Living with the Lockdown – Treasure Hunt #20

cat opener
IT’S ALL ABOUT CATS … Today’s Treasure Hunt is about an animal that is both always elusive, and relatively rare on More Mesa, a true American native, the Bobcat. Although there were a few sporadic sightings on western More Mesa from 2008 through 2015, we have not seen one in the last 5 years. However, we are happy to report a verified Bobcat sighting on the west side of More Mesa a few weeks ago, and another last week in a neighborhood near the east side of More Mesa!

But before I launch into the mysteries of the Bobcat, I thought it would be both fun and interesting to look at “American” cats in general.

Mountain Lion on moss covered rocks during spring timeMountain Lion: The largest of the cats found in the U.S. is the Mountain Lion, also known as a Cougar. Although originally, they may have been more evenly distributed across the United States, their populations are currently highest in the western states. This distribution is the result of eastern Mountain Lions being systematically eliminated by early settlers and subsequently declared extinct. (Remember we talked about Mountain Lions still being around in the west but not in the east. That was part of the issue on the Western Fence Lizard and Lyme Disease?) However, clever western Cougars are now migrating eastward and occupying territories previously home to their long-gone eastern cousins; specifically, they are showing up in the mid-west and along the east coast.

Mountain Lions, oddly enough, live in the mountains above Santa Barbara and you might even be lucky enough to see one on the San Antonio Creek Trail out of Tuckers Grove. One was even reported on the east side of More Mesa in 2015. Despite weighing 150 lbs (on average) and being called a Mountain Lion, this animal is not a member of the genus Panthera (Lions, Tigers, Leopards and Jaguars) and is more closely related to the domesticated cat than it is to Lions.

Domestic Cat: By far the most numerous cat we have in the United States is not a native, but the common house cat … the second most popular pet in our country. Cats were domesticated in America when settlers arrived from Europe, bringing cats with them across the Atlantic. These were not your “lay on your lap and purr” cats, these were “working cats”; kept around to catch mice and other rodents on ships. It wasn’t until the 19th century that the idea of keeping felines as pets really flourished. Currently, Americans lead the world in cats, with 94 Million of them as pets and another 57 Million feral. (Unhappily, 69% of songbird deaths are attributed to feral cats.) Outdoor cats are also believed to be the biggest human-caused threat to other wildlife; specifically, they are responsible for the decline of 27 mammal species and extinction of 123 different bird species. By all means, love your cat but … Please spay it and keep it indoors.

north america cat rangeBobcat: The American “wildcat” we are featuring in this issue is the Bobcat, a native animal that is, for the time being anyway, a species of “Least Concern”, and is in the genus Lynx (short-tailed cats). The Bobcat has the largest range and is the most abundant of any wildcat in North America. Its population numbers between 750,000 and 1 Million animals.

Life spans for all the cats we’ve talked about are similar, and relatively short. Mountain Lions, live between 8 and 13 years. Pampered and protected house cats (aided and abetted by vets) last 13-17 years. Bobcat lifetimes top out at about the same as their wild brethren; 10-12 years.

tri-cat

Anatomy … Well Equipped

canatomyThe Bobcat weighs in between 11 and 30 pounds; about twice that of the average house cat … although I have known some domestic cat owners who have overindulged their pets to the point of tipping the scales at more than 30 pounds. Bobcats are between 26 and 41 inches long, not including the tail. They have long legs, large paws and black-tufted ears. Their name derives from their short (4-7 inches), black-topped tail which appears to be “bobbed” or cut off. (More on this at the end of the Bobcat story.) Predictably, Northern Bobcats are stockier and have thicker coats to help them survive in colder temperatures.

Bobcats may look cute and cuddly, but they are actually fierce predators. Not only can they run 25-30 mph, but like Superman, they can leap as far as 12 feet to capture prey. Indeed, they have been known to take down animals much larger than they are; such as young deer! Bobcats can also swim, but they would rather not. In addition to running and leaping, they also have some skills similar to domestic cats. For example, they use their whiskers like fingertips to feel around habitats to determine whether an opening is big enough to fit through. Their great night vision is critically important as you will see below.

Habitat … Everywhere

Why are Bobcats the most widely distributed cat in North America? The answer is that they have adapted to living in a variety of different habitats; mountain woodlands, coniferous forests, swampland, deserts and even in suburban areas (as we found out). They are so versatile that the “exact” appearance of the Bobcat coat depends on its habitat. That is, the colors of its coat and spot patterns allow an individual animal to remain as camouflaged as possible in its surroundings. The historical range of the Bobcat once extended right across North America, but hunters eager to acquire the soft Bobcat fur, and loss of its natural habitat has led to its disappearance in some areas.

Solitary hunters by nature, bobcats lay claim to an area of land that can be anywhere from 1 to 18 square miles, with males having larger territories than females. Moreover, they will defend their territory against individuals of the same sex.

