morning at the marsh

It’s amazing how much you can see early in the morning before the cyclists and hikers have hit the trails around the local marsh.  And it always amazes me to find such a diversity of wildlife inhabiting a small wild oasis in the urban landscape! I’m sure if I had spent more time on this hot, humid morning, I would have seen even more.

floating island-

Dense mats of cattails float around the marsh propelled by the prevailing water flow.  They attract a wide variety of wildlife that may hunt from their edges, nest in their stalks, and hide within small crevices from the peeping eyes of photographers.

great blue heron-

Great Blue Herons are often found along the shoreline, usually obscured by the vegetation.

great blue heron-

Another heron was making its way down toward the shoreline — perhaps the mate of the other one?

great egret-

I can always count on seeing a Great Egret or two foraging near the edge of the marsh.

green heron-

What else is hiding here in this vegetation near the shore? A Green Heron pops up to see if I’m a dangerous predator.

green heron-

A less nervous juvenile Green Heron hunted in the shallows.

common loon-

Out in the water, a Common Loon swam by.

double crested cormorant-

Nearby, a double-crested Cormorant surfaced from its dive, and took a look around.

I spotted something white way out in the middle of the marsh, swimming quickly away from me, and grabbed a quick shot of a Trumpeter Swan family with their two, seemingly newly hatched, cygnets.

trumpeter swan family-

It’s a bit late to find these newly hatched chicks; perhaps the first nesting failed and these are result of a second nesting attempt. The chicks have a lot of growing to do before they reach the body size of the adults which can weigh more than 20 lb.

trumpeter swan family-

Photos I wish I had taken

I met a fellow nature photographer (Jim Radford) quite by accident at a marsh near both of our homes, and he has graciously shared some of his amazing photos with me.  I asked him if I could share some of them with my blog readers because they illustrate the subject of my last blog post (“red-necked swans“) so nicely.

trumpeter swan-Jim Radford

Trumpeter Swans showing the rusty head and neck from iron staining are quite common among the thousands of swans overwintering at Monticello, MN. Photo by Jim Radford

trumpeter swan--Jim Radford

Close-up of the iron staining on head feathers of a Trumpeter Swan.  This stain does not leach out, but will only disappear when the head feathers are molted.  Photo by Jim Radford

trumpeter swan--Jim Radford

A good view of the many colors of Trumpeter Swan plumage. Juvenile birds (hatch year) have gray plumage, which gradually turns into pure white by the spring of the next year after hatch. A few birds in this shot show light patches of rusty-colored feathers from iron staining.  Pristine white swan heads may be from birds with newly molted feathers, or birds may not have fed in streams or lakes with high iron-content water.  Photo by Jim Radford

trumpeter swan--Jim Radford

Is there anything more beautiful than the white on white of Trumpeter Swans flying overhead? Photo by Jim Radford

red-necked Swans

No, there is no such species as a Red-necked Swan, and no, they aren’t from rural hilltops in Appalachia — these are Trumpeter Swans that apparently have been feeding in water rich in iron salts which have become deposited in their white head and neck feathers.

trumpeter swans-

Although I was forced to shoot directly into the sun, which caused deep shadows on the birds, nevertheless the swans’ heads and necks are much darker than their bodies.

trumpeter swans-

Closer view shows up their rusty-colored heads and necks, with minor staining of their body behind the wings.

Way back in 1955, E.O. Hohn reported this discoloration of white feathers in a variety of waterfowl (e.g., Snow Geese, another all-white bird).  He was curious whether this was some aberrant pigmentation so he leached the feathers with a mild acid, which removed the color entirely.  He then tested the leaching solution for iron, which proved positive.

And there you have it — rusty-colored Trumpeter Swans marked by where they have been spending their winter in high iron-content water.

trumpeter swans-

You can see the rusty color better on the head of the bird who is preening, as the sun lights up its head.

