weather – Discover-Nature

Seaside

Shorelines of oceans, seas, and large bodies of water around the world are habitats for plants and animals that thrive in challenging conditions. Tides occur twice each day when water levels rise over a six hour period to cover large areas before receding to leave those same areas open to the air until the next tide starts to move inland again.

^{Nearshore habitat zones by King County, WA;} ^{Littoral Zones by US Government}

Shoreline habitat has been classified into zones often known by many different names. The intertidal zone is the area affected by changing temperature and salinity conditions as water moves in and out with each tide. The subtidal zone is the lowest and is exposed to air only during extreme spring tides or storms. The backshore zone is the highest and is exposed to water only during extreme spring tides or storms.

^{Starfish & anemone in tidal pool by Jonathan Levy}

^{Sea urchin in tidal pool, Bahia de Banderas by Jim Hoffman, Mar 2017}

Many species of animals live in each zone and are adapted to living completely submerged as well as completely uncovered by water for several hours each day. They handle the change in temperature and salinity with exposure to air or water. Tidal pools may keep some animals submerged for far longer periods. Temperature, dissolved oxygen, and salinity change far less for these organisms.

Bryozoans by John Turnbull, Sep 2021; Sea anemone by Barb Ignatius; Squat lobster, Glathea rostrata, by FWC Fish & Wildlife Research Institute, Aug 2013

Some species can be found in every zone in the ecosystem, but many are anchored to rocks or dug into the bottom. Species may prefer one zone, but get washed into another zone by wave action. Many organisms have tough outer surfaces to put up with battering waves and exposure to sun and wind. All of the occupants are subject to a wide range of predators from those that move on dry land to underwater hunters. Let’s take a look at a few of the creatures able to live in these ever-changing conditions.

The sea anemone clings to rocks and protects itself by drawing in its tentacles to become a jelly-like blob. The squat lobster can be found under stones along the shoreline. Its tail is fan-shaped and facilitates quick escapes when the animal is threatened by pulling the lobster through the water with powerful strokes. Bryozoans are small filter feeding organisms protected by a hard exoskeleton that the animal can withdraw into for protection.

^{Dog whelk, Nassarius livescens, by Budak, Dec 2016}

A mollusk called a dog whelk is a stealth predator often found on rocky surfaces. It uses its tongue to drill through the shells of other mollusks, where it squirts a digestive juice into the prey’s shell which kills and partially digests the prey. The dog whelk then uses its tongue to suck up the soupy meal. The starfish is another fierce predator. It wraps its arms around a shellfish and pulls it apart. Upon opening the shell, the starfish pushes its stomach out of itself and into the prey’s open shell where it empties its digestive juices inside, and similar to the dog whelk, creates a tasty, soupy, meal.

Sea urchins can be found clinging to hard surfaces where they feed on algae and other small, encrusted animals. Fan worms look like a leathery tube among underwater rocky crags. Several feathery tentacles fan out into the water to filter out microorganisms flowing by.

Shorelines create a habitat that is constantly changing with tides moving in and out, inconsistent weather conditions, and a large variety of flora and fauna coming and going. Learn more about this fascinating habitat at the Jurica-Suchy Nature Museum or a natural history museum near you.

^{Botanical beach at Port Renfrew by James Wheeler; Feather Boa kelp in the surf by Kqedquest, May 2007; Rocky intertidal zone in Oregon by Minustide, May 2015}

Insects Over Winter

It is starting to get chilly in the Midwest as we head toward winter. Insects also recognize the shorter daylight hours and dropping temperatures. They use two main strategies to cope with winters: freeze avoidance and freeze tolerance. Avoidance may require travel or a dry place to stay warm. Tolerant insects can stay here and control their body’s response to freezing temperatures. Staying in place has several advantages including being able to emerge early in spring, allowing those insects to feed before predators are out.

^{Clockwise from upper left: Monarch butterflies on migration by Dopeyden, Getty Images; Cecropia moth cocoon by Sylvie Bouchard, Getty Images; Milkweed bugs by Rick Wood, Rick Wood’s Images; Four-lined plant bug, Poecilocapsus lineatus, by Heather Broccard-Bell, Getty Images Signature; Common pill-bug by Ines Carrara, Getty Images}

Those insect groups that opt for traveling to warmer climates often make a one-way trip. Monarchs are one of the best known insect migrators. Monarchs east of the Rocky Mountains leave in early fall to arrive at overwintering sites in the mountains of Mexico. Their offspring return to the southern U.S. in spring to breed, and this second generation returns to the East and Midwest over the following summer. Monarchs west of the Rockies overwinter in Baja, California, and many of the same individuals that fly south do return, but their trip is considerably shorter allowing time for breeding during summer months in the northwest U.S.

