Who’s Back?

The herons, that’s who!

Last week the Great Blue Herons, Ardea herodias, returned to their favorite nesting tree by the lake.

Because herons can grow to 5 feet tall, they need to make nests large enough to fit everyone. These huge bundles of sticks high in the trees are a striking sight. If there are enough trees around, and enough feeding grounds, several families of herons will nest in colonies.

And they like to re-use old nests. After they refurbish their nests for the new season, they lay their eggs, then spend the next few months raising their very large babies. This job involves catching a whole lot of fish dinners.

So watch for long-legged birds with s-curved necks flying over lakes with fish in their mouths, or look for them stalking silently in the shallow waters at the edge of streams or marshes.

The Amazing Ant Lion

Someday, in your travels, you might spot a small round hole in the dirt, about the size of a drinking straw.

And even better, surrounding the hole, there might be a downward pointing cone of dirt or sand, maybe several inches across, leading down into the hole.

If you see both of these, you may have found the dwelling of an Ant Lion, or as it is sometimes spelled, Antlion!

(The cones in this image are about 2 inches across)

Given the size of the hole, you may suspect this creature is not really a lion, and you would be right.

But it is not an ant either! To the regret of nearby ants.

In fact, to an ant, it must seem as fierce and deadly as a lion! Because the whole point of the hole in the ground and the slippery-slope funnel-cone leading down to it is to trap ants, which will then be grabbed by the horrific looking jaws of the Ant Lion, injected with venom and enzymes, and sucked completely dry of life!

Yiiiiikes!

Crazy-ferocious Ant Lion, photo courtesy of Phil Meyers

It sounds like something from a horror movie! So much so, in fact, that the Ant Lion was used as a model for a sand-dwelling monster in the movie Dune!

Like many other insects, Ant Lions go through several surprising life stages. As adults, Ant Lions look like frail dragonflies, who fly around for a few days, then lay eggs and die.

The eggs eventually hatch and grow into larvae, what we usually think of as worms or grubs. Ant Lion grubs are certainly remarkable looking, with those immense jaws, sticking out front like lobster claws. Their bodies, generally an inch long or less, are covered with dark hairs and bristles, adding a wild and wooly look to their ferocity.

And here’s another clue—near the sand-funnel with the hole at the bottom, you may notice a meandering trail in the dirt, like a little ditch. And this wandering line, which looks something like a doodle you might draw on paper, gives the Ant Lion its other name—the Doodlebug!

But why do they do the doodling they do?

Well, look at the size of their jaws! Because their jaws are so enormous compared to their body size, they have to walk around backwards! You would probably meander too, if you had to walk around backwards all the time.

Ant Lions are so clever that they are found all over the world, so you can look for them even if you are not in the desert. And, given how many kinds there are, when being formal, we will not be specific, but just call them by their family name, Myrmeleontidae.

So watch for, and warn any ants, if you see the signs of these remarkable predators!

 

Who made a saguaro hole in one?

Out in the desert, you may hear a loud “Chirrr” sound. Look up, and you may see a flash of black and white wings, then see a brown-headed individual running or hopping up the trunk of a tree, if there are any trees around, or a cactus. If it’s a cactus, that’s got to be a fairly death-defying move, navigating among the thorns.

When you see all of these clues together in southern Arizona or northwestern Mexico, it’s quite likely you have spotted a Gila Woodpecker.

You can recognise Gila Woodpeckers, Melanerpes uropygialis, both male and female birds, from the thin vivid black and white bars across their wings and back, and their brown heads. In addition, the male has a red patch on his forehead. And, as well as their distinctive “Chirrr” call, they also make loud peeps.

In an unusual and clever tactic, they use their tails to prop them up vertically as they locomote, hunting for insect meals on bark or cactus skin, or when they hammer out nests.

The big black holes you see in the sides of many saguaros? Credit goes to these folks!

They use their strong beaks on their well-cushioned heads to whack nest holes into the sides of saguaro cacti, and if they can find any, other tall woody plants of the desert, including cottonwoods.

The nest holes they excavate in saguaros, which are often used by other birds, eventually harden into “saguaro boots.” These woody, rounded, boot-shaped forms remain even after the saguaro dies, and have been used as containers by humans since the olden days.

The fog comes.

on little coot feet.

You may have already heard the correct quote the way Carl Sandburg originally wrote it— “The fog comes. on little cat feet…” But this is different. This is coot, not cat. And coots have strange and amazing feet.

Well, just look at them—first of all, they are quite big feet, not little feet!

And they are not long and skinny-toed like crow feet. Or wide and webbed like duck feet.

Instead, coots do have skinny toes, but with foldable fins on each toe.  So the contrast with crow feet is clear—coots are water birds.

But the contrast with ducks, those other water birds, is extremely interesting. Ducks have webbed feet, with webbing between the toes. When ducks pick up their feet, or move them forward in the water, the whole foot folds, to reduce drag. Then, as they push back, their feet flatten out again, so they press against a lot of water to propel them forward.

Coots use a more subtle system. For them, foldable skin flaps extend out on either side of the toes. When they lift a foot, or move it forward in the water, the flaps fold, reducing the drag against the water. Then when they push back, the flaps widen out and provide a lot of surface area for propulsion. This also helps them walk confidently over bogs or swamps or other kinds of squishy ground.

