sharing the space

Sharing the space:  something we often see in nature, where species or individuals divide up the resources in a way that maximizes their gain while reducing competition from closely related individuals.  Some sparrow species seem to be flexible in where they forage, adjusting their resource use based on the presence of other birds.  For example, at the Alviso marina park in the southern San Francisco bay, we saw Song Sparrows, Field Sparrows, and White-crowned Sparrows in the same area of the park, but in quite different micro-habitats.

song sparrow in swamp grass-

This particular Song Sparrow was practicing his song, but only half-heartedly. Just a warm-up before the breeding season gets going.

Song Sparrows were found in brushy areas and dried grasses of the wetland in the park, although they can often be found on the edge of more open, grassy areas in other habitats.

white-crowned sparrow-

Juvenile and adult White-crowned Sparrows foraged in small flocks together. First-year birds have brown and white crowns; adults are a more striking black and white.

White-crowned Sparrows are migrants, overwintering in the lower 48 states but flying as far north as northern Canada and Alaska to breed in the spring.  Some birds may be permanent residents along the California coast, but these particular individuals were not acting territorial.  In the park, the White-crowned sparrows foraged at the base of shrubs and along rocks and logs on the shoreline, picking at the seeds in the litter that accumulates in crevices.  In their higher latitude or altitude breeding sites, they prefer open grassy meadows dotted with small shrubs in which they place their nests.

adult white-crowned sparrow on anise seed-

An adult White-crowned Sparrow perched on a dried wild anise plant gets a better view of where to forage next.

The third species we saw in the park, Field Sparrows, were found in the field (as their name implies), i.e., in grassy meadows dotted with occasional tall annual plants and shrubs.  These birds are typical of “old fields”, areas that are undergoing successional change from cultivation back to shrub and forest.

field sparrow-

Field Sparrows aren’t particularly colorful (except for their pale pink beak), but they sing a song that sounds like a bouncing ball, and are usually easy to spot once you’ve heard them.

These are just a few of the ground-feeding seed-eaters that most likely can be found in the park area:  Golden-crowned Sparrows and Towhees are also seen on occasion.  The variation in habitat throughout the park makes it attractive to a wide diversity of wildlife that can share the rich resources.

From here to there

Left this scene…

Turkeys in the snow

Turkeys in the snow — my winter landscape of white and shades of brown.

To enjoy a brief respite of color and warmth in sunny California

Magnolia in bloom

Magnolia just ready to bloom

Spring green

The hummingbird visited these jasmine flowers after I had put the camera away — of course.

Winter rains have brought on a flush of new green in the California landscape, my favorite color.

the benefits of black feathers

Adding to the white, gray, and brown monotone colors of the winter landscape now, the resident birds also seem to be mostly shades of black, white, and gray or tan.  In fact, many of them use black as a primary “color” of their plumage.  Is black somehow advantageous to birds in the winter?

american crow-

Of course, crows are black all year, so their plumage color can’t be an advantage just for winter time.

I usually feel warmer with a dark colored sweater or jacket on a cold day, and we know that black absorbs and holds radiant heat energy much better than other colors.  So, do birds utilize their dark brown/black feathers to stay warm?

turkey vulture basking

Turkey Vulture basking in early morning on a northern California riverside.

Some birds, like Turkey Vultures, Anhingas, Cormorants, and Roadrunners, do use their dark plumage to advantage to warm up on cold mornings, basking with their dark feathers spread widely apart so heat can reach the skin below.

anhinga basking

Anhingas dry their feathers by spreading their wings, but their dark brown back feathers also give them a boost of warmth on cool mornings.  Photo taken on the Anhinga Trail in the Everglades.

However, wind ruffling the feathers of a crow reveals a flaw in the idea that their black feathers are used to keep them warm.  Their feathers are only black right at their tips, and are white-gray underneath; in fact their skin is pale as well.

american crow-white feathers beneath black ones

A crow sitting high on a tree branch in a steadily blowing wind must feel the chill on a day when the temperature is below 0 F.

This seems more like an adaptation to avoid overheating in summer sun, than conserving heat in winter cold.  In summer heat, black feather surfaces would heat rapidly, becoming warmer than the surrounding air, and would enable the bird to actually unload heat produced internally, reflected through the whitish underlayer of feathers to their outer surface.  This helps explain how large-bodied, dark-feathered Ravens can survive in hot, arid environments as well.

raven-grand canyon

Soaring above the canyon keeps them cool, but down at the bottom of the canyon where the food might be found often gets well above 100 F.

