Sunday, April 20, 2014

Real Ducks Don't Wear Swim Goggles

Hooded Merganser pair (c) John Ashley
Hooded Mergansers have special adaptations for sharp vision above and below water 

Ever opened your eyes underwater? Of course you have. Doesn't work so well for us terrestrial types, does it? But what about aquatic animals like fish or even semi-aquatic ducks? How can they see underwater without wearing goggles?

Can I clear up the fuzziness in a few words? Probably not.

Eye diagram (c) National Eye Institute
Land-lubber eye diagram (courtesy NEI)
Modern animal eyes are quite a marvel. The whole complicated assembly evolved to serve one purpose - bending light. A combination of eye parts redirects light waves to converge on the fovea (Latin for "pit"), a small spot on the inner light-sensitive layer, the retina, lining the back wall. Half of all the optic nerves reporting from the eye to the brain originate from this pit, which has the highest density of color-sensitive cones and is responsible for sharp vision.

For the most part, our modern eyes use just two parts to bend light into focus, the cornea and lens. The cornea is that curved outer part that you rub when sleepy. Behind the corneal cover and iris opening (the pupil), sits a clear and flexible lens that gets mushed about by tiny muscles, changing shape to bend light into different magnifications. Changing the eye's magnification power is just another way of saying that you are changing your focus between near and far.

In land animals, our curved cornea accounts for a whopping two-thirds of the eye's ability to focus light (called "accommodation"). It works mostly because light changes speed when moving through different mediums, faster through air in front of the cornea but slower through our liquid eyeball. This bends the light rays in towards the lens.

For us mere humans, our eyes working above water have about 40 diopters of optical power. (One diopter means the lens can focus at 1 meter, or 39 inches. Two diopters focuses at one-half a meter, and so on. More diopters equals more magnification power.) A young person can reshape their lenses to gain an additional 20 diopters. But this drops to 10 extra diopters by age 25 and fades to only about 1 extra diopter by age 50. Thus, the reading glasses I'm currently wearing and the extra diopters I keep adding to my camera's viewfinder.

Fine. But what about underwater?

Our land-lubber eyes are mostly filled with liquid, so when we open our eyes in water, the light is moving from water into a similar liquid (with a similar refraction rate), and this effectively removes our corneas from the equation. Limited to just the lens, our land eyes can only manage to focus incoming light behind our pits. The result is fuzzy fish - and perhaps the inspiration for those fur-bearing trout in Iceberg Lake.

So how do aquatic animals see? Well, it depends. We used to think that animals with clear nictitating membranes (a retractable, lubricating outer layer) used them like goggles whenever underwater. That theory was quickly dispatched, but several different solutions would eventually come to light.

Westslope cutthroat trout (c) John Ashley
Westslope cutthroat trout
Fish have corneas to protect and contain their eyes, but these don't really help with clear vision. However, most fish have convex (bulging outward), almost round, lenses with an internal density gradient. This gradient allows fish eyes to bend light inside the lens itself instead of just at the lens surface.

But some fish also spend parts of their lives out of water. Some of these semi-terrestrial fish have an extra chamber behind the cornea, which allows them to still see well when the focal point is projected beyond the primary cornea, when these fish moves between air and water. The famous four-eyed fish has hourglass-shaped pupils, with the top half of the retinea adapted to seeing in air and the lower half adapted for seeing in water - It can see above and below at the same time! Unfortunately, the nearest of these cool species lives in South America.

Other fish and some birds, like penguins and albatross, have a flattened cornea, so the small amount of optical power lost by the cornea underwater is still within the focusing ability of their lenses. Other diving birds that chase fish underwater arrived at yet another answer. Some of the duck species here at the lake can see clearly in air (flight, landing, predator avoidance, etc.) and also underwater when in pursuit of pursue fish. Goldeneyes and Hooded Mergansers fall into this fish-eater category.

Remember those tiny muscles that reshape the lenses? Well, they're not so tiny in fish-eating bird species. These birds use their comparatively-larger eye muscles to squeeze their lenses into the opening (the pupil) formed by the colorful, constricted iris. By squeezing lens against iris, the lens distorts enough to become close-focusing. With these super-deformable lenses, diving ducks can immediately compensate for corneas - so valuable above water - that become useless underwater.