Plus, these clever feet are picturesque—green and gray and black and white—with striking patterns and colors for someone we think of as just little monochrone water birds.

Well, yes, not to mention red eyes and a red-brown forehead badge, and a charcoal back and white tailfeathers, and their pleasing football-shaped bodies.

Where are you from Mr. Finch?

Tis the season to look up at an ocotillo plant and find a small red and brown bird with an ocotillo flower in its mouth.  This is the House Finch, Haemorhous mexicanus.

You may have heard that these creatures are recent imports, but that’s only true if you live in the eastern United States. Unlike many other U.S.animal arrivals, they are not native to Asia or Europe, but to the western U.S. and Mexico.

They took an uncommon journey to get the east—they were imported decades ago to Long Island by dealers who had the idea of selling these cheerful little folks. But either people were not buying, or somehow the birds escaped, and soon had a great time spreading all over the east coast. Now they have the curious distribution of heavy populations along the eastern US, and the western side of the continent, but have only recently converged toward the Mississippi.

Maybe they were avoiding riverboats?

In any case, look for these lively birds around feeders, and, way back west, in blossoming ocotillos.

See nictitating membranes in action!

There’s a great nature event happening right now. Biologists have set up video cameras to watch a growing bald eagle family in the US National Arboretum in Washington DC, and anyone with an internet connection can watch them at any time.

You can visit the DC EagleCam, 24 hours a day, at  http://dceaglecam.eagles.org

Even though this is the east coast, bald eagles also winter in the desert, usually in the high country. But the relevant  feature right now is that sometimes you can get a glimpse of the eagle’s nictitating membranes at work.

Here’s how. It’s best to watch in the day time. Click on one of the two cameras so you can more easily see the adult eagle’s eye, and enlarge the image, by clicking the bracket-box at the lower right corner of the video.

You will most often just see the eagle blinking–but every so often, you get to see the “third eyelid” swipe part way or all the way across the eye, starting from the corner nearest the beak. Wow!

And if you get so busy watching the adults and chicks and their activities you forget the third eyelid, that’s OK too!

…..Image taken April 6 2016 from dceaglecam.eagles.org © 2016 American Eagle Foundation, EAGLES.ORG

Check out the nictitating membranes!

If you had to make your living in a desert, or under water, or by sticking your head into a rotting carcass to get your food, you’d probably appreciate a handy combo of goggles and windshield wipers.

And that’s what many creatures, including Turkey Vultures, have.

But instead of using the awkward term “combo-goggles-windshield-wipers,” we use the sleek and easy to remember name, “nictitating membranes.”

Uh huh!

Nictitating membranes are also called third eyelids, and are often translucent, so the eyes get protection while allowing some vision.

Sometimes these thin membranes rest under the lower eyelid, and rise from there, but more often, they are tucked into the corners of the eyes nearest the nose, and move back toward the sides of the head when in operation.

It can be unnerving the first time you see them in motion, a space-alien moment. But when the membrane is closed, it often just looks like a gray or white eyelid.

Here’s a Turkey Vulture doing a demo for you!

First picture, nictitating membrane is open, and in the second, the translucent membrane is covering the eye.

Who’s standing tall and alone?

A striking sight in the Sonoran desert is a lone saguaro cactus.

Saguaros (Carnegiea gigantea) provide food and shelter to a surprising number of creatures. This includes humans, who harvest their fruit, and use their skeletons for fences and construction.

These cacti have an amazing variety of adaptations to the desert.

First, check out the color of the stems, a pale green, indicating they contain chlorophyll. Since saguaros do not really have leaves, the stems have to do the work of photosynthesizing and producing food. The pale color keeps the plants from absorbing too much hot sunlight and getting burned.

If you look closely, you will see lines of defensive thorns on vertical accordion ridges. The whole plant can expand to hold more water after a good rain, then accordion back in as it uses the water

What you can’t see is the root structure. Instead of sending down a big tap root, like many plants, they send out numerous very long horizontal roots near the surface, to better gather any moisture nearby.

That’s why they’re lonesome looking—they need to grow far apart. And that’s why, in the old days before we realized it was unethical, (now it’s also illegal) people would dig them up in the desert, transplant them, and they would die, because the majority of  the root structure was left behind.

Did You Hear a Droplet?

Sometimes in the desert, you may hear a loud and distinct sound like a very large droplet of water dropping into a pool.

The droplet-dropping sound is actually the call of a Curved-billed Thrasher, a brown bird with a distinguished down-curving bill and surprising orange eyes.

The Cornell bird labs characterize the call as a sharp, whistled “whit-weet”at their website www.allaboutbirds.org

Perhaps it only sounds like water to parched desert dwellers.

These birds, relatives of mockingbirds, live in the southwestern United States deserts and through much of Mexico.

Wildlife Rescue Open House

If you are near the Phoenix, Arizona area next weekend, you have an opportunity to meet and learn about some of the cool creatures of the hot desert.

The open house is on November 21 and 22, 2015, at the Adobe Mountain Wildlife Center.

www.azwildlifecenter.net/events.asp

Because this is a wildlife rescue station, the population changes all the time. Depending on who is recovering there, you may see eagles, desert tortoises, bobcats, falcons, or ringtails.

Or maybe even the creative and industrious packrat!