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table of contents
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| The first Mallard duckling arrived at WildCare on April 10, after being found stranded in a storm drain. He was quickly joined by lots more on April 15, and they keep coming.. Photo by Melanie Piazza |
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| Our first Western Scrub Jays came in on April 8 when their nest was destroyed. Photo by JoLynn Taylor |
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| A whole nest of baby finches arrived recently. This is why we ask people not to trim their trees in the spring. Photo by Melanie Piazza |
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| This one-week-old coyote came in on April 15, and is the first eyes-closed baby of his species ever brought to WildCare. Compare him to the 6-week old Gray Fox below. Photo by Stephen Shaw |
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| A whole busload of people from WildCare went to Sacramento to support SB 1480, legislation Jamie Ray (front, in white jacket) worked to put on the agenda. Photo courtesy of Alison Hermance |
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| Relocation of trapped animals is illegal in California. SB 1480 will help assure that wild animals get humane treatment and that property owners are told the truth about what will happen to a trapped animal. Photo by Maggie Sergio |
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| This emaciated hawk is now strong enough to eat small pieces of food. Photo by Kate Lynch |
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| Fledgling hummingbird being fed from a syringe. Photo by Alison Hermance |
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| California Scorpions look scary, but their sting is like that of a bee. Photo by Marge Gibbs |
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| This six-week-old Gray Fox is about the same weight as the 2-week old coyote above. This one went back to his mom. Photo by Alison Hermance |
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| This just-hatched Kildeer chick weighed 9 grams and was the size of a golf ball on April 18. Photo by Melanie Piazza |
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dear mother
Excerpts from emails to her mother in Australia by Kay Lovegrove, WildCare volunteer
“Let’s see your butt.” We hear a lot of strange things in the Clinic but this was particularly odd. So Mum, of course I had to go and have a look. A squirrel baby with a huge, deep gash on his butt. Awful. Melanie (Medical Director) was demonstrating how the injury prevented the squirrel from raising his tail – not good for the squirrel’s future welfare. The squirrel didn’t seem to realize that he was at death’s door and was sucking down food from a syringe like there was no tomorrow. (Maybe he did know that his situation was grave?)
We don’t name our patients officially, but I secretly named him Pig. Someone had felled a tree and the nest of baby squirrels was collateral damage. Pig was rescued immediately but his sister wasn’t found until the next day. She had been unprotected from the weather, on the ground, on a cold night, no milk, no mum. Melanie said she wasn’t hopeful that the little girl would survive another night. “But,” Melanie said as she coaxed Little Girl to take a suck on the syringe, “never underestimate a squirrel.” (More on this later.)
baby season
Anyway, Baby Season has begun. Our 2012 inaugural duckling arrived in the Clinic this week and nudie (without feathers) jays, pigeons and finches arrived in the Birdroom. I did my first intake of a baby bird, a house finch, while carefully supervised by Françoise, the Birdroom Queen. I won’t live long enough to know all she knows about birds. The chick was the size of my thumb. No feathers but thankfully no obvious wounds. I had to check eyes, ears (yeah right, they are nigh-on impossible to find), mouth, nares (nostrils), wings, vent (bum), bones, look for parasites, and goodness knows what else. We put him in an incubator to warm up and attended to the paperwork — intake form and patient record card.
The chick was breathing hard so we checked his lungs – with a stethoscope. Such a big, human tool for such a tiny morsel, and put him in an oxygen box. He was still alive when I left that night. A big jay chick had snuggled up against him in the incubator that they shared. This is against the rules because big chicks can unwittingly smother little chicks. I knew that Françoise would separate them when she took them home for through-the-night care and they did look rather sweet cuddled up together.
Another sweetie was a one-week old coyote pup that was bought into WildCare on Sunday. He was found alone and very cold on a walking trail. The staff at WildCare warmed him up, gave him fluids and set about finding some siblings for him. Most young animals that are orphaned are more likely to survive if they are raised with others of their own species and age. He found a temporary home and two brothers at a wildlife rescue organization in the Sierras. His eyes were still closed when he left for his new lodgings.
SB1480
Last Tuesday a busload of WildCare volunteers and other interested people went to Sacramento (State Capital) to support SB1480, legislation introduced by Senate Majority Leader Ellen Corbett to reduce the number of mammals orphaned by wildlife trappers. The bill places restrictions on nuisance wildlife control operators (NWCOs) that will require them to treat animals humanely and be honest with their clients.
What often happens is that the exterminator turns up, removes an adult raccoon, telling the client “I’ll remove the raccoon, release it somewhere safe and you won’t have any more problems.” That’s a lie. It is illegal to relocate wildlife here, so he either breaks the law or lies to the client and just kills it. (The fact that relocation is illegal is actually good because all that relocation does is cause problems with other people and animals, and it spreads disease.)
Any raccoon babies left behind when the mother was removed die slowly of dehydration and starvation. The unsuspecting homeowner has a big expense and mysterious odor problem somewhere in his/her future that will require another visit from the NWCO. It’s a kind of shady practice that benefits the NWCOs at the expense of wildlife.
Jamie Ray, a wild animal rehabilitator from San Francisco (SF-ROMP) has been trying for 10 years to have a law passed to make the extermination process more honest and humane. Last Tuesday the Senate Committee passed this bill, so we are all one step closer to that goal. It was a good, good day.
adult patients
We have had a lot of raptors in the Clinic. Many of them emaciated. We had to tube-feed a gorgeous female Red-tailed Hawk for some time. She responded well and resumed her regal persona and fierce determination to be free. One of the very experienced medical staff had her forehead scoured when she opened the cage door and the RTHA made a swooping break for freedom. The hawk didn’t get far because she wasn’t fully recovered and she was in Ward C. Eventually she was moved to an outside aviary where she could get her flying chops back and dream about