So diving ducks have sharp vision above and below water? Well, yes and no. According to one research team, these ducks don't switch over to their "underwater eyes" until they get close to something of interest (usually a fish), within about a bill's length away.

Like me, diving ducks appear to have brief flashes of clarity sandwiched between longer periods of fuzziness. Otherwise, I could have cleared this up in half as many words.

Friday, April 18, 2014

Hang Ten

sunning turtle (c) John Ashley
It's official. We briefly cleared a sunny 60F degrees this afternoon before the clouds and rain moved back in. And the first turtle of 2014 emerged from the lake bottom mud to do a little basking in the sun. The surface ice broke up about a week later than last spring, so the water temperature is finally starting to rise. Another week or two of warm-ish days, and the arctic grayling will move into the stream and start spawing. Summer is on its way.

Wednesday, April 16, 2014

Montana Eagle and Osprey Cams

Still image from Miles City Bald Eagle cam
4/21/14 UPDATE: We have a baby Bald Eagle this morning! Either someone reported the wrong egg-laying date, or the eagles have learned how to use a microwave for incubation. While the chick is young, watch for frequent feeding bouts, as they can't eat much at one time - yet.

A pair of Bald Eagles nesting in Miles City, in eastern Montana, laid their second egg about one week ago. The two adults will take turns keeping the eggs at a constant 99.5F degrees for approximately 35 days. Incubating eagles also roll their eggs over about every two hours. If the eggs make it, there should be chicks in the nest starting around May 12th. You can follow their progress on a live eagle cam here.

More eagle cams can be found here and here. Eagle information here.

The Osprey have returned to their Montana nests as well. Iris has returned to her Missoula nest (webcam here), and Ozzie and Harriet are back in their Lolo nest (webcam here).

Tuesday, April 15, 2014

Orange Eclipse Across a "Pink" Full Moon

April 2014 lunar eclipse (c) John Ashley
Lunar eclipse of April 2014, photographed left to right at 16-minute intervals.
In the wee hours this morning, the sun, moon and Earth all lined up like school children. Because Earth was in the middle of the line, the sun cast Earth's shadow across the moon - an orange lunar eclipse of April's "pink" full moon. Pink refers to wild ground phlox, which is the first spring wildflower to bloom somewhere (though no one ever specifies where).

This composite photo shows the eclipse progression in paired images made at approximately 16-minute intervals, starting from the left. The familiar full moon (left and right bookends) glows before and after the eclipse. After the eclipse begins, you can either expose the camera for either the sunny (upper left) or the shadowed (lower left) side of the moon. Halfway through, the totally eclipsed moon is a lovely shade of orange (center). On the right, the shadow images are above the sunny images. If you combine any pair, you would get a complete and detailed moon image. To my brain, all of this makes more sense visually than verbally. (To other brains, maybe not so much.)

The orange color during the eclipse comes from sunlight passing through Earth's stratosphere, where it gets scattered and reddened. Sunlight passing through the Earth's upper stratosphere, the ozone layer, absorbs red and passes turquoise-colored light on to the lower edge of the eclipsed moon; some cameras recorded a turquoise edge, but this color wasn't visible from northwestern Montana. (There's a lot more science to it. See here.) Also, this eclipse really wasn't a so-called "Blood Moon" because the upper atmosphere is currently clear, lacking in volcanic ash particles that would have darkened the Earth's shadow to red.

If you close your eyes and imagine you are standing on the moon during the eclipse, Earth would be surrounded by a ring of sunlight. Half of that light is sunset and half is sunrise, all at the same time. An unmanned NASA moon probe, Surveyor III, actually photographed this "ring of fire" during an eclipse (lunar from the Earth's viewpoint, solar from the moon's vantage) in April, 1967.

Today's event was the first of four eclipses this year, three of which are visible from Montana. October 8th will bring another total lunar eclipse to the Pacific Northwest, while October 23rd brings a partial solar eclipse to the western U.S.

NASA Eclipse Web Site

Saturday, April 12, 2014

Eagles on Ice

A young Bald Eagle (right) harasses an adult that was trying hard to eat a fish.
The surface ice that's covered our lake all winter finally blew off this week, here at the end of the road. High winds and rising temperatures were more than the rotting ice could withstand, and it all broke apart over two afternoons (time-lapse video below).

