Category: elf owl

An Incredible Explosion of Life

July brought us over six inches of very welcome rain! The summer monsoon – one of five distinct seasons here – has returned to southern Arizona after a two-year near-absence. Purple martins are cruising above the treetops and a family of Mississippi kites has been visiting us for days. We are seeing rattlesnakes on a daily basis. On sultry, warm nights, elf owls have been calling in the wee hours of the morning. Saguaros are fattening as they transport water in their tissues. Native grasses are  sprouting. The land and its life are rejoicing.

The changes on the landscape are incredible, happening with amazing rapidity and soaring fecundity. The mesquite bosque surrounding our home had been without a green understory during the entire past two years. Not any more! One glance out the window reveals a near-jungle of dense greenery standing five feet tall – much of it composed of one dominant plant with the unflattering common name of “pigweed.”

Fresh growth emerges with stunning speed and vigor after nitrogen-rich summer rains soak the land. This image is a week old; the understory plant community has doubled in height since then.

Pigweed is known to botanists as Amaranthus palmeri, and it is certainly not a “weed.” In the conventional sense, most of us consider weeds to be troublesome non-native plants. This one is a native species, and its presence speaks of great benefits to the land and its wildlife.

One of the primary winter forage plants for the deer that inhabit this river valley is pigweed. A good source of winter forage is critically important to wild ungulates. Rabbits, hares, javelina, and many rodents feed on the green plants in summer. Once the seed heads form, they tend to remain through autumn and winter on dead, standing plants. Great numbers of various species of sparrows winter in southern Arizona. The  seeds of pigweed are heavily fed upon by many of these sparrows and other native birds as well. Something that is very obvious, but often overlooked by many people, is the fact that the dense stands of pigweed are shading the ground. I can’t stress enough how important shade is in desert ecosystems! The ground retains much more moisture and soil temperatures are far lower, allowing fungal hyphae and numerous other microflora and microfauna to work in shallower horizons of the soil. This benefits all life.

The summer rains bring many creatures out of hiding. Among these are toads, countless insects, red velvet mites, and the largest millipedes living in the United States…

Giant millipedes spend nearly all of their lives underground, typically emerging only after monsoon rainstorms. This one was about five inches in length; some sources claim this species can reach up to nine inches in length. These fascinating, innocuous arthropods can live for ten years, growing longer as they add more body segments every time they shed.

I had taken several shots of the millipede, working close to the ground, before I noticed this small diamondback curled sixteen inches away. It never made a sound. When left undisturbed, these snakes are rarely aggressive. Their primary method of defense is stillness and excellent camouflage.

When one of these huge beetles comes flying by, it is guaranteed to get your attention. This is a palo verde root borer, measuring in at three inches in length. These beetles are another example of the many species that are brought out from hiding by the rains.

For many of our of native amphibians, monsoon rains furnish their only chance to reproduce successfully.  A strong population of spadefoot toads inhabits this valley, but they remain completely sequestered until strong summer rainstorms bring them up from their deep underground burrows. On July 3rd, the first monsoon storms rolled in –  a succession of two storms with plenty of lightning and life-giving rainfall. That night, the landscape was ringing with the voices of hundreds upon hundreds of spadefoot toads.

Couch’s spadefoot toad is the most abundant amphibian in the Middle San Pedro Valley, but only summer residents witness them.

A pair of Couch’s spadefoots mating. These amphibians must lay their eggs in water. In desert environments, the toads wait for summer storms to create suitable pools of water. Here, the male is grasping the female in a posture known as amplexus – when she lays her masses of eggs, he releases sperm into the water.

Spadefoot tadpoles mature more quickly than almost any other tadpoles on the planet – in as little as nine days. This is a species that has evolved to live in a hot, dry desert environment, where pools of water are not only rare, but tend to be very short-lived. It pays to mature quickly under such demanding conditions.

It is hard to say what to call the amphibians in this brief period of their lives; tadpoles or toadlets? At this stage in their development, the tails shorten very quickly. As newly formed toads appear, they can be seen hopping by the dozens out of their natal pond.

Just two days ago, despite the fact that I am always on the lookout for rattlesnakes, I nearly stepped on this one that was well camouflaged under the ramada. I am glad that we did not have an unfortunate interaction.

A Rare Bird Surprise, a Huge Insect, and the San Pedro River in October

It has been quite a while since I crafted a new post for this blog. During the past month, my life had been turned upside down with growing trepidation over the presidential election. I was not in a frame of mind conducive to writing. Now that the election is over, I feel a huge sense of relief and renewed hope. This was an election not only for the people, but one that will benefit wildlife and wild places as well.

I walked a perennial reach of the San Pedro River recently. There was  a new beaver dam, just a tiny one that was still under construction. Turkey, javelina, bobcat, deer, coyote, opossum, raccoon, and skunk tracks were visible in the mud along the stream’s edges. I was intrigued to find a set of feline tracks that suggested ocelot or jaguarundi, for they were certainly not made by a bobcat and were just as surely not left by a cougar, even a very young one.

A small, new beaver dam was discovered. This one was constructed using quite a few stones in addition to the usual combination of mud and tree branches.

October has finally brought some relief from the heat that so characterized this summer…109 consecutive, record-setting days of temperatures cresting at 100°F. or higher. The nights have cooled off and crisp air now graces our mornings. Our local woodlands have quieted considerably with the departure of many migratory birds, but there have been some amazing avian happenings here this month. A very rare event happened not long after the sun had set a few weeks ago. My wife, Kathleen, and I stepped outside to listen to the nocturnal sounds coming from the mesquite forest that surrounds our home. 

We heard it almost at once, a mysterious, alien-sounding voice emanating from midway up in the trees, only a few dozen yards distant. It was certainly an owl, but not a species that we had ever heard here before. On many a night, we have listened to the calls of great horned, western screech, barn, and elf owls in this woodland, but this was something new, something distinctly different. It suggested a screech owl, but both of us readily agreed that it was not “right.”

I had a growing hunch, so we went back indoors where we consulted a very useful website (xeno-canto.org), one that offers a multitude of audio files for most bird species across the globe. The first species that we chose to listen to was a bird whose range barely extends into the United States, a bird that inhabits oak and conifer habitats high on mountain slopes in extreme southeastern Arizona… 

As soon as we heard the recordings, we realized we had a whiskered screech owl hidden in the darkness of the tall mesquites only yards from our home! This was an owl that should not be here, for we live far from the high mountain slopes in the floor of a low-elevation valley. I believe that a major wildfire event from this past summer may provide the answer to this enigma. Less than 20 miles distant, the Bighorn Fire torched nearly all of the mid-to high elevation habitats off the face of an entire mountain range, the Santa Catalinas. Countless birds were driven off of those mountains, subsequently appearing in nearby places where they would ordinarily not be expected. For example, my friend Woody Hume, a very capable naturalist, told me that he had numbers of western bluebirds appearing at his place of residence not long after the fire. That is a species one does not expect to see during summer in the valley floor. Other such unusual species have been reported here this year. I would not be surprised if the owl that galvanized our attention had been living high in the Catalinas and wound up here, temporarily, as it looked for a new place to live.

A fully grown praying mantis crawls across my screen door. This is a gravid female, ready to lay her egg case, as evidenced by her swollen abdomen.

October and November brings new happenings in the insect world of southeastern Arizona. It is common to find adult preying mantises at this time of year. It is impressive to see one of these three-inch, bright green insects in flight. The individual pictured is an introduced species that has become widespread and firmly established in southern Arizona and other parts of our country.