By Ty Fitzmorris
A Siva Hairstreak nectaring on Rosemary flowers.
April arrives in a thunderous proliferation of life— a raucous, enlivening yawp in the Wilds after the long quiet of winter. Snowstorms are an increasingly remote possibility, and the majority of the month is sunny and warm, with butterflies, returning migratory birds, native bees, growing and flowering plants, and mammals in the thrall of mating and bearing young. There is more activity in the natural world than can be easily followed, and the flowering of plants, emergence of insects, return of migrant birds and bats, and the appearance of mammalian young all begin now.
The verdant wave of spring swells up from the deserts along south and western facing slopes and riparian corridors, as the new leaves of riverside trees unfurl and the earliest flowers unclasp. These first flowers provide nectar and pollen for butterflies, solitary bees, flies and damselflies that are looking to find mates and lay eggs. Many species of mammals are giving birth, as are the Beavers and Porcupines, while the young of other species, such as the Black Bears, are emerging from their dens and beginning the long process of learning to forage and navigate their landscapes, preying on these early insects and plants.
A breeding plumage Mallard basks in the late sunlight on Oak Creek.
The wave of spring migration gains in volume through April, as the murmurs of the first swallows and bats trickling quietly northward along the creeks grows into a roar of neotropical warblers and broad-winged hawks. Warblers follow riparian corridors northward, wearing a bewildering array of breeding plumages as they glean insects from the broad leaves of cottonwoods, alders, willows, and sycamores, ultimately headed as far north as the arctic circle. Broad-winged hawks, including Swainson’s, Rough-legged, and Ferruginous, follow the rise of thermals, large rotating columns of heated air that rise off of broad plains, such as those in Chino Valley. Swainson’s Hawks can be seen in groups up to 10,000 strong as they migrate between the Argentinian pampas and the Canadian tundra, a flight only rivaled in scope by the Peregrine Falcon.
Butterflies, the real vanguard of spring, fly in amazing diversity beginning this month, as they mate and lay eggs. Look especially for orange and black checkerspots, commas, question-marks, yellow and sometimes blue swallowtails, dark, low-flying iridescent skippers, and soaring, gold-tinged Mourning Cloaks. In some areas without flowers many of these species can be seen drinking the sap of tree wounds, and damp patches of mud along riversides can provide amazing observation spots.
A very brief survey of what’s happening in the Wilds--
- Black Bear cubs cautiously emerge from dens with their mothers and begin learning to forage for grubs, leaves, and roots.
- Leaf-buds of Gambel Oak and Aspen swell nearly to opening.
- Porcupines give birth late in the month, usually to one baby, and will spend more time than usual on the ground. Porcupines feed on the inner bark of conifers, including Douglas Fir and Ponderosa Pine, and can live up to 10 years. Their babies are born with their eyes open, their teeth already erupted, and their spines harden within hours.
- Long-tailed Weasels give birth to 4-5 young.
Example: Maverick Mountain Trail, #65
Ponderosa Pine Forests
- Cherry trees (Prunus virginiana) flower, along with wax-currants (Ribesspp.), paintbrushes (Castillejaspp.) and locoweeds (Astragalusspp.).
- Ponderosas ‘weep’ sap from their branch-tips, creating a slight daytime rain of small, watery sap drops. Pines may release sap for several reasons, including the movement of water and sap into their growing branch-tips, defense against insect pests, notably bark beetles, and most unusually, to communicate with other trees. As the chemical composition of one tree’s sap changes in response to pest attacks, it can trigger similar changes in nearby trees, which fortify them against the pests.
- Bark beetles, including the infamous Ipsbeetles, emerge from soil and begin excavating nuptial chambers in Ponderosas. Healthy Ponderosas can fight off a beetle infestation, but in drought years, which are worsened by the overcrowding of trees that has resulted from the last century of fire-suppression, beetles may overwhelm tree defenses and kill many trees. Interestingly, though, it is not the beetles themselves that kill the trees, but rather fungi that the beetles carry that infects the living wood of the tree, making it digestible for the beetles.
Example: Miller Creek Trail, #367
- Acorn Woodpeckers continue breeding and tending young. These woodpeckers are unusual in that they nest in colonies, and tend the young of other, often related, nestmates.
- Coyote pups emerge from their dens, though the group of siblings will remain together for up to a year before pairing off with members of other families and establishing their own packs.
- Valerian begins flowering. This plant is extensively used as a muscle relaxant, sedative, and soporific.*
- Black, Gray, and Arizona Oaks change color and drop last year’s leaves, as they grow soft, lighter-colored ones. This ‘spring fall’ is an unusual adaptation among the trees, and coincides with flowering for several of our oaks.
