prey – Discover-Nature

Bird Beaks

Beaks or bills? Two interchangeable words naming the horny part of the jaw of a bird. They have numerous uses including gathering food, feeding, preening, and display, and are often used for functions that would be accomplished by arms and hands on other animal species. Let’s take a closer look at their structure and how birds use them for feeding.

Beaks come in a variety of sizes, and most are proportionate to the size of the bird’s head. Two or more of the bones comprising the lower jaw in birds are often fused together, increasing the strength of the overall structure. Birds do not have teeth, allowing the jaw bones to be lightweight, making it easier for a bird to hold its head out in front of its body while flying.

^{Barn owl, Tyto alba, skull showing fused jaw bones by Didier Descouens, Jul 2010}

Beaks are made from bone covered with keratin, a structural protein providing strength and rigidity. Yet beaks have some flexibility which adds to their dexterity when in use. The inner surface of the keratin layer is constantly growing while the outer surface is equally being worn away by use. Both upper and lower jaws are jointed where they attach to the skull, allowing for extended movements including the ability of a bird to open its jaws wider than most other animal species.

^{Great white pelican, Pelecanus onocrotalus, by Craig Adam, Feb 2013; Red-headed woodpecker, Melanerpes erythrocephalus, by Mark Moschell, May 2016; Evening grosbeak, Hesperiphona vespertina, by Fishhawk, Feb 2021}

A beak is specialized for every species depending on diet and food gathering methods. Cone-shaped beaks, found among cardinals, grosbeaks, and finches, can trap, cut, and crush seeds. Scoop-shaped beaks allow skimmers, spoonbills, and pelicans to slide their lower jaw under slippery prey, then catch and hold onto it . Beaks tipped with a chisel-like point are used by woodpeckers probing into crevices in hard materials. Along with a reinforced skull, keratin reinforces the beak’s toughness, standing up to repeated hammering and prying movements.

^{From upper left: Blue-gray gnatcatcher, Polioptila caerulea, by Dave Wendelken, Jul 2023; Pied flycatcher, Ficedula hypoleuca, by Edward Anderton, Jun 2012; Ruby-throated hummingbird, Archilocus colubris, by Mark Moschell, Jun 2019; Great-horned owl, Bubo virgianus, by Kevin Milazzo, Feb 2021}

Narrow tweezer-like beaks, used by gnatcatchers, warblers, and wrens, stab or seize small insects from branches. Wider and flatter tweezer-shaped beaks on purple martins and flycatchers can snatch an insect in flight. Long, slender beaks on hummingbirds are made for sucking nectar from the deep recesses of long, tubular flowers as well as catching tiny insects, such as fruit flies. Sharply pointed, hooked beaks are used by eagles, owls, hawks and shrikes to stab prey and hold on while pulling the meat apart into mouthful-sized chunks.

Many beaks serve more than one feeding function, as species change their diet from one type of food to another as seasons change. Tongues are an important addition to the mouth, manipulating food items for beaks to be more effective. Different sizes and colors of beaks convey information to other individuals about a birds sex and maturity level. This essential body part provides birds with many of the same capabilities as other animal species. Come to the Jurica-Suchy Nature Museum, or a nature center near you, to learn more about the many adaptations of birds.

^{Ruddy Duck, Oxyura jamaicensis, by Sergey Yeliseev, Nov 2013}

Pamir Wildlife

The Pamir Mountains form the western edge of the Tibetan Plateau. A pamir is a high-altitude valley or plateau surrounded by mountains. Many valleys in this range exceed 14,000 feet in altitude, and peaks reach well above 20,000 feet, making these some of the highest mountains on the Euroasian continent. The area contains the major center of glaciation in this part of the world, and all of the nearby mountain ranges are still being forced upwards by movement of the Indian-Australian tectonic plate pushing northward under the continent.

