Morning visitors

It’s that time of the year again, when the bugs and the deer discover all the tasty plants in my garden.  While the Japanese beetles ravage the leaves of the apple trees and raspberries, the deer fawns chow down on the wildflowers.  I don’t mind them, though, they are pretty cute, and very shy.

White-tailed deer fawns

Breakfast at the wildflower garden buffet

White-tailed deer fawns

The twin is completely hidden underneath the giant cup plants.

White-tailed deer fawn

Hyssop must not taste good to deer; they left it for the bumblebees.

This time, last year: a foxy morning

The usual suspects have returned to the back yard this summer, but one of my favorites is still missing, the pretty little red foxes.  So, here’s a glimpse of their visit to the backyard last year.

June 30, 2017:  What a delight to see my favorite canids lounging in my Minnesota backyard this morning.

red fox-

In addition to brief, one minute naps, there was quite a lot of scratching and grooming going on.

red fox-

And when they stopped digging at their own fleas or whatever was itchy, they groomed each other.

red fox-

must be some good stuff inside the other fox’s ear…

I watched these two foxes for several minutes, but can’t figure out if they are a male-female pair, or two youngsters, or what.  Male foxes are usually noticeably bigger then females, and these two seem to be identical in size. They do seem a bit small and skinny, so maybe they are younger, but this year’s kits would not be this big yet, having been born in late March, and just out of their den in early May.  It’s a mystery.

red fox-

Shot through the not very clean porch window at 500 mm —

Building a nest

This is a tale of “if at first you don’t succeed”, keep trying.   Mr. and Mrs. Robin decided to build a nest above a light fixture on our garage.

Male American Robin

Mr. Robin: “this looks like a great place for a nest”

It’s a very unstable platform, and every stick added seemed to fall between the lights to the ground.

Robin with nest material

Incoming: bring more nest material…

Robin getting nest material

Outgoing: get more nest material…

But gradually, after a few sticks held in place, and with the addition of some critical flexible, long leafy material, a platform began to take shape, and the nest cup was added on top.

Robin with nest material

It’s a busy two or three days of flying back and forth adding to the nest structure.

Robin nest on exterior lights

Well, at least this nest is well protected from the rain…

I hope it’s strong enough to hold the weight of several growing chicks.

Back yard visitors

It’s nice to see familiar wildlife in the backyard.  These were my first (vertebrate) visitors since returning from May travels.

A singleton fawn (no twin around?)

Single fawn without doe

No mom around either…maybe it’s just exploring on its own.

Tom Turkey

Tom Turkey came to visit because I finally filled the bird feeders again.

Tom Turkey displaying

His display was half-hearted (no tail fan), but his gobble was pretty loud.

Tom Turkey

A beautiful bird, with a homely face.

now if only the fox family would come to visit…

eye level

My neighbor called to tell me there was a big snapping turtle on his patio, so I went over to make friends.  It was indeed a big one, maybe a female looking for a soft garden spot to lay some eggs.  I decided to get down on turtle level to take some photos.

Snapping Turtle

Snapping turtles often come up into our yards from the lake across the street. Sometimes they bring a collection of algae on their shells, but this turtle is remarkably clean.

They are called snapping turtles for a good reason. Those toothless jaws can produce a powerful pinch, strong enough to tear flesh.  And if they can’t nail you with a vicious bite, snappers will put a nasty gouge in your skin with those long, sharp toenails.  Beware of picking one of these up!

Snapping turtle

That’s eye level, for sure. Look at all that loose skin under the head, which allows them to stretch their head far out of the shell and take a good bite of something.  They can extend their neck and flex it perpendicular to their body, latching their jaws onto whatever is nearby.  I was a little surprised not to see leeches or some other ectoparasites clinging to the turtle’s skin.

Once the turtle got tired of watching me, it moved off the patio toward the garden, raising itself up on its toes to step over a hose. How does a beast whose eyes are at the top of its head know where it’s feet are in relation to an obstacle on the ground?  Obviously, snapping turtles have a wider visual field than you might think.

Snapping Turtle

Snapping turtle walks over kinked hose by rising up on its toes!

Boldly Invisible

A continuation of the discussion in the last post of why black accent or coloration is so widespread, especially in small birds…there are still more questions to answer.

For example, you would think that a boldly striped, black and white animal would be an easy target to spot against the homogeneous green or gold African savanna.

zebra-

But how many zebra do you actually see here?