NOTE added after posting:  Based on the amount of reddish-brown staining of neck feathers all the way down to the breast, I might speculate even further that these particular birds were feeding in deep, iron-rich waters, where they had to “tip-up” to feed (as shown below).

trumpeter swan tipping up

Alone again…un-naturally

trumpeter swan-reflection-

A lone swan resting on the ice in the early morning in a vast landscape of white looks forlorn by itself.

trumpeter swan-reflection-

I was able to stand directly across the inlet from the swan, and the bird seemed unperturbed by my presence, resting on its one leg.

Trumpeter Swans most often pair for life, but not until they are about 5-7 years old. Perhaps this is a young bird, or perhaps its mate has died — in any case, this lonely swan has been hanging out at the inlet to Sucker Lake in the Vadnais Heights reservoir system for the past couple of weeks. Pairs of Trumpeters come and go there, but there is always one lonely bird, perhaps this same one.

trumpeter swan-

On another day, a lone swan swam in the inlet with a few Mallards for company.

trumpeter-swans-on-the-mississippi-1

Too bad Lonely Swan doesn’t know there is a party going on about 50 miles up the Mississippi River at Monticello, where the Trumpeter Swans feast on corn handed out to them daily. 

For those music lovers in the crowd, the reference in the title of the post is to a hit song from the 70s — Alone Again, Naturally (by Gilbert O’Sullivan).

Trumpeter take-off

More scenes of flying birds from our Crex Meadows field trip last week-end: Trumpeter Swans on the move.

Crex Meadows-flowage

A typical scene at Crex Meadows wildlife refuge, near Grantsburg, Wisconsin — Trumpeter Swans on the far distant shore.

Crex Meadows is a 30,000 acre network of marshes, lakes, wet meadows, and intermittent oak forest, part of which is set aside as a refuge for waterfowl breeding in and migrating through the area.  It is a remnant of old Glacial Lake Grantsburg that covered this area more than 10,000 years ago.  A variety of bird species use it as a staging area for migration south, like the Sandhill Cranes featured in yesterday’s post.  Trumpeter Swans are usually in great abundance here as well, although we only saw about a dozen of them.

Trumpeter Swans-Crex Meadows-

Swans were feeding and preening themselves quietly in the shallows of the larger lakes. 

Trumpeter Swans-Crex Meadows

These birds seemed quite a bit more skittish than the swans that overwinter in areas of open water near the Twin Cities. But there were hunters in the nearby area shooting at ducks (hopefully not swans), so they might have been leery of human presence.

By size alone, Trumpeter Swans are the largest living species of waterfowl.  They are also one of the heaviest birds capable of flight, with big males weighing up to 30 pounds (14 kg).  Even with large wingspans of 6-8 ft (~ 2 meters), taking off from a horizontal surface takes some effort.  Consequently, swans typically flap their wings to lift their bodies out of the water and then propel themselves forward pushing their large webbed feet along the surface water — launching themselves into the air with a running take-off.

Trumpeter Swans-Crex Meadows-

Slow, deep wing flaps keep their heavy body airborne until they can cruise with the aid of wind.

Trumpeter Swans-Crex Meadows-

Swans fly with their necks outstretched, unlike the more streamlined profile of herons and egrets that tuck their long necks back in a S-curve.

Trumpeter Swans-Crex Meadows

It seems when a couple of swans get jumpy, the whole crew takes off. Not quite the classic V-formation but perhaps they were just hopping over to the next lake — away from us.

Fall scenery

The weather has been spectacular lately.  In fact, too nice for the trees to develop their maximum fall foliage color.  Warm days AND nights mean the color is less intense, develops very slowly and out of synchrony with other trees, and then leaves fall before the whole tree has even completed its color change.  Oh well, the scenery is still something to marvel at, as we slowly approach the dreaded winter deep freeze.

fall color reflections

Early morning light on this shallow bay created a picturesque reflection.

fall color

Green and orange-gold go well together in the fall.

hoverfly on heath aster

Late blooming asters continue to attract a few insects.

pink-edged sulfur butterfly on heath aster

Warm days bring out the bumblebees and the few remaining sulfur butterflies.

trumpeter swans

Trumpeter Swans are on the move; soon the ducks will be too.