^{Honeybees in hive by OK-Photography, Getty Images}

Many different species of insects can control or stop ice formation in their bodies. Honeybees cluster together and shiver, generating enough body heat to keep the air above freezing in their hive. Other insects get rid of all the food and water in their bodies, becoming dehydrated and unable to freeze. Some species can control where ice crystals may form in their bodies, and prevent their formation inside cells that would cause harm to the insect. Insect species that retain some water use cryoprotectants, chemicals resulting from large amounts of sugar. One such chemical is glycerol, which lowers the freezing temperature of water and other liquids.

^{Dragonfly larva with fish by Mauribo, Getty Images Signature}

^{Fast running stream by Mburnham, Getty Images}

Some insects remain active throughout the winter. Aquatic insects in immature stages can easily spend the winter in fast moving or deeper water that does not freeze. Some insects move inside warm and protected places like attics, sheds, and gaps in house walls. They also overwinter in tree cavities, under bark, inside dead plants, and in old burrows. Allowing vegetation with hollow stems to stand through the winter will provide many populations a safe place to spend the season.

The insect version of hibernation is called diapause, when growth and development is halted until longer daylight hours prevail. Late winter weather patterns with warm periods interspersed with cold periods endanger many species. Another change we have experienced in recent years involves warm temperatures lasting later in fall and starting earlier in spring. These changes interrupt the historical natural cycles, causing insects and other animals to abort hibernation and actively look for food or mates. Food plants do not produce enough to support animal populations, or another cold period returns, and species are not able to adapt, and often perish.

^{A garden in winter by Vermontalm, Getty Images; Snag and deadwood in winter by BayDavn0211, Getty Images; Spring garden and returning insects by Anthony Lerma, Getty Images}

Insects are a vital part of healthy habitats, providing pollination services and food to many species. We can help overwintering insects by leaving dead stalks standing until late spring to provide safe habitat. Leaves left piled up provide nutrients, insulation, and a place of shelter. Uncovered soil can also host ground nesters such as native bees. Snags and logs provide lots of cavities protected from the weather. Selecting some plant species that bloom early or late in the year will provide additional food at those times. Growing plants in clusters enables insects to find all they need in one place. With a little planning, everyone’s backyard can be an inviting habitat for insects year-round.

Autumn Foods

Meteorological fall began September 1st, marking the beginning of cooling temperatures that lead into winter, the coldest time of the year in the northern hemisphere. As the days begin to cool, many plant species are producing ripe fruits and seeds and starting the process of going dormant until next spring’s warming temperatures and longer days signal a beginning of the next growing cycle. Some animals, especially birds, travel long distances, migrating to areas that stay warm throughout the year. Those who stay through the coldest months depend on having food sources available even while plants are dormant.

_{Grey-headed coneflower seed head by Laura Fischer Photography}

The best winter food sources for wildlife are native plants with berries and seeds available throughout the colder months. Birds including woodpeckers, robins, waxwings, bluebirds, thrushes, chickadees, quail, and thrashers rely on robust insect populations in summer. In winter, when insects are no longer available, having another food source such as seed heads and berries left standing in your garden fulfills this need while adding visual interest and wildlife watching opportunities for you.

^{Food items shown above: Acorns on forest floor by Liz West, Oct 2006; Shellbark hickory nuts by HeikeRau, Getty Images; Pine cones with seeds by GordonImages, Getty Images}

Several tree families including pine, hickory, oak, and cherry offer fruit and nuts lasting through the winter. Along with grass and wildflower stems, trunks and branches also provide habitat for insect eggs and larva that will emerge in the spring. Over winter, insects in these stages are available as food for foraging species that use beaks and claws to dig them out. Stems growing close together provide additional benefits as thickets that provide protection against cold winds and harsh weather and hiding places that are safe from other predators.

^{Berries & Seeds above: Aster seeds by David Hansche, Getty Images; Sunflower at sunset by Hazal Ak, Getty Images; Wild elderberries by StargateChris, Getty Images; Thistle seeds by JTCanada, Getty Images}

Sunflowers, elderberries, and serviceberries are important food sources for fall migrators and winter inhabitants, providing fat and energy to stay warm and active. Aster, thistle, and conifer seeds released throughout the colder months are a favorite food source for finches and other small perching birds. Oak acorns, beechnuts, and hickory nuts are eaten by many woodland animals including squirrel, chipmunk, deer, wild turkey, fox, and quail.

^{Wildlife enjoying an offering: Blue tit on suet by Hedera.Baltica, Dec 2022; Lunch by Audrey, Feb 2008; Pine siskins on thistle by Yooperann, May 2015; Purple finches by Stan Lupo, Oct 2016}

Some of these animals also forage through our backyards in winter as many berry producing plants in the wild are stripped bare during late autumn and early winter. Backyard plantings and feeders provide important supplementary food sources for these animals. A variety of species to consider planting include American persimmon, blackberry, blueberry, elderberry, raspberry, cranberry, paw-paw , and prickly pear cactus, holly, sumac, hackberry, viburnum, hawthorn, bayberry, red cedar, and juniper. You can learn more under Garden For Wildlife on the National Wildlife Federation website at https://www.nwf.org/Garden-for-Wildlife/Food.