Disruptive patterns of black and white break up the outline of an animal’s body, making it difficult to detect them in a complex background.  Maybe this is why a herd of zebra can be referred to as a “dazzle”?

Looking at a single chickadee against a plain white or tan or gray background makes them standout because of their bold black and white markings.

Black-capped chickadee-

But finding them in their more typical, complex background of myriad tree branchlets and leaves is much more difficult.

chickadee family-no highlights-

How many chickadees hiding in the bushes?  They blend in well with highlights of snow on branches or in the background, deep shade on unlit branches, and the tan of leaves and bark.

chickadee family-with highlights-

Here they are!  Highlighted with a little illumination in Lightroom photo editor.

Birds that live in complex environments like the dappled shade of a forest, or the complex vegetation of a wetland or grassland, often have complex feather patterns (especially dark and light) that more or less blend with their background, or at the least, make them difficult to detect until they move.  Some of the boldest black and white patterns, like the stripes on a Kildeer’s breast, actually distract one’s eye from the outline of the bird’s body.

kildeer-defending-chicks-

Until she moves, mama Kildeer isn’t obvious in this marshy wetland. I didn’t even notice her chick standing silently on her right until I was editing the photo for a blog post.

Some birds emphasize camouflage even more by combining spots of white or bands of dark and light on their feathers.

barred-owl-camouflage

A sleeping Barred Owl has pretty good camouflage in this leafless Amur Maple forest.

barred-owl-close-up

Stripes down its breast and spots on the wings and back of the Barred Owl help break up the solid outline of its body.

brown creeper-

The blotchy brown and white plumage of Brown Creepers lets them hide in plain sight on the rough bark of mature trees where they forage in crevices for prey.

So, one of the answers to why so many birds, especially those residents that live in the northern temperate forests all year, adopt splotchy patterns of black or brown and white plumage is that they maximize their ability to hide in plain sight by being boldly invisible.

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?

Spike and the boys

“Spike and the boys” — it’s not a new band, but a herd of White-tailed deer bucks that roam the backyard and beyond.  There are three mature (big) bucks and three first-year bucks with tiny antler spikes protruding from their foreheads — hence “spikes”.  They are browsing for anything edible in the backyard on this cold, snowy day.

first year white-tailed buck (spikes)

Two of the three spikes were doing a little playful head butting in the wildflower garden.

first year white-tailed buck (spike)

Number 3 of the trio ambled over to see what all the fun was about, chewing something as he ambled.

white-tailed buck-

Meanwhile the big boys were serious about finding something nutritious to eat. They have been through this long winter drought of good forage before.

Males lose 20-30 % of their body weight during the fall rut, as they follow the does around waiting for their opportunities to mate with them.  That allows little time to eat, and consequently, they may enter the winter period of low food availability with less fat than they will eventually need to survive.  Their winter browse on evergreens, leaves, and shrubs may not sustain them completely either, and they may continue to lose weight throughout the winter, despite trying to reduce their metabolism by being less active and lowering their body temperature and heart rate: lessons that the “spikes” will need to learn quickly.

white-tailed buck-

One of the big boys has already lost a portion of his rack on the right side.  It must get tricky maneuvering those irregular curves on his head through the dense branches of the forest undergrowth.

white-tailed bucks

Spike and the boys suddenly come to full attention, looking intently at the wetland valley below the brim of the hill. There are dogs and people walking down there.

white-tailed buck running away

And off they go, bounding out of sight, raising that white tail flag to indicate to the others that it’s time to flee.

why are cardinals so red? — continued

The proximate (immediate) answer to the question of why cardinals are red is that they have a diet rich in carotenoid pigments (e.g., the pigment that makes carrots orange), and will incorporate those pigments into their feathers as they develop each year during feather molt.  To read more about this process, click here to read an article from Bird Watching Daily that explains where feather colors come from.

northern cardinal

Resident Cardinal male posing on a garden stake in the backyard.  He’s bright and he’s loud, and he makes sure his mate and all the other would-be holders of his territory know it.