Uck-weed

It’s real name is Duckweed – that scummy stuff that coats the surfaces of ponds and marshes and even the critters swimming around there.

mallards and wood ducks on a duckweed pond-

A mixed flock of Mallards and Wood Ducks floating on a pond of duckweed.

duckweed - Lemna species

From a distance, it just looks like scum covering the water surface.

duckweed - Lemna species-

Up close, it is only slightly more interesting. The “scum” is actually leaves of one or more species of Duckweed that float on the surface, attached to each other by slender threadlike filaments.

But it seems that Duckweed is highly nutritious and is even promoted as a supplementary feed for livestock.  Gram for gram it contains more protein than soybeans, and it grows incredibly fast — in fact, it is one of those species that exhibits exponential growth, doubling every so many hours.  With its high protein content (35-43%), low fat (5% poly-unsaturated fat), and low fiber content (5-15%), it is highly digestible, yielding more calories with less work.  Although it is regularly consumed in some cultures in southeast Asia, Duckweed is high in oxalates, which makes it potentially toxic to your kidneys, so it’s not high on my list of edibles.

duckweed-bioponicaDOTnet

From Off the Grid News: Feed your livestock AND your family with prolific, fast-growing Duckweed!  Use it instead of spinach in your salads…

Instead of eating it, Duckweed may prove valuable as a source of biofuels because it grows so fast, has so little fiber, and contains 5-6 times the amount of starch that corn does.

Duckweed is a primary food source for lots of wildlife, including Mallards, Wood Ducks, Canada Geese, Painted and Snapping Turtles (I thought they were carnivorous!), even Beaver. I’m going to add Trumpeter Swans to this list, because I saw them gobbling it up the other day.

Trumpeter Swans eating duckweed

A pair of Trumpeter Swans dabbling for duckweed on nearby Sucker Lake.

Trumpeter Swans eating duckweed

Strings of Duckweed dangle from their mouths as they gobble up their highly nutritious, protein-packed meal.

All in all, it seems that “Uck-weed” has a lot going for it, as a food source and a potential fuel source.  I’ll stop denigrating pond scum now.

the best of the rest (in 2014)

Landscapes — I wish I took more photos of the vastness of the beautiful landscapes I see. Sometimes they are so vast, I am at a loss as to quite how to best capture them. We spent a lot of time exploring prairies out in central Minnesota this past year, and so the top ten landscapes are mostly prairie shots.  But Minnesota is a transition zone between tall grass prairie and broadleaf forest, so there are a couple of forest shots as well.  The photos are arranged in chronological sequence of season (sort of), so this is a seasonal Minnesota perspective.

trumpeter swans at Monticello, MN

Sunrise on the frozen Mississippi River in Monticello, MN last February. The temperature was a balmy -22 F (-30 C). Water vapor from the open water rises like steam in this intensely cold air.

minnehaha falls, Minneapolis

The extreme cold of the 2014 polar vortex created some spectacular waterfalls, like this one on Minnehaha Creek in Minneapolis taken in March.

I couldn’t leave the next photo out, even though it’s not Minnesota.

Northern California foothills in April

We escaped the polar vortex with a short trip to northern California in April. The light at sunset created a beautiful pattern of green and deep gold.

old MN farm house-HDR-black-white

My favorite farm scene out in central Minnesota, taken with HDR and then converted to black and white.  Taken in May.

mississippi river in flood - downtown Minneapolis

Torrential rain in May and June caused flooding along the Mississippi and raised the water level flowing under the Stone Arch Bridge through Minneapolis.

glacial lakes state park, MN

All that rain in May and June filled the prairie potholes and created an intensely green prairie landscape in June and July.

butterflyweed on the MN prairie

Orange highlights from blooming Butterflyweed dotted the green prairie landscape in July.

northern minnesota mixed forest

We traveled up to the Northwoods in July to see the northern bogs and mixed forests there.

northern minnesota farm

Typical northern Minnesota landscape, flat with lots of puffy clouds, grain silos, and acres and acres of crops.