Nature journaling is a great way to track your observations and learn more through later research

Opportunities to observe wildlife in your own backyard can be an exciting way to learn. Try tracking which plants are being eaten and at what times during the changing seasons. Record the weather conditions during those periods to learn what foods are relied upon during colder, harsher winter weather. Try a variety of suet, seed and nut varieties in feeders to attract a range of animals to your backyard for fun wildlife watching and education.

Tornado

Springtime in the Midwestern United States brings with it everything from light to heavy showers, including tornados. In Illinois, we see an average of 54 tornados a year, with most of them occurring in the month of May. Tornados also occur in other parts of the world during springtime, including Europe, eastern and western China, South Africa, southern Brazil and both the east and west coasts of Australia, but not as frequently as in the U.S.

A majority of storm fronts move from southwest to northeast, which is a contributing factor in the Midwest to the formation of violent storms. There are three types of tornados. Non super-cell tornados are small, narrow, and last for only short periods of time, usually only a few minutes. Wind speeds are low, topping out near 80 mph, capable of causing only minor damage. Squall line tornados are generated by smaller thunderstorms traveling one after another forming periods of rain interspersed with calmer conditions. As the end of a squall line bends, small tornados may form with lower wind speeds, usually causing no damage. Super cell thunderstorms are the largest, most powerful storms that can generate tornados ranging from small to great in size and intensity.

^{Upper left: Thunderstorm during VORTEX2 by Sean Waugh, NOAA-NSSL Lower left: Funnel cloud approaching the ground by National Severe Storms Laboratory, NOAA Right: Supercell often associated with violent weather by National Severe Storms Laboratory, NOAA}

Rainstorms form when cool, dry air overlays a layer of warm, moist air. As the warm air rises to higher altitudes, where there is less air pressure, it expands and cools, losing its ability to hold moisture. As water condenses from the cooling air mass, water vapor floating on the air forms clouds. As more warm, moisture laden air moves into the system, the water vapor droplets become heavy enough to fall as rain. As rain falls, it cools the lower air layer, reducing the warm air flow until the rain stops.

^{Photomontage of the evolution of a tornado : Composite of eight images shot in two sequences as a tornado formed north of Minneola, Kansas on May 24, 2016, by Jason Weingart}

Thunderstorms form in the Midwest from warm, moist air moving in from the Gulf of Mexico and cool, dry air blowing in over the Rocky Mountains. A third source of air from the jet stream may wick away enough rain drops so that the lower air mass does not cool, and the warm air keeps feeding and intensifying a storm. As air moves in different directions and at different speeds, the whole storm will start to swirl, tending to pick up speed toward the center of the storm, eventually creating one or more funnels of rotating air.

Tornados are categorized based on the Enhanced Fujita scale from EF-0 to EF-5. This scale gives an estimate of wind speed and severity of damage inflicted. A little more than half of all tornados are found in the EF-0 range where wind speeds do not exceed 85 mph (137 kph) and damage is minor. Less than 1% of all tornados are recorded in the EF-4 (winds 166-200 mph) and EF-5 (winds over 200 mph) ranges. Another recent discovery is that most of the more severe storms tend to produce multiple tornados rotating around each other. Occurrences of multiple small funnels are difficult to observe within a large and often opaque mass of water, wind, and debris. This discovery helps to explain damages where one house may be completely destroyed while the neighbor is almost untouched.

The afternoon is the most likely time of day for these conditions to exist, once the sun has had a chance to heat the earth and air masses in the lower altitudes. In the Midwest, most tornados occur between noon and 8:00pm. Weather services are constantly monitoring conditions to be able to identify when weather patterns exist that may result in the formation of a tornado. Outside warning sirens are used by many municipalities to let people know that dangerous conditions are imminent. If you are hearing a warning siren, move inside and stay away from windows. Tune into radio, television, or internet resources to obtain the most up-to-date information for your area.

Midwestern Prairie

Grasslands make up the largest habitat in North America and cover about one-quarter of the Earth’s surface. There are many different types of grasslands, each with its own descriptive name. Prairie, found in North America, is from the French word for “meadow;” steppes, found in Asia, is Russian for “flat, grassy plain;” pampas, found in South America, is from Quechua meaning “flat surface;” and veldt, found in Africa, is from Afrikaans meaning “field.” In all of these areas, grasslands are characterized by flat or gently rolling countryside.

From upper left: The African veldt by Cello8, May 2007; Sunrise on the Mongolian steppes by Nicolas Mirguet, Apr 2011; Pampas grasslands, Uruguay, South America by Guilherme Boettcher, May 2010; Nachusa Grasslands, Lee County, Illinois by Justin Meissen, Jul 2007

Prairies in Illinois were formed by the action of glaciers retreating northward at the end of the last ice age. Massive ice fields compacted the soils and flattened the landscape. Many areas retained much of the melting ice in ponds, creeks, and rivers. These provided much needed moisture to help establish the new flush of vegetation that moved in as the climate warmed.

