big bruiser in the backyard

This guy is big! The biggest one I think I have seen near my backyard, anyway. He calmly strolled onto the neighbor’s lawn about 20 feet from their house, and plopped himself down on the lawn for a morning rest.

buck with big antlers-

The photo doesn’t do justice to his size and girth, but it’s obvious he has a pretty massive neck.

Not only are there multiple tines in his rack, but some are quite broad, meaning this guy took in a good measure of protein and minerals (e.g., calcium) in his summer diet while those antlers were developing.  Maybe he discovered a nice vegetable plot with peas and beans, or a stash of acorns.

buck with big antlers-

You would need to develop those neck muscles just to hold up the weight of those antlers.

Males need a high protein (as much as 16% protein in younger animals), mineral-rich diet not just to grow antlers but to develop the protein and fat stores that will carry them through the energy-intensive rut season and the remainder of the winter.   How much leafy green stuff would they have to chow down each day to take in that much protein?

That’s a trick question, because the protein they absorb doesn’t come directly from their food, but from the microbial fermentation products, and from digesting the microbes themselves, that deer and other ruminant herbivores raise in their complex, four-compartment stomachs.  So, the better they feed their microbial friends, the more nutrients the microbes pass onto their deer hosts.

buck with big antlers-

He looks like a champion contender, doesn’t he, ready to take on the competition?

Males might lose as much as 30% of their body mass during the rut, depending on the level of competition and number of competitors they face, so gaining as much mass as possible during the summer is integral to their success and their survival.

I know I’m doing my part to sustain these guys, judging from the number of perennials in my garden that get munched down to their roots every summer.

losing their spots

Signs of fall are beginning to appear as a few maple trees show some red and gold color in their leaves, the squirrels are busy collecting nuts off the trees, Canada Geese fly in V-formation overhead, and a few of the wildlife start growing their winter coats.  I first noticed the latter when the fawns suddenly appeared in the backyard without their spots.

White=tailed fawns-fall molt-

Just a trace of spots linger on the flanks of one of the twin fawns that have ravaged my wildflower garden all summer long.

White-tailed fawn - winter molt

The tawny brown coat with white spots is slowly being overgrown by the longer gray brown winter fur, which provides the deer with much needed insulation to survive the cold.

White-tailed fawns - winter molt

Not all of the fawns have started growing their winter coat, though.  It’s interesting that in these twins, one is clearly well ahead of the other in development of the winter fur — which lends further proof to the observation that twin fawns are usually fraternal, not identical.

What this tells me is that there have been at least two sets of twin fawns that have been eating up the backyard garden — and I thought it was just one hungry pair that had been doing all the damage.

Double trouble

The deer really like my backyard:  they eat my plants, they bed down in the wildflower garden leaving big depressions in the vegetation, they rest right under the bird feeder, and believe it or not, the half-grown fawns chase the foxes right out of the yard.  But I enjoy watching them parade through, so I just keep replanting the garden.

white-tailed fawns-

Make yourself comfortable…

white-tailed fawn-

By all means, help yourself to the garden perennials. This shrub rose may not recover, but oh well…

white-tailed fawns-

Yes, please do eat the buckthorn. I didn’t want that to spread in the backyard.

And where do these two learn where the best places to forage are?

white-tailed doe

From mom and dad, of course.

white-tailed buck-

This one has developed a taste for hostas.

Old friends in new places

Cave Creek ranch in the Chiricahua mountains near the New Mexico border is an idyllic haven for birders and hikers.  The scenery is pretty incredible too.

Cave creek near Portal, AZ

The view from my porch looks out over the creek and up into the rocks.

Cave creek near Portal, AZ

We’re set for an early morning hike up Cave Creek, to see if we can find some new birds we haven’t seen before.

Cave creek near Portal, AZ

Like the creek in Madera Canyon, sycamores line the banks of Cave Creek, stretching their limbs far and wide to create wonderful shade.

Sycamores can grow to be giants, but occasionally a limb snaps off, and we find animals taking advantage of the nook created by the amputated limb.

Great Horned Owl

This Great Horned Owl created a nest cavity in one of the huge clefts left after a limb dropped.  We also found a western Screech Owl seeking refuge during the daytime in a similar cavity in another sycamore.

Desert animals are often pale in comparison to others of their kind in other climates, as this Great Horned Owl is.  But there is more to the story than just differences in color.

Animals in this part of the U.S. seem to be entirely different geographic races of their parent species, and the extent of differences in their DNA, their color, their song, and their behavior have led scientists to begin splitting the southwestern desert species off from their representatives in other parts of the U.S. and Mexico.  That’s great for birders that like adding species to their life lists!

Coue's white-tailed deer

The white-tailed deer are much smaller than their relatives in my backyard in MN. In fact, they are technically known as Coue’s white-tailed deer, a dwarfed race, or is it a different species?

