A cruise on the Delta

Five rivers feed into the 200,000+ acres of wetlands that make up the second largest river delta system in the U.S. just north of Mobile Bay in southern Alabama. The Mobile-Tensaw delta’s expanse of swamp, bog, natural rice paddies, canals, and rivers makes this area of Alabama a real biodiversity hotspot where you can find more species of fish, turtles, snails, crayfish, and oak trees than anywhere else in North America. Harvard ecologist E.O. Wilson has called it North America’s Amazon, and so it was a real treat to venture out on a small boat to explore some of the smaller waterways of the delta for ourselves.

Wild rice and Phragmites reeds grow along the edges of the river, almost closing off the small waterways in the labyrinth of corridors throughout the delta.
A variety of snails colonize the floating vegetation in the swampy bogs.
Clumps of rice seed fell into the bottom of the boat as we passed through narrow canals. A Yellow Warbler might not be interested in the seed, but there are plenty of insects in this vegetation.
We must look carefully on the river banks before stepping out of the boat — there are plenty of alligators in the delta waters.
Cruising up the Tensaw river we entered a cypress swamp where the trees grow right in the water, completely independent of any land surface.
Cypress forests are a haven for all kinds of birds — small migratory warblers as well as large waders like a Great Blue Heron.
In the Spring, these waterways are lined with brilliant flowers.
Spanish moss hangs from the Cypress’ lower branches, and odd vertical stumps arise from the tree’s roots. Their function is not certain, but they might assist in collecting more sediment to buttress the tree roots in the soft, muddy river bottom.
Honeybee nests can be found where large branches have broken away from the trunk. This is a “honey” tree.
Not only is there great diversity of vertebrate animals in the delta, but there are hundreds of species of insects as well. And some are really big — like the praying mantis..
and this 4-inch lubber grasshopper (which is not fully mature yet).

The southeastern U.S., and the Mobile delta in particular, was a refuge for species driven south during the ice ages of the Pleistocene glaciation. Warm temperatures year-round and plenty of rainfall (averaging 70 inches per year) ensure the most equitable conditions for life to survive, and so it has in this cradle of biodiversity.

Amazing sand beaches of Dauphin Island

We took a car ferry to Dauphin Island which sits at the mouth of Mobile Bay, and then drove west to Pelican Point beach for a (hot) walk in the late morning sun. The beaches along the gulf coast of this part of Alabama are composed of finely ground, minuscule particles of quartz that originated in the Appalachian mountains, were ground down by erosion and river action before being transported to the gulf, where minerals were further reduced in size by wave action over tens of thousands of years. The result is an eye-blinding, fine, white sand that actually squeaks as you walk over it.

It’s hard to decide which is whiter — the sand or the puffy cumulus clouds. Little islands of sea oats grasses and herbaceous perennials help stabilize the dunes. But this is harsh habitat for these plants that have few mineral nutrients and precious little fresh water resources and must deal with a lot of salt water spray.
Farther away from the ocean, more perennial grasses can establish mats of vegetation.
In salt water pools behind the beach, one might find a few shorebirds foraging for food. We were surprised to find a tiny Least Sandpiper poking around in the vegetation at the water’s edge.
Even farther away from the ocean, the vegetation is much thicker and more diverse with all kinds of perennial grasses and forbs growing on the sandy matrix. I surprised a Great Blue Heron and Black-bellied Plover as I came around the corner of this small pond.
A flock of Red-winged Blackbirds (all females and immature males) were feasting on the sea oats.
The Dauphin Island fishing pier ends far short of the ocean now, due to sand buildup between Pelican Point (which used to be an island) and Dauphin Island.
Looking toward the interior of Dauphin Island, you can see the successive ridges of white sand dunes deposited over time, and colonization first by grasses, then various species of shrubs, and finally dense stands of pines and oaks, the species best adapted to growing in dry, sandy conditions.
In the interior of the island, you can find huge, old live oak trees, covered with mosses and epiphytes, and surrounded by saw palmetto and a variety of flowering plants. These are impressive giants, both in their size and in their survival in a climate of intense heat, periodic drought, and occasional hurricane landfall.

Alabama’s gulf shores are an ecological wonder!

Fields of gold

Prairie parkland landscapes are at their peak golden color now. The fall landscape is transforming daily, and with the nice fall weather lately, it’s a glorious time to be out walking around. I’ve given up trying to find the migrating birds at this points and am just enjoying the golden colors everywhere.