White River Prairie, Wisconsin by Joshua Mayer, Aug 2016

Several different types of prairies can be found, differentiated by the mixture of grasses and flowering plants, called forbs. We classify prairies as wet, mesic, meaning moderately moist, or dry. The determination is made based on how much water is retained in soil layers, but can be greatly influenced by temperature, rainfall amounts, and fire. Grasses have narrow leaves, can grow in drier environments, and are the dominant plant type in most prairies. Forbs have broad leaves and require more moisture than grasses. Prairie plants often have deep root systems to access water and nutrients.

From upper left: Big Bluestem, Andropogon gerardii by Matt Lavin, Sep 2019; Rattlesnake master, Eryngium yuccifolium by Adam B, Jan 2017; Grey coneflower seed heads, Ratabida pinnata by JanetandPhil, Nov 2010; Frosty Prairie dock, Silphium terebinthinaceum by Anne McCormack, Dec 2010; Indian grass, Sorghastrum nutans by Douglas Mills, Sep 2015

Animals that inhabit midwestern prairies are adapted to this habitat. They are able to find water and food in drier conditions, when water is scarce. They avoid the hazards of fire sweeping across the landscape. They keep warm during cold winter months. They avoid predators in a landscape with few hiding spaces. Many species are able to burrow underground for warmth, to avoid fire, and to escape predators. Others live near the ground in thicker vegetation that provides cover from wind, cold, and attack.

From upper left: American toad, Bufo americanus by Alan Huett, Jul 2008; Sedge wren, Cistothorus platensis by Joshua Mayer, Jul 2015; Thirteen-lined ground squirrel, Spermophilus tridecemlineatus by ChristaR., Nov 2016; Prairie kingsnake, Lampropeltis calligaster by Peter Paplanus, May 2022; Northern harrier, Circus hudsonius by Wendy Miller, Dec 2010

At this time of year, prairie plants are starting to go dormant and many bird species are migrating southward to warmer climates where food and water is abundant. It is a great time to get out and observe plants as they set seed and surprise us with the many hues of autumn. Birds are abundant as flocks fly overhead on their migration. Birds that spend the winter here are searching for areas that will provide seed and cover during the coming cooler months. Other animals are out to gather plants for insulation in their winter dens or seeds to store in their larder. Keep your eyes and ears open as you walk the prairie paths this month.

Midewin tallgrass prairie preserve, Wilmington, IL by CheapShot, Jun 2012

Beat The Heat

This week, the weather has been hot for the upper Midwestern U.S. with temperatures topping out above 100°F. Combined with high dew points in the mid-70s, the heat index temperature was upwards of 110°F. Here are some ways that plants and animals keep cool in the extreme heat.

^{Mojave Desert by LezusRocks, Getty Images}

^{Kit fox at entrance to desert den by Stevelenzphoto, Getty Images}

Desert environments, where hot conditions exist daily, are home to numerous animal species that live underground. Heat from the sun penetrates soils and sand layers for several inches, but at 20″ below the surface of the sand in the Mojave Desert, temperatures are fairly constant around 86°F while the surface may be over 110°F. Few large mammals are known to use burrows, although kit foxes and humans are two examples. Basements and lower levels in buildings are often preferred areas on hotter days.

^{Shaded walk in the woods by Felixmizioznikov, Getty Images}

Shade from trees is highly effective in creating cooler areas. Leaves are lighter in color than most soils and paved areas, and leaves reflect much of the sun’s radiation upwards, away from the shady area underneath. Denser foliage and rough leaf textures enhance the cooling effect. Under a shade tree, temperatures may drop up to ten degrees and other surfaces no longer exposed to direct sunlight, including our skin, may be 20 to 40 degrees cooler.

^{African elephant by Petr Polak, Getty Images: Black-tailed jackrabbit by Rancho_Runner, Getty Images; Fennec fox by Nattanan726, Getty Images}

Vasodilation occurs when blood vessels near the skin’s surface expand so more blood flows next to the skin. Many animals living in hotter climates, including fennec foxes, black-tailed jackrabbits, and African elephants, have large ears with broad, flat surfaces devoid of hair, fur, or other insulation. The ear’s large surface area is covered by a thin layer of skin and blood vessels. During hot weather, heat carried in the blood through the ear is readily lost to the outside environment, providing a cooling effect for the rest of the body.

^{Large crowd by Shaunl, Getty Images Signature}

Evaporative cooling is another method through which heat can be dissipated from a body. Trees use this method by losing water vapor through their leaves during photosynthesis, cooling the air under the leaves. Humans employ this method in a process called sweating. We lose warm water through skin pores directly to the air around us. Sweating also moistens our skin’s surface, indirectly providing additional cooling as air moves across the skins surface and wicks away additional heat. An important aspect enhancing the effectiveness of this method is our posture. Being supported by two legs, rather than four, exposes much less surface area to the direct rays of the sun, and much more surface area to air currents.

