it always brings a smile to my face
some of these birds are molting, so they are looking a little ragged – but still beautiful
20160916 sunset and full moon rise
Epic evening of no winds and clear skies (rare this summer here!)
The sun set almost directly behind Mt Tamalpais from this vantage, and the full moon rose exactly in between the two peaks of Mt Diablo to the East.
epic
owl
when you see this wild eye, it can’t be anything else but what it is … and it is beautiful
great-horned owl (adult female) / contra costa county CA
last nap before the night
This pair has been around for a number of years – why no young? Theories to come …
the showdown
As I was winding down my day while traveling in southern CA recently, I had the pleasure of watching a showdown between a juvenile red-tailed hawk and an adult Cooper’s hawk (likely a female). When I got back to the house where I was staying, I noticed the juvenile red-tailed hawk perched in a relaxed manner on the peak of the house next door, watching the sun go down.
This hawk is most likely about 1 year old, quite an accomplishment to have survived its first year (raptors have mortality rates in the first year as high as 70%!). Juvenile red-tailed hawks lack a red tail, often have lighter colored eyes than adults, and have some spotty patterns on the belly band (versus more streaking in adults). It seemed relaxed as it faced the setting sun, evidenced by its fluffed-out feathers and its left leg lifted up into its belly feathers. You can see on the right leg, there appears to be a band on this bird – possibly it was caught and banded during the migration last year.
I relocated to a second-story balcony which afforded better views of the bird, and as I stood there watching suddenly another raptor appeared on the scene! On a power line at about eye-level to me, an adult female Cooper’s hawk alighted and assumed a similar relaxed pose to the red-tail, with one foot up as it surveyed the area.
Cooper’s hawks are part of the Accipter genus of birds in the Accipitridae family, and can be extremely difficult to discern from their close relative the sharp-shinned hawk – a smaller version of this bird. Most raptor species exhibit reverse sexual dimorphism, meaning the females are larger than the males. What makes the identification of a Coopers versus a sharp-shinned hawk especially difficult in addition to very similar plummage is that a male Coopers can be about the same size as a female sharp-shinned hawk. In the above picture, there are some really helpful features that help key this bird as a Cooper’s hawk.
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rounded termination of the tail feathers (versus more straight across in sharp-shinned)
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dark “cap” on the head feathers (versus more of a full hood on a sharp-shinned hawk)
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eyes are placed more towards the front of the skull (sharp-shinned hawks’ eyes seem almost in the center of their skull when viewed from the side)
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thicker tarsus, or leg bone (sharp-shinned get their name from having an incredibly thin tarsus)
I am not 100% certain that this bird is a female, but that is my initial guess based on size relative to the red-tail (which I thought could be a female based on her large size – but again, no great scale for reference).
The Cooper’s hawk didn’t remain relaxed for long – as soon as it spotted the red-tailed hawk perched above it became much more alert, dropping its leg down and staring intently (though, to be honest, all these birds seem to only have a single facial expression – and if there is one word for it, it is “intense”).
She relocated to a place on the power line closer to the red-tail to get a better look …
In the above picture, you can see the white feathers that protrude below the tail on its ventral side. This is a helpful feature to identify accipiters in the field from a distance, but one needs to be aware that Northern harriers have a similar white patch that appear on their dorsal side.
Finally the Cooper’s hawk decided to move in on the red-tail – likely it has a nest in the area and did not like the red-tail hanging around too close. The Coop flew up on top of the chimney, and the showdown began. You can see the size difference fairly well in this photo (with the Coop on the right).
red-tailed hawk (left) and Cooper’s hawk
At this point, the red-tail took notice of the Coop but still had a leg up (no pun intended) and was facing away from it. In what had to be some sort of bird statement, the red-tail proceeded to slice (poo) in the direction of the Coop!
juvenile red-tailed hawk slicing
Casually, the red-tail then turned to face the Cooper’s hawk, then took off right in its direction flying just to the north of it. The Coop jumped off right after the red-tail and pursued! At first the red-tail tried to do some circles and gain altitude, but it eventually became a full on chase. There wasn’t much actual contact, but the Cooper’s hawk made its point and the red-tail seemed fine with relocating to a tree not too far away.
juvenile red-tailed hawk (left) and pursuing Cooper’s hawk adult
Awesome to see these birds and witness this close encounter!
ravens
this pair of ravens was keen on my sunset snacks at the top of Wildcat Peak / Tilden Alameda County CA
newt tracks
CA newt (Taricha torosa) tracks in soft muddy silt / Tilden Reg Park, Alameda County CA
You can see in this photo a great example of the understep walk that these awesome little creatures move in, with the five-digit rear feet landing just behind the four-digit front feet. So cool to see them walk. Note also the tail drag in the middle.
night life updates
Some photos and updates from the last few weeks. Spring seems to have started in the beginning of February this year, the buckeye trees (usually the first to bud and the first to lose their leaves) were budding in some places as early as the end of January. Since then, the warm and sunny weather has drawn out flowers and buds all around. Fortunately, as I write this, the rains have started again – and we are due for much more.
Great-Horned Owl and Mount Tam at sunset / Contra Costa County CA
Two weeks ago (week of Feb 15th), on two different nights, I saw the Wildcat Canyon “Bottomhill” great-horned owl couple mate. The timing coincides almost exactly with when I saw another pair mate last year – I thought maybe the weather would affect the pattern, but apparently not. It’s somewhat odd as most literature indicates great-horned owls being an early breeder (compared to other raptor species), and in many areas are on nests in January in the snow. I guess owl culture, like human culture here in the Bay Area, is different in these parts as well (I joke – probably the Mediterranean climate is a factor, though I’d be curious to know how breeding behavior here compares to other warm areas). As I get deeper into my own observations of the world and its critters, I realize how little we actually know. Scientists in the past seem to have been content to generalize regarding behavior, and while there are patterns and a spectrum of those behaviors that are “typical,” often in reality it may be different based on local factors. That’s what makes it fun to be out there. Personality and local flavor.