While Bobcats stake out at least two or three different shelters, the most frequently used is the “natal” den (nursery), which is often a cave or rocky, cave-like opening that the cats fill with dead plants for bedding. Additional dens can take the form of anything from bushes to hollow logs.

Dinner … Hunt at Dawn and Dusk

cat huntingBobcats are carnivores and crepuscular hunters; that is, they are active at both dawn and dusk. Specifically, they wake up about an hour before dawn, hunt and then go back to sleep in the early morning. Then about three hours before sunset, they wake up again, hunt, and resume sleeping at midnight. An hour before dawn the whole cycle repeats itself. From this, you can see why Bobcats are rarely seen by humans.

Wonderfully equipped for hunting, the Bobcat has excellent hearing because its long ear tufts act like hearing aids; enabling the Bobcat to pick up on the soft footsteps of prey. When it is running at 25-30 mph, it places its back feet into the same spots where their front feet stepped; a strategy to reduce any noise that might alert prey. Their widely varied diet depends on the food sources near them. Though the bobcat prefers rabbits and hares, it also hunts mice, squirrels, insects, deer, geese and other birds and chickens … the later getting  the Bobcat into a lot of trouble!

Social Life … Limited to Reproduction

Bobcats are loners, except when it comes time to breed, sometime between December and April. The large territories of the males overlap with those of many females, and even to some extent those of other males. A male will “court” a receptive female and then breed with her many times over a period of 1-2 days. When they are done, he will move on to the next female that is signaling her readiness to mate. Like the spiders, the males play no role in rearing the young.

bob kittensBobcat gestation is 8-10 weeks and produces a litter with up to 6 kittens, but more likely 2-3. The tiny kittens weigh 10-12 ounces and will nurse until they begin consuming meat. The young will be born in a “natal den”, but mother bobcats move their kittens from one den to another on a regular basis. This helps throw predators off the little ones’ scent. The “absentee dad” issue presents a big problem and a potential threat to the whole Bobcat population. That is, when mother goes off to hunt, the tiny newborn kittens are not only extremely vulnerable but even blind until they are six days old. Coyotes and Owls, among other predators, take bobcat kittens. Young will remain with their mother for about 8 months and learn how to hunt independently. Females reach sexual maturity at about one year and tend to have a single liter a year.

Bobcats … Only to be Admired

Bobcats do not attack people … ever. However, under no circumstances should anyone attempt to touch or handle a wild bobcat, or her kittens. If you are lucky enough to meet one, keep your distance, protect your pets, back away slowly, take a photo and be ever so grateful that you got to see such a beautiful and elusive creature!

Threats … Other Animals and Us

bobcat treeThe Bobcat is itself, a fierce and dominant predator in its natural habitat. Therefore, adult Bobcats are only threatened by a few animals, the biggest concern to them being Mountain Lions and Wolves.

By far the biggest threat to Bobcats is humans! Because of the beauty, softness and density of their fur, Bobcats were hunted nearly to extinction in the early 20th century. Although they rebounded to almost 4 million strong, there are now only about 1 million left. The reason for this large decrease includes both loss of habitat by encroaching human populations and hunters. They are killed, both legally and illegally, for sport and their valuable pelts. Unhappily, due to the Bobcat’s penchant for eating chickens, they are regarded as a nuisance and are often shot by farmers.

Folklore … Fun

bob catroglyphsRock art often gives us clues to the lives of early people. For example, I found this photo (by Doug Sherman) of an Arizona petroglyph that does look an awful lot like a bobcat. In addition, we do know that the bobcat plays both negative and positive roles in Native American mythology. For example, in Hopi stories he is greedy, selfish and acts badly toward women, but in Zuni stories, Bobcat was believed to have hunting medicine.

A Blackfoot legend tells how the Bobcat came to look as it does. The story begins by telling us that a Lynx ate all the roasted squirrels belonging to an Old Man who was sleeping. The old man was so angry when he awoke, that he grabbed the Lynx by the ear and shortened his head by banging it into a stone. Then he pulled out the long tail, and after snapping it in half, he stuck the brush part in the Lynx’s rear. Finally, he stretched the legs and the body of the Lynx until they were long and skinny. Then the old man threw him on the ground and said “You Bobcats will always have a bob tail, you will always be short of breath and you will never run very far.”

WOW … he was really mad!!

bob cat closer

Stay safe … Valerie

Living With the Lockdown – Treasure Hunt #19

spider kids

THE BEST LAID PLANS …

The plan was to have PART II of the story about spiders to appear on Halloween. Obviously, that didn’t happen. So, what was the problem? As you probably know, Constant Contact has been sending our More Mesa Updates for many years. For all of those years we used their template; one that worked very well for us. Enter the Smart Phone! Because much of its material is being read on Smart Phones, Constant Contact decided to retire the original template and substitute a new one designed to work especially well for the Smart Phone. My excuse … it took me several days and several desperate calls to Constant Contact staff to learn how to work with the new template. I rest my case. Pretend it’s Halloween and enjoy Part II.