^{Forest path by Inga Nielsen, Getty Images}

While sweating is good for cooling, it is removing water from the body, which must be replaced for the process to continue. Exposure to today’s temperature extremes may result in a loss of three gallons of water or more from an average-sized human. As you are out enjoying nature during hot days, remember to keep hydrating to stay cool and keep other bodily systems healthy.

Boreal Forest in Winter

The boreal forest is the largest tract of woodland on earth covering 11% of all land area, half again as large as the Amazon rainforest. It stores 30% of the sequestered carbon on earth. The area also contains a mosaic of wet meadows, ponds, lakes, marshes, and bogs interlaced among the trees. Tree species include many conifers, dominated by spruce, plus aspen, birch, willow and alder. The animal life is abundant, with every species that was there before European settlement still remaining.

^{Boreal Forest panorama by Mliberra, getty Images}

The boreal forest is distinguished by short, hot, wet summers and long, dry, cold winters. When the last glaciers retreated northward, many holes and fissures were left behind. As the ice melted, all of these depressions were filled with water. The underlying geology is mostly granite shield, a rock layer that holds the water in and contains few minerals that dissolve in water, yielding very clear water that does not promote algae or bacteria growth. Most lake life is found in the shallow, warmer edges which also provide support to nearly all of the land-based fauna.

^{From upper left clockwise: Alder tree by Mantonature, Getty Images Signature; Spruce trees by Hannu Koskela, Getty Images; Willow tree by smarko , Pixabay; Aspen trees by Adamisovitsch, Getty Images}

Winter time presents many challenges including less sunlight, colder temperatures, less available water, less food and shelter, and increased severe storms. Animals that are active daily have higher energy requirements in winter. They must often change their dietary sources to whatever is available in winter. Grey squirrels and beavers cache food during warmer periods. Birds eat foods higher in calories such as nuts, seeds, dried fruit, and insects found under tree bark. When changes are consistent from year to year, species develop adaptations to meet the requirements of each season and are able to live comfortably throughout the year.

Shelter becomes not only a place to hide from predators, but also provides protection from weather extremes. Snow of different thicknesses and weight covers the landscape. Snow is also a great insulator, keeping cold winds away from exposed skin. There is normally a layer of air between the ground and the snow cover immediately above. Temperatures in this space are warmer than the exposed air above the snow creating a winter habitat that is vitally important for many species. Mice and voles create burrows under the snow where they can huddle together for added warmth. Similarly, air pockets surrounded by a heavy growth of conifer needles create spaces above the snow cover for birds and some larger mammals to shelter. And many larger species will nestle into the snow pack to shelter from storms and wind.

^{Spruce grouse by Impr2003, Getty Images}

^{Willow ptarmigan by Alex Berger, Mar 2022}

Spruce grouse, Canachites canadensis, and willow ptarmigan, Lagopus lagopus, are not able to fly more than several yards. They grow feathers on their feet to insulate them and aid in traction. Grouse use the air layer at ground level to shelter in.

^{Portrait of a snowshoe hare by Jim Cumming, Getty Images}

^{Canada lynx by Carol Gray, Getty Images}

Ptarmigan, along with snowshoe hares, Lepus americanus, and short-tailed weasels, Mustela erminea, all change color to pure white to hide from predators. Snowshoe hare and Canada lynx, Lynx canadensis, have very large feet that aid in walking on snow without sinking in. Arctic fox, Vulpes lagopus, are winter specialists with compact bodies and short legs and ears that limit their exposure to cold, and large, furry paws that enable them to walk on top of the snowpack. With their long, bushy tails wrapped around their heads, they can withstand winds and temperatures to fifty below zero.

^{Stayin’ warm, Arctic fox by PEDRE, Getty Images Signature}

You can learn more about this cold but wondrous habitat by searching online for boreal forest, referring to the southern portions of the habitat, or taiga, referring to the northern portions. Also, look for information concerning seasonal adaptations for species in your own area, or visit a local natural history museum such as the Jurica-Suchy Nature Museum in Lisle, Illinois.

Junco Winter Adaptations

Juncos spend the winter spread across the United States. They spend summers at breeding areas in southern Canada, and in fall males migrate to the northern states while females migrate farther south. Males have several adaptations that allow them to more easily survive in colder climates, and allow them to return early to breeding areas to claim the best territory for attracting a mate among the females that come back a few weeks later.

^{Male dark-eyed junco, Junco hyemalis by Christian Gott, dec 2022}

^{Female dark-eyed junco, Junco hyemalis by Joseph Higbee, Dec 2014}

Junco males are small, round-bodied birds with a slate gray back and are larger and weigh more than females. According to Bergmann’s Rule, large bodies have a smaller surface area relative to their volume, and are therefore able to retain more heat than longer or skinnier bodies. Being able to retain more heat for longer periods, an average-sized male junco can go two hours longer without food than an average female, and a large male may go more than ten hours longer between meals. This can be an essential factor when living through a colder period.

