Snowy portrait

A great surplus of the fluffy white stuff has been accumulating in the backyard this past week, and there are predictions of more to come.  Squirrels have been busy excavating in the snow looking for fallen seed.  Every now and then, they seem to take a break and just hang out on a branch.

Red squirrel in snowfall

Red squirrels are usually dashing around the backyard, scurrying up branches, hopping from limb to limb. This one stopped for a short rest.

Red squirrel in snowfall

The more typical view of red squirrels, i.e., just before making a mad dash up a branch.

I don’t know what this frantic chasing up and down branches is all about, but I did notice that the red squirrels run toward birds in these same branches that have just come back from the feeder with a seed or a peanut.  Maybe they are hoping the birds will drop whatever they are eating and fly off, leaving the tidbits for the squirrels to find?

How do birds predict the weather?

I’ve noticed that the frenzied feeding activity at bird feeders (see yesterday’s post on “finch feeding frenzy“) usually coincides with a precipitous drop in temperature the next day, but I’ve wondered what enables birds to predict that occurrence.

house finches and goldfinches

Sure enough, the day after I photographed the finch feeding frenzy, the overnight temperature dropped from 20 F above zero to -10 F below. Moderate winds added to the chill making the effective temperature for us humans about -30 F!  No birds visited this feeder the next morning until later in the afternoon when the sun had warmed the air up to just about zero degrees F.

Cardinals, Blue Jays, Nuthatches, Chickadees, Slate-colored Juncos, House Finches, and Goldfinches all made an appearance at the bird feeder during the morning hours the day before the frigid temperature drop.

cardinal and goldfinch-

Mr. Cardinal didn’t stay long — the finch mob must have scared him off.

white-breasted nuthatch-

Nuthatches zoom into the feeder, pick out a peanut treat, and zoom off, while the finches just sit and gobble up sunflower seeds.

But it’s not the temperature drop the birds are predicting, it’s the drop in barometric pressure. Low barometric pressure in one area means there will be air movement from a higher pressure area, and in the winter, that usually means Minnesota will receive a big blast of frigid Canadian air.

And the data bear this out:  barometric pressure reached a low point at noon on the day of frenzied finch feeding and increased almost 30 mm by midnight the next day, bringing with it bright sunny weather but a 30 degree drop in air temperature.

It seems that birds are the only land vertebrates (with a couple of exceptions) that possess a paratympanic (i.e., next to the ear drum in the middle ear) barometric sense organ, and it is derived from the same hair cells in sharks and their relatives that provide those fish with information about their jaw movement relative to the prey they intend to gobble up.

black-capped chickadee-

Chickadees and Nuthatches go for the high energy peanut treats in preparation for a blast of cold weather.

So, is a 30 mm change in barometric pressure (a little over 1 inch) enough to trigger such a feeding response in my backyard finches?  Yes, it is.  Experimental data on White-throated Sparrows showed that they could detect a pressure change of as little as 10 mm:  when barometric pressure was decreased artificially in a chamber holding migratory sparrows, they immediately began feeding when the lights were turned on; when the pressure was higher (and normal), they became active, preening and hopping around in the chamber, but not feeding.

And why is it just the birds that have evolved this magnificently sensitive sensor?  In addition to predicting weather fronts, the barometric sensor is most useful for maintaining level flight at a particular altitude during migration.

What about mammals, especially humans?  Can we detect changes in barometric pressure?

gray squirrel foraging in a snow bank

Gray Squirrels were out in numbers looking for seed scattered in the snow by the finch mob.  Did they know what was coming the next day?

Only one species of bat possesses a physical sense organ that detects barometric pressure, but mammals, including humans, can sense changes in pressure in their ears, sinuses, sometimes joints, but there is no specific receptor for the sensation.  Rather it is changes in pressure within a confined cavity that elicits the sensation, and not in everyone.

Mammals in the living desert

Although it is far easier to find birds in the southwestern deserts, more than 100 mammal species live there too, a few in some of the harshest and most challenging environments.  Most are usually active only at night or in the twilight that precedes sunrise or follows sunset.  Why?  Because daytime temperatures can be very hot, water is limited so keeping cool by evaporation is dangerous, and there aren’t very many places to retreat to cool shade.