Why are Humans Afraid of Spiders?

grass spiderDespite the enormous benefit spiders are to us, humans are ambivalent about spiders. Fear of spiders is mostly cultural and not hard-wired into our DNA, as is the fear of snakes. (We talked about this in an earlier Treasure Hunt.) Also fear of spiders is definitely not universal. In warm countries, spiders are welcomed and appreciated since they rid households of less welcomed insects like cockroaches, flies and earwigs … all year long. Colder countries have the fall-winter change we’ll talk more about below. And, some of these colder countries also have less welcome species like Black Widow Spiders and a dangerous species of Funnel Spiders. (In the event you read Part I of Spiders very carefully, be assured that the species of Funnel Spiders on More Mesa is completely harmless. The one from Australia is the one to watch out for.)

Fear of spiders, known as arachnophobia, is so common that it is on the “top ten” list of phobias around the world. Some people think spiders are “creepy” because of their large number of legs (eight) and their habit of scuttling around in dark corners. They do that because dark corners are where they find food; food consisting of other critters you don’t want in your home anyway. Indulge me in another plea for spiders. They rarely bite, and all but a very few are harmless to humans. Yes, in our area, the Black Widow should be avoided, but even a bite from dreaded large Tarantulas produces only slight irritation. Granted they are definitely not cuddly, but maybe you could cut them some slack … given all the they do for us.

Why are Spiders Associated with Halloween?

halloween clip artHere are some current explanations:

    • during the Middle Ages belief in witches was rampant; as was the belief that they were at the height of their power in the fall. Somehow spiders became the sidekicks of witches and the same superstitions about witches were attached to spiders as well.
    • The colors of fall are typically orange and black and many spiders are black. So, with some sort of crazy logic, spiders were then considered representatives of fall … when Halloween is celebrated.
    • An associated legend had it that spiders were thought to have magical powers because they could spin webs.

What’s really going on? Fall is a time when spiders produce young. But more importantly, late fall is a critical time of year for many insects. They are searching for safe and warm havens in which to spend the winter … like your house. When that happens, your house becomes a veritable grocery store for spiders. Not as exciting as witches, magic and supernatural stuff, but more of nature doing what it has to do to adapt to changing weather conditions.

Spider Lifeways Are All About Females

Transitioning from the supernatural to more practical issues, spiders have to make a living, keep from getting eaten and ensure that the species persists. That is where we go from here. So, I started studying about webs, a fascinating subject. But as I learned more and more about webs, I noticed that the pronoun “she” was always used. Then I learned that the world of spiders is all about females and the tremendous amount of hard work they do. All of this was strangely familiar! Following is a typical “To-Do” list for a female spider.

Food Shopping

big webIn Part I you might have seen some hints about procuring food when you are a Crab Spider, but when it comes to spider grocery shopping, most of us think of webs. Since spiders are carnivores, webs become perfect butcher shops; places to procure protein; whether it walks in, flies in or otherwise.

A web spider has virtual rope factory inside her. The spinneret glands, located in her abdominal region, squirt liquids that solidify immediately into several different kinds of silk. The tensile strength of spider silk is comparable to that of steel wire of the same thickness. However, as the density of steel is about six times that of silk, spider silk is correspondingly stronger than steel wire of the same weight. Web silk’s unmatched combination of strength and toughness allows it to survive the strongest winds as well as the most frantic attempts of captured prey to escape. And if you are not impressed with the above comparisons, I recalled back in my youth learning that the Norden bombsight used Black Widow silk for the crosshairs … that’s how strong it is!

There are a bewildering array of webs, each species building a fixed pattern, with the talents of different species varying greatly. Webs are not only supermarkets but also serve as a safe retreat from enemies and sometimes as a residence as well. Some webs are crude and some extremely delicate, but the one web usually considered the most beautiful, and the most beloved, is the Orb Spider web. Although web building takes between one and two hours in real time, you can watch the tiny (half inch) Spiny Orb Weaver creating her 12 inch diameter web in a couple of minutes. During the build the spider will coat some of the fibers with a sticky substance that entraps any unwary meal, but leaves other strings of the web clear for her to traverse. If the spider gets tired of waiting for dinner to be collected by the web, and would like to sleep, she drops a single line to a convenient “bedroom location” and keeps it attached to one of her legs. When prey wanders into the dining room, the web will vibrate at specific frequencies that are associated with prey capture. At the call of this dinner bell, she will wake and hurry out to inject killing venom. In this video, watch how she packages up dinner in a silk bag and then enjoys it later.

spider treePreparing Dinner Unlike most humans a spider drinks its dinner. This means that before it can consume prey, it must convert a meal into liquid form. This is accomplished by injecting special digestive enzymes into the prey, waiting for liquification and then sucking up dinner. Its stomach can stretch to hold very large amounts of liquid, so the spider cannot really ever overeat. On the other hand, if times get bad, a spider can survive for extremely long periods of fasting … perhaps up to 1 ½ years.