^{A cozy tree cavity by Steve Valasek, Apr 2014}

^{Accommodations for one… by Hedera Baltica, May 2016}

Tree cavities provide excellent places to shelter in winter. At night and in severe weather, juncos seek a small, tight space big enough for a single bird that provides protection from wind and moisture. During daytime hours, while foraging, juncos can often be found in conifer trees whose year-round needles provide a windbreak and a place to remain out of sight of predators.

^{Male junco with fluffed-out feathers by Ken Gibson, Dec 2016}

Juncos have a normal body temperature of 107˚F, well above the average outside temperature on a winter day which could be between -10˚F and +20˚F. Maintaining body heat requires a high-caloric diet to create the heat and resources to not allow the heat to escape. Birds have muscular control over their feathers and are able to fluff them, trapping air next to their skin. Preening is a daily activity where oil secreted from a gland above the tail is rubbed on all of their feathers providing a moisture barrier that keeps water, snow, and cold winds away from their skin. Both feathers and trapped air make up two layers of insulation that work efficiently to retain body heat.

During extreme weather, it may be advantageous to remain sheltered and inactive when the amount of calories burned to get a meal is more than the calories in the meal. When sheltering for longer periods, juncos may intentionally lower their body temperatures a few degrees, entering a state of torpor. This state lasts for only a few hours, but saves enough energy so that the bird does not need to forage for an extended period during a day. Using muscular control, birds can generate body heat by contracting and releasing their muscles, similar to shivering in mammals, and bring their body temperatures back to normal and resume daily activities.

^{Juncos feeding on ground by mwms1916, Apr 2015}

^{Juncos feeding on ground feeder by synspectrum, Nov 2015}

Northern U.S. flocks of juncos in winter are 70% or more males, while most females spend winters in the southern U.S. This is also true for several other species that migrate with juncos including tree sparrows, song sparrows, and mourning doves. Juncos will be leaving in late winter to return to breeding grounds across Canada, but for the coming few months we will certainly enjoy their presence in our area.

Desert Habitat, pt.3

In the past two blogs, we have explored deserts and the plants which inhabit them. Animals native to these habitats have general adaptations for coping with temperature extremes, aridity, and finding water, food, and shelter. Strategies include hunting during cooler hours including at dawn, dusk, or overnight; obtaining water from sources other than standing water; burrowing underground to avoid temperature spikes and solar radiation; ability to conserve water in their body; ability to dissipate body heat; and being well-camouflaged. Look for each of these adaptations in the following species that live in our desert regions.

Greater roadrunner, Geococcyx californianus, by Tony Cyphert, Sep 2018

Ord’s Kangaroo Rat, Dipodomys ordii, by Andy Teucher, Jun 2005

The greater roadrunner, Geococcyx californianus, can only fly for several seconds at a time, but can reach speeds up to 17mph when running. They hunt early in the morning, retiring to shade when temperatures heat up mid-morning. Water requirements are met from foods including grass and prickly pear cactus, plus prey that includes lizards, scorpions, and rattlesnakes. Roadrunners do not urinate, but can excrete salt and save the water. They have an un-feathered area under their chins used to dissipate body heat. Ord’s kangaroo rat, Dipodomys ordii, is another species that gets all of their water requirements from the seed they eat. Individuals live in underground burrows, coming out only at night to feed. They conserve water in their bodies and do not sweat or pant. They have many predators, but with a 9-foot jump and excellent hearing, they are hard to catch. Seeds are collected and stored in their burrows, and they will gain 50% more water from the underground humidity before being eaten.

Horned Toad, Phrynosomasp., by TJFrom AZ, May 2009

Gila monster, Heloderma suspectum , by Karla Kishinami, Apr 2012

Horned toads, Phrynosoma spp., are small, ant-eating lizards with thick scales to conserve water and deter predators. To escape a predator, these animals can squirt a directed stream of blood from their eyes up to five feet away. They are sandy-colored with undefined outlines allowing them to easily hide amid rocky outcrops. Normally active during the day, they can retreat to burrows or under rocks if temperatures become too hot. During winter, horned toads will spend a period of inactivity, called brumation, in underground burrows. The Gila monster, Heloderma suspectum, is another lizard with armor protected skin marked with black and pink coloration that camouflages them well in sandy soils. They shelter from daytime heat under rocks and shrubs, emerging in early morning or evening to hunt small mammals, lizards, insects, and bird eggs. One of only two venomous reptiles in North America, their venom adversely affects their prey’s nervous system. The short, thick tail stores water in fatty tissue for use when needed.