Assistance in regulation of body temperature might be one explanation for why so many birds have black feathers or black-tipped feathers, but there are a host of other possible explanations, as well.  One likely possibility is that the melanin pigment that colors the feather dark brown to black (depending on its concentration) binds to the keratin protein in the feathers and strengthens them and helps them resist wear.

birds with black wingtips

Large-bodied, white birds with black wingtips.  White Ibis photo by Ronnie Maum; Snow Goose photo from Birds of North America online; Northern Harrier photo by Jerry Ligouri.

During feather development, granules of melanin are deposited in the helical strands of keratin protein that make up the filaments that are in turn packaged into the barbs and barbules that make up the feather.  Melanin-enriched keratin has been demonstrated to make feathers stiffer, more durable, and resistant to abrasion.  The outer (primary) flight feathers are the propellers in the generation of powered flight, making it essential for them to be stiffer and wear-resistant.

But what are the benefits of black plumage patterns in all the other birds we see in the winter landscape?  Is black important for thermoregulation, resistance to wear, cryptic camouflage, something else…?

black and white birds

Birds in the Minnesota backyard, clockwise from upper left: Downy Woodpecker, Black-capped Chickadee, Yellow-bellied Sapsucker, White-breasted Nuthatch, and Northern Flicker.

Your thoughts?  What about all those other mostly black birds:  Red-winged Blackbirds, Pileated Woodpeckers, Puffins, Anis, Petrels, Auks, Grackles and Cowbirds, Coots, Moorhens, Frigatebirds, Starlings, and more.  Why black?

Like water off a duck’s back

It’s obvious where that expression, “like water off a duck’s back” came from.  Duck feathers shed water amazingly well — their plumage seems almost impenetrable.

mallard drake - feathers shedding water

Droplets of water bead up and slough (or sluff) off the outer feathers of duck plumage.  This guy had just righted himself from tipping up to scrounge algae off the rocks at the bottom of the creek bed.

No doubt part of staying warm in the chill winter temperatures and winds is staying dry, and duck plumage is intended to do just that.  Not only are the feathers incredibly dense, laid down in overlapping layers in feather tracts, but they are coated with a waxy residue from a gland at the base of the ducks tail that waterproofs them.

mallard hen

Beads of water are shed from all surfaces from head to tail end on this hen Mallard.

But what about those bare feet, exposed to near freezing water temperatures and standing on cold rocks or ice or snow for hours on end?  Feet don’t shed water, just the feathers.

mallard drake standing on ice

Cold toes?

This drake has just climbed out of the water, and is standing on ice, not something we would be comfortable doing (barefoot).  What happens when we reach for ice cubes in the freezer with wet fingers? The ice sticks to our fingers and is difficult to remove without losing some skin in the process. So how do ducks keep their wet feet from sticking to the ice?

mallard ducks-on ice

Ducks slip and slide on ice, but their feet don’t stick to the surface.

The secret is to maintain very cold toes that are the same temperature as the surface on which the duck stands or walks.  This is achieved by having arterial blood going to the foot run in parallel with the vein that is bringing cold blood back from the foot — making a heat exchange unit that promotes cooling the extremities while preserving the warmth of the body core.  Engineers have used this principle in the design of heaters and air conditioners, among many other uses.

mallard hen on ice

And this makes it nice for ducks to stand around admiring their reflections in icy pools.

too cold…

It’s -13 F right now, and with a moderate wind blowing, the wind chill makes it -36 F.  That’s too cold for me, but not too cold for the hungry birds and squirrels in the backyard to come into the bird feeders for a meal.

basking gray squirrel-

Gray squirrels don’t venture out until the sun is well up on these really cold days. And before they cross snow patches to get to the feeders, they bask on the trees for a while to warm up, orienting the darker fur on their backs directly toward the sun.

basking chickadee-

Even the chickadees take a few minutes between trips to the feeder to bask a little, fluffing their feathers out to make their tiny bodies into an almost spherical shape.

basking blue jay-

The bluejay must have been too cold to move — it just sat there looking around, squinting into the sun.  I could see the wind ruffling up its feathers — brrrrrrr.