Sonoran desert at Palm Desert, CA

No place to hide from the heat in this leafless, spiny forest of cactus, unless you’re a small, burrowing rodent.

Mammals cope with the heat by avoiding it, storing it, unloading it, or offsetting it by consuming the water-filled bodies of their prey.  Here are a few examples of these strategies in mammals of the Living Desert Zoo in Palm Desert, CA.

Avoiding the heat: bats, rodents, kit fox, coyote, mountain lion, bobcat

Big carnivores need to retreat to sheltered crevices or caves during the hot daytime hours, while mice can keep cool in underground burrows.  Their dense fur is an adaptation to keep them warm on clear, cold desert nights, and in the winter.  In addition, water lost by panting to keep cool can be replaced by the body water in their prey.  Their home range might even include a water source like a spring or pool.

Mountain Lion, Living Desert Zoo, Palm Desert, CA

Bobcat, Living Desert Zoo, Palm Desert, CA

Coyote, Living Desert Zoo, Palm Desert, CA

Storing the heat: pronghorn antelope, bighorn sheep

Large-bodied herbivores can’t escape the heat, so they tolerate it by storing it in their large body mass, and allowing their body temperatures to fluctuate several degrees over the course of the day.  Heat gained during the daytime can be unloaded by radiation or convective cooling at night.  Bighorn sheep can withstand dehydration for several days (to a level that would kill a human) and can replenish all of their body water immediately upon drinking.

Pronghorn Antelope, Living Desert Zoo, Palm Desert, CA Bighorn Sheep, Living Desert Zoo, Palm Desert, CA

Unloading the heat:  jackrabbits, mule deer

Both deer and rabbits seek shade during the day, but use their very large and well vascularized ears to radiate heat away from their body.

Mule deer, Living Desert Zoo, Palm Desert, CA Jackrabbit, Living Desert Zoo, Palm Desert, CA

Fennec foxes from Saharan and Arabian deserts use a similar strategy to unload heat from highly vascularized, over-sized ears. Apparently the large surface area of their ears also helps them hear prey moving around under ground.  It’s interesting to see such convergence of strategies in unrelated animals from different continents.

Fennec, Fox, Living Desert Zoo, Palm Desert, CA

And what about the unlovely Javelina?

Javelina, Living Desert Zoo, Palm Desert, CA

They look ill-suited to be desert dwellers with their short extremities, stocky bodies, and bristly hair.

Their solution to the challenges of desert life?  Live near the water and stay in the shade, for example, under a trailer!

“elephants” on the beach

We hiked about a mile and a half out to the sand dunes at Año Nuevo state park, and were excited to find the giant forms of sleeping Elephant Seals there.

Elephant seals at Año Nuevo state park, CA

One of several inter-dune spots we visited where mostly male Elephant Seals congregate to wait for arriving females. A single female nursing her newborn pup in the center foreground.

Elephant seals at Año Nuevo state park, CA

Males arrive first (November to March) to establish their territories; females (short-nosed individual in the center) arrive later, giving birth after their 11 month gestation within about 5 days of their arrival.

Elephant seals at Año Nuevo state park, CA

There is a lot of machismo on display, and mock battles take place between all ages of males. Although they are sexually mature at 5 or 6 years, they usually can’t maintain a harem of females until they are big and strong enough at 11-12 years.

Elephant seals at Año Nuevo state park, CA

What’s the big nose for? Likened to an elephant trunk, which is how these seals got their name, their proboscis grows in length, can be inflated with air, and gives their low-pitched staccato vocalization a deeper and more threatening tone.

Elephant seals at Año Nuevo state park, CA

Males might try to have their way with females even as they emerge from the sea, but females hold their own, and remain unreceptive until after they have given birth.  This female is expressing her displeasure with a male’s advances with sharp barks and open mouth gape.  

Elephant seals at Año Nuevo state park, CA

Mature males reach about 14 feet in length and might weigh more than 2 tons. Females are much smaller, 10 feet in length and reaching about 1500 pounds max. Elephant seals are the largest seals and far outweigh potential terrestrial predators like the grizzly bear.

Elephant seals at Año Nuevo state park, CA

Mature males collect a harem of females which they defend from other males, by engaging in vocalizing, assuming threat postures, or in actual fights. Once the females have their pups, they become sexually receptive, allow males to fertilize them, and the next cycle of gestation begins while they are still nursing the current year’s pup.  In this harem, I count at least 5 pups.