Tarantula, Aphonopelma sp., by Saguaro National Park, Nov 2020

Western coral snake, Micruroides euryxanthus, by Ashley Wahlberg, Apr 2016

The tarantula, Aphonopelma spp., shelters in deep burrows lined with silk to prevent the sand from caving in. They are nocturnal hunters of insects, arthropods, and small lizards with a bite that delivers a small amount of venom to stun their prey. Venom immediately starts to break down tissue to liquify the meat, allowing the spider to use sucking mouth parts to draw in its meal. The Western coral snake, Micruroides euryxanthus, is brightly colored with red-white-black-white banding and venom that is twice as deadly as most rattlesnakes. They are very secretive, living under rocks or buried in the sand. Coming out at night or on some overcast days, they hunt for lizards and other snakes. Venom causes rapid paralysis and respiratory failure, although due to their small size and small amount of venom injected, they are not a threat to humans.

Like many environments, a healthy desert community exists when plants, animals, and habitat are all present and undisturbed. With much of the life in deserts underground, walking off trails and driving off roads can negatively impact what is under the surface. Removing plants and rocks used for water and shelter is equally damaging. I encourage you to get out, observe, and enjoy this unique habitat, or research many of the fun and interesting adaptations at a local natural history museum.

^{Pictures above clockwise: Bark scorpion by Josh More, May 2014; Cactus wren by Mick Thompson, Feb 2019; Jackrabbit, by Mark Gunn, Mar 2014; Javelina, Sonora Desert, by Richard Bonser, Jan 2005; Tarantula hawk wasp by Jim Mulhaupt, May 2010; Sonoran mud turtle by Grigory Heaton, Sep 2022; Round tailed ground squirrel by Wendy Miller, May 2022; Hoary bat by Michael Pennay, Sep 2009; Cactus deermouse by J.N.Stuart, Oct 2011}

Desert Habitats, pt.2

Pequop Mountain foothills, Great Basin Desert, Nevada by Matthew Roth, Apr 2016

Big sagebrush, Artimesia tridentata by RCWinton, Aug 2008

There are four major deserts in North America. The Great Basin runs from central Idaho to northern Arizona. It is a high altitude plateau, with very cold winters, mild summers, and few plant species characterized by big sagebrush, Artimesia tridentata.

The Mohave Desert, a small area covering southern Nevada and southeastern California, is known for its cold, rainy winter season resulting in hard freezes leaving little water available. The Joshua tree, Yucca brevifolia, a yucca variety growing above 3000′, is the tallest plant in the area.

Joshua tree, Yucca brevifolia, by Melissa Delzio, May 2011

The Chihuahuan Desert, covering the high altitudes of northern Mexico ,is subject to hard freezes from arctic winds scouring its surface. Winter rains occasionally occur supporting a rich diversity of low shrubs and small cacti.

The Sonoran Desert, covering southern Arizona and the Baja Peninsula, has high and low altitudes, hot to mild temperatures, and periodic rainfalls. The winter season, with mild temperatures, does not limit the plant and animal diversity as much as in the other three, colder deserts. The Sonoran Desert, which includes several habitat types, supports a rich variety of species including 2000+ plants, 350+ birds, 100 reptiles, and 30 native fishes.

Desert plants exhibit many similar features that make them well-adapted to the hot, dry conditions of their native habitat. Most are succulents, plants with thick, fleshy stems to retain water for use during hot, dry periods. Plants often have spines in place of leaves to reduce the surface area exposed to wind and heat, greatly reducing water loss from evaporation. Spines also add a layer of protection to prevent animals from eating the plant. Stems are green, containing chlorophyll and water, and this is where photosynthesis takes place. Bloom periods and pollination occur during winter or nighttime when cooler temperatures prevail.

Creosote bush, Larrea tridentata, in flower by Malcom Manners, Apr 2017

Century plant, Agave americana, by J.Maughn, Mar 2020

Several distinctive native species characterize North American deserts including cacti, succulents, and other plant varieties with spines. The creosote bush, named for its distinctive antiseptic smell, grows three to nine feet tall and has small yellow flowers. This plant grows in colonies of cloned bushes which may live for long periods as epitomized by the King Clone of the Mohave Desert, estimated to be about 12,000 years old. The century plant, another long-lived plant, is a species of agave noted for its large cluster of wide leaves with spiny edges. The plant may live up to 30 years, but flowers only once, then dies.

^{Clockwise from top: Prickly pear by Fishfoot, Mar 2018; Prickly pear buds by Diandra Rodriguez, Nov 2011; Prickly pear cacturs in bloom by Stepan Mazurov, May 2009; Prickly pear cactus glochids by Tracie Hall, Nov 2017}

Often seen cacti include the prickly pear cactus which is actually a group of several species all native to North America. Modified stems, called pads, are often mistaken as leaves. These store water, photosynthesize food and sugars, and produce flowers. All species grow long, single spines in addition to glochids, clusters of very fine, tiny spines. Glochids are often not noticeable but can be easily detached if brushed against and once lodged in the skin are painful and difficult to remove. The saguaro cactus is another common plant. Its distinctive shape, with a tall central column and “arms” growing at right angles, is easily recognizable as one of the Sonoran Desert’s native species. It is the largest cactus in North America, growing to over 40′ high, and living 100 years or more. White, waxy flowers open only at night to attract bats, its preferred pollinator.