Recycling And, since the Orb Spider is a tidy, thrifty critter and protein is expensive, she is also an avid recycler; i.e. the protein from the old web is never wasted. When the web is no longer usable, she eats and digests it. The web protein then goes back into the silk glands to be made into a new web. In this way, even if a spider misses a few meals, she can still go on spinning webs!

Taking Out the Garbage Like any good housekeeper the spider tidies up. Since dinner has been liquified and ingested, any prey body parts that are left over need to be cut out of the web and discarded. This same process is used for any extraneous and useless material that is blown into the web by accident … like leaves.

spider romanceRomance? In Part I we mentioned that female spiders have absolutely no interest in reproduction until their very last molt. As you will see, it is a completely different story for the males. Males are much smaller than the females, do not live as long as the females, are more heavily decorated than the females and have a much shorter “To-Do” list. It has one entry! Their entire lives revolve around a single aspect of their existence … depositing sperm. They are obsessed with this one thing and this one thing only. This singular drive is the reason their webs are messy and badly made. Why? … because males are not territorial and spend their lives moving around looking for girls. Under these circumstances building a good web would not make sense, since they will abandon it as soon as they have accomplished their purpose, and moreover, accomplished it with all the available females in the area. For the males, who are both nomadic, and somewhat dispensable, building a web is an exercise that is more like “pitching a tent” than building a home.

Courting human couples frequently go out to dinner. However to the contrary, males spiders try to make sure that the gals have already eaten. This tactic is imperative because if a female is hungry, she may just eat the potential suitor instead. Further, there is always that danger, even if she has already eaten. That is why the legs of the males are often longer than those of the female. In cases where the date is not going well, this anatomical difference gives the male a chance to escape. (In the photo notice how gingerly the male is approaching.)

A male spider will display several behaviors during courtship, hoping the female will accept his sperm. These behaviors include pulling on the web, rocking his body, pushing the female’s legs, vibrating his abdomen, tapping on the web, making rolling motions with his palps and tapping the female spider. (Reminds me of dance moves I have seen on T.V.) How the sperm gets to the right place is really complicated as I discovered in a really long and graphic article I waded through. (You probably really don’t want to know!

spider egg sacPregnancy At this point the female has both eggs and sperm in her body. Since she is so good at spinning, she spins a disc of silk and then deposits both eggs and sperm on that disc. This is when fertilization actually occurs. To protect the fertilized and hardening eggs she completes the task by spinning a cover over the disc to form an egg sac. In some species, she carries the sac with her everywhere, and in others she just deposits the sac somewhere safe and guards it, as is shown in the photo. One of the reasons females are so much bigger in some species is the need for her to carry around that heavy burden of the egg sac. Sacs can contain hundreds of eggs that will hatch into spiderlings in 2-3 weeks.

spider kids 2Looking After the Kids Just as mother guarded the eggs, she will guard the newly hatched babies. Once spiderlings fully emerge, they usually settle close to the nest area for several weeks before moving on and staking out their own territory.

spider head studyIntelligence And for something really unbelievable, we are discovering that the spider possesses genuine ingenuity and inventiveness in both its web design, as well as in many other areas. Recent studies published in National Geographic showed many species of Jumping Spider could plan out intricate routes and detours to reach their prey — a quality usually observed in larger creatures. And almost everything is much larger than the Jumping Spider! It is between 0.125 and 0.750 inches long. And its brain … it’s the size of a poppy seed.

Epilogue

spyder guyIt is all too clear that Stan Lee knew absolutely nothing about spiders when he created Spider-Man in the early 1960s. No self-respecting male spider would be wasting his time as a superhero when he could be mating with thousands of female spiders instead. I guess Lee probably didn’t care, since Spider-Man is often ranked as one of the most popular and iconic comic book characters of all time.

And, of course you knew that I would mention one of the scariest monsters in Harry Potter, Aragog. This giant spider that sired a multitude of giant spiders in the Forbidden Forest, was the size of a small elephant and had legs 18 feet long. Apparently J.K. Rowling did not know much about spiders either, or she would have made Aragog a female.

Stay safe … Valerie

Living with the Lockdown – Treasure Hunt #18

spider bannerIN KEEPING WITH HALLOWEEN … HOW ABOUT SPIDERS?