One one side of the lake, our white-headed neighbors have been refurbishing their nest for a couple of cold and snowy weeks now. When the first cracks appeared in the ice, one the eagles flew out, plucked a fish from the narrow lead, and landed on the lake ice nearby. No doubt hungry, he had just set about tearing the fish apart when a young, sub-adult eagle landed a few meters away.

Now we had a stand-off.

Whenever the adult turned his attention to lunch, the younger eagle would feign a mild bluff charge. Sometimes this just meant jumping a few steps towards the adult. Other times the youngster would fly at and over the adult. After 15-20 minutes of intermingled stare downs, feeding bouts and food mantling (covering the fish with spread wings), the adult gave up and flew off to his nest. The youngster quickly hopped over to eat what was left of the fish.

What intrigued me about the young bird's behavior was how it resembled the Bald Eagles' duck hunting technique in spring. When there are large rafts of tightly-grouped ducks - especially Coots - the Bald Eagles make frequent flights over the nervous ducks. (I know, Coots are rails not ducks, but stick with me here.) Eagles fly towards these rafts at a moderate speed and altitude, just low enough to make the ducks skitter in a semi-mild panic.

The eagles are essentially shuffling the deck, looking for the odd duck that does not move like the rest. Most of the time, the ducks just skitter off a ways and the eagle returns to a tree branch, still hungry. The eagle spent very little energy in the effort. But every now and again the shuffle allows an eagle to spot a weak or injured duck, and the chase begins for real. Now the eagle focuses intense efforts on the odd duck, and he stooping in fast and low. If he misses the first time, he'll keep circling and stooping until succeeding or giving up.

The eagle's high-energy efforts were saved for the duck that stood a better chance of becoming lunch. Until then, he just made low-energy bluff charges. Efficient behaviors are well-honed in wild animals, and inefficient animals are soon removed from the gene pool - guess it's a good thing that I'm somewhat domesticated instead.

Tuesday, April 8, 2014

Butterflies Before Wildflowers?

We finally cracked 60 degrees here at the end of the road, and the warm sunshine was irresistible. Yesterday, our spring butterflies turned out en masse for the first time this year.

Fifteen or twenty flitted about as only butterflies can, taking turns basking and puddling in our muddy driveway. But they only stayed for one sunny hour in the middle of the day. For now, the only butterflies we'll see during the warmest parts of these spring days are those species that overwinter as adults. Various other butterfly species overwinter as eggs, caterpillars or chrysalises, so we won't see them as fancy-flying adults until summer.

Why show up so early? Our driveway still harbors piles of crusty snow in the shady corners. The only wildflowers up so far are little buttercups, and I've never seen a butterfly feeding on them. As you may have noticed, not all butterflies feed on flower nectar. In fact, our spring butterflies rely mostly on tree sap and that insect super-food, animal dung. A nice pile of that is just the ticket after a long hibernation - the fresher the better.

Mourning Cloak butterflies (c) John Ashley
Two adult Mourning Cloak butterflies basking in the sun
Yesterday's largest and shyest visitors wore the chocolate-brown wings of our state butterfly, the Mourning Cloak (Nymphalis antiopa). They're one of the most common butterfly species in the U.S., including all across Montana. Mourning Cloaks typically overwinter in tree crevices, and a sunny day can bring them out to fly in the middle of winter.

One of them (top left) looked a little worse for the wear, missing quite a few wing scales, which isn't unusual considering that he emerged from his chrysalis last July and is now an elderly eight months old. Shortly after emerging, the young guys rested through last summer's heat (estivation) before flying again last fall, feeding and storing energy for their torpor through the winter (hibernation). By last October they were hunkered down for the winter, just like us, waiting for this week to arrive. Now that it's finally spring-like again, these adults will fly, feed and mate, and females will lay their eggs between now and May.

Compton Tortoiseshell butterflies (c) John Ashley
Adult Compton Tortoiseshell butterfly
One medium-size butterfly also paid us a visit yesterday. The boreal Compton Tortoiseshell (Nymphalis vau-album) is a butterfly of southern Canada and northern U.S., including the northwestern corner of Montana.

He's also eight months old, but he remained active throughout last summer and fall before hibernating in November. Between now and June, the adults will mate and lay eggs that will hatch into a month-long caterpillar phase. Then each caterpillar literally melts inside a chrysalis and, like magic, fresh adults will emerge in July.

