You “otter” see this!

We didn’t expect to see so many sea otters on our boat tour of the Elkhorn Slough in Monterey Bay. Several were in sight at any one time, almost every one with a youngster riding on top as the adult paddled along on its back.

Sea Otters propel themselves with their hind feet while floating on their backs. This mama has a small youngster curled up on her chest, its head tucked under its body.

Sea Otters were once very abundant in the coastal marshes and estuaries of western North America, but extensive hunting up until the early 1900s culled their numbers to just a couple thousand animals. Conservation efforts have increased their numbers somewhat, but they are only found in part of their original range. Sea Otters are an important part of the coastal ecosystem because they prey on the sea urchins that ravage the kelp beds and keep the herbivore numbers in check.

The Sea Otter diet is largely made up of shelled invertebrates like mussels, abalone, snails, and sea urchins. Otters are unusual in carrying and using a tool, a good-sized rock that they can tuck into a fold of skin, to pound on shells to break them apart. They can also open some shells with their incisors.

Sea Otters bring their prey to the surface, and consume it while floating on their backs. Naturally, some of the food drops onto their fur as they eat, so they continuously roll over while eating to dislodge food fragments. In addition, they meticulously groom their fur to keep it clean and fluffy (i.e., with lots of air pockets).

The density of otter fur is one of their most important adaptations to marine life. It is extremely thick, with about 1 million hairs per square inch! Multiple layers of fur shed water and trap air, enhancing their ability to float on the surface and keep a dry layer of fur next to their skin. Young otters have an extra layer of inner fur to trap air which gives them extra buoyancy. While grooming them, their mother may actually blow air into their fur, making them so buoyant, they float like corks.
Long vibrissae on their noses help them detect prey under the water. Sea Otters apparently also have an excellent sense of smell, and their eyesight is as good above water as below the surface. When they dive, otters can close their nostrils and ears to water entry.

Otters breed at all times of the year, and pregnancy usually lasts about 4 months, but females can delay the implantation of the single embryo until conditions are best for the pup’s development. Pups stay with the mother 6-8 months, before venturing out on their own, when they are almost full adult size.

This little otter won’t be with its mom much longer…

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the three amigos

We had our own personal boat tour of the Elkhorn Slough, a 7-mile long tidal estuary on Monterey Bay that was the first estuarine sanctuary in the U.S. It began with a 60-acre purchase by The Nature Conservancy in 1971, and has grown to over 800 acres today. The entire 1.5 square mile marine reserve provides critical habitat for a variety of mammals (discussed in the next post), more than 300 species of birds, and a host of invertebrates and plant species on which the birds and mammals depend.

By some strange coincidence, a number of the bird species we saw on our boat tour had arranged themselves in groups of three — thus, I labeled the trios “the three amigos”. This is the time of year when bachelor groups of males break up and mated pairs are more often seen together, so seeing groups of three was somewhat odd.

White Pelicans are still hanging out in large flocks at the slough, but three loners were standing together. Male and female White Pelicans look alike, so we don’t know whether this was a group of just bachelor males or not.
These Eared Grebes swam together, dove together, and posed together, as they hunted for small crustaceans and fish in the rich estuary waters. The sexes look alike, so one or more could be female. Eared Grebes nest in dense colonies, so it’s not unexpected to find them in small groups together.
Pigeon Guillemots (relatives of Puffins) are handsome black and white birds with red legs and feet. The sexes look alike and are similar size, although in California, the female Guillemot has a slightly larger bill. Although they may be enjoying the largess of the estuary, they will soon set up nesting territories on steep cliffs all along the west coast of North America.
A trio of Brandt’s Cormorants had settled on some rotting pier posts to establish their nests. They seem to be sitting on eggs already in the estuary; they would have to be tolerant (or good friends) to nest this closely together. Brandt’s are the largest Cormorant in North America and are easily distinguished by their vivid, cobalt blue throat and eyes.
“I’m so pretty…”

The Big Trees

We hiked through the cool, majestic big redwoods of the Forest of Nisene Marks in the Santa Cruz mountains the other day. I’m always impressed with the immense change in microclimate that these big trees produce, growing along the coast and trapping cool, moist air from the ocean each morning. The light filters through dense branches high above the trail, and only a few scattered sunbeams actually make it to the forest floor. So photography is a bit challenging under dim light conditions.