Elephant seals at Año Nuevo state park, CA

Pups are born with black coats, which eventually are replaced with the light brown fur. They gain about 10 pounds per day, but are nursed for just one month, reaching about 250 pounds before their mothers return to the sea to feed.  They are on their own to learn how to swim and to find food!

Elephant seals don’t eat or drink while on land, instead subsisting on the fat stores acquired during their many months at sea.  When they leave the breeding beaches, males and females take differ routes to feeding grounds either along the coast (males) or open ocean (females), but both feed at extreme depths, up to 5000 feet deep in dives lasting almost 2 hours.  (There are some special adaptations for that activity, to be discussed later). Preferred foods are usually benthic forms like rays, bottom-dwelling sharks, squid, hagfish, etc.

Elephant seals at Año Nuevo state park, CA

Bearing the scars of many battles on his thickened neck skin, this giant bull elephant seal looks passive at rest.  But watch what the bulls can do to each other in the video below.

From David Attenborough’s “life in the freezer”

 

a dog and her ball

McNab border collie-Australian shepherd mix For those following the travelog, yes we made it to California, just an hour before a major winter snowfall hit Donner Pass.  Cars were delayed 17 hours on I-80 and chains we didn’t have were required after 36 inches of snow fell on the Sierras over the weekend.

The grandkid cousins had a chance to play together and exercise the McNab border collie that lives here in CA.  She’s great entertainment for the kids, and gave me a chance to practice my high speed (and she is definitely a high-speed chaser) photography.

McNab border collie-Australian shepherd mix

Look at that take-off!

McNab border collie-Australian shepherd mix

my ball!!

McNab border collie-Australian shepherd mix

Granddaughter thought she could try to keep up with the dog…hah!

McNab border collie-Australian shepherd mix

In most fleet-footed chasers, the flexion of the spine and extension of its entire length is what makes the animal gain a lot of ground in one stride, and if they can flex and extend quickly, they can achieve great speed and distance covered.  

McNab border collie-Australian shepherd mix

Look at the extension as she grabs for the ball.

McNab border collie-Australian shepherd mix

Eye on the ball…

McNab border collie-Australian shepherd mix

McNab border collie-Australian shepherd mix

Success!

Crossing America — Wyoming

Take the vast, open prairie of South Dakota, and remove the cows and farms, add some bunch grasses, sage brush, and pockets of stunted juniper, along with a few rolling hills, and you have Eastern Wyoming.

Eastern Wyoming highway

Eastern Wyoming open spaces

Snow makes this landscape completely homogeneous. There’s a tiny house/farm in the distance.

Eastern Wyoming open spaces

There is a lot of open space here, miles and miles of monotonous sameness.  Oh look, a mountain ridge in the view adds a little variety to the landscape.

Somehow on our way from I-90 to I-80 in eastern Wyoming, we got off the beaten track and stumbled across a road through a picturesque canyon right before sunset.  One of those construction signs with lighted messages warned us, “wildlife next 10 miles”.  This was quite exciting because we had seen a total of exactly one hawk the entire day.  Sure enough around one corner, there were three mule deer standing next to the road, but they quickly scurried away.

Mule deer, Sybille Canyon, Wheatland, WY

Two mule deer does just as surprised to see us as we were to see them.

We spotted a raven or two as we drove along the smaller roads, but the winter landscape in this part of Wyoming seems devoid of wildlife: few hawks, no coyotes, no antelope, no jack rabbits, no cattle, no people.  It might as well be the Gobi desert.

In the twilight we negotiated our way back to I-80 and were treated with a glorious sunset.

Wyoming sunset

Wyoming sunset

The next day, following I-80 west from Rawlings to Evanston and then into Utah, the Wyoming landscape got more and more interesting, as rolling hills of sagebrush gave way to rocky cliffs, deep canyons, and taller juniper interspersed with a few pines.  But the sparseness of human settlement did not change. This is land for the very rugged, independent, individualists of us, who really enjoy their alone time.

a Wyoming farm

Nearest neighbor…25 miles?

Wyoming cliffs near Rock Springs

Bald Eagle over cliffs near Green River, WY

Flying over the cliffs near Green River, a Bald Eagle glided slowly toward the river. That was one of 4 raptors we saw that day.