After a month of travel in Southern Africa, we came back to a spectacular show of fall color.

fall color on the mississippi

I could look at this scene all year.

And now it’s back to the monotonous colors of winter in the backyard.

snowfall-backyard

Happy New Year from the Minnesota Backyard.

Cold weather and one-legged birds

Do you find that ice cubes sometimes stick to your warm fingers as that slight moisture in your fingertips instantly freezes on contact with the ice surface?  So then, why don’t the webbed feet of ducks, geese, swans, gulls, etc. freeze to the ice?

mallard-hen

Standing with her bare webbed feet on snow and ice doesn’t faze this mallard hen. Why not?

A wonderful adaptation of the circulatory system in the legs, called a counter-current heat exchanger, warms the cold venous blood returning from the foot while it cools the arterial blood flowing to that site.  The “exchanger” is actually a network (rete) of arterial blood vessels wrapped around a central vein, and the counterflow between the two sets of blood vessels allows a steep gradient of temperature to be created between the body core and the webbed foot.

countercurrent-exchange-figure

With no heat exchange (left), the foot stays warm and loses heat to the ice. A warm web would also stick to the ice! With heat exchange (right), arterial blood going to the foot is gradually cooled by giving up its heat to the vein bringing blood back from the foot. Thus, with heat exchange, foot temperature is about the same temperature as the ice it is resting on. Voila! Less heat loss! [Figures from (Ask a Naturalist)]

This anatomical adaptation for reducing foot temperature has important implications for staying warm in cold weather.  Even with reduced blood flow to the legs, the bare areas of the foot and leg are potential sites of great heat loss in extreme cold weather.  So, the less leg and foot surface area exposed, the better.

Birds have perfected the one-legged stance of the yoga “tree pose” and adopt it frequently when temperatures dip, placing their center of mass directly over one leg and tucking exposed limbs into their plumage.

trumpeter swans resting on one leg

Trumpeter Swans maintain perfect balance, with their head tucked under a wing for additional protection from heat loss.

ring-billed gull eating fish

On first glance, you might think this was simply an unfortunate, one-legged Ring-billed Gull, But the “tree pose” is used in all activities — whether resting or eating.  

black-crowned-night-heron

At rest, long-legged herons and egrets often tuck one leg up into their belly plumage to reduce heat loss while standing in cold water.  Even shorter-legged Black-crowned Night Herons take advantage of this behavioral strategy.

red-shouldered hawk retracted leg

A Red-shouldered Hawk sat on a cold steel pole in my backyard one fall morning, and fluffed its belly feathers over its legs as it perched on just one foot (right photo).  A few minutes later, when the sun had reached that spot, the bird let the sun do a little warming of its bare legs and feet (left).

Would the one-legged, yoga tree pose work for us, while we wait at a cold bus stop?

How-Do-Tree-Pose-Yoga

Humans posing like trees.
It’s unlikely this would promote heat conservation for humans in cold weather, though.

 

Swan dredging

I don’t know if there is an official term for the way swan dig with their powerful webbed feet to dislodge plants rooted in lake sediments, but I call it dredging.  They create ripples of circles around their bodies as they move from side to side digging deep into the lake or creek bottoms.  It looks like they are marching in place.

swan dredging

swan dredging attracts ducks

Mallards also profit from the dredging action as the digging brings up plant parts and other buried food.  I usually find a few ducks tagging along with the swans, who don’t seem to mind sharing.

swans-geese-ducks foraging on lake shoreline

Canada Geese also like hang out with the swans and ducks, probably hoping to get some of that dislodged vegetation.  

A peaceful late fall scene on the shore of Sucker Lake in St. Paul.