Green Comma butterflies (c) John Ashley
Adult Green Comma butterfly, also called the Green Anglewing
Flitting around these larger butterflies was a "flutter" of 10-15 smaller Green Commas (Polygonia faunus), which some folks know as Green Anglewings. Their wing scales use the same color pallet as the Tortoiseshell, but the outer wing margins are more deeply scalloped.

These guys are more easy-going than the other two species - a couple even landed on me - and they will eventually add nectar to their diet when the summer wildflowers finally arrive. But for now their menu is provided entirely by animals, in the form of dung and carrion.

The arrival of spring butterflies makes winter seem like maybe it wasn't so bad after all. Their reappearance also marks the start of a different season that you, like me, have no doubt been waiting for all winter. That's right, moth season is back!

Saturday, March 29, 2014

The Ides of March

Harlequin Duck courtship flock (c) John Ashley
A courtship flock (6 males 1 female) of Harlequin Ducks flies over the Straights of Georgia in British Columbia
March, 44 B.C.

Roughly two thousand years ago, a soothsayer warned the Roman Emperor to beware the ides, or middle days, of March. While travelling to the Theatre of Pompey in mid-March, the soon-to-be-assassinated Julius Caesar joked that, "The ides of March have come," and the emperor was still very much alive. He dismissed the ominous warning. The soothsayer looked him in the eye and replied, "Aye, Caesar, but not gone."

March, 25 years ago.

In mid-March, the Exxon Valdez lay bleeding on Bligh Reef. The ship's radar had been disabled more than a year earlier, dismissed as unneeded and too expensive to repair. A disputed 11 or maybe 32 million gallons of poisonous crude oil slowly smothered 1,300 miles of wild Alaskan coastline and 11,000 square miles of Prince William Sound. Many of the local fishermen began a slow, painful trek towards bankruptcy, divorce, depression. The mayor of Cordova committed suicide. Soon, 22 orcas, 247 Bald Eagles, 2,800 sea otters and more than 250,000 seabirds would also pass.

March, 15 years ago.

Ten years after Valdez, I'm crouching over white-washed stones on a wilderness beach in Prince William Sound on a perfectly calm, blue-sky morning. Unusual weather for these parts. Prying at the wet rocks just above tide line, I'm looking for the greasy-blue sheen and gas-station stench that would allow me to damn an entire industry, again. But I don't find anything on the surface.

Aboard the Discovery in Prince William Sound
Nothing is where I expect it to be. No noticeable petrochemical residue or odor. But neither can I find any scampering crabs or little isopods or amphipods hiding in the rocks. I scan across what looks like a pretty little beach but, down on hands and knees, it appears to be perfectly sterile. I splash back into a Zodiac with four other biologists and motor back to the Discovery, our research ship and temporary home. Time to get back to work.

We didn't come all this way to go beach combing. We're spending a week here in the Sound catching seaducks in open waters - Surf Scoters mostly, but also Harlequin Ducks. Every evening, a lady bush pilot deftly drops her seaplane into the salty water and idles up alongside our ship. We pass the Scoters over to her in pet crates, on their way to research facilities at the Alaska SeaLife Center in Seward and a date with a veterinarian. Some of them will soon carry transmitters that will feed Scoter migration secrets up to a satellite, then down to a cluttered computer screen back in Anchorage, manned by two USGS biologists. Good guys, the kind of people who want to do the right thing.

But for now, we're spending our nights tied off to the dock in Cordova harbor. Some evenings we walk uphill to the local pub for a greasy dinner and maybe a game of table-top hockey on a beautiful, sawdust-covered, maple table that runs almost the length of the bar. I'm afraid to try too hard against a big, burly local fellow. Who knows, he might be a depressed former fishermen. But to my amazement, he turns out to be surprisingly good-natured - and adaptable.

The researchers are flexible, too, and half of this crew is also monitoring these Harlequins. In the immediate aftermath of the spill, an estimated 1,044 to 1,838 Harlequin Ducks died in western Prince William Sound, coated in oil. Much of the oil would eventually pile up in the intertidal zone, where any surviving ducks would do most of their feeding - eating those crabs and critters that used to live there, and gorging on fish eggs that used to appear in spring.

