The rainfall of the July monsoons is one of the most important ecological events of the year for the Central Highlands. Photo by Ty Fitzmorris.
By Ty Fitzmorris
By the beginning of July, all of the denizens of the Central Highlands are at their most parched and sun-scorched. During a rainless, hot June, with relative humidity reaching as low as one percent, many plants withered, while birds, mammals, and insects scoured the landscape for food and water. But one day in early July, the afternoon stormclouds build to a deep, rumbling gray, and break open, and massive, round raindrops fall on the thirsty land as the wild creatures emerge from their dens to marvel.
Though the climate of the Central Highlands can be harsh for part of the year — dry and fire-scorched in early summer, cold and snowy in the winter — these tough times are typically followed by some of our most resplendent seasons. So it is with the annual drought of June, which is followed by the coming of the monsoon rains in July. Especially in years like this one, in which fire danger is very high and the forests are kindling-dry, the first rains are a real cause for celebration.
They are, however, something of a mixed blessing — they will bring a second wave of growth and flowering, but in the short term they bring lightning, which, when combined with the low fuel-moistures from a dry June, might lead to a proliferation of new fires. Lightning-storms are some of the most awe-inspiring sights in the natural world, and, interestingly, they are a source of nitrogen for our nitrogen-limited soils. The energy of the lightning strike combines nitrogen with ambient oxygen, forming nitrogen oxides, which are bound into the soil, increasing plant growth.
When the rains come, we enter the second massive proliferation of life in the Central Highlands, which will continue until September. Birds fledge their young while reptiles hatch, and some mammals, such as the bats, give birth, while others begin their mating seasons, as do the Badgers. A second “spring” of flowering happens now, led by the deep purple four-o-clocks (Mirabilis spp.), varicolored penstemons, golden columbines, clovers, and monkey-flowers. But most noteworthy is the explosion of insect life during this time, especially at night. Beetles fly in huge diversity, from the massive Grant’s Hercules Beetle (Dynastes granti) to the Glorious Scarab (Chrysina gloriosa), considered to be the most beautiful beetle in North America. Thousands of species of moths, from giant Saturn moths to small bird-dropping mimic moths to beautiful Cecrops-eyed Silkmoths are also flying now, and can be drawn to porch lights for close observation. During the daytime butterflies, dragonflies, damselflies, and cicadas abound, while the ants launch their nuptial flights. The dazzling diversity of life in the Central Highlands in July is extraordinary, and is one of our most wonderful times of the year.
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Common Merganser young learn to fish by watching their mother but are still unable to fly. Photo by Ty Fitzmorris.
A very brief survey of what’s happening in the wilds …
High mountains
• Ravens teach their young to fly now, waiting for the approach of monsoon storms and flying in the rolling blasts at the leading edge of the storm system. Ravens are unusual in that they fly preferentially in storms and perform extraordinary aerobatics in gales and high winds.
• One-month-old Elk calves begin travelling with their parents and start to lose the spots that have helped hide them during the first few weeks of their life.
• Badgers (Taxidea taxus) begin courting and will soon form pairs and mate. These remarkable creatures are important predators of pocket gophers, venomous snakes, and mice and rats.
• Orange Milkweed (Asclepias tuberosa) flowers, attracting fritillary, checkerspot, and, most notably, Monarch butterflies.
Visit: Maverick Mountain Trail, No. 65.
Ponderosa Pine forests
• Bergamot (Monarda menthaefolia) flowers. The beautiful lilac flowers of this plant draw in native bees in large numbers, giving it its other name, Beebalm. The flowers of Bergamot are edible, and spicy to taste, used in salsas, while the leaves are fragrant, and often used as a mint-like spice.*
• Several species of ants have their annual nuptial flights within days after the first rains. Some species are so consistent that they fly almost the same day every year. Early in the morning, winged males and females fly in tremulous clouds from the previously unobtrusive colony entrance. After mating, the males die, and the females shed their wings and start their own colonies.
• Wiry Lotus (Lotus rigidus) flowers. These very small snapdragon-like flowers are bright iridescent yellow, but change color to orange and then to red after they are pollinated. Their yellow appears bright to us because it includes a certain amount of ultraviolet pigment, and human vision sees just barely into the ultraviolet spectrum. Bees, by contrast, see ultraviolet clearly, and flowers of this color are called “Bee-purple.”
Visit: Miller Creek Trail, No. 367.
Pine-Oak woodlands
• Young Western Screech Owls begin to lose their down and molt into their adult plumage. During this time, they stay near their parents and hunt with them just after sunset.
• Longhorn Oak Borers (Enaphalodes hispicornis), large, lumbering black beetles with long antennae, emerge from their underground pupae and begin looking for mates. These beetles are harmless, though they are large and somewhat alarming.