Basking to gain what little radiant heat the sun provides at this time of year can be effective in warming up, but wind currents that penetrate fur and feathers carry that precious heat away.  What can a small animal do to cope with this intense winter cold?  Activity helps, as muscles generate heat, but that comes at a cost to be repaid by eating more.  Shivering helps, and when animals are not active, muscles engage in isometric tremors that generate heat, which is also expensive, but not as much as flying or running across the snow and climbing trees.   The only animals that seem unperturbed by this weather are the feisty little red squirrels.

red squirrel-

Red Squirrels must generate a lot of heat dashing around, because they spend almost no time basking and a lot of time digging into the snow looking for buried treasures (food) and running up and down trees to stash whatever they find away.

Mug shots — take 2

Birds and mammals seem to sense when you’re staring at them, willing them to stare back so you can get a great portrait with the glowing eyes looking right out of the frame.  It’s hard to achieve though, and mammals in particular resist eye contact, as that often is interpreted as a threat to them.  This is where telephoto magnification is essential, but even when I am quite a distance away, mammals just as often turn away as I raise the lens to focus.  Obviously their eyesight is a lot better than mine.

Common Loon-

A Common Loon emerged from a dive right in front of me providing a unique close-up of the detail in its feathers.

female Pileated Woodpecker

This female Pileated Woodpecker was so busy drilling into the tree, she didn’t notice (?) me walking closer to get my best shot.

european forest buffalo (wisent)-

A European forest buffalo (wisent) intent on eating and with no interest whatsoever in raising its head to make eye contact. I can see that they have long golden eyelashes though…

javelina-

Young Javelina crossing the road in front of our car near Portal, Arizona. Hairy beasts with long snouts, beady eyes, and stubby legs, not at all related to pigs (which evolved in Eurasia), but convergent in looks and habits.

mule deer-

Mule deer look like White-tailed deer (a different species) but have enormous ears, darker (blackish) tails, and darker gray fur. Usually found only in western North America plains, deserts, mountains, grasslands, etc.  Deer don’t see as well in the daytime as some more diurnal animals, and they often stare motionless for a few moments before bounding away or turning their back on the camera.

white-tailed buck-antler growth

Antler growth begins in the spring in White-tailed bucks. This looks like the start of what will grow into a large rack, and I wonder if this guy is the same animal as the one in the next photo.  I kept waiting for this guy to turn around and face me, but no…all I got was a side view.

white-tailed buck-antlers-

I’m behind a glass door and across two backyards from big buck, but he raises his head to look toward me when I tap on the window.

mexican wolf-at the Sonora desert museum, Tucson

A Mexican Wolf just barely raised its glance toward observers as it strolled through its pen in the Sonora desert museum in Tucson.  This is a subspecies of the Gray Wolf, but is on the verge of extinction in its native habitats in the southwestern U.S. and northwestern most Mexico due to loss of open hunting areas and predator removal.  Their fur coat has accents of black and white on the back and their under hair is yellower than that of the Gray Wolf.

mountain lion-

Big cats overheat quickly in the desert sun, as this one did pacing in its pen at the Sonora desert museum. Back in its cooler cave, panting, the puma/cougar/mountain lion finally raised its head and looked in my direction. Pumas are usually found in the mountains, but will venture into grasslands and even more arid desert habitat if there is sufficient game.

Mug shots – take 1

It’s great when you can get really close to the wildlife, i.e., right in their “faces”, to grab a “mug shot”.  I didn’t get many this year, but there were a few opportunities, assisted either by my extremely long (600 mm) telephoto lens or my trusty macro, to get up close and personal with the local wildlife on our travels and in my backyard.

hoverfly-on coneflower

Hoverfly gleaning pollen and/or nectar from New England Asters.

american-painted-lady-on sedum

American-painted-lady-on fall-blooming Sedum; they came through by the dozens to congregate on late-blooming flowers

honeybees-on-new-england-aster

Honeybees foraged on New England Aster; I saw more of them this year than in the last 5 years combined.

small-carpenter-bee-ceratina-spp

A tiny carpenter bee feasting on pollen from newly opened anthers on a coneflower.

bullfrog-

We found a Bullfrog calling in a desert oasis in Arizona. Kind of ugly, but beautiful eyes…that might be a mosquito on his upper lip trying to get a meal.

chuckwalla-

A Chuckwalla was sunning itself at the Sonora desert museum in Tucson. Dark pigmented scales on its underside help it soak up heat from rocks. Chuckwallas love to hide in rock crevices and resist being pulled out from their hiding place by puffing up their body with air, expanding into any empty space in the crevice.

snapping turtle-

Snapping Turtles have large jaws and long necks, but this one was protecting itself by withdrawing into its carapace.  My what beady little eyes you have, Mr. Turtle.

