…and makes some adjustments.

The first day of autumn has been a red letter day in our yard. Not only was there a Western screech owl calling last night — a new species for the yard, as far as my observations go — but this afternoon, in the heat of the day, a young Desert iguana raced under a creosote bush in the front yard, when I went out to get the mail.

I whipped out my tiny Canon Elph but the little ‘zard was all warmed up from hanging out in the midday sun, and it sped away before hiding in the shade under the creosote where I could see him but couldn’t get a picture. So I pinched this nice photo by Jason Penney from the excellent Reptiles of Arizona website which you can check out for more detailed info about this lizard. When full grown, Desert iguanas (Dipsosaurus dorsalis) are large lizards — almost 6″not counting tail and up to 16″with it — with a blunt face, long tail, and distinctive buffy coloration below a colorful pattern of speckles. This little guy shone pale gold as it raced across the cement driveway; its color gave away its identity even before I got close enough to see him well. Tiger whiptails (Aspidoscelis tigris) the lizards we see most often around here, are darker and lower to the ground.

The little iguana was also exhibiting another trait of its kind: it was out in the hot part of the day, when most other lizards have retired to shaded shelter or underground to rest and digest their forage. Diet is another thing that makes Desert iguanas distinct from our other lizards — they’re largely herbivorous when mature, eating a variety of desert vegetation, including the yellow flowers of creosote bushes, which they will climb to feast on. The first Desert iguana I ever saw was among the spring wildflowers at the Desert Botanical Garden, grazing in the hot sun like a small-scale reptilian cow, even leaving behind it large (for a lizard) fibrous pellets of poop like plant-eaters do. And, yes, they are related to their better known cousins, the Green “Tastes Like Chicken” Iguanas (Iguana iguana) of Mexico and Central America. I don’t know what something that feeds on pungent creosote blooms would taste like.

But this is why seeing him was especially exciting: there are only a few in the neighborhood, and that number appears to be shrinking, at least by informal observation. It’s only a theory, but mortality of Desert iguanas (specifically in our neighborhood) seemed to accelerate after the City re-coated our streets with a dark sealant. It makes for good basking, perhaps, the dark surface heating up earlier and staying warm later than the old gray road, and sadly, for several weeks, I would see Desert iguana roadkill regularly: three along one stretch of a heavily-used street nearby alone. So, seeing this little guy who was perhaps this year’s hatch, or more likely a yearling, was a very welcome sight.

Etymological notes:

Dipsosaurus is constructed of Greek elements, meaning “thirsty lizard”; dorsalis refers to the spine, which in Desert iguanas is protected by prominent, keeled scales.

Tiger whiptail, photo by E. Shock

Aspidoscelis tigris: Aspidoscelis is also from Greek elements, and means “shield leg” because of the sturdy scales on the whiptail’s legs, and “tigris” because it is stripy.

Last night was a busy night in the yard. Well, I suppose they’re all busy nights, but last night I was awake to appreciate it. Before human bedtime, the geckos were at their posts under the porch lights (our yard residents are the non-native Mediterranean Geckos, not the indigenous Western Banded, but they’re still charmingly rubbery voracious devourers of insects, especially moths), and the Butte was going off sporadically, the coyote pack’s yelps ricocheting off the slickrock. There might have been the sharp yip of a Gray Fox, which also inhabit the neighborhood, but it was faint. Somewhere, the spadefootlets must have been hopping around foraging in the dark, as well.

After “bedtime” though, things really got going. A female raccoon marauded past the bedroom trailed by at least one kit from this year. Last year there were two separate families, one with two, the other with three kits each. That’s a lot of pounds of raccoons living off the yard, plus Papa, too, who has only half of a tail, diminishing his raccoon-gestalt but not his swagger. We’re not sure how many there are this year, because our view of them is most often through the arcadia door, and sightings are limited to who rolls by the framed glass, like watching a dog show on the TV animal channel.

Last night the main event (for me), however, was again being awakened by an owl. Not the Great Horned owl this time, but an owl I’d never heard in our yard: a Western screech owl. They’re not uncommon in the area — I’ve seen them peering out from day-roosts in saguaro cavities at the nearby Desert Botanical Garden — but we’ve never heard or seen them in our little scrap of modified desert. This one called from just after 2 am until the Butte really exploded about half an hour later, when the owl stopped. Its mellow short hoots were emitted in a cluster which descended slightly at the end. It sounded much like the “Morse code call” of its cousin the Whiskered screech owl, but that species doesn’t live in this part of Arizona. The call was soft but regular, and started up again at 4 am, and went on for at least 45 minutes, when I fell back to sleep.