Visit: Little Granite Mountain Trail, No. 37.
Pinyon-Juniper woodlands
• Juniper berries proliferate on some trees while other trees have none. This is because some of our species, such as One-seed Juniper (Juniperus monosperma) and Alligator Juniper (Juniperus deppeana) have their male and female flowers on separate plants, while others, most notably Utah Juniper (Juniperus osteosperma) have both on the same plant. These berries, which are actually cones surrounded by fleshy tissue, are important food sources for many birds and mammals.
Visit: Tin Trough Trail, No. 308.
Grasslands
• Young Sonoran Mountain Kingsnakes (Lampropeltis pyromelana) hatch after the first rains. These snakes are harmless to humans, though they somewhat resemble the venomous Sonoran Coralsnake (Micruroides euryxanthus). Their identities can be determined by the simple rhyme “Red on yellow kills a fellow, red on black is a friend of Jack.” If the red on the snake’s body borders yellow, the snake is the venomous Coral Snake, if the red borders black, then the snake is the more common Kingsnake. Either way, all of our Prescott snakes like to be left alone, and will move away from people given the chance.
• Bluestem Pricklepoppy (Argemone pleiacantha), also known as “tissue-paper flower” for obvious reasons, blooms.
• Parry’s Agave (Agave parryi) seed pods begin to grow by the end of the month.
Visit: Mint Wash Trail, No. 345.
Rivers, lakes, & streams
• As the monsoon rains arrive, our intermittent creeks, such as Granite, Butte, Aspen, and Miller Creek, begin running, sometimes in turbulent flash floods.
• Young Common Mergansers are nearly grown, though still unable to fly. They will stay with their mother and learn to fish for several more months before striking out on their own.
• Arizona Blackberry (Rubus procerus), which is, in spite of its name, not native to Arizona, begins bearing its delicious berries along the perennial streams of the Verde Valley.*
• Golden Columbine (Aquilegia chrysantha), one of our most beautiful flowers, appears now.
• Grand Western Flood Plain Cicadas (Tibicen cultriformis) emerge at night from their larval homes in the roots of cottonwoods, sycamores, and willows. These alien-like creatures climb up trees and buildings in the thousands and slowly shed their larval skins, as the winged adult breaks through. Once their wings harden, the cicadas fly into the treetops. This is by far the most conspicuous insect in the Central Highlands, and very little is known about its ecology or biology.
• Dragonflies abound above creeks and lakes. Look for Giant Darners (Anax walsinghami), Flame Skimmers (Libellula saturata), and Twelve-spotted Skimmers (L. pulchella).
Visit: Willow Lake Loop Trail, off of Willow Creek Road in Prescott.
Deserts/Chaparral
• Prickly pears, mesquites, and mimosas bear their seeds and fruits while Western Pipistrelles and Western Mastiff bats bear their young and horned lizard eggs hatch.
• Couch’s Spadefoot Toads (Scaphiopus couchi) emerge at night, sometimes in the hundreds, to eat, mate, and lay eggs after the beginning of the monsoon rains. The tadpoles can mature in as few as eight days, a crucial desert adaptation since pools rarely last long.
• Tarantulas emerge in sometimes large numbers with the rains. These spiders are harmless to humans, but should not be handled due to stinging hairs on their abdomens.
• Rainbow Hedgehog Cactus (Echinocereus pectinatus) and Buffalo Gourd (Cucurbita foetidissima) flower.
Visit: Agua Fria National Monument.
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Prescott weather
Average high temperature: 89 F, +/-2.8
Average low temperature: 57.8 F, +/-2.7
Record high temperature: 105 F, 1925
Record low temperature: 34 F, 1912
Average precipitation: 2.88”, +/-1.72
Record high precipitation: 8.8”, 1908
Record low precipitation: 0”, 1993
Max daily precipitation: 2.96”, July 24, 1970
Night skies
• July 12: Full Moon at 4:25 p.m.
• July 26: New Moon at 3:42 p.m.
• July 28: Delta Aquarid Meteor Shower peaks after midnight. This shower should produce a large number of visible meteors since the two-day-old New Moon will set early and leave dark skies for meteor spotting.
• July 29: Alpha Capricornid Meteor Shower peaks after midnight. The overlap of these two showers during a dark time of the month should produce some extraordinary meteors. The Capricornids are characterized by slow meteors, most moving at no more than 15 miles per second, and can produce brilliant fireballs.
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Ty Fitzmorris is an itinerant and often distractible naturalist who lives in Prescott and runs Peregrine Book Company and Raven Café as a sideline to his natural history pursuits. Contact him at Ty@PeregrineBookCompany.Com with questions or comments.