Washed up herring in British Columbia
Every spring in Prince William Sound, and all up and down the north Pacific coast, the Harlequins congregate on localized herring spawns, eating fish eggs and putting on weight in preparation for migration and nesting. In this Sound, these herring used to account for half the annual commercial catch by Alaska fishermen. But while some of the larger fish species eventually rebounded, the small herring have never recovered.

Fortunately, the population of Harlequin Ducks in the western, oiled, half of Prince William Sound may have finally stabilized. But female survival is relatively low (compared to Harlequins in the un-oiled, eastern half), and there hasn't been any real population increase. There are places where Valdez oil still persists, hidden under six inches of intertidal sediments, and Harlequin Ducks continue to be exposed to the hydrocarbons through the food chain. Of course, pro-industry research claims otherwise. But according to my biologist friends - the ones actually out there on the Sound - oil exposure rates are slowly declining and the outlook for Harlequins here is "good." It's a start, anyway.

Herring roe at Cape Lazo (c) John Ashley
Herring roe on Cape Lazo, Hornby Island visible in the distant haze  
March, 2014.

Another beach, this one about 1,100 miles south and east. I've seen a lot of herring spawn over the years, but never like this pile. Squishing and squeaking under my boots is almost 12" of fish eggs piled up by the waves at Cape Lazo, a rocky point halfway up the east coast of Vancouver Island. But the spawn is two weeks old and this is just a small remnant.

Most of this 2014 spawn event took place further south, along select beaches of the two large islands that I can just see through the morning haze. I've been drawn to Denman and Hornby Islands since the early 1990's to watch Harlequins, who for countless generations have congregated to feed on this local herring spawn.

This is where most of our "Rocky Mountain Harlequins" live for the other 7-12 months each year. The Straights of Georgia (its official name) contains the protected waters between Vancouver Island and mainland British Columbia. Ducks from wintering areas northward and as far south as coastal Washington are drawn here each March, fattening up on fish eggs before flying eastward to nest on streams in British Columbia, Alberta and Montana.

For the past three summers, biologist friends in Glacier National Park have been catching and marking Harlequins with blue leg bands. Every band has a unique two-digit code, a way to identify and follow individual ducks over many years. When I was banding back in the 1990's, I managed to find more than a dozen of the banded Glacier Park Harlequins here on these islands during the herring spawn. I had high hopes for 2014.

But among tens of thousands of seabirds gathered for the spawn, I only found two blue-banded Harlequins. Unfortunately, they were both old guys from earlier projects. At the peak of the herring spawn, I couldn't find any of the 138 recently-banded Montana Harlequins. Where were they? I don't know. Did they come to feast on the spawn? Don't know for sure. Maybe I just missed them, but it appeared unlikely.

Harlequin Duck (c) John Ashley
Collecting a Harlequin back feather in Glacier Park
After we returned from the coast, I received another bit of confounding information. The Glacier researchers had clipped part of one small back feather from each Harlequin captured, and chemically analyzed these feathers for stress hormones. These were body feathers that were entirely grown on salt water, in the Straights of Georgia.

Four hundred miles east, on McDonald Creek, the female Harlequins that did not nest had, as a group, "significantly higher levels" of stress hormone (corticosterone) in their bloodstream during the 3-4 weeks that these feathers were grown, as compared to the nesting females.

In other words, it looks like something that is stressing Harlequins on their salt water wintering areas is also affecting their reproduction in the relative sanctuary of Glacier National Park - and possibly affecting Harlequin reproduction across Montana, Alberta and British Columbia.

These data are still being analyzed and will soon be reported to the rest of the world. For now, I can't help but think that it's an ominous sign. Could the source of stress be pollution, disturbance, food? I don't know. No one knows. I wonder about next March - and feel a knot twisting inside.

The work continues.

Harlequin Duck flock at Hornby Island (c) John Ashley
Harlequin Ducks await the falling tide to feed on herring spawn on exposed rocks. Hornby Island, March 2014.

Wednesday, March 5, 2014

Montana's Mule Deer

Officially at least, the status of Montana's mule deer population is listed as "stable," at roughly 220,000. The numbers are increasing in the central part of our state, stable to slightly decreasing in the west, but 20-32% below the long-term average in the east.