This tract of almost 10,000 acres of coastal redwood forest was once clear-cut once to provide lumber for the growing towns of central California. The land was donated to the state by the family of Nisene Marks, a passionate nature lover.
Wildflowers, like this delicate Trillium, were in abundance on the forest floor.
But the forest was really quiet, except for the trilling warble of a few Pacific Wrens. This is not a place to find a lot of birds, but it is a serene wilderness with lots of beautiful hiking trails to traverse.
This Pacific Wren was elusive at first and then hopped up into plain view. Its song is similar to our Midwestern House Wren, and it pierces the quiet of the redwood forest stillness.
One of the interesting creatures of the redwood forest is the Banana Slug, so named for its resemblance to said fruit. This shell-less mollusk looks vulnerable because it stands out with its bright color on the dark forest floor, but only a very few predators can tolerate the tongue-numbing, viscous slime it secretes to retard dehydration.
Two pairs of tentacles on its head help the banana slug navigate its environment. The upper pair contain light-receptive cells on long, protruding stalks. The lower pair are used to sense certain chemicals in the forest litter so the slugs can locate their favorite food: tiny mushrooms. They also consume and recycle the vital nutrients in animal droppings and dead plant material, leaving behind rich fertilizer.
Other decomposers, like these fungi that resemble our Midwestern “Turkey tails”, add to the forest nutrient cycle. Redwoods that can live for thousands of years are resistant to decomposition, unlike the pine or deciduous trees present in this forest.
Looking up at the Big Trees, towering above us in the redwood forest.

The Rock

it juts right out of the ocean, a lone, huge boulder of a rock, standing 580 feet high. Morro Rock is one of the “nine sisters of San Luis Obispo County”, a series of volcanic plugs that rose into softer rock about 20 million years ago. The Rock is part of the state park and is closed to hikers and climbers so that Peregrine Falcons, Western Gulls, and Brandt’s Cormorants (among many other bird species) have a protected place to breed and raise their chicks.

Almost 500 feet above us, a group of Brandt’s Cormorants have established nest sites on a shelf of the rock face (arrow— you may be able to see them if you click on the photo to enlarge it). Western Gulls have staked out their favorite nest sites on the various rock ledges as well. The minute dots of birds against the rock face gives you a sense of just how massive this rock is.
Along the shore you can find plenty of shorebirds, as well as some great views.
Western Gulls are plentiful, and they quickly hone in on what the humans around them are eating for lunch on the beach.
Left-over French fries…yes, they love them.
Gulls don’t bother the napping Harbor Seals, but this one looks surprised by the fly-by.
A pair of California Thrashers were setting up housekeeping along one of the hiking trails in the park. Like other members of the Mimid family (mockingbirds and catbirds), thrashers are notable songsters. Thrashers construct complex songs that contain phrases from many other songbirds, strung together in long series with few repeats, often lasting 3-5 minutes. One study found almost 3,000 phrases in a single California Thrasher song.
They may be plain-looking but friendly little California Towhees are easy to find in California chaparral vegetation and are sort of an indicator species of the California scrublands. They scratch around the base of plants for hidden seeds, the same way Fox Sparrows do in the Midwest.
Red -shouldered Hawks have a strange distribution in North America. They are mostly an eastern bird of the forests, but a limited western population occurs west of the Sierra Nevada mountains from Northern California to northern Baja California. We were fortunate to see one of the birds fly into the tree where the other hawk perched, just as we were leaving the state park.

Behold, the beaks!

We have been stopping along the California coast at various sites from San Diego to the Santa Cruz area to check out the shorebirds there. What a wealth of diversity of birds, and what a diversity of adaptations they exhibit, especially in their beaks.

Of course the beak is the primary tool for extracting food in shorebirds, so you would expect to find specialized structures to do that. For example:

Beaks come in different lengths, different curvatures, different thicknesses — all designed to find and extract prey from different locations in the shore environment. (Illustration of beaks in Western Australian birds by Peter Dann)

Even closely related species (e.g., in the same genus) exhibit particular beak structures that allow them to specialize on certain food resources. Few species exhibit the extreme specialization of the Curlews, whose very long and decurved bill is designed to extract crabs and other soft-bodied invertebrates embedded deep in the wet sand or mud.

Long-billed Curlews are the largest of the Sandpiper group of shorebirds, and almost seems oversized for the bird’s small head. Its sensitive tip can locate prey buried far below the surface.
The closely related Whimbrel is half the size of the Long-billed Curlew, but it, too, uses its long, decurved bill to seek out prey buried deep in sand and mud. Where both species are present together, they would be foraging at different depths and thus avoid competing directly with each other.
Willets are common on the ocean shoreline as well as inland, and seem to be more generalist feeders. They probe for crabs and other invertebrates in the sand and mud, but forage for insects, and even plant material away from the shore.
Another member of the same genus as Willets, the Greater Yellowlegs, is about the same size, but weighs half as much as a Willet. This bird is more of a specialist on aquatic invertebrates and fish, using its beak to stir up the water and dislodge its prey from the bottom.
Marbled Godwits use their long, slightly upturned bill to sift the wet sand for tiny invertebrates. Here, they are probing shallow surfaces out of the water, but they also stand belly deep in the water with their heads and necks fully immersed to hunt for prey.
Avocets use their sword-like, upturned bill to sieve the shallow water for small invertebrates. They sweep their bill side to side in the water, picking up minute crustaceans, worms, and even tiny fish.