But I’m interested in the evolutionary basis for why cardinals stand out among other species residing year-round in northern climates in retaining their bright red coloration instead of molting to more muted shades during the non-breeding season, like, for example American Goldfinches do.   Cardinals undergo a post-breeding feather molt, just like other species, so why risk attracting predators with bright red, when you might escape notice with a dull brown plumage instead?

summer vs winter American Goldfinch plumage

Summer (top) vs winter (bottom) American Goldfinch plumage

Does sexual selection (that is, female choice for the most beautiful male, as Richard Prum argues) play a role?  Please see the yesterday’s Back Yard Biology post for more information about the importance of beauty in female choice.)

Some additional facts regarding male-female relationships in Cardinals and their close relatives, the Pyrrhuloxias of the southwestern U.S., might help to answer the question.

Cardinal vs Pyrrhuloxia--DFW Urban Wildlife

A comparison of two closely related Cardinal species, the Pyrrhuloxia, Cardinalis sinuatus (1 and 2) and the Northern Cardinal, Cardinalis cardinalis (3 and 4). Illustration in Chris Jackson’s DFW Urban Wildlife blog.

The first thing you notice from the illustration above is that the Pyrrhuloxia male and female look more alike than Northern Cardinal male and his mate do.  Why might that difference have arisen in such closely related species? And does it have anything to do with female choice for brightly colored, beautiful males?

The second and interesting difference between the two species is that Pyrrhuloxia share a pair bond only during the breeding season, breaking up in the non-breeding season into loose, often mixed-species flocks of seed-eating birds that move around to find food in their dry, desert habitat.  Each year, males vie for available females by staking out and advertising their territories, often very aggressively.  In contrast, Northern Cardinals may maintain their pair bond year-round, often for multiple years, unless one of the pair dies, and the pair stays in the same general area in which they nested, year-round.

cardinal courtship feeding-rudiger merz

A year-round pair bond exists in Northern Cardinal mates, which renews its strength in the spring with courtship feeding.  (Photo by Rudiger Merz)

Female Cardinals are making a choice of more than just a breeding partner; they may be choosing a life partner and his residence (territory).  Richard Prum might argue: what’s a male to do, but be the most beautiful thing she has ever seen?  And if he is better looking than his neighbors, she stays with him through that year and the next.  They raise multiple broods of young Cardinals together, and he passes on his good looks to the next generations.


This is an amazing high definition video of male and female Cardinals feeding their chicks (by FrontYardVideo).

In other words, it’s possible that their long-term pair bond and high fidelity to a territory year-round makes it possible for choosy female Cardinals to drive the accentuation of  beauty (in this case, “redness”) in their male partners, to the extreme that male Cardinals never lose their red color during the year.

let sleeping foxes lie

Morning coffee in hand, I ventured out to a somewhat chilly “sunroom” porch this morning and found a red fox sleeping nearby.

red fox-sleeping in snow

Morning light hasn’t made it to the backyard yet, and the thermometer on the backdoor says -10 F.

So I sat, camera in hand, and waited for the fox to wake up — for an hour and a half.  It was a long nap, perhaps needed after a long night of hunting mice, or the like.  It got boring watching the fox nap, so I opened the window for a close-up, clearer telephoto shot.

red fox-sleeping in snow

Curled up, fur fluffed up, nose tucked under tail for protection — the fox is quite comfortable at this frigid temperature.  This seems to be the typical posture of canids (dogs) sleeping in the cold.

artic fox sleeping-curious expeditions.flickr

An arctic fox sleeping in a similar position (Curious Expeditions on Flickr photostream).  Note the nice pocket of insulating snow the animal has created around it.  Arctic Fox can tolerate temperature extremes of -70 F without shivering.

wolf sleeping-Jeffrey Lepore-Science Source

A gray wolf using the same heat conservative posture while sleeping in snow (photo by Jeffrey Lepore/Science Source)

red fox-

Finally awake, now that the temperature is all the way up to O F. It must be time to get on with the day’s activities.

red fox-eating snow

First on the agenda, eat some snow — replenish some body water lost in the nightly adventure.  I could see the fox biting chunks, chewing, and licking the edges of its sleeping area.

red fox-eating snow

Licking the moisture off its muzzle

red fox-

Stretching — this is a signal that the fox will either lie down for another nap, or take off in a few minutes.

red fox-

Yawn — wow, that is a huge gape between its jaws, big enough to bite something pretty chunky. Too bad the woodchucks are hibernating.

red fox-

Looking over at me, as I tap on the window, wishing the window were open instead of closed, so I could get a better photo.

red fox-stretching

A final stretch out, and the fox is off to make its rounds of the backyard.

red fox