^{Pamir Knot, Hindu Kush satellite image by Jeff Schmaltz, NASA}

^{Pamir Mountains by Amanov Dmitry, Jun 2014}

Wildlife in the Pamir region is well-adapted for high altitudes, long, cold winters, and short growing seasons. Mountain people use the land for grazing large herds of domesticated sheep and yaks, but grazing space must also be shared with wild sheep, wild yaks, dozens of bird species, over 700,000 insect species, and many large predators. Let’s look at a few of the more notable species.

^{Himalayan vulture, Gyps himalayensis, on Rupin Pass trail by SahanaM, Oct 2018}

^{Himalayan vulture, Gyps himalayensis, by OK-Photography, Getty Images}

The Himalayan vulture, Gyps himalayensis, inhabits the pamirs up to 18,000 feet. These birds easily soar on warm thermal updrafts, but are not capable of long distance flight. They are often found basking in the sun on high, rocky perches. Traveling in large flocks, they follow grazing herds, keeping watch for dead animals. They can be aggressive to most other predators at a kill site, but give way to snow leopards, wolves, and cinereous vultures. The biggest threat to current populations is from drug overdoses of diclofenac, an anti-inflammatory drug that has been heavily used to treat injury in domesticated herds.

^{Herd of Marco Polo sheep in the Tien Shan mountains, by okyela, Getty Images}

^{Marco Polo sheep, taken at Berlin Zoo by Cloudtail, Aug 2018}

The Marco Polo sheep, Ovis ammon polii, is the largest sheep in the world, with large, spiral horns reaching six feet in length, with spans up to five feet across. They feed in the early morning and spend the remainder of the day basking quietly in sunny grassland. Their feet and hooves provide sure footing among sharp ridges and loose scree, and they spend nights sleeping among large boulders for protection. As the climate has warmed, there has been a loss of snowpack, resulting in less available fresh water for drinking and growing thick grasslands. These factors are driving the sheep to lower altitudes where they are more susceptible to predators including gray wolves, red fox, and brown bear.

^{Snow leopard, Panthera uncia, by Irbis1983}

^{Snow leopard, Panthera uncia, by Bernard Landgraf, Jan 2005}

Snow leopards, Panthera uncia, have seen a steady decline with a current population of fewer than 10,000. Their thick fur, gray/white with black rosettes, provides great warmth in colder altitudes, but is prized by poachers, who constitute their main threat. They are solitary animals, active for several brief periods daily, and dependent on healthy populations of ibex and sheep to eat. Powerful legs and furred paws enable them to pursue prey, in any weather, across rocky mountain terrain. After making a kill, they move the carcass to a protected area to eat. At one time, these predators were hardly ever seen, but overgrazing has caused humans to move domesticated animals into areas where snow leopards normally hunt, providing more opportunities for these predators to be killed by protective herdsmen.

^{Wild yak, Bos mutus, by Adarsh Thakuri, Jun 2008}

^{Wild yak, Bos mutus, by the Editors of Encyclopedia Britannica}

Wild yak, Bos mutus, can live in extreme conditions at altitudes up to 20,000 feet. They are large animals standing 6′ tall, weighing 1500 pounds, with black horns spanning six feet. Black, long, fine hair hangs all the way down to their feet, providing warmth for the body and legs. Yaks are very social, forming large herds of several hundred animals. They graze in two groups, with the females typically found about 300′ higher in altitude than the males. Females with young often keep to high, steep slopes where predators, including wolves and bears, are less prone to roam. Wild yaks readily hybridized with domesticated species, resulting in a natural spread of the gene pool.

^{Apollo swallowtail butterfly, Parnassius apollo, by Hectonichus, 2007}

^{Clouded Apollo swallowtail butterfly, Parnassius apollo, by Zeynel Cebeci, Adana Turkey, May 2016}

Butterflies are another common inhabitant of high-altitude mountain regions, particularly from the genus Parnassius, known as the snow Apollo swallowtail family. They are color adapted with dark bodies and wing bases that readily absorb heat from the sun providing a source of quick energy. Their normal ranges are found above 14,000 feet, and they are active for only 2-3 months annually, during the short summer season. Dozens of species have been identified with many having very small populations, numbering only a few hundred individuals. Poaching for collectors remains their main threat.