The prairie at Tamarack park in White Bear Lake looks golden with stems drying Big Blue Stem and Indian grass, as well as a healthy crop of Showy Goldenrod. Leaves of a few of the maples and ashes have begun to change color also.
There is a similar scene in the restored prairie at Reservoir Woods in St. Paul where the low vegetation is a solid mass of several species of Goldenrod, with a few purple and blue asters and the stems of Indian Grass mixed in.
Bright yellow plumes of Showy Goldenrod rise above the rest of the vegetation in this landscape. And the flowers are a major attraction for honeybees and bumblebees by the dozens.
I don’t think I’ve seen this many honeybees in a native landscape for quite some time. Goldenrod and Asters are the late blooming plants in the fall that bees depend on to stock their larders with pollen over the winter.
Stiff Goldenrod with its erect, rigid stems and fat, almost succulent looking leaves is also in full flower not, but is not nearly as attractive to the bees as the Showy Goldenrod.
Stiff Goldenrod flowers seem larger and more attractive to my eyes, but not to the bees.
Canada Goldenrod has already bloomed and is putting out seeds that the migrating sparrows and finches will appreciate.
Earlier in the fall the American Goldfinches began harvesting the seedheads of the Meadow Blazingstar and led their newly fledged offspring over to the seedheads of the Canada Goldenrod.
What new things will I see on tomorrow’s walk?

the “good morning” hummingbird

What could be more pleasant than to sit outside on a coolish, bright sunny morning with a cup of coffee and a camera watching Ruby-throated Hummingbirds forage on Salvia flowers? The light was harsh and full of high contrast until the birds visited just the right flowers…

Salvia flowers are the right color, the right depth for the hummingbird’s bill and tongue, and the right fit for its head to pick up pollen from the flower’s protruding anthers.
Peek-a-boo, it looks like the hummer is keeping an eye on me while I’m keeping an eye on it.
I never get tired of watching their acrobatic flights between flowers as they probe each one for the tiny bit of nectar at the bottom of each floral tube.

Soon these tiny bundles of energy will undertake a giant-sized migration south to the Gulf coast. There they will again stock up on sugar-rich nectar to convert to fat stores that supply the energy for them to cross the Gulf of Mexico (the smallest birds to do so), without stopping, to get to their overwintering sites in Central America.

Because of their high requirement for sugar during their migration, they become frequent visitors to backyard nectar feeders at this time of year. To keep these little dynamos healthy on migration, remember to change the sugar solution in your feeders every 3-4 days, so it doesn’t grow mold or bacteria.

Mystery footprints?

On a morning hike after a much needed rain the other day, I came across some strange “prints” on the trail.

What’s going on here? As I scuff the “prints” with my shoe tip, I feel something woody beneath the raised “rootlets”
Truly strange-looking formations…

Were these tree roots exposed by recent rain having washed away soil? Was it a result of moss colonies that had dehydrated and died in the long drought during June and July? I really had no idea why these formations were here in the middle of this part of the trail. But in the first photo, you can see ferns on both sides of the trail, making me wonder if there was some connection between the density of ferns in this particular location and the strange “footprints”. So I kept looking…

Aha! There are indeed ferns growing out of some of the formations.
Ferns reproduce by sending up leaves from their rhizome (root-like structure) or from spores on the under side of their leaves.

I’m guessing these formations might be fern rhizomes exposed by recent rain. Do any of my readers know if this is correct?

Color me green!

When I went out to pick raspberries this morning, I found something much more delightful than a bunch of mating Japanese beetles (the scourge of the berry patch!) — a couple of 1-inch Gray Treefrogs hiding in plain sight on the green leaves of the raspberries.

From the side, this little one with its dark facial markings and dark lateral stripe was more obvious.

Although this species is named the Gray Treefrog, because they are quite gray with a dark blotchy pattern sometimes, in bright sunlight on a green background, they are well camouflaged as they match their background. In fact, this frog even matches the particular shade of green of the raspberry leaf on which it rests.

I wonder if they eat Japanese beetles? There are plenty of other insects resting on the raspberry leaves for these little guys to dine on. But these frogs are really only active at night, and usually seek shaded vegetation for their daytime rest.
The color matching camouflage is impressive in both the shade (this photo) and the sun (photo above).
How exactly does a gray treefrog become green?
Looking more like the gray treefrog, I photographed this maxi-sized (2.5-inch) adult in the early morning while it was sitting under an evergreen in the leaf litter.

Frog skin contains a stack of color-producing cells called chromatophores, and many frog species like the Gray Treefrog, have 3 sets of them: a deep layer called melanophores that contain a black/brown pigment called melanin, an intermediate layer called iridophores that lack pigment but contain particles that can reflect blue light, and an upper (most superficial) layer called xanthophores that contain yellow pigment.

Now, it should be more obvious how a Gray Treefrog can transform quickly from its gray color that is produced by the dispersion of deep-lying melanin pigment to a bright green color, produced by the interaction of blue-reflected light from the iridophores passing through the yellow pigment of the xanthiphores (i.e., blue plus yellow equals green to our eyes).

The dispersion of pigment in frog skin is controlled by nerves and hormones, which act on the chromatophores to aggregate (condense) or disperse pigment. Physiologically, in a matter of seconds, when melanophores aggregate their pigment to uncover the iridophores and xanthophores disperse their pigment, a gray frog turns green!