Wyoming is challenging, and mystifying, and interesting, and welcoming.  Towns have unusual names like Winner (where you introduce yourself by saying you’re a Winner-ite), Chugwater (how do you suppose it got that name?), and Guernsey (are there actual cows there?).  Friendly hotel and restaurant personnel provide wonderful service, with nary a country twang in their speech.  And I bet they are strong enough to throw a hay bale up on a pickup!

Looking back — wildlife encounters in 2018

Our travels took us far and wide this year: Peru, England, Scotland, Iceland, California a few times, New England and Maritime provinces of Canada, Florida, and of course, northern Minnesota.  There were so many interesting, colorful, and unique encounters with wildlife it was hard to pick favorites, but my choices are partly based on diversity of subject material.  Of the ones below (that made my top 15 list), which are your favorites? (You can click or tap on each image to enlarge it to full screen and use the back arrow to return to the post.)

Red Fox

Red Fox in the MN back yard, January 2018

White-tailed Buck

White-railed Buck in the MN backyard January 2018

Male Anna Hummingbird

Male Anna Hummingbird displaying in the CA back yard, January 2018

Blue Tit

Blue Tit, in Norfolk, England, in April 2018

Atlantic Puffin

Puffin from Farne Islands, England, April, 2018

Gray Wolf

Gray Wolf, MN Zoo, August, 2018

Icelandic ponies, Hella, Iceland

Icelandic ponies, Hella, Iceland, May 2018

Juvenile White-crowned Sparrow, San Jose, CA, February, 2018

Grey seals

Grey seals on the Farne Islands, England, in April 2018

Cream-colored Woodpecker

Female Cream-colored Woodpecker, Ceiba Tops Lodge on the Amazon, Peru, March 2018

Alpaca in the Andean altiplano, Peru

Alpaca grazing in the Andean altiplano, Peru, March 2018

Masked Crimson Tanager at Ceiba Tops Lodge, Peru, February, 2018

Yellow-bellied spider monkey

Yellow-bellied Spider Monkey, Ceiba Tops Lodge, Peru, February 2018

Red Squirrel, Rothiemurchus estate, Scotland, May 2018

Red Squirrel, Rothiemurchus estate, Scotland, May 2018

Seed thief

Early one morning, just as it was getting light, I strolled out to the porch overlooking the back yard with my coffee and saw this.

deer robbing bird feeder-

So that’s why this bird feeder has been emptied so quickly recently…

After the first few nights when temperatures dropped into single digits in the back yard, there were dozens of chickadees, nuthatches, and goldfinches flocking to this feeder in the early morning.  I filled it almost daily, thinking I was feeding just birds.  Apparently not.

doe robbing bird feeder-

I rapped on the window, and the yearling doe stopped in mid-chew to stare at me.

doe robbing bird feeder

And then she continued with her breakfast, unperturbed by my presence at the window.

So I yelled through the window at her, and she finally moseyed off…

white-tailed doe-

“OK, I’m leaving”, she seemed to say

white-tailed does

And off she went with a friend, to explore some other back yards.  

I’m sure the sunflower seeds gave this animal an added boost of protein for a few days; who knows, it might help her survive the long winter fast she is about to endure.  Needless to say, I raised the feeder on its perch, so she can’t reach it — at least until the snow pack around its base gets higher.

Birding in a Florida salt marsh

What a pleasant surprise to find such a rich and interesting wildlife refuge just an hour north of Cape Canaveral — Blackpoint Drive, a 7 mile road along dikes in a salt marsh that is part of the Merritt Island National Wildlife Refuge.

Blackpoint Drive wildlife refuge, Titusville FL

A typical scene along the dike roads of mangroves and pools in the salt marsh.

Here’s how the Fish and Wildlife Service describe this unique area.

Imagine a broad, flat expanse of salt marsh stretching from where your car is parked to the Indian River, a distance of about 1 mile. The only obstruction is an occasional hammock of palms or a mangrove-rimmed pond, and behind you, on higher ground, slash pines. Marsh streams gracefully wind through the marsh and provide a thoroughfare for microscopic plants and animals, shellfish and fish. Egrets and herons are poised along the stream edge, like spearfishermen patiently awaiting a meal. Secretively, sparrows search for insects in the chest-high grass. Occasionally, tides aided by a strong wind flood the marsh, and on the ebb, nutrient-laden waters are exported to the river. The marsh and river are one.