In 2013, Montana hunters harvested 6,803 mule deer does (females), far below the 20-24,000 annual take during 2007-09. They also shot 30,990 mule deer bucks last year (and more than 88,000 white-tailed deer). Still, Montana's muley population is well below the 10-year average of 286,000, and hunters are grumbling.

Mule deer buck (c) John AshleyTwo weeks ago, state wildlife managers gnashed their teeth, wrung their hands, and reduced mule deer quotas by eliminating antlerless (female) and "B" (additional male) tags in most of Montana's hunting districts for the next two years. The hipshot blame-game richocets around in letters-to-the-editor and in some hunting blogs, each writer blaming the drop in hunting tags on his own pet peeve - too many predators / hunters / houses, or deep winter snows and dry summer droughts.

They're all correct. Partially, anyway. But many of them the lack hindsight into what started these mule deer population swings in the first place. It all started, inadvertently, after we tried to remove fire from the landscape.

Montana's stable mule deer populations of the early-1800's were hunted to local extirpation in less than 50 years by a flood of well-armed Euro-american settlers. But this cultural sea-change also put into motion a series of events that soon drove mule deer populations to unprecedented high levels by the mid-1960's, only to have them crash again. What's going on here?

Mule deer are primarily browsers, and the availability of shrubby plants determines where they can survive, especially in winter. Big sagebrush is the single most important mule deer browse in the Missouri River Breaks, while bitterbrush and Rocky Mountain juniper are also critical in the Bridger Mountains. These taller shrubs are important, as snow depth and duration also play major roles in limiting mule deer populations. (Montana's herds took a "huge hit" during the harsh winter of 2010-11.) These large deer also need rough, broken terrain where their pogo running style, called "stoting," gives them an advantage over most predators (muleys can leap over obstacles that predators have to run around).

When the first settlers arrived to the Intermountain West (Montana, Idaho, Wyoming, Utah, Nevada) in the late 1700's and early 1800's, mule deer were scarce in some part of Montana and plentiful in others. Their natural range was limited to edge areas where forest and grasslands met, including some lightly-burned forested areas.

During the mid-1800's, hungry miners, ranchers and homesteaders took a heavy toll on populations of mule deer, elk and bighorn sheep. By 1900, the sight of a single one of these animals was considered "most unusual." But the mule deer populations eventually rebounded between the early 1930's and mid-1960's, for many reasons.

A new concept, conservation areas, helped protect mule deer from unregulated hunting, while predator control that began in 1914 also reduced deer mortality to a degree (though predators tend to remove the weakest individuals while hunters try to remove the healthiest ones). After the 1918 transplant of 6 mule deer from Yellowstone Nat. Park to augment the 13 surviving deer at the Nat. Bison Range, 1,829 more mule deer would be moved to various locations around Montana over the next 30 years. Overgrazing by domestic animals (cattle and sheep) in the 1920's greatly reduced grasses and forbs, leading to rangeland plant succession from grass dominance to shrub dominance. Then the livestock numbers fell dramatically across the plains during the Dust Bowl era of the 1930's, reducing livestock competition with native deer.

But overarching all of this, it is generally agreed that a change in fire frequency was the primary reason for the temporary mule deer population explosion during the mid-1900's. As a new culture swept over the existing one, fire was effectively removed from the landscape when Native Americans were forced onto reservations.

Frequent fires at low and mid-elevations kept Montana's plains and mountain valleys thick with grass while preventing encroachment by shrubs and trees. Sagebrush stands are largely dictated by the number of years since the last fire, with a fire interval of 20 years or less short enough to relegate this important mule deer food to isolated patches.

Central Montana mule deer herd (c) John AshleyIn central and eastern Montana, extensive grassland fires swept the plains every year until at least 1877. In western Montana, large forest fires only burned during exceptionally dry years (like 1889, when roughly 530 square miles were charred). One study found that 60 out of 145 low-elevation fires, from written accounts during the 1800's, were started by natives for forage enhancement, food gathering, warfare and communication. Grassland fires were also ignited by lightning and fur trappers, while prospectors started numerous fires in the mountains. In western forests, the ponderosa pine / Douglas fir stands in the Bitterroot Valley burned, on average, every 4-20 years. Higher and cooler forests in southeastern Montana burned, on average, every 20-40 years.