A New Class …

The next two Treasure Hunts will be about a creature which is found all over More Mesa and also epitomizes the month of October; the spider! Spiders are not insects. They are in an entirely different Class; the Arachnids. This Class owes its name to a famous story from Greek mythology, that goes like this. It seems that an upstart Greek maiden named Arachne thought she was such a superb weaver that she challenged the goddess Athena to a weaving contest. This was a little presumptuous as, among several other things, Athena was known as a goddess of the arts. Athena however, accepted the challenge. When both weavers were done, Arachne’s weaving was so beautiful that Athena had to grudgingly admit defeat.

arachneHowever, given that she was also the goddess of warfare, she worked herself into a rage and destroyed Arachne’s work. Arachne, being a really sensitive artist was so upset that she hung herself. At this development the goddess calmed down at little, took pity on the weaver and loosened the rope. Then she turned the rope into a web and the maiden into a spider. Thus, we have the class Arachnida and the very first indication of the powerful role of females in the spider world.

spider diagramWhat is it Anyway? … Ask any kindergartener and they will tell you that spiders have eight legs, eight eyes, two body parts and are “way cool.” In the diagram you will see that the first body part, the cephalothorax, is where the eyes are located, legs are attached and most of the muscular structure is contained. The cephalothorax is actually the head and the thorax, but with a solid connection instead of a flexible neck; i.e. the head cannot rotate. The second body part, the abdomen, holds the digestive and reproductive organs and is usually the largest part of the spider. (It also holds the silk producing elements, the “spinnerets”, that you will read about in Part II.)

Legs – The eight legs of the spider are usually long and hairy. Hairs are used to pick up scents, sounds, vibrations and to detect air currents. Males usually have longer legs to keep the female at “arms length” during courtship. (More on this in Part II.)

Palps – There are a pair of palps on the front of the first body part. These are part of the complex mouth and seem to be used mainly as sense organs, perhaps for taste and odor. In male spiders the ends of the palps are modified into complex structures used during mating. (Believe me, it’s complicated!)

spider mouthMouth Parts – Spiders are carnivores. To facilitate hunting these hollow claw-like appendages contain venom glands that allow the spider to inject poison into the prey thereby killing it and allowing the spider plenty of time to wrap it up for a later meal.

spider eyesEyes – Spiders usually have eight eyes, but few have good eyesight. They rely instead on touch, vibration and taste stimuli to navigate and find food. (Only a few spiders, like the wolf spider, need good vision.) Of the eight eyes, the job of the two very large front eyes is to get a clear, color image and judge distance. And while they are large, these are simple, single lens eyes that are NOTHING like either human or insect compound eyes. The small side eyes, called ocelli, needed because the spider cannot move its head, detect when something is moving. You need a lot of them to get a 360 degree view in order to spot your dinner or an unwanted diner!

spider moltMolt – What the kindergartener won’t tell you is that the spider has an exoskeleton; a hard covering that is like a suit of armor to protect body parts and organs. The exoskeleton cannot grow, which means that the spider, like insects, must periodically crawl out of the whole outside of its body in order to grow larger. Needless to say, this is a complex process and one in which the spider is very vulnerable, wisely choosing to “hide out” until the molt is over.

Spiderlings will molt as often as once a month and adults about once a year. Bigger spiders have more molts than smaller ones, with the molt requiring from 15 minutes to 15 hours to fully harden, depending on the size of the spider. And while all the early molts are about growing into a larger body, the very last molt is one which also includes a “one-time only” interest in reproduction … and decidedly different from reproductive activities of mammals. (See Part II.)

Size – In most of the 45,000 species of spiders that we currently know are on earth, females are larger than males and sometimes incredibly larger than the males. Most of the largest spiders are from the Tarantula family. The largest spider known on earth is the Goliath Birdeater (12 inches) from South America and the smallest is the Patu Digua (male 1/5 the size of head of a pin) from Columbia.

Lifetimes – Most spiders live about a year, except really big ones. For example, some female Tarantulas live up to 40 years, while their male counterparts are only around 4 years or less. How do we know this … because some people keep them for pets. (Figure that!) Although giant spiders do not tend to be aggressive, they will (like smaller spiders) bite to defend themselves or their egg sacs.

Enemies – Spiders have lots of enemies. They include birds, fish, lizards, Tarantula Hawks (these are actually wasps), spider wasps, centipedes, scorpions, other spiders and even, in the tropics, monkeys. But one of their worst enemies is the human race; and we don’t even eat them.  We use pesticides to destroy them (as well as all their food sources), we stomp them, drown them and some of us even vacuum them up. (Be sure to read Part II of Spiders to learn more about all our misconceptions about spiders.)

spider defenseDefense – The principal way that spiders try to escape their predators is to avoid being seen. Some of them live in burrows where a predator would have to do some major digging to find them. These underground dwellers also make sure they have well camouflaged doors. Spider mimics try to look like the background of where they live and still others mimic a dead leaf, a twig, a stem or even bird droppings! In the image on the right a crab spider has turned yellow and captured an unsuspecting bee for dinner. Only recently scientists have officially documented the camouflaging  capabilities of a crab spider. It is one of the few spider species that can reversibly change the color of their bodies to match the colors of the flowers where they hang out and stalk prey. Although it can take up to 25 days to change color, once changed they can largely remain unseen. What colors are on their pallet … white, yellow and green. See how this works for a clever crab spider. In the final analysis, a spider’s worst enemy is weather; in the form of drought, flooding or a long cold winter. Since these kinds of things happen to all the organisms in the population, things eventually sort out.