Blackpoint Drive wildlife refuge, Titusville FL

An island of palmetto on higher ground stands behind the sea of grass in the salt marsh.

Although we were visiting before the big influx of winter migrants arrived, there was still plenty to see, which is why a 7 mile drive took us more than 3 hours. Butterflies, lizards, lots of birds, alligators, and even a errant manatee that wasn’t supposed to be in this area of the salt marsh crossed our path.

Tri-colored Heron, Blackpoint Drive wildlife refuge, Titusville FL

Tri-colored Herons were common in the shallow pools lined by mangroves.

Tri-colored Heron, Blackpoint Drive wildlife refuge, Titusville FL

This one was pretty tame, and walked right up to us.

Greater Yellowlegs, Blackpoint Drive wildlife refuge, Titusville FL

Greater Yellowlegs foraged in the shallow mudflats.

Blackpoint Drive wildlife refuge, Titusville FL

A few flocks of small dabbling ducks floated in the deeper pools, but quickly took cover in the mangroves when they spotted us.

Alligator, Blackpoint Drive wildlife refuge, Titusville FL

Floating in some of those same deep pools were alligators of various sizes, from small like this one to very large.

Little Blue Heron, Blackpoint Drive wildlife refuge, Titusville FL

A solitary Little Blue Heron stalked its prey.

Great Blue Heron, Blackpoint Drive wildlife refuge, Titusville FL

Mangroves make useful perching spots for both Great Blue Herons and Great (White) Egrets.

Yellow-dumped Warbler, Blackpoint Drive wildlife refuge, Titusville FL

Yellowthroat and Yellow-rumpled Warblers were frequently seen foraging in the low bushes and mangroves along the water’s edge.

Juvenile and adult Common Moorhens, Blackpoint Drive wildlife refuge, Titusville FL

Common Moorhens must have raised their brood in these pools lined by mangroves. This juvenile bird is flanked by two adults in the background.

Manatee, Blackpoint Drive wildlife refuge, Titusville FL

The manatee was swimming along the edge of a small stream, squeezing itself through culverts that connected waterways. Apparently they are restricted from this area because they get stuck and have to be rescued and removed by wildlife biologists.

Black Vultures, Blackpoint Drive wildlife refuge visitor center

We found Black Vultures resting in the shade on the lawn of the visitor center 2 miles up the road from the wildlife refuge. It was close to 90 degrees and very humid, so no wonder they took refuge here.

What an amazing area, the last remnant of the natural salt marshes that probably lined the eastern coast of Florida before it was extensively developed. Not only is it a haven for wildlife, but it’s a natural barrier to storm surge and salt water intrusion inland.

Jumping for joy?

When visiting the Minnesota Zoo with the grandkids the other day, I was fascinated with what was going on in the Dhole (pronounced with a silent “h”), or Asiatic wild dog pen. What I think might have been the male Dhole was doing a jump-dance step in one corner of his circuit around his pen.  It looked like this, but had no vocalization with it.

Dhole, Asian dog

Dhole, Asian dog

Dhole, Asian dog

Dhole, Asian dog

The jump-dance step was repeated several times, so it might have been part of a display for the female in the pen, or it might have been some type of aberrant displacement behavior, an artifact of being bored in its captive environment.

Dhole, Asian dog

Was he showing off for his mate?

Dhole (Cuon alpinus) are native to central, south, and Southeast Asia, but are not members of the familiar Canis genus that includes domesticated dogs, coyotes, wolves, African jackals, and even Australian dingoes.  They have shorter legs, different dentition, and differences in skull anatomy that distinguish them from members of the dog genus.

Dhole, Asian dog

Dhole are highly social animals, living in large clans of related individuals, but they lack the strong social hierarchy of wolves. They are typically diurnal hunters, going after medium and large-sized hoofed mammals and their young. Small groups of 3-5 individuals hunt cooperatively to bring down their much larger prey, much like African hunting dogs do. Although Dhole seem docile and non-aggressive in their clan in the wild, efforts to tame them have failed, as captive youngsters have remained shy or become vicious to handlers.  Dhole — an interesting dog “cousin”.