Hairy woodpecker, Cave Creek, AZ

Here’s a familiar bird, a male Hairy Woodpecker, but it looks quite different from the MN variety, as it lacks the spots on the wings, and has a broad white stripe down its back.  Would a MN female Hairy Woodpecker refuse to mate with this bird?  If so, then they would be considered separate species.

Brown Creeper, Cave Creek, AZ

Brown Creepers have been divided into four groups now, one in Mexico, and three others in the U.S. divided into eastern, Rocky Mt, and Pacific races.  Differences in song and plumage have been known for some time, but recent DNA analysis has confirmed the separations.

We met some new friends along the Cave Creek trail, but apparently our “old friends” may be new as well.

Feeling frisky

A light snow yesterday morning brought the local deer herd by the backyard to clean up all the spills under the bird feeders.  First, a small group of does wandered through the yard, and then a couple of young bucks, who were too cool to feed on fallen bird seed but felt frisky enough to put on a shoving match instead.

deer-butting-heads

“Big brother” shoved “little brother” (no doubt they are completely unrelated) several feet, repeatedly bumping heads.

deer-butting-heads-

Kind of unfair that one young buck has antlers and the other doesn’t in this shoving match. But ouch, this looks like a good way to get your eye poked by an antler tip.

deer-butting-heads-

Junior has had enough of this.

deer-butting-heads-

Completely disinterested in each other now, they went their separate ways. It must be lonely being a young buck in the winter… nobody to hang out with.

resting in the backyard

Back in Minnesota once again, I looked out my porch windows and found three deer resting on the neighbor’s lawn.  I assume this is the same doe and twin fawns that I saw perusing the flower beds in the backyard before I left town in August.

doe-and-fawns

My presence alerted the doe, but all three were resting comfortably in the shade when I first spied them, chewing their cud and digesting their morning repast.

early fall white-tailed deer fawn

This is notch-ear — observed earlier this summer. The fawns have now molted out of their spotted coat and acquired the mature tawny hair color.  This youngster seems a bit muddy on the nose and forehead.

early fall fawn

Its sibling couldn’t care less that I’m 100 yards away clicking the camera shutter.  I think I can see little antler buds on its forehead, making this a male-female pair of fawns.

whitetail fawns-

A month ago ( see post on lazy summer days) they looked like this.  Note, the notch-eared fawn on the right.  

white-tailed deer doe

The doe looks over at her twins as if to say, “Rest time is over; time to get out of here.”

lazy summer days

What do you do on a hot, summer day when soft, grassy lawns and the sweet aroma of wildflower blooms beckon?  It calls for a short nap in the grass, I guess, even for wildlife, and the backyard was the perfect place yesterday.

whitetail fawns-

A pair of fawns wandered by, one of whom decided on a short rest while munching on fallen leaves.

whitetail fawns-

Still spotted, although they’re now half the size of their mom.  The left ear of the fawn standing has a torn notch — perhaps it had an encounter with a predator early in life.

whitetail doe-

Mom watched me warily from the woods, as I snuck up on her darlings.

red fox kit-

A little later a red fox kit wandered by, checking out the squirrels at the bird feeder.

red fox kit-

And then settled down for a little rest near the wildflower garden while still watching those squirrels.

red fox kit-

Resting in the shade on a hot summer day…that’s the life.

“here’s looking at you”

With huge, globular eyes that make up about 50% of their head, dragonflies are amazing visual predators.

dragonfly eyes

A sampling of beautiful dragonfly eyes from a Google search

And those eyes are key to their success as highly visual predators.

halloween pennant-8111

Halloween Pennant dragonflies search from the tips of the highest plants in grassy fields, with their orange-banded wings fluttering in the breeze.

In fact, they are probably the most efficient predators in the animal kingdom, with an astounding 95% success rate per attempt.  In comparison, lions are lucky to succeed once every four to five tries and great white sharks only manage to catch what they are after half the time.  How do dragonflies do it?

Here's looking at you...

Here’s looking at you… the facial disk of the Horned Clubtail.  Depending on the angle of incoming light (and observer position), the eyes might look turquoise blue.

Enough clues? The eyes and more particularly, the wiring of retinal cells to the brain is key to their hunting success.

The eyes and more particularly, the wiring of retinal cells to the brain, is key to their hunting success.

Those giant optical domes on the top of their heads give them a 360 degree view, and contain as many as 30,000 optical units (ommatidia), each with a complement of photopigments that can process images separately.  Thus, instead of one retinal focusing area, they have thousands.

The eye of a dragonfly, showing the individual facets or ommatidia that contain visual pigments. Each facet can detect and send an image to the insect's brain. Imagine having 30,000 eyes!

The eye of a dragonfly, showing the individual facets or ommatidia that contain visual pigments. Each facet can detect and send an image to the insect’s brain. Imagine having 30,000 eyes! From Science Blogs, July 8, 2009.

In addition, where human eyes have three photo pigments, dragonflies have 15-30 pigments that can detect light in ranges beyond human capability, including detection of polarized light.  What if we could see images in UV or infra-red, or whatever other spectral wavelengths dragonflies can resolve?