spider holeTypes of Spiders – There are many types of spiders living on More Mesa and in your house or garden.  Among these are the famous Orb Weavers that charm and delight us. (We will talk a lot about these in Part II.)  There are also Wolf Spiders, who are one of the few species with good eyesight. They have to catch prey by running it down. Their lives are hard, strenuous and dangerous; and actually, more like that of a cheetah than a wolf. Finally, on a foggy morning in More Mesa you may be able to see dozens of funnel that are the home of Funnel Spiders in the grasses.  Look for the hole in the funnel, she’s waiting for some unwary insect to drop in for lunch!
Let’s go back to that kindergartner again. Most adults would not agree with the kindergartner’s assessment of the spider as “cool”. They may shudder and use words like “heebie-jeebies.” However, spiders have intrigued humans since ancient times, and were often seen as mystical because of their ability to weave intricate webs. Much like the bat, cat, and the owl, spiders (as Halloween symbols and otherwise) are creatures considered to be endowed with supernatural qualities. And, like other creatures of the night, they were associated with witchcraft. More clinically oriented people will cite spider bites as a problem, but the reality is that spiders rarely bite and only a few species are dangerously poisonous, viz. the Black Widow and the Brown Recluse in the US. (Only one death has been reported in the last 20 years.) On the flip side, spiders are an incredibly powerful aid to the entire human race. It is the large numbers of insects, many of them pests, that are trapped by spiders, that make them invaluable to us and to the balance of nature. In fact, Spiders catch and eat more insects than all of the other insectivorous animals put together. They deserve our hearty applause!

applause

It is hoped that when you finish reading all the different, yet strangely similar activities of spiders, you will be fascinated by the various ways they “make a living”. During the research for this Treasure Hunt I was both intrigued and amazed at these tiny creatures … and realized that they are not so spooky after all. While reading Part II (coming up soon), the women among our readers may recognize, as I did, some startling similarities between the lives of female spiders and all the things we do. Stay tuned for the rest of the tale of the spiders … and most of all …STAY SAFE … Valerie

Living with the Lockdown – Treasure Hunt #17

Barn Owl Chicks
Barn Owl Chicks

WHOOOOO? IT’S OWLS – PART II

We hope you enjoyed the first half of the owl story; the head. This Treasure Hunt discusses all the rest; what goes on below the owl’s head.

Flying … Stealth is the Name of the Game

Large, soft wings give most owls the ability to fly slowly and silently. Several factors enable this advantage. Not only do owls have larger wings in comparison

Feather Edge-Photo by Kay Schultz
Feather Edge-Photo by Kay Schultz

to both their body mass and that of most other birds, but the wing feather is completely different from those of other birds. Instead of the usual sharp edges,
owl wing feathers are “comb-like” and break down the turbulence that normally creates the “swooshing” sound of a bird in flight. Instead the sound is muffled and the owl flies silently, enabling it to listen for tiny sounds from the movement of prey. Take a look at this short video, which is labeled “4. Owl Flight is Silent”. It shows how all the wing features of an owl combine to insure that it will arrive at its prey without a sound.

Soft Owl Feather
Soft Owl Feather

Just so you know … owls don’t get to eat when its raining. Their soft and effective feathers are not waterproof and they can’t fly when the feathers are wet.

Hunting Strategy … Time for Talons and Beak

Owls generally have a hunting territory away from their daytime roost.
As soon as a target is located, the owl will fly towards it, keeping its head in line with the target until the last moment. This is when the owl pulls its head back, and thrusts its feet forward with its talons spread. However, owls have an unusual adaptation that involves their feet. Like other raptors, owls typically have three talons pointing forward and one pointing backward. But owls can rotate one of their forward-pointing toes to the back, making their toe arrangement more like that of a woodpecker, and becomes, yet another body part that is able to swivel! The advantage of this talon talent is evident when the owl grasps its food. If a rabbit or mouse is struggling to get away, it’s very helpful to have an equal number of talons on each side to ensure the prey won’t free itself. Exhibiting truly exceptional grip, owls also have the ability to lock their toes around an object so that they don’t need to continually contract their muscles. This gives them maximum grip with minimal effort!

The force of the impact of the talons is usually enough to stun the prey, which is then dispatched with a snap of the beak. Once caught, smaller prey is taken away in the beak, or eaten immediately. Larger prey is carried off in the talons.

Powerful Talons--Photo by Deane Lewis
Powerful Talons–Photo by Deane Lewis

Food … Finally We Get to Eat!

Owls are carnivores, but their main food largely depends on the species of owl. For example, in the case of More Mesa’s owls, the Great Horned Owl eats larger mammals like rabbits, squirrels, raccoons, big birds and skunks! (It’s OK … owls can’t smell!) Long-eared, Short-eared and Barn Owls eat smaller mammals, like voles, mice and rats. The smallest owls, Western Screech and Burrowing eat insects, small birds and sometimes small mammals. Here comes the test to see if you were paying attention in Part I of owls! All our owls have yellow eyes except the Barn Owl that has black eyes. Who hunts when?