Post-1900, the exclusion of fire for 80-100 years led to tremendous expansions of big sagebrush into former grasslands, and bitterbrush expansions into some forests. New, large-scale logging also converted forests to shrubfields, which increased browse for mule deer. Side-by-side comparisons of range photographs that span 100 years or more show marked increases in trees and shrubs.

In the early stages of this plant succession, mule deer populations benefited as shrubs replaced grasses. Later stages of this succession, however, show that conifers are replacing important browse shrubs, and the decline in edge habitat and edible plants has caused mule deer populations to fall.

Nowadays forest fires no longer benefit mule deer as much as they used to, because modern fires are burning far hotter than ever before. After not allowing small fires for the past 100 years, our forests have reached the point where we can't put out every new start by noon the next day - as we used to boast. Fed by the heavy fuel loading, modern forest fires now scorch more underground roots and shoots, and sterilize the soil, which in turn reduces or even prevents the normally vigorous return of grass and shrub stages.

Modern-day wildlife managers are attempting to use hunters to hit an artificial target - an artificially high but stable mule deer population - that's being pushed in all directions by many different forces. Good luck with that. Meanwhile, thinning projects and prescribed fires can help mule deer and other native wildlife by slowly working the land back towards a more natural vegetative state - in Montana and all across the west.

Believe it or not, such work is happening on a small scale. One such conservation / hunting group, the Mule Deer Foundation, is currently working on thinning and burning projects near Miles City and Ashland, to go along with educational and noxious weed projects in various central and eastern Montana locations.

It's one thing to grumble about a problem. It's something else to roll up your sleeves and work at making it better.

Montana Mule Deer Foundation news
Mule Deer Working Group 2013 Status Report

For an eye-opening view from the mule deer's side of the equation, watch the new PBS video, "Touching the Wild." You'll never look at deer hunting the same way again.

Monday, February 3, 2014

Vega, A Rising Star Over Montana

The bright and occasional north star, Vega, sits low on the horizon and shimmers across a foggy
Lake McDonald between the dim winter Milky Way (left) and Comet Lovejoy (right). (Click to enlarge.)
On the rare cloudless night, thick blankets of stars warm our winter sky over western Montana - at least for those of us living beyond the shroud of city lights. And from lounging around summertime campfires we remember that the constellations seem to spin circles around the "north star," named Polaris, which though dim is still the brightest star in the Little Dipper constellation.

But Polaris isn't always our north star.

Polaris currently sits almost straight in line with the Earth's north-south axis of rotation. But the Earth isn't perfectly round, and gravity from the sun and moon pulls a little wobble into our spin. This wobble makes that imaginary point in the northern sky (the "north celestial pole") move in a giant circle lasting 25,765 years, a movement called the Earth's "precession." This means that over time the precession changes which star we perceive to be the north star. Several stars (and a whole lot of empty space) happen to fall along this circular path.

When a pinpoint of light arrives at the north celestial pole, and appears in the same place for many human generations, it is quite useful to the people living on this wobbly, spinning top. For our cave-dwelling ancestors 12,000 years ago, it was the bright star Vega that aligned as their north star. And in roughly 12,000 years from now, Vega will once again take its turn as our north star, passing within four degrees of the north celestial pole. Vega is more than twice as massive as our star, the Sun, and it is the second-brightest star visible from the northern hemisphere (after Arcturus).

The star we now know as Thuban served as the north star for the ancient engineers, who used Thuban to help them design and build Stonehenge and the Great Pyramids, roughly 4,000-2,700 years ago. Even though it's a dim star, Thuban sat precisely in the polar position in the year 2,787 B.C. And roughly 21,000 years from now, Thuban will once again reoccupy this prime spot in the night sky.

Our current navigational star, Polaris, is one of the dimmest stars that we can see with the naked eye. Polaris currently sits about 0.7 degrees off the celestial north pole, heading out on its long journey around the night sky. It'll complete its current lap in about 23,000 years. (Polaris is also the current pole star for Saturn, about 6 degrees off center.)

Down in the southern hemisphere, the south celestial pole currently falls in a dark region within the constellation Octans. The nearest stars are very faint, so the folks down under currently don't have a "south star." Just one more reason to spend a little time admiring the dark, star-lit skies over Montana, and anywhere else that the sky is still dark enough to contemplate the stars.