At the Jurica-Suchy Nature Museum, we have many of these and other species on display in our mountain region diorama. Consider a visit to learn more about the wildlife of high-mountain plateaus worldwide.

^{High-altitude species from around the world on display at the Jurica-Suchy Nature Museum include: Marco Polo argali sheep, Alaskan brown bear, bighorn sheep varieties, mountain goat.}

Cicadas

Cicadas are found in habitats with deciduous trees on every continent except Antarctica. There are about 3,000 species worldwide; and 170 make their home in North America, including several species divided into three groups with 13-year or 17-year life cycles, found exclusively in the eastern and central United States. The map below shows where various groups are located.

Cicadas hatch from eggs laid in tree branches. After dropping to the ground and burrowing into the soil, they spend the majority of their lives as a nymph living underground. Using their rostrum, a long, sharp rigid structure that can penetrate the outer layer of tree branches and roots, they feed on the sugar and water flowing through the xylem tissue of the tree. Species classified as annual cicadas actually live from one to nine years, some emerging each summer. They are active for four to six weeks to mate, lay eggs, and then they die.

Look closely to see the rostrum sticking out in front of the nose

Magicicada after emerging from final molt by Karly Tuminello

Cicadas have wide set eyes, short antennae, and large, clear wings with membranes clearly visible. The surfaces of their outer wings are covered by small, blunt, waxy spikes. They are water repellant, keeping the insect dry. These spikes can also break up and kill any potentially harmful bacteria landing on the surface.

^{Magicicada species showing short antennae & clear wings by Karly Tuminello}

Beneath the wings are muscular structures called tymbals which can be flexed creating a sound like banging a drum. The buzzing sound commonly associated with cicadas is a result of rapidly flexing these muscles. Tymbals are found on both sexes, and are used to hear sound as well as produce sound. Males often form large groupings to enhance their sound and attract more females to a single location.

Magicicada waiting for wings to harden after molting by Karly Tuminella

Nymphs start to emerge when underground soil temperatures are above 64⁰F, usually in late May in the northern hemisphere. Males emerge about two weeks before females. After emerging, the nymph will find a suitable perch and molt to reveal a fully winged adult; then spend from one to six days waiting for their wings to harden. Males fly up into nearby deciduous trees to find a suitable mating perch and begin calling to attract a female, which will join the male after her molt is complete. After mating, the female lays about 600 eggs. She cuts 25 to 30 small slits in branches and deposits about 20 eggs in each where they will remain for six to ten weeks before hatching. Both sexes may mate several times with different partners, although most only mate once.

Cicada’s mouth parts are strong enough to pierce tree bark, but they do not bite or sting, although they may pierce human skin if handled roughly. They do not pose any danger to humans and have not been known to carry any harmful disease. They feed on sap, not foliage, so they pose no threat to mature trees. Younger or smaller trees with only a few branches may be overwhelmed by the many slits made by a female laying a full brood of eggs. Lots of slits may cause scarring that could kill smaller branches.

^{Empty cicada husks provide food for many species by Karly Tuminello}

Cicadas and their empty husks do provide food for many predators including birds, fish, mammals, herps, and other insects. The emergence of the periodical cicadas will provide a feast for their predators, whose populations will boom next year before being reduced by less available food over the following several years. One theory for why there are periodical species concludes that cicadas emerging in mass numbers can overwhelm the predators need for food, allowing a great number of cicadas to breed and maintain their own high population. Other theories also exist to explain this natural phenomenon, but whatever the reason, they are harmless insects with a very interesting life cycle for us to observe this year.