Digestion … It’s Not That Easy

Like other birds, owls cannot chew their food – small prey items are swallowed whole, while larger prey are torn into smaller pieces before being swallowed. For example, Barn Owls swallow their prey whole, skin, bones, and all … and they eat up to 1,000 mice each year.
Rather than being stored for later, the owl’s dinner is passed directly to the digestive system. Owl stomachs have two parts, one that does the chemistry necessary for digestion and the other (the gizzard) is what holds, and eventually compresses the trash (fur, teeth, bones, feathers etc.) The digestible part is allowed to pass through the system with useful components being absorbed into the body and the waste of food digestion being excreted at the end of the digestive tract … the “white stuff” that birds leave everywhere.
Several hours after eating, indigestible parts (trash that is still in the gizzard) are compressed into a pellet that ends up, after several meals, being the same shape as the gizzard. (Think of the gizzard as a trash compactor and you get the idea.) The pellet then travels

Snowy Owl Eliminating a Pellet--Photo by Leslie Abrams
Snowy Owl Eliminating a Pellet–Photo by Leslie Abrams

back up from the gizzard to the “chemistry section” and remains there for up to 10 hours before being regurgitated. Because the stored pellet partially blocks the owl’s digestive system, new prey cannot be swallowed until the pellet is ejected. Regurgitation looks really painful, but at least the owl can eat again.

Pellet-Photo by Leslie Abram
Pellet-Photo by Leslie Abram

The Cycle of Life

Most owls reach sexual maturity and are ready to reproduce in about a year. The decision to reproduce is not always at a specific time of year, but often based on available food supplies. Also, various species begin courtship at surprising times of the year. For example, the Great Horned Owl begins in December; even in very cold places! As might be expected, and after we have explored their lifeway in such depth, courtship among owls is mostly about sound. Depending on the species, various specialized hooting is used for attracting mates, as well as nodding and bowing and appropriately enough … billing and cooing.

Although variations exist for different species, owls are usually monogamous, or pair with the same mate for several seasons. They don’t construct nests as such, instead they are opportunistic nesters, using ready-made sites or taking over the abandoned nests of other birds. They also use holes in trees, barns or other buildings. And when you provide these birds with an owl box, they think they have died and gone to heaven! However, Burrowing Owls nest underground; appropriately enough, in abandoned burrows.

Great-horned Owl Family
Great-horned Owl Family

Depending on the species, the nest will mostly house a few eggs. During incubation, eggs are rarely left alone. The female, who is always larger than the male, will incubate the eggs. She develops a brood patch, which is a sparsely feathered part on the belly, with a higher density of blood vessels than other parts of the skin. This allows eggs to receive warmth directly from her through this area, and they will hatch in about 30 days. Owl chicks, similar to the Western Gull chicks we talked about in a previous Treasure Hunt, hatch with the aid of an “egg tooth.”

How Cute is this Little Guy?
How Cute is this Little Guy?

Dad delivers food to the nest up to 10 times a day. Prey is ripped apart by the adults until such time that the chicks can swallow it whole. At that time the chicks also begin producing pellets. They fledge anywhere from 4 to 10 weeks, depending on the species. Parents care for the fledglings an additional few weeks to few months, and then the circle is complete again.

Mythology

Throughout history and across many cultures, people have regarded owls with both fascination and awe. In ancient times owls represented wisdom and helpfulness. However, by the Middle Ages in Europe, the owl became an associate of witches and the inhabitant of dark, lonely and evil places. In the eighteenth century, science eliminated some of the mystery about owls, and now with superstitions dying out in many parts of the world, the owl has returned to its position as a symbol of wisdom.

Finally, and you knew this was coming, we have to talk about the major role played by owls in the Harry Potter tales. Since Harry’s world does not have a federal postal service, owls carry all the mail … messy … but they get the job done! And, in addition to mail service, Harry’s owl Hedwig, provides warm companionship whenever he is blue and lonely. (FYI: Hedwig is a Snowy Owl and native to Arctic like regions!)

snowy owl

We are indebted to owlpages.com for providing its very professional and accurate information on owls, as well as several of our most interesting photos.

Remember: Six Feet Apart and Stay Safe,

Valerie

Living with the Lockdown – Treasure Hunt #16

owl bumberWHOOOOO? … IT’S OWLS

Burrowing Owl
Burrowing Owl

Many members of this treasure’s family live on More Mesa. However, they may be more difficult to see, although easier to hear … especially if you are willing to venture out onto More Mesa at night. The last Christmas Bird Count recorded a phenomenal six separate species of owls on More Mesa. Over the many decades we have been collecting sightings data, these are the most owl species ever recorded, at one time, and there are some species we have rarely, if ever seen!