The female always seems to initiate the act, and she starts by chasing down the male on the occasions that I’ve witnessed it. She lands close to him, and starts to do a vocalization very similar to a juvenile owl. When the male flies towards her, she starts a repetitive “hoo hoo hoo hoo” sound that reminds me of a monkey. As the male mounts her, flapping for a few seconds, she lets out a high pitched vibrato whistle and then its over. It will be interesting to see what happens this year, as last year many of the nests didn’t appear to successfully raise any young (drought related?). There are four pairs whose territories I regularly walk through, with a possible fifth – then another not far away. Of all those pairs, I only confirmed one successful nest last season.
Great-Horned Owl and moon / Wildcat Canyon Reg Park CA
Despite the very dry February, the vernal pools are deep and wide from all the rain in January, and have been extremely active with tree frogs and California newts. The newts migrate from their hiding spots under leaf litter back to the area from which they hatched to mate and lay eggs. The frog chorus, if you can sneak up on them, is incredibly loud when nearby. Nights of wandering under warm skies and no winds to a live symphony of frogs, and owls flitting around, is pizza for the soul.
California newts in a vernal pond / Wildcat Canyon Reg Park CA
I caught a few interesting moon shots this month, one was a moon halo and the other was an interesting rainbow effect on clouds as the full moon rose last time.
2015 Oct 11 – the voles are back! (and a tropical kingbird)
We are seeing quite a bit of vole sign once again in the Bay Area, which is a good for most animals around here, except of course for the voles, really – they are one of the top items on the menu for many many animals. It’s interesting that they’ve rebounded right now in the worst part of the drought here in California. We noticed a severe drop in their numbers about two or three years ago (which is a normal part of their cycle), but it’s a good sign that they’ve returned. Now we just need some water.
These small rodents that resemble mice move mostly above ground, and they tend to create “runs” as they utilize the same pathways over and over. These runs create little tunnels in the grass and sometimes recessed runways in the ground.
a “vole’s-eye view” of a vole tunnel in the grass / Sonoma County CA
overhead view of vole grass tunnel or “run” (on right), clear area on left has vole scats
re-purposed gopher hole – voles have excavated this old gopher hole to use as shelter
There seems to be a very marked decrease in the frequency of raptor sightings the last two years in this area, by my observation – and though it’s difficult to determine why this might be, certainly the vole population crash coupled with the severe drought must be a one-two punch that all predators on the landscape are experiencing.
Bring on the rains, el Nino!!!
We also saw a Tropical Kingbird today, which is a very rare visitor to this area (a type of flycatcher). The pictures were taken through a lot of fog, but we had good views of the bird hunting and perched for five minutes at least. Our friend Moss made the ID, based on the notched tail (differentiating it from a Western Kingbird). Nice sighting!
2015 Oct 11 golden eagle, dark morph red-tail, and vultures
I was driving down a road in Sonoma County today and noticed a large kettle of turkey vultures flying above an agricultural area – probably numbering almost 40 birds! It was somewhat unusual, and certainly not something I’ve seen yet this year. I pulled over to take another look, knowing that often golden eagles will “hitch” a ride along with a group of vultures. As I was counting the vultures, boom!
Eagle!
Golden Eagle in a kettle of Turkey Vultures / Sonoma County CA
I followed the kettle, which conveniently for me also was following the road in my direction! I made a number of stops as I followed it, and during my final stop the Eagle was kind enough to turn around and do a fly-over for me.
juvenile Golden Eagle / Sonoma County CA
Such a beautiful bird – as I observed it I noticed that it lacked any under-wing white patches, but its uniform feather coloring and uniform-length flight feathers indicated that it was probably a first-year hatch bird. It appears it has lost one of its left secondary feathers, which initially made me think perhaps it was older and undergoing a molt, but I still think this bird is a hatch year bird (meaning it hatched this spring).
As it glided back past me and rejoined the group of vultures, a dark morph Red-Tailed Hawk took exception to its presence and launched after the Eagle from its perch among a grove of eucalyptus trees, screaming loudly as it flapped quickly towards the larger bird …
vocalizing adult dark morph Red-Tailed Hawk / Sonoma County CA
adult dark morph Red-Tailed Hawk / Sonoma County CA
The Red-Tail launched into the kettle and did a few dives at the Eagle, but they were half-hearted attempts – more bark than bite. The kettle of vultures, with the Eagle still flying in it, slowly floated away from the Red-Tail’s territory as it retreated back to a perch in the trees.
Here in the West, especially towards the coast it seems, we have more frequent occurrence of “dark morph” Red-Tails (they have a very diverse variety of feather patterns and tones), and often I’ve seen people mistake these birds for Eagles. To the untrained eye, this is totally understandable. But when you see the two together, there is little doubt about the ID. Golden Eagles are quite a bit larger, have distinctly different plumage when observed closely, different wing shapes, and different shapes/silhouettes when viewed from below. Turkey Vultures are only slightly smaller than Eagles, and both can hold their wings in a slight dihedral shape when soaring – to the naked eye they can appear very similar – but upon viewing them with binoculars, they also have very different silhouettes and feather colors, and an experienced observer can distinguish the two from each other even without binoculars.
“bird on a mission” – adult dark morph Red-Tailed Hawk / Sonoma County CA
nice comparison of a Turkey Vulture (left) and a juvenile (but full-size) Golden Eagle (right) /Sonoma County CA
















































