Dinosaurs At The Museum

Dinosaurs roamed North America millions of years ago, and while they are no longer part of the wildlife, we are able to see, study, and learn from them at the Jurica-Suchy Nature Museum (JSNM). Bones, skulls, teeth, and stomach contents unearthed at various sites are housed in numerous worldwide institutions.

^{Triceratops at JSNM by DonArnold, Oct 2023}

Triceratops was a common visitor to areas of western North America in the late Cretaceous period, from 68 to 66 million years ago. The name is Greek meaning “three-horned face.” The animal’s distinctive skull has two long horns located above the brow line of each eye, and one shorter horn off the tip of the nose. The brow horns, situated high on the head, may have exceeded three feet in length on the largest animals. A frill, or bony structure surrounding the back of the head, makes the head seem larger than the skull alone. In Triceratops, the frill could exceed seven feet from side to side.

Triceratops were large animals standing 10 feet tall with a length, from nose to tail, of about 30 feet. Their teeth were long and intimidating, but these animals were actually vegetarians. The teeth were used to shear through fibrous plant material that was difficult to cut and chew. The horns were very strong. They were used for defense against predators and when dueling for territory with other Triceratops individuals.

^{Tyrannosaurus rex half skull at JSNM by DonArnold, Oct 2023}

Tyrannosaurus rex, Greek for “king of the tyrant lizards,” is another species from the western United States. These animals moved swiftly on two huge rear legs. The body weight was balanced over these legs by a long, heavy tail and a massive skull. A full grown adult was estimated to be 13 feet tall, 41 feet in length, and weighed about 10 tons.

The skull cast at the Jurica-Suchy Nature Museum has several openings, thought to reduce the mass of the bony structure. It is very wide at the back, tapering to a narrow nose in front. The eyes are situated to provide excellent binocular vision, allowing the animal to accurately judge size and distance while running at a good pace. This was helpful for trapping prey and avoiding attackers.

^{Artistic rendering of Edmontosaurus by DariuszSankowski, Pixabay}

^{Edmontosaurus femur at JSNM by DonArnold, Oct 2023}

Several other fossils found in North America are on display at the museum. One is a femur from an Edmontosaurus, a genus of hadrosaurid or duck-billed dinosaur that lived alongside Triceratops in the western U.S. This dinosaur was a plant eater that could move on either two feet or all four feet. It is one of the best-studied species in the world due to the large numbers of bones that have been found. The skull held several hundred teeth, although only a few were in use at any given time. The rest were ready replacements for teeth that broke or wore down from the abrasive plant material in its diet.

^{images clockwise: Diplomystus analis; Diplomystus dentatus; Icthyosaur Stenopterygius Quadriscisius; Knightia alta; Mioplosus; Notogonius Oscuius; Perca obtusa; Phareodus testis; Priscacara liops; Pterosaur Phyllurus Ramphrhynicus; all images by DonArnold, Oct 2023, JSNM}

Other fossils available to view at the Jurica-Suchy Nature Museum include several fish species from the Cretaceous period that can be seen in the gallery above. Come on out to the museum to see these fascinating specimens and learn more, or take a trip to visit a natural history museum near you.

Oak-Hickory Forest

Oak-hickory forests makeup one-fourth of all the woodlands in the eastern United States. At the end of the last ice age, oaks were only found in the Appalachian Mountains and the driftless section where glaciers did not form in southwestern Wisconsin. In the last 15,000 years they have repopulated the land from the Mississippi River to the Atlantic coastline.

Clockwise from top left: Quercus alba, white oak by Chris Andrei, Getty Images; Quercus palustris, northern pin oak by Michel VIARD, Getty Images; Quercus rubra, northern red oak by ValerijaP, Getty Images; Fraxinus pennsylvanica, green ash by Garsya, Getty Images; Carya ovata, shagbark hickory by Elmar Langle, Getty Images; Prunus serotina, black cherry tree by Ina Hensel, Getty Images

Oak-hickory forests are an open woodland community where trees make up less than 10% of the plant life. Species of both the red oak and the white oak groups dominate these wood including Northern red oak, Quercus rubra, black oak, Quercus velutina, white oak, Quercus alba, and bur oak, Quercus macrocarpa. Two members of the hickory family, shagbark hickory, Carya ovata, and bitternut hickory, Carya cordiformis, are also found in abundance. These forests are rich with several other tree species most notably red maple, Acer rubrum, sugar maple, Acer saccharum, black cherry, Prunus serotina, black walnut, Juglans nigra, and green ash, Fraxinus pennsylvanica.

^{Arisaema triphyllum berries by ES3N, Getty Images}

^{Arisaema triphyllum, jack-in-the-pulpit by Holcy, Getty Images}

The open structure of the forest supports a large variety of other plants that offer food, shelter from predators and weather, and places to raise a family. Food sources are plentiful including fruit-bearing plants of the genus Vaccinium, which includes blueberries and raspberries, and vines from the genus Vitis, which includes several species of wild grape. Bloodroot, Sanguinaria canadensis, and Jack-in-the-pulpit, Arisaema triphyllum, along with several clovers, attract birds and insects that attract larger predators, creating a rich forest community. It is estimated that oak-hickory forests support over 300 animal species including birds, mammals, insects, reptiles and amphibians.

^{Oak woodland by fotoVoyager, Getty Images Signature}

Oak trees provide a haven for wildlife. Acorns, the fruit of an oak tree, are large and heavy, so they do not spread far from the tree. They offer good nutrition and are a favorite of many wildlife species, whether eaten immediately or cached and eaten over time. Oak trees retain their dead leaves throughout the winter, not letting them fall until early spring. The leaves provide shelter from wind and rain, as well as hiding many smaller birds and mammals from airborne predators. Oak trees have craggy bark providing shelter for insects and other small animals including many amphibian species that overwinter under the bark.

After dying, oak leaves retain tannin, a chemical that slows down their decay. As leaves build up on the forest floor year after year, they create thick layers used by amphibians, reptiles, small mammals, and insects for shelter from predators and weather. In winter, the leaf layer provides insulation from the snow and cold, allowing small animals to move around under the snow, hunting for food, or moving to other sites. However, the leaves can be advantageous to some predators, as well. Owls, and other nighttime hunters, have excellent hearing and can easily detect the sounds from crackling leaves as prey attempts to hide and flee.

^{Gnarled tree with large cavity from wepix, Getty Images Signature}

^{Nature lives forever in fallen trunks by Oleksiy Brunets, Getty Images}

Many tree species are susceptible to dry rot of their interior wood, and none more-so than members of the red oak family. This provides natural cavities for woodland species. Woodpeckers, owls, chickadees, and nuthatches, plus squirrels, raccoons, bats, amphibians, and reptiles all use cavities for shelter and protection. Almost 40% of animal species inhabiting oak-hickory forests will use cavities at some point in their lifetimes. As trunks and branches decay and fall to the forest floor, they create opportunities for food and shelter. In addition, animals drawn to these spaces provide food for larger predators.

As you walk through forested areas over the summer, take note of the tree species and the overall structure you observe Can you spot holes in trees, logs laying on the forest floor, and thicker layers of leaf cover? Are the woods open where you can see possible lanes of movement? What plants have fruit or seeds? Keeping a journal of observations helps us to identify the changes and enjoy these rich habitats.

^{Dry oak forest in springtime by Meinzahn, Getty Images}

^{Swamp oak forest in springtime by Aleksander, Getty Images}

The Ocean Deep

Seventy percent of the Earth’s surface is under the ocean, and only a small portion is in shallow water along continental shelf areas. The ocean is divided into five zones; the sunlight zone, above 650 feet; the twilight zone, extending to 3300 feet; the midnight zone, down to 13,000 feet; the abyssal zone, down to 21,300 feet; and the hadal zone, extending to the bottom of the ocean. Below 3,000 feet, no light penetrates from the surface; the water temperatures are freezing; and oxygen levels are very low. The pressure exerted on any surface at sea level is 14.7 pounds per square inch (psi), and humans can withstand three to four times this amount, or 45 psi to 60 psi. At 3,000 feet deep, the pressure is 1,345 psi.

^{Delta submersible by Robert Schwemmer, CINMS, NOAA, Oct 2010}

Pressure keeps sea water from becoming solid ice, even when it is at freezing temperatures. It also makes exploring the ocean difficult, requiring special submersible vehicles. Everything moves more slowly under pressure, and a submersible can take an explorer deep into the ocean given enough time and oxygen. Deep sea creatures can survive because the structure of their bodies is lean and contain no air spaces. Let’s take a look at a few of the wondrous creatures that live in these habitats.

^{Humpback anglerfish by August Brauer in Public Domain}

In the darkness of deep areas, many species find food and mates by touch. Others may use bioluminescent communication – the ability to create light from a chemical reaction between luciferin and oxygen within an organism’s body. Lights show up as spots of various colors on different parts of the body and may be used for attracting a mate, confusing a predator, or attracting prey. Lanternfish have several spots located on their heads, undersides, and tails. Female anglerfish and dragonfish have a shaft that protrudes from their head out in front of their mouths with a glowing tip attracting prey within striking distance. Gulper eel use the lighted tip of their tail as a lure to attract a meal.

^{Tripod fish by NOAA Okeanos Explorer Program, Public domain, 2010}

^{Fangtooth fish by Sandra Raredon-Smithsonian Institution, Public domain}

Tripod fish have two pelvic fins and a tail fin that are elongated and can be filled with fluid to stiffen them, allowing the fish to stand on the ocean bottom while conserving energy. Two long, wavy pectoral fins act as arms to detect prey floating or swimming by and push the prey toward their mouths. Fangtooth fish is another species that can detect vibration and nearby movement. This species is only six inches in length, but have the largest teeth in proportion to their body size of any fish in the ocean. The long lower fangs fit into pouches in the roof of their mouths so their teeth do not pierce their brain cavity.

^{Dragonfish teeth array by UC San Diego Jacobs School of Engineering, May 2019}

The dragonfish, another small fish about six inches long, has a frightening array of teeth located on its jaws and tongue. Their teeth are transparent and their bodies are black, making them impossible to see even in depths where there may be some light. The jaws are loosely hinged, allowing the fish to open its mouth wider than normally hinged jaws would allow. Prey swimming nearby may not notice the wide opening, nor be able to detect the transparent teeth, making the dragonfish a top predator of invertebrates, squid, and shrimp. In addition, when biting, they inject a highly toxic poison to paralyze and kill their prey. This toxin can be dangerous to humans getting bitten or attempting to eat this species.

^{Giant spider crab by Michael Coghlan, Jan 2014; Gulper eel by Claf Hong, Mar 2005; Lanternfish, Myctophum punctatum1 by Emma Kissling}

Some fish practice diel vertical migration, a pattern of movement where a species feeds near the surface at night and moves back into deeper waters to rest during the day. Lanternfish come up to feed on zooplankton and fangtooth fish feed on squid in shallow waters. Some species, including anglerfish and gulper eels, have elastic-like skin for their mouths and stomachs. Mouths can be opened extremely wide to swallow prey larger then themselves. The food is contained in a similarly elastic stomach which shrinks slowly as digestion progresses. Several different species of spider crabs roam the ocean depths scavenging for meat or plant material that falls to the bottom.

Deep-sea animals are seldom seen, but are not immune from climate change and human impacts. Scientists continue to study changes in deep-sea food webs caused by overfishing, ocean acidification, and expanding low-oxygen zones. Learn more about the habitat and species of these areas at the Jurica-Suchy Nature Museum at Benedictine University or your local nature museum or aquarium.