Western Screech Owl
Western Screech Owl

The largest of our hooting avians is the Great-horned Owl at 23 inches. Significantly smaller are the Barn, Short-eared and Long-eared Owls, all of which are between 13 and 16 inches. Our tiniest owls are the Burrowing and the Western Screech Owls, about 10 inches

Although we think of owls as hunting only at night, that is not the case. (More about this when we look at owl sight.) You can quickly determine the hunting habits of an owl by the color of its eyes; black or brown hunt at night, yellow hunt at dawn and dusk and orange hunt in the daytime. However, a majority of the owl family are nocturnal creatures and do most of their hunting when light levels are low. Why? Because many owls hunt for rodents, and rodents are active at night. The next obvious question is, “How does an owl hunt in the dark?” The answer is that its head, and all the elements of the head have evolved precisely for this very purpose; that is, hunting in the dark. Specifically, owls have incredible sight, a neck that can rotate its head a full 270 degrees and amazing hearing.

HEADS UP! … PART I

This treasure hunt proved to be so fascinating and interesting that the tale could not be told in a single issue. So, the story of the Owl will come in two parts; first we will describe all the functions that are carried out in the head and the next issue will conclude the tale with details of what happens in the rest of the owl’s body.

Incredible Sight … At Night

Owls have extremely large eyes, in a very small skull. The eye is tubular in shape, accounts for up to 5% of the owl’s weight and is held in place with bones. It’s definitely nothing like our eyes, that are round, weigh .0003% of our body weight and are held in place with muscles. Light collection is also aided by a reflective surface behind the retina which reflects the image back after it has passed through the eye. This gives the owl a chance to collect twice the light for discerning the image. That information is then passed on to the brain.

barn owl head burrow head tufty head

We discussed rods and cones of bee eyesight in an earlier Hunt. Cones are important to bees since they have a great need to see colors. For owls, it’s all about rods! Faced with low light levels, you need lots and lots of rods. Indeed, owls have 5 times as many rods as humans, one million rods per square millimeter! As a result, they can see 35-100 times better than we can at night. For example, Barn Owls can see a mouse at 6-7 feet with an illumination the equivalent of the light of a match a mile away.

Filoplume
Filoplume

The downside of owl vision is that they are very farsighted, and cannot focus well on objects that are within a couple of inches. So, to compensate, Mother Nature has equipped them with whisker-like tiny feathers (filoplumes) around their beaks and feet to help them detect objects close in, as well as “feel out” the food they have captured.
Another factor on the “upside” is that most bird eyes are usually at their sides, but owl eyes face forward, as do ours. This means owls also have binocular vision, similar to ours, and it gives them increased depth perception … even in the dark. A final feature of owl eyes is that the iris of the eye can adjust so owls can see in the daytime, unlike other nocturnal animals that can only see at night.
And to wrap up, these, oh so important, owl eyes are well protected with three eyelids. The upper eyelid closes down when the owl blinks and the lower closes up for sleep. The third is a translucent membrane that moves horizontally from the inner corner of the eye to the outer. Its task is to view prey, while keeping the eye safe during the last part of the capture.

Third eyelid - Photo by Evan Hitch
Third eyelid – Photo by Evan Hitch

The Swivel … Takes it All In

Great-horned owl looks over its back
Great-horned owl looks over its back

With its huge eyeball, held in place with bones, an owl cannot roll its eyes to look around. Instead, when pinpointing prey, it moves its entire head, an incredible 270 degrees in either direction and 90 degrees up and down. How can it achieve these feats? First, owls have twice the number of vertebrae in their necks as other birds. And second, they have a blood pooling system that collects blood to power their brains when neck movement cuts off circulation.

Hearing … Sophisticated Sonar

When they cannot see their prey, Owls rely on hearing. A hunting owl, therefore, will use the calls and movements made by a mouse, vole or shrew to direct its strike. These sounds are channeled in many owls by a very pronounced facial disc, which acts like a “radar dish”, trapping and focusing the sounds into the ear openings. Even the owl beak is designed pointed downward to maximize sound collection.

Barn Owl face has a very pronounced facial disk
Barn Owl face has a very pronounced facial disk

Owl ears are hidden inside feathers and they are higher on one side than the other. This positioning allows the owl to pinpoint and position its prey by turning its head until the sound reaches both ears at the same time. The accuracy of this sound/brain interaction is owl skullsuch that owls can detect a left/right time difference of about 30 millionths of a second! To see owl hearing in action, check out this video of a Great Gray Owl. This species lives in evergreen forests in the far north and on high mountains. In these environments, prey is very often beneath the snow, even in summer. As a result, the Great Gray is virtually blind when it hunts. It seems “flying blind” isn’t a problem when the rest of your face is configured to listen.

Be on the lookout for Part II of the Owl Story that will discuss flight, hunting, food, digestion, reproduction and owls in mythology. More fun to come!

We are indebted to owlpages.com for providing very professional and accurate information on owls.

Remember: Six Feet Apart and Stay Safe,

Valerie