This has been a subject of interest every time I visit the California shore, and there is more information about this (and a video) in a previous post: “sharing the resources”

Flowers of the desert

Although we have been a little early in some places and a little late in others, we still have seen some of the spring wildflower show as we travel.

One of the most exotic flowers we saw were on this claret cup cactus, actually an endangered species found only at the intersection of Arizona, New Mexico, and Mexico — which is exactly where we were when we saw it. The plant puts out brilliant scarlet flowers on cylindrical stems that mound together into a cactus clump.
The color of the flowers suggests it might be pollinated by hummingbirds, although the shape of the flower is wrong. However, the “flower” is actually the outer sepals and petals combined, and the nectar reward for the hummingbird pollinators is in the central chamber surrounded by hundreds of thready stamens.
Cylindrical flowers of the Ocotillo are the more typical hummingbird floral type, but a number of other birds enjoy these flowers for their nectar, as well as the insects they attract.
Why bother probing into the flower for nectar when you can just rip the flower off the stem and eat the whole thing, as this male Pyrrhuloxia is doing?
Looking for insects on unopened Ocotillo buds? A male Gila Woodpecker might enjoy both a nectar and an insect reward from these flowers.
A female Rufous Hummingbird foraged on a bunch of Penstemon flowers in the early morning at Cave Creek ranch in Portal Arizona.
A Clear-wing Moth and Pygmy Blue butterfly foraged on the bush lupine right outside our room at Cave Creek ranch in Portal Arizona. This plant had so many flowers and apparently so much nectar, it was constantly moving with the all the butterflies and bees swarming on it.
The Southern California deserts didn’t receive enough rain this year to produce much of a wildflower show, but the Desert Agave still bloomed here, along with many Ocotillo plants, giving this desert in Anza Borrego State Park some color. The Agave plants only send up one flower spike in their lifetime, as tall as the plant’s energy resources will allow, to attract bats to pollinate them.

Birding is such hard work

We sit quietly in chairs placed strategically near bird feeders, waiting expectantly with cameras on laps and binoculars glued to eyes, searching for that iconic shot of some new bird we’ve never seen before, or a better shot of a bird we have seen many times before. When we’ve exhausted the possibilities at one site, we get in the car and move on to the next one. It’s such hard work…(not). But it’s the thrill of the hunt for the best shot that keeps us going from place to place.

From my chair I could see hummingbirds coming to any one of six feeders (two shown here), but most were too far away to get good close-ups of the action. Oranges, jars of grape jelly, platforms with seed, and containers of suet mix were spread out in the trees in front of us — a real bird buffet. All we had to do was sit and wait for birds to show up.

In Portal, Arizona, in the foothills of the Chiricahua mountains, you are welcome to visit the backyards of the local residents to sit and photograph the birds that visit their feeders. At this particular backyard, a Roadrunner (lower left of the photo) walked through the backyard looking for an unwary bird to capture. It made a half-hearted attempt to lunge at a hummer on one of the feeders in the photo above, but gave up and moved on. We heard it had grabbed and eaten a Cactus Wren just a half hour before.

This is a collage of the Broad-billed Hummingbird’s approach to the feeder. If the bird catches the light just right, it shows off it’s beautiful iridescent blue and green feathers. Photos taken at 1/2000th of a second stop the rapid wing action as the bird hovers in place. Click on the image to view it in full screen.
Even though the feeder is large in comparison to their size, hummingbirds aren’t very tolerant of others trying to feed at the same time they are. Here, a female Blue-throated hummer feeding on the left is much larger than the approaching make Broad-billed Hummingbird, and just her presence there is enough to make him hesitate to settle on the feeder.

Of crystals, flies, and plovers

How would crystals (in particular, selenite crystals, a variety of gypsum), flies, and tiny little shorebirds called plovers possibly be related to each other? Well, this is a story of mutual benefits, with humans actually playing a positive role in the story for once.

The expanse of the Great Salt Plains covers about 11,000 acres in northern Oklahoma. It is thought that the salt flat was formed during repeated water level risings of an ancient inland sea millions of years ago. Salt is continually brought to the surface by evaporation from an underground saline water source rich in calcium and sulfate, the main chemical components of gypsum.

Digging for Selenite crystals, a particular form of gypsum, is popular with crystal collectors, and so people come to the salt flats in Oklahoma to unearth some rare beauties to take home each year from April to October, the only times crystal harvesting is allowed on the Salt Plains National Wildlife Refuge.