Great Blue Heron-

Eye to eye with a Great Blue Heron

molting mallard ducks-

Male Mallard Duck before molting a new set of showy feathers

Black-capped Chickadee-

Chickadee with an attitude…

winter blah — happy solstice everyone

The lyrics from California dreamin’ are running through my head this morning as I look out at our ever-present gray world:  “all the leaves are brown (the ones still on the tree), and the sky is gray (for days on end)…”

deer-herd-in-the-snow-

It’s a gray world…

And the weak sun screened behind the dense clouds doesn’t help much.  This is the time of the winter solstice, the least daylight we’ll have this year.  According to the experts that track these statistics, those of us at 45 degrees north latitude will have 8 hours and 46 minutes of dim light today, and the sun will rise only 21.5 degrees above the horizon at noon.

For comparison, that’s 6 hours, 51 minutes less light today than during the June solstice, when the sun rose to 68.5 degrees above the horizon at noon.  Here’s what that difference in sun angle looks like in geometric space.

eorbit3 from zebu.uoregon.edu

Path of the sun and its position at noon for viewers at 45 degrees north latitude, at winter solstice (21.5 degrees) and at summer solstice (actually 68.5 degrees, not 66).  For those interested in how to calculate the angle of the sun at solstice, click here for a description from an earlier post.  Diagram from zebu.uoregon.edu

It’s no wonder that animals and humans alike just want to curl up and rest until the sun comes back out again.

sparring in the snow

The deer herd wandered through the backyard for the first time in quite a while.  A few does, three bucks, and assorted youngsters of the year.  Two of the bucks got into a couple of short shoving matches, primarily instigated by “big buck” (he of enormous girth photographed in mid-November).   The rut might be mostly concluded, but there seems to be enough residual hormone circulating to ensure the male dominance hierarchy is still on-going in the herd.

White-tailed deer bucks

“Big buck” on the approach to his younger, smaller herd member…

White-tailed deer bucks

One minute they are ambling through the woods picking up the stray leaves and twigs to eat…and the next minute they are butting heads.  Buck on the left is getting shoved backward by “big buck”.

White-tailed deer bucks

Ouch, “big buck’s” antler tine looks like it’s poking into the smaller buck’s right eye.

White-tailed deer bucks

Staring contest — who’s the boss? You can tell “big buck” is asserting his dominance just by the difference in the posture of the two.

One minute they are ambling through the woods picking up the stray leaves and twigs to eat...and the next minute they are butting heads. 

Back to amicable feeding, side by side…

One minute they are ambling through the woods picking up the stray leaves and twigs to eat...and the next minute they are butting heads. 

and then suddenly, “big buck” turns to face off with his buddy again…(the difference in the size of the two bucks is more noticeable in this shot, and their antlers seem to be different colors)

White-tailed deer bucks

once again locking horns (antlers)…

White-tailed deer bucks

and once again, the smaller of the two bucks gets a tine in the eye

Now we see the advantage of that larger, more complex rack on older bucks, with tines that can reach into the sensitive facial areas of their competitors.  Of course, the added stature and muscle mass helps those big bucks push their smaller competition around as well.  Thanks for the show, boys.

The teaser

The resident (and very territorial) male Anna’s Hummingbird in my mother-in-law’s backyard proved to be quite a challenge to photograph. He always sat with his back to me, singing his scratchy sing-song, and he preferred to hover in front of me with his back to the sun.  In fact he hovered above and around me for just seconds before dashing away to hide in the middle of the bottlebrush shrub.  What a tease!  You have to be really quick on the trigger (shutter) to catch these guys in prime light, and there were many more misses than successes with my attempts.

Male Anna’s Hummingbird

Male Anna’s Hummingbird

Male Anna’s Hummingbird