So far, like the generously rainy Monsoon of 2008, this has been a generously owly season in the yard, and this Western screech owl, who may always have been here, or who may be a new neighbor, ushered in fall last night; I’m glad I was awake to hear it. With luck maybe we’ll catch a glimpse of it sometime, hunting pocket mice and crickets under the desert trees. Right now, though, I think I need a nap: the first nap of Autumn!

“The northern autumnal equinox takes place today, Monday, Sept. 22nd, at 15:44 UT (11:44 a.m. EDT) when the sun crosses the celestial equator heading south for the year. Autumn begins in the northern hemisphere, and spring in the southern hemisphere. Happy equinox!” (Spaceweather.com)

***

Update to an earlier post:

Our local Great horned owl has a friend. Last night from about 4 am we listened to two owls duetting and singing antiphonally for about half an hour, the higher hoots of the female alternating with the lower calls of the male. It’s early in the year for coursthip, but my guess is that these are our usual, established owls reinforcing their pair bond.

Last night at 3.00am exactly, I heard the Great horned owl call. Very close, somewhere right in the back yard. The windows were open because a light monsoon event had brought fresh rain-cooled air, so the call, though soft, carried clearly.

Great horned owls are regulars in our area because there are plenty of perches, and plenty for them to eat. A favorite owly destination is a big Aleppo pine in our back yard. At night that tree is stuffed with roosting doves and other perching birds, a veritable Fresh and Easy for owls. Sitting outside at dark with friends, we’ve watched a horned owl glide stealthily into mid-level branches and then listened as panic ensued among the roosting doves as the owl hopped between branches as if it were going aisle to aisle in a grocery store, filling a cart. Finally it burst out of the needles with a meal clutched in its talons. We got a good look at it is it slid past us, sihouetted against the lights of the house. The feather pool under the pine the next morning was evidence that it had enjoyed a bit of mourning dove.

They are not called “Flying tigers” for nothing. Horned owls, like toadlets, will eat anything that moves and fits down the gullet. Rock squirrels, snakes, desert cottontails, other birds (even other owls), insects, and bats — all are fair game. Even small pets may be at risk, if left unsupervised after dark. The first owl I ever saw was at the family dinner table when I was a kid: a thump, a commotion, and we looked up to see the underside of a Great horned owl pressed to the window, wings flapping against the glass. The owl was trying to separate the family cat (a calico named Ringo, to give you an idea how long ago this was) from the window ledge. A grown cat is awfully heavy prey, however, and the owl had to give up after a few seconds. No one was hurt, but the bird went away hungry. (It was a spectacular view of an owl in action, and I’ve wondered if that was THE bird for me, in a formative sense — I was no more than seven). The boldest hunters are often adults with young to feed — a nest full of hungry owlets requires a lot of sustenance. During that time of the year, parent owls sometimes can be seen hunting even during daylight, working a day job to put food on the table. So, hatching and fledging are timed to coincide with the local peak of yearly rodent production, usually spring, but in the desert areas often much earlier.

Our local owls have reproduced, and sometimes I’ve heard the distinctive, raspy oink of a horned owlet begging, installed on the top of a phone pole while its parents search the alleys for rats or young cottontails to stuff into it. (If you enjoy camping, you’ve heard a sound like it: the creak made by the plastic hinge on a cooler lid when it’s raised.) The female makes the same sound during courtship while soliciting her mate for food. In our area, courting owls can be seen and heard duetting on phone poles and rooftops, visible against the fading sunset sky. As they call together or alternately — the male and female have slightly different voices and cadences — they bow and “hoo.” She holds her tail up, soliciting attention from the male, who strikes a courtly pose to “sing,” tail raised and wings down, maximizing himself like an operatic baritone (he’s smaller than her). Here’s an excellent quote, where the author’s voice slides from ornithologist to owl, almost inadvertently:

“Courtship is fairly boisterous and involves bowing, bobbing, posturing, vocalizing, and allopreening. These elaborate activities lead, as one might hope, to copulation.” (from Hans Peeters, Field Guide to Owls of California and the West, my current favorite owl sourcebook. In the same series as the excellent book on Horned lizards, the California Natural History Guides, published by the UC Press)

If it’s still light enough while all this is going on, you can see flashes of white feathers at their throats, the “gular patch”, flashing as each hoot puffs the owl’s throat briefly. It’s a semaphore for them, like the feather tufts on the top of the head: a way of producing meaningful signals to each other: facial expressions without flexible tissue like lips or eyebrows.

As big, powerful generalist predators, Great horned owls can make it almost anywhere. Their range is right across the US and Canada through Central America and into northern South America. They live in urban, rural, and wilderness areas: desert, woodlands, mountains, wetlands, grasslands and cities, so the chances are you have them where you live, too. Keep an eye open, an ear cocked, and the Chihuahua in at night.

Below are Horned owl salt and pepper shakers from Three Star Owl. Each pair is an adult with an owlet in different stages of development ($48/pair).