Saguaro cactus by Ralph Earlandson, Apr 2017

Many natural history museums have excellent displays of plants and animals from world-wide desert biomes, including one of my favorites, the North American desert display at the Jurica-Suchy Nature Museum. In my blog next week, I will introduce some of the notable animals and their adaptations to desert life.

Desert Habitat, pt.1

A biome is a type of global habitat characterized by temperature, rainfall, latitude, elevation, and wind pattern. Plants, which are unable to move about, are used to characterize each type of biome, and are well-adapted to their native habitat. The desert biome is the driest habitat found on earth. In a desert, plants are widely spaced and are adapted to life with little or no moisture except for annual periods when brief rains may be heavy, sparse, or not occur at all. Even within these harsh conditions, plants may be present supporting a rich diversity of species.

_{Clockwise above: Hidden Valley, Joshua Tree solitude by Don Graham, Apr 2013; Sonoran Desert sunset by Jasper Nance, May 2009; Sonoran Desert layers by Art DiTommaso, Apr 2020; Mohave Desert by Melissa Delzio, May 2011}

A common factor of all deserts is the aridity or lack of moisture. Aridity can be determined by how much water is available in the habitat combined with the rates of evaporation from heat, radiation, and wind exposure. Another consideration in determining aridity is how much moisture the air can hold. Neither extremely hot nor extremely cold air easily retains moisture. Freely running water is only available in the desert for the briefest period of time immediately following a rainfall, a scarce and unpredictable event.

Deserts form in areas where dry air predominates. Understanding how weather influences the Earth’s surface helps to identify where to find the world’s desert regions. At the equator, air is warmed by direct sunlight causing it to rise and absorb large amounts of water from the oceans. When the warm air mass encounters cooler air at higher altitudes, it spreads out both northward and southward. Cooler air causes the absorbed moisture to condense into rain in tropical latitudes. The outward moving air mass, now dryer and cooler, also begins to fall back to the earth’s surface, picking up heat from the sun’s radiation and the hot ground. Air masses generally descend and move back towards the equator around 30˚ latitude, which is where many deserts occur.

Rain shadow on leeward side of mountains on Oahu by Loren Javier, Jun 2010

Exploring Greenland’s grass and Dry shrub vegetation by Eugene Kaspersky, Jul 2016

Deserts can also be formed from rain shadows and temperature extremes. As prevailing winds encounter mountains, air is forced up the windward side and flows down the leeward side. As air rises, it cools, once again condensing any moisture into rain which falls on the windward side. Dry air coming over the mountain forms a rain shadow that leaves little moisture for the habitats on the leeward slopes. Temperature extremes occur in both hot and cold regions. Dry, hot air descending from the tropics form warm deserts. Cold, dry air from polar winds form cold deserts such as those found in Antarctica and Greenland.

Desert temperatures vary widely, both daily and seasonally. Dry air and cloudless skies allow a maximum amount of solar energy to reach the surface where it is absorbed and converted to heat, raising daytime temperatures dramatically. At night, air temperatures plummet as solar radiation ceases and heat is quickly wicked away into the cooler atmosphere. Temperatures may fluctuate as much as 100˚ in a 24-hour period. Ultraviolet radiation also presents other challenges to living organisms. Intense sunlight can damage skin cells, degrade retinal tissue, and destroy chlorophyll molecules in plants.

Rain in the Sonora Desert summer monsoon season by Kevin, Aug 2013

Green Sonoran Desert after brief winter rain by Wayne S. Grazio, Fwb 2017

Deserts experience seasons, just as those found in other biomes. In desert areas of Arizona, there are five recognized annual seasons. Spring, February through April, is characterized by mild temperatures and windy days. It is a dry season as warm winds wick away all exposed moisture. Summer, in May and June, is hot and dry, with many species remaining dormant to escape the heat. Summer monsoons, July through mid-September, signals a change in wind direction bringing moister air northward from the tropics. Frequent thunderstorms occur most years providing a period of replenishment for shrubs and trees. Autumn, in October and November, returns to warm and dry conditions. Winter comes in December and January bringing in mild temperatures and the possibility of a few rain showers.

The climate of the world’s deserts makes survival difficult, but many species have adapted to these conditions in some remarkable ways. Next week, we will investigate the desert regions of North America and their vast diversity of life.

_{Clockwise above: Blooming hedgehogs by Jasper Nance, Apr 2010; Desert globemallow by Take-A-Hike Arizona, Mar 2009; Desert woollystar, Eriastrum eremicum, Sonoran Desert by SSBiker1, May 2011}