Selenite crystals can come in many shapes, colors, and transparency. They may range from finger size to huge stones weighing as much as 50 tons. (Photo from Wikipedia)

The large holes left by excavating the crystals gradually fill with saline water and host a collection of microscopic organisms growing on the floor and sides of the holes. Along come brine flies that lay eggs on the surface of the water. When the eggs hatch, the larvae drop to the bottom and feed on the bacterial mats. After growing and pupating, adult flies hatch from their pupal cases and rise to the surface of the water to fly around searching for a mate to start the cycle all over again.

But, along comes the tiny shorebird, the Snowy Plover (along with a host of other shorebirds that might also nest in the salt flats) to pick off the adult flies as they emerge from the water before they can fly away.

Their small size (5-6 inches in length) and inconspicuous plumage makes these little birds hard to spot, whether on rocky ground or on sand or salty soil.
Unless they move, they really are hard to spot. Their nest is just a scrape in the soil surface, sometimes lined with shells for camouflage. When the eggs hatch, the chicks can almost immediately run around to follow their parents and feed themselves on fat brine flies.

Unfortunately for the Plovers, their required habitats for nesting are being taken over by beach development or other human recreational activities, and their nests are vulnerable to being crushed underfoot by hikers that wander into their nesting areas. But this unexpected benefit of having crystal harvesters (who are restricted in the areas they can dig) leave holes that can “grow” a food source for the plovers seems to be an ideal solution for nesting birds in Oklahoma.


Roadside finds

Wending our way through the small towns and narrow roads of the central Plains States south, we came across some notable discoveries — things we would never see on busy interstate highways.

A female Prairie Chicken, foraging right alongside the road and unperturbed by our car backing up to get a better view of her.
We almost drove right by this little piece of prairie as we took a sharp curve on a road out of Red Cloud, Nebraska. Her family home is nicely preserved in town.
At a park in Red Cloud, we found a pair of Cooper’s Hawks perched in the trees near the bathroom. One of them was munching on a recent kill.
McAllister Park in Lubbock, Texas looks arid and deserted of life, but turns out to be a birding hotspot in the middle of busy freeway traffic! Black-tailed Jackrabbits were abundant, and boldly hopping around out in the open, so I guess there were no Great Horned Owls around.
Also found at McAllister Park were several pairs of Burrowing Owls, perched on the edge of burrows originally constructed by the Prairie Dogs there.
Right at the edge of the road leading up to Carlsbad Caverns were a pair of young male Bighorn Sheep munching on what looked pretty inedible. The Chihuahuan Desert here in southern New Mexico is really bleak looking, without a shred of green visible except for the Juniper needles. How these animals survive here in this hot, arid place is truly amazing.

A model of coexistence?

As a general rule, complete competitors in the natural world cannot coexist, unless they divide up the resources somehow, by hunting in different areas or at different times, or specializing on slightly different food items in their diet.

On the wet prairies and marshes at Cheyenne Bottoms and Quivira National al Wildlife Refuge near Great Bend, Kansas, we saw several Short-eared Owls and and as many Northern Harriers, not only hunting in the same areas and habitats, but at the same time of day!

A Short-eared Owl landed in the grass after an unsuccessful prey capture. Some studies show that owls are successful capturing mice in open grasslands about 44% of the time.
Short-eared Owls traverse the fields in short, coursing flights, searching the same area intensively and listening for mouse activity. Long wings make gliding over the habitat seem effortless.
Northern Harriers make rapid flights across longer distances than the owls, turning infrequently and flying quickly. If they detect movement, they may hover over a spot, honing in on the prey.
Short-eared Owls hunt by sound, even though they are usually hunting in daylight. Their facial disks collect the infra-sounds that active animals make like a parabolic reflector and relay it to their ears. The owls consume mostly rodent prey, especially while feeding young.
Head down is the way we usually see Harriers hunting. Unlike other hawks, Harriers use hearing as well as vision to find their prey. Rodents make up a big part of their diet as well, but they also eat large insects, amphibians, and reptiles, as well as birds.

One study of niche overlap of Short-eared Owls and Northern Harriers in Utah found that their home ranges overlapped as much as 70%, but within their home range the two raptors hunted and nested in different parts. In addition, in this particular study, the owls tended to hunt most intensively in the mid-afternoon, while the hawks concentrated their hunting in the evening hours before dusk. So, even though the two raptors seem like complete competitors, they seem to have found a way to share the resources cooperatively…usually.

However, Sean Crane (500 pix) photographed a Harrier and a Short-eared Owl fighting over a vole in Washington — which is evidence that the two don’t always get along.