A newly emerged male Common Whitetail has the wing markings of a male and the abdominal coloration of the female. Over the course of the next week, he will gradually transform to the powder-white abdomen typical of males.

A newly emerged male Common Whitetail has the wing markings of a male and the abdominal coloration of the female. Over the course of the next week, he will gradually transform to the powder-white abdomen typical of males.

Photopigments sensitive to blue and UV light are concentrated in the upper part of the compound eye, so that prey (or predators) above them stand out against a perceived white background.  Pigments sensitive to longer wavelengths (green, yellow, red) are concentrated in the lower part of the compound eye and allow prey flitting below the dragonfly in dense vegetation to be detected.

This Dot-tailed Whiteface continually moved its head up and down as it scanned for prey. Each time I tried to get in front of it to photograph its white face, it flew away.

This Dot-tailed Whiteface continually moved its head up and down as it scanned for prey. Each time I tried to get in front of it to photograph its white face, it flew away.

In addition to their heightened visual sensitivity and acuity, dragonflies exhibit single-object tracking, which means they keep a particular prey item exactly on a collision course with themselves. (Kind of sounds like a drone, doesn’t it?)

And that’s where the fancy flying comes in handy. To keep the image of the prey in exactly the same place in their visual field, a dragonfly might fly up, down, sideways, backwards, even upside down, if needed. Four wings that can move independently facilitate this maneuverability, and in fact, they don’t even need all four.

This female 12-spotted Skimmer has lost half of its hind wing, but it's doubtful that it comprises hunting success.

This female 12-spotted Skimmer has lost half of its left hind wing, but it’s doubtful that it comprises hunting success.

These amazing little machines have been around for several hundred million years, feasting on slower flying, less visually talented prey.  Such a visual formula for hunting success ensures that they will be around for a while, keeping those pesky mosquitoes in check.

[This is an edited version of a previous post from Backyard Biology]

Lost and found

The local deer herd wanders through the back yard several times a week.  There are three bucks of different sizes, all of which still have their antlers, and six good-sized does.  With one exception, they all seem to have come through the winter looking very healthy.  The exception looks a bit skinny and has a mangy coat — but will probably survive, since winter seems to have given up its hold here.

white-tailed deer bucks-

The two largest bucks seem to get along well, and I often seen them together, browsing or dozing in the sun. The bigger of the two (on the left) has a bigger rack and seems a bit beefier, or perhaps just didn’t lose as much weight over the winter as the other buck (in back).

This might be the same pair I observed hanging around together last December. They did some friendly sparring, but usually were quite docile around each other.

white-tailed deer bucks-

Big Buck does not like Little Buck however, and usually gives him a head butt or a threatening glance.

This is the time of year when bucks lose part or all of their antlers, as a zone of separation between their skull and the antler bone begins to break down and the connection is loosened.  The tangle of vegetation the deer wander through might be enough to dislodge a loosened antler, although I have never found any piece of an antler out in the part of the way backyard the deer inhabit.

white-tailed deer-

Does on high alert…as workmen (in yellow and orange) enter the far backyard to dredge out the ponds there.

The other day some workmen interrupted the deer herd’s exploration of my backyard, and the entire herd bolted.  Some ran up the hill toward the neighbor’s house, and one buck came galloping up toward my garage on a dead run headed for the front yard.  Now there is only a narrow three foot gap between the garage and some lilac bushes, but Mr. Buck must have negotiated the gap quickly because I didn’t even see him after his mad dash.  But look what he left behind.

white-tailed deer antler-

Either he hit the bushes or the side of the garage with his antler and it popped off.

white-tailed deer antler separation point-

A tiny spot of blood on the separation point of the antler, but it was obviously ready to be dropped.

white-tailed deer buck-

I’m guessing it might have been the medium-sized buck’s antler based on its size, but don’t know for sure.

white-tailed deer antler-

Your loss, Mr. Buck. But I think I’ll keep what I found.

Snow day

A “snow day” in Minnesota usually means kids get out of school, businesses close early, and we are warned to stay indoors until snow plows have made the roads manageable.  Although none of that happened, high winds and rapidly falling snow made it seem like much more of an emergency than it really was.  But the effect on the landscape was truly beautiful, as only heavy snowfall can be.  I gazed out my porch windows wishing some little animal would stop by and get framed in the puffy snowflakes that were accumulating on every surface.

Not more than 5 minutes later, the deer herd wandered into the yard, nosing around for fallen bird seed or scraps of months-old dead plants.  And this was the scene…

deer herd in the snow-

The deer seemed surprised that there was so much white stuff covering up the food. White splotches on the deer are the snowflakes closest to me as I shot the view through the porch window with my cell phone camera.

deer herd in the snow-

There is usually something to eat in the wildflower garden in the spring and summer, but not now.

deer herd in the snow-

Then it’s off to the neighbors yard to see if there is anything good to eat over there.

And that will be the last of snowy scenes on this blog for a couple of weeks, while I’m traveling to warmer, greener, and more scenic spots in tropical climates.