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.

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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.

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.

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!

What kind of Rat?

A Pack Rat, that’s what!

More specifically, a White-throated Woodrat, Neotoma albigula.

There are several different kinds of related Woodrats, just to make things confusing for humans. And in addition, Woodrats are not the same as the rats we usually think of, when we think of rats–those are the Old World Rattus rats.

Woodrats or Pack Rats look more like giganto mice, with their big ears and big dark eyes. Their tails are also fuzzier than the bare Rattus tails.

These amazing creatures can survive on the moisture they get from the vegetation they eat, and do not need to drink water. How’s that for a desert adaptation!

Quite a while back we talked about Pack Rat middens, the amazing homes the White-throated Woodrats build in the desert.

These folks must have special skills, to build such large defensive structures without getting nasty stab wounds, since middens often include a lot of cactus branches.

Ocotillos and visitors

So, the original idea here was to talk about how Ocotillo plants (Fouquieria splendens) in bloom seem to host bird or pollinator visitors at almost any time of day.

It seemed like a good idea to do at least one random sample of observation before declaring this.

And sure enough, during a 3 minute segment one spring afternoon, a few days into full bloom for the ocotillo, there were two bird visitors and several pollinator insects. Now this was just one casual observation, but it indicates how often you see creatures near or on these plants.

As noted in an earlier post, Verdins, (Auriparus flaviceps) the very small birds with yellow heads, are frequent visitors, apparently looking for insects. Finches are also common. And hummingbirds can be seen throughout the year.

It is amazing that any birds can find a firm foothold on the thorny stems. Clever feet.

Remember that the ocotillo is not a cactus, although it may look like one during some parts of the year. It’s in a completely different group. In fact, for most of the year, it looks like a bundle of dead sticks, and if you first saw one for sale in a garden center, you might wonder what they were trying to sell.

Who’s an invertebrate?

An invertebrate is somebody with no backbone.

Wait, who you callin’ spineless? I’m happy as a clam!

Yes, for example, a clam is an invertebrate. As are many other squishy aquatic creatures, like  the 30 foot long ocean worms! Yikes! So are octopods and squids. The mighty Kraken!

Insects are also invertebrates, as are spiders, and those wild scorpion creatures!

You might notice a pattern here—many invertebrates, especially aquatic ones, like the magnificent octopus and kin, may have no hard structure at all.

Others often have external support systems, like shells in mollusks, or the exoskeletons surrounding insects and Transformers. Especially desert creatures, who like a bit more protection from the elements.

And by the way, when you think of spineless jokes? Just remember, it’s probably good form to be polite. Especially about invertebrates. Remember, there are way way more kinds of them than there are of us bony beasts. And way way way more individuals!

And some of them bite or sting! No way!

And some of them look so amazing they will knock your socks off!