Example: Little Granite Mountain Trail, #37
- Lemonadeberry (Rhus trilobata) flowers. This species gets its name from its tasty, though sour, berries, which can be used to make a lemonade-like drink.*
- Cliff-rose (Purshia stansburiana) begins flowering, drawing flies and small halictid bees to its blooms.
- Airborne juniper pollen begins to decline noticeably.
- White-tailed and Mule Deer shed their antlers.
- Ringtails, cat-like relatives of Raccoons, begin mating.
Example: Tin Trough Trail, #308
- Spring butterflies fly in dazzling diversity. Look for fritillaries, sulphurs, blues, duskywings, grass-skippers and swallowtails.
- Many flowers blooming, especially in low and mid elevations. Look for the small yellow flowers of Barberry (Berberis haematocarpa), visited by native bees, and the fragile white flowers of Evening Primrose (Camissonia brevipes), visited by evening moths.
- Parry’s Agave begins growing its long, asparagus-like flowering stalk. Though these agaves flower only once, the plant itself does not die, but resprouts a new rosette of leaves from its base after flowering. The flowers are visited by many species of insects, birds, and bats.
Example: Mint Wash Trail, #345.
- Creeks run feebly, full of spring algal growth, while water-striders reach full size and hunt for other insects on the surface of the remaining water. As the last water dries up in one area, many water striders grow wings and fly to water nearby.
- Black Hawks, whoarrived this last month from their wintering grounds in Central America and Southern Mexico, rebuild their streamside nests and court mates. Males sometimes place a single green branch on a nest, and stand proudly on it, advertising their nest-building prowess and attractiveness as a partner, while females circle them, assessing.
- Beavers give birth to their kits in their streamside dens, who will remain with their parents for up to 2.5 years. Beavers are keystone species in our riparian ecosystems, shaping everything from the flow of rivers to overall riparian diversity. They have been known to live 20 years in the wild, and they typically mate for life.
- Damselflies, including indigo bluets and iridescent rubyspots, emerge from their aquatic pupae in lower riparian areas and begin mating and laying eggs. Dragonflies also appear now, including the charismatic Flame Skimmer (Libellula saturata).
- The leaves of riparian trees completely unfurl now, including those of Velvet Ash, Arizona Alder, Arizona Sycamore, Fremont Cottonwood, and Boxelder. Cottonwoods also release their cottony seeds, while the helicopter-shaped seeds of Boxelder ripen.
- River Otter young open their eyes for the first time.
Example: Bell Trail, #13.
- Sugar Sumac (Rhus glabra) flowers. It is named for its sugary sap, which has been used as a sweetener. The berries, though edible, are sour.*
- Iridescent tiger beetles (subfamily Cicindelinae) emerge from their pupae and begin hunting for flies and other insects. These beetles are among our most spectacular insects, iridescent green and purple with cream-colored spots, though they are difficult to see. They often fly ahead of hikers on trails, landing and running quickly, and can sometimes be seen with binoculars.
- Eastern Collared Lizards (Crotophytus collaris) can be seen sunning on rocks in riparian uplands. These brightly colored lizards are predators of small insects, mammals, and reptiles.
- False Mock-orange (Fendlera rupicola) begins flowering and is visited by bumblebees and carpenter bees.
- Ocotillos, paloverdes, Creosotebush, Mammilariaand Echinocereuscacti and Velvet Mesquite flower, drawing an extraordinary diversity of native bees.
Example: Agua Fria National Monument
In The Skies
- 7th- Full Moon & Supermoon at 7:35pm. This is the third (of four) 'Supermoon' of 2020, during which the Moon will be on its closest approach to the Earth, and will appear very slightly brighter and larger than normal.
- 22nd—Lyrid Meteor Shower Peak & New Moon at 7:27pm. This meteor shower runs from the 16ththrough the 25thbut peaks tonight after midnight, producing up to 20 meteors per hour, some of which leave luminous trails. The new Moon will provide for perfect viewing conditions, especially during this time of year, when night skies tend to be clear.
Climate Note: Winter temperatures and precipitation for the period from December 2019 through March 2020 were very nearly at their 118-year average at the Prescott Weather Station, which will likely lead to a beautiful spring across our region.
Average High Temperature: 67.1oF (+/-4o)
Average Low Temperature: 34.3oF (+/-3.1o)
All-time High Temperature: 88oF (2012)
All-time Low Temperature: 11oF (1899 & 1924)
Average Precipitation: .89” (+/-1.11”)
All Time High April Precipitation: 6.9” (1926)
All-time Low April Precipitation: 0” (8.5% years on record)
Maximum Precipitation In One Day: 3.4” (4/17/1917)
Maximum April Snowfall: 9.8” (1965)
Source: Western Regional Climate Center