Saturday, January 4, 2014

Montana Six-plumed Moth

Montana Six-plumed Moth (Alucita montana) (c) John Ashley
The Montana six-plumed moth has a half-inch wingspan made of feathery plumes
Two years ago this week, I photographed an innocent little moth that was perched on a friend's back porch in southern Arizona. It was an ordinary brown moth, but it had the most incredible antennae that looked just like two small bird feathers. Those "quadripectinate" antennae were the perfume that lured me into the small but dedicated world of "moth-ers" and the vast universe of "mothing."

By comparison, birding is challenging because there are 914 bird species in North America, but our moths number more than 12,000 species! If you think our 35 similar-looking flycatcher species makes for a confusing clade, try separating 73 mostly-gray dagger moths. At least the 1,400 Geometrid moth species vary in color and shape. But behavior can also make mothing more difficult than birding because moths are mostly nocturnal, well-hidden through winter, and vastly harder to see even when they're active in summer.

And so it was two summers ago, back home in Montana, that I found myself crawling around the yard after midnight, wearing kneepads and a headlamp and dragging around a macro lens with ring flash. At dusk, I had spread a white thrift-store sheet over a wooden sawhorse and lit it on both sides with every kind of light bulb I could find around the house. Incandescent, halogen, and four compact fluorescent bulbs thrown in for good measure.

That night was my first whiff of National Moth Week. Around the world every year in July, citizen scientists set out to photograph as many moths as they can find, submitting their photos for experts to identify, which helps illuminate a little bit of the mysterious void that is moth natural history.

Moths occupy one of those overlooked areas that has a huge effect on our own success, in spite of us mostly sleeping through it. While bees and butterflies handle the daytime pollination of plants, it's bats and moths that take over the night shift. I recently read in "The End of Night" that, collectively, moths pollinate 80% of the world's plants. Valuable things happen while we're snoring.

Montana Six-plumed Moth (Alucita montana) (c) John Ashley
MT six-plumed moths are smaller than Lincoln's head!
So this August I was awake again for my second Moth Week, but this time I used black lights which were much more effective. The beautiful discoveries in my own driveway got me to wondering. Were the moths in some exotic place, like Glacier Park, even more amazing than my backyard species? Two nights later I was back out after midnight, trying to document the park's native moths.

Sure enough, my favorite moth from that night in Glacier was a small species I'd never noticed before. With a wingspan of less than half an inch, the Montana six-plumed moth (Alucita Montana) is no ordinary night flyer. Each of the moth's two forewings and two hindwings is divided into six plume-like branches. When spread out and overlapped, they effectively form a pair of intricate and amazing wings. I was lucky enough to photograph two individuals that night in Glacier.

A few nights later, I was surprised to find another Montana six-plumed moth perched on my garage wall. And then another. Two nights later, two more. Once I started looking, I would eventually realize that these little moths were consistent visitors almost every night for the rest of summer.

And it didn't end when summer turned to fall.

As temperatures dropped and the moths disappeared from our yard, one or two six-plumed moths moved indoors with us, into our kitchen. We began a nightly routine that started around 7PM, when one of these tiny moths would begin buzzing around me as I sat writing at my desk. Now, it appears that we live with a resident moth or two that I never bothered to notice two years ago.

One moth's feathery antennae pulled me into National Moth Week, which introduced me to many more amazing animals, including our Montana six-plumed moth. And though I'm still just a moth newby, the adventure continues to expand in different directions. A Ph.D. student from Fujian Agriculture and Forestry University in Fuzhou, China, contacted me for help finding Diamondback moths in Montana (I sent him to an expert). And earlier this week I was asked to collect certain moth species next summer as voucher specimens for the Lepidopterists' Society and two natural history museums.

Also this week, we found ourselves camping once again in the driveway of our friends' house in southern Arizona. As we piled into our camper for the night, a moth flew in towards our light and, SNAP!, our young border collie ate it.

Man, birders have it so easy.

Behind the lens: photographed with Nikon D800, 105mm 2.5 macro with extension tube and ring flash. And I haven't seen the issue yet, but the top photo is also in January's Montana Outdoors magazine. Score another one for Montana's charismatic micro-fauna.