Color changes can even happen while frogs are sitting in the dark in my covered water tank. It just depends on their physiological state, the temperature of their environment, and the amount of hormonal or nerve stimulus they are experiencing.

A hike in a Sierra meadow

There are lots of trails to explore in the Lake Tahoe basin, and we took the grandkids on a “walk” from their cabin on Fallen Leaf lake all the way to a swimming beach on Lake Tahoe — an almost 7 mile hike. Naturally, there were a number of stops to rest and swim at places along the way, and there was a promise of ice cream at the end of the hike, and that’s all it took to get the kids there.

The water of Fallen Leaf lake is as clear as that of Lake Tahoe, but right now the water near shore is more of a greenish color due to all the pine pollen accumulating there. If the glaciers that created it had continued to carve their path from the Glen Alpine valley, this lake would simply be a bay of Lake Tahoe.
The trail along the east side of the lake wanders through countless meadows and stands of Jeffrey pine (the one that has a scent of vanilla wafting from the cracks in its bark). The tall meadow lupine was in full bloom.
Another blue-purple flower that I thought was forget-me-not turned out to be Pacific Hound’s Tongue, so named for the shape of its basal leaves that resemble a dog’s tongue. The flowers were loaded with small Two-banded Checkered Skipper butterflies feasting on nectar.
Juncos are already far along in their nesting cycle, feeding their rapidly growing chicks.
A Red-breasted Sapsucker checked us out as we walked under him on our trek by the salmon run on Taylor Creek. I wonder if this is the same bird we saw here in April at this spot?
White-headed Woodpeckers are somewhat common in the pine forest here in the Tahoe basin. This female was feeding chicks in the nest (on her left) and not at all shy about us walking near her.

Beautiful eastern Nevada

Camping in a new spot, never visited before, in the Ruby Mountains of northeastern Nevada. Serene and peaceful, with wide expansive views of peaks, in the middle of an aspen grove, and surrounded by meadow of wildflowers — what’s not to love about this place.

The Ruby range — we will climb into the foothills of these mountains to our campsite at Angel Creek.
Setting up camp in the aspen grove
There was lots of woolly mule’s ears in the aspen meadows showing off their bright yellow flowers.
Dense stands of showy lupines dotted the rocky hillsides.
A large patch of blue iris under the aspens had just finished blooming.
Spotted Towhees were common in camp, singing continuously to us all evening and the next morning.
House Wrens were noisily advertising their territories in early morning — kind of an unwelcome alarm clock actually.

Home on the range

We’re back at Fort Robinson in northwestern Nebraska, this time with grandkids to enjoy the sights and the wildlife. With three visits in the past two years, I’m beginning to feel like this place is “home”.

Sunset drives are always full of surprises… bison and pronghorn were grazing in the still-green pastures on some of the 22,000 acres of the park.

More wildlife was spotted near the road the next morning on our drive through Smiley Canyon in the park.

The spring wildflowers were abundant in the grassy meadows as well: a purple Penstemon, the white of the Yucca flowers, and small orange Globe Mallow flowers brought a lot of color to the green pastures.

the beautiful California Grasslands

Driving south from the Pinnacles National Park, just east of Monterey Bay, we encountered a small valley within the inner coast range of mountains with beautiful pastoral scenes of the oak savanna for which California is well-known.

The valley floor was once carpeted with native grasses that remained green in summer heat (like those in the Midwest), but European grasses introduced as forage for grazing cattle have taken over the pastures. This green landscape will soon turn gold-colored as the grasses dry out.
The grassy meadow gives way to oak savanna or oak woodland on the hillsides where soil is even drier and where cattle can retreat during the mid-summer heat.
Yellow-billed Magpies are endemic to the coastal and Central Valley grasslands of California from which their close relatives, the Black-billed Magpies, seem to be restricted. Competitive exclusion between the two species does not account for the strict boundaries between them, but one research study did show that Yellow-billed Magpies can tolerate (and breed in) the higher temperatures and drier conditions of the valley grasslands during the summer. Black-billed Magpies are found only at high elevations in cooler, wetter habitats in California (like the Sierras).
Blackbirds follow cattle around on the grasslands, waiting for the cattle to stir up insects as they move.
But this flock weren’t the Red-winged or Brewer’s Blackbirds we expected. They were the locally endemic, rarely seen Tri-colored Blackbirds, with red and white wing epaulets. Unlike their Red-winged cousins, Tri-colored Blackbird prefer to nest in huge colonies in wet marshes, placing their nests close together, with some colonies containing hundreds of thousands of birds (in the mid 1900s). Their population has declined markedly in the past 50 years with conversion of wet marshes to agricultural fields in the Central Valley.
It was wonderful to see so many Western Meadowlarks as we drove through the short grass prairies of the western U.S. and California grasslands. Their sweet song fills the meadows, and we notice how many more of them we see perched on fence posts as we drive, unlike a similar drive through backroads of our Midwestern grasslands.