tool use – 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}

Bird Beaks

Birds have an amazing ability: flight. They use their wings, equivalent to our hands and arms, to lift themselves into the air and keep themselves aloft. But they still need to be able to do all of the things that mammals use their forelimbs for, and for that, birds have beaks, also called bills.

^{Female mallard, Anas platyrhycnchos, by Traci L. Smith Images}

^{Mallard diving for food by Alexas_Fotos, Pixabay}

A bill has an upper and lower jaw bone covered with toughened skin. The edges of each bill may be serrated for cutting, grooved and etched for grasping, or smooth. On some species, edges are soft, pliable, and loaded with nerve receptors that can detect what is moving through the bill. This allows birds that siphon their food from murky water to detect food even when it is not visible.

^{Black skimmer, Rynchops niger, fishing by Nick Dale, Getty Images}

^{Atlantic puffin, Fratercula arctica, by Stockomotion, Getty Images Signature}

The bill’s skin sheath constantly exfoliates, or peels. New skin constantly grows from underneath, drying and hardening to replace the old skin. Excess layers of skin grow at the bill’s tip where most of the wear and tear takes place. Skimmers, of the genus Rynchops, have bills that grow at twice the rate of other species. They feed by trailing their lower bill in the water as the fly, wearing the skin down at a faster rate. Other protuberances and colors may enhance the bill. Atlantic puffins, Fratercula arctica, grow a bright orange, yellow, and black bill extension only during breeding season.

Bill shapes vary greatly among bird species and are used in a variety of ways for feeding……

Pelicans, genus Pelecanus, have hooked upper tips and a large pouch hanging under the lower jaw allowing them to scoop slippery fish out of the water and hold onto them.

^{Pelican hooked tip & pouch by McCaig, Getty Images}

The long-billed curlew, Numenius americanus, has a slim, curving bill that can reach deep into sand and mud for insects, clams, and small crustaceans.

^{Curlew probing the beach by Dypics, Getty Images}

The American oystercatcher, Haematopus palliatus, can pry open oysters and other bivalves.

^{Black oystercatcher with clam by Victoria Morrow, Sep 2020}

Ruby-throated hummingbirds, Archilochus colubris, have long, slim bills for probing deep flower nectaries to sip the nectar inside.

^{Ruby-throated hummingbird, Archilobus colubris, by Mattcudaphotos}

Whippoorwills, of the family Caprimulgidae, have bills fringed with bristles to catch insects by swinging their bills left and right while in flight.

^{Eastern whippoorwill, Antrostomus vociferus, bill with fringe by Budgora, Jun 2022}

Close-up of Eastern whippoorwill bill with fringe

Bills make great multi-use tools for many other daily activities. These may include preening, building nests, digging, turning eggs over, defending oneself, attacking prey species, scratching, assistance when moving and climbing, and displaying color and shapes during courtship and breeding. Other bill shapes are shown on the Jurica-Suchy Nature Museum’s ‘Bird Beak Adaptations’ slide below. Come to the museum to learn more about these wonderful adaptations and other fascinating birds facts.

Nuthatches

In northern Illinois, it is still winter, and we have enjoyed watching various birds at our backyard feeders, including nuthatches. There are four species native to North America and about two dozen more found world-wide. Taxonomists have moved several species back & forth between genera in recent years, making the exact number of species vary from time to time. The name is from an English reference to the behavior of wedging a nut into a crevice and pecking at it until the inner portion is hatched and can be eaten.

White-breasted nuthatch, Sitta carolinensis by Mdf, Dec 2005; Pygmy nuthatch, Sitta pygmaea by Len Blumin, Mar 2006; Brown-headed nuthatch, Sitta pusilla by Anne Davis, Nov 2013; Red-breasted nuthatch, Sitta canadensis by Katie Herr, Dec 2013

Nuthatches have short tails and legs, compact wings, powerful bills, and strong claws. Nuthatch species have similar markings including varying hues of grayish-blue wings, black caps, a white throat, and light colored white-buff-reddish bellies. In most species, a dark eye-stripe and white cheeks frame each side of the face. Males and females are hard to distinguish, although males may have darker hues on their bellies.

White-breasted nuthatches, Sitta carolinensis, stand 5″ tall with a white face completely surrounding the eyes. They range from southern Canada to Mexico. Red-breasted nuthatches, Sitta canadensis, have a white face and neck and range from southern Canada to the central U.S. Brown-headed nuthatches, Sitta pusilla, have a white belly and cheeks with a white spot at the nape of the neck. They are found in the pine forests of the southeast U.S. Pygmy nuthatches, Sitta pygmaea, characterized by a white spot under their eyes, are found west of the Rocky Mountains from British Columbia to central Mexico.

White-breasted nuthatch, Sitta carolinensis, heading down by Sarunas Burdulis, Feb 2021
Click > below to listen to the song recorded by Aidan Place, May 2020

Nuthatches are the only birds that can walk head first down a tree trunk, allowing them to forage up or down a tree trunk, seeing insects in crevices missed going the other way. They are comfortable eating while hanging upside down, as are woodpeckers; however, the nuthatch does not use its tail for support relying solely on the strength of its feet. They eat insects and invertebrates when available, but will readily feed on seeds, peanut butter, and suet in colder periods. Food items are often cached in crevices in trees and then covered by lichen or bits of bark.

Brown-headed nuthatch, Sitta pusilla by Shawn Taylor, Mar 2020
Click > below to listen to the song recorded by PT Xiao, May 2022

Nuthatches prefer open woodlands near sea level in temperate climates. In warmer southern regions, they live at slightly higher elevations. They use abandoned woodpecker holes or natural cavities in trees for nesting. Inside, they build a small cup from twigs, lined with soft material for their eggs. Entrances may be protected in a variety of ways. Red-breasted nuthatches collect pine resin to line the rim of the nest hole and avoid it themselves by diving straight into the hole. White-breasted nuthatches often crush blister beetles and rub the remains around the rim, using the foul smell to deter potential predators.

Red-breasted nuthatch, Sitta canadensis by Walter Siegmund, Jul 2008
Click > below to listen to the song recorded by Matthew L. Brady, Jan 2023

Nuthatches are one of only a few animals that use tools. A small piece of bark is often used by red-breasted nuthatches to apply resin to the nest entrance. Bark splinters are also used by brown-headed nuthatches to pry up bark on tree trunks and extract the insects underneath. If the tool performs well, the bird will carry it from place to place. Pygmy nuthatches live in large, extended family groups with other relatives often helping to care for younger birds. They nest in large family groups, huddling together for warmth on cold nights. Red-breasted nuthatch irruptions are common in the central U.S. when the weather turns harsh in Canadian boreal forests, making it difficult to find enough food.

Pygmy nuthatch, Sitta pygmaea by Becky Matsubara, Aug 2019
Click > below to listen to the song recorded by Ron Overholtz, Jan 2019

Nuthatches are a favorite species at backyard bird feeders. They will turn up daily for seeds, nuts, peanut butter, and suet, and are entertaining as they flit in and out, taking food items away to cache in nearby trees or other crevices.

Listen to additional calls and songs for each species at the following sites: White-breasted nuthatch: https://xeno-canto.org/species/Sitta-carolinensis Red-breasted nuthatch: https://xeno-canto.org/species/Sitta-canadensis Brown-headed nuthatch: https://xeno-canto.org/species/Sitta-pusilla Pygmy nuthatch: https://xeno-canto.org/species/Sitta-pygmaea

A Big, Cool One

Elephants are the largest land mammals and they live in a variety of habitats in tropical and subtropical regions. Their native habitat is often savanna, grassland or forest although they can also be found in desert, swamp, and highlands. These areas get twelve hours of sunlight each day, with warm, daily temperatures averaging from the lower 70s to above 100˚F for animals living in the desert. Heat and gravity are two natural factors that affect all large animals, and elephants have some unique methods and body design to compensate for both.

^{Walking in Kruger National Park by Simone Eman, simoneemanphotos}

Elephants have a massive skeleton with solid bones in their feet, legs, hips, and ribs that provide excellent support for all of their weight. Lots of muscles, both large and small, allow easy movement while still protecting their vital organs. But not all of the bones are solid. The skull is honeycombed throughout, so it is light enough that the neck can support the head and allow for many small and precise movements of the trunk, the ears, and the tusks. The brain is small for an animal of this size, but elephants are quick learners, have an excellent memory, and are one of the smartest animals.

^{Elephant’s foot by sboofek, Getty Images}

^{Elephants foot tread by skynavin, Getty Images}

While small animals, such as ants, can hang on to a vertical surface, elephants require a solid set of legs to stand and walk on. They actually stand on the tips of their toes, located along the front edge of the foot. The center and back of the foot is one large pad behind and under the toes that cushions each step and helps to carry their weight. The large, round flat of the foot spreads the weight evenly over a larger area, and their soles have treads to provide traction on slippery or uneven surfaces.

^{Elephant ears by Harvey Sapir, Pexels}

Heat from the sun, and from the exertion of the muscles performing under the tremendous weight of the body, must be dissipated efficiently. This task is handled by the elephant’s ears, which are very large and very thin. Hundreds of blood vessels run through each ear close to the skin to radiate heat away from the body. The blood, now cooled, can be circulated throughout the body. Skin over the rest of the body is thicker, but there is little to no fat underneath, nor is there any fur or hair covering the outside to trap heat. The skin also has many wrinkles creating much more surface area than smooth skin, allowing more heat to be lost to cooler air and water.

^{Celery anyone…by eugen_z, Getty Images}

An elephant’s trunk is a nose-arm-hand all wrapped into one. They can pick up large and heavy objects as well as being able to manipulate the sensitive tip to grab tiny and delicate objects. To help control the heat, they often will suck in a trunkful of water and using the end of the trunk like a shower head, spray all of the water across their body to wet down and cool off. Similarly, they can snuffle up a load of dust to spray across dry or wet skin to create a coating to help keep away biting insects and provide protection from the sun.

Elephants are built to move easily and efficiently in their environment, and they have several methods and adaptations to deal with their size and the heat. Next week we will discover more about family life and the lands they live in.

The Elephant Trunk

An elephant’s trunk is an amazing body part. It is a 300 pound nose-arm-hand about seven feet long. It contains 50,000 muscles, but no bones or cartilage, making it strong and flexible. A vast array of nerves controls it. Elephants use their trunks for a variety of tasks including:
• smelling an approaching rainstorm from 150 miles away
• locating food by smell including grass, branches, and fruit
• lifting objects up to 400 pounds
• reaching food 20 feet off the ground
• using it as a snorkel when swimming underwater
• using the top and bottom lip to pick up a single seed off the ground
• sucking up to 2.5 gallons of water and squirting it into their mouths
• sucking up water to squirt over their backs to cool off
• curling it around large quantities of food to place in their mouths
• controlling the shape and size of the nostril to modulate sounds
• snorting dirt to spray over their backs
• picking up and throwing objects in defense
• entwining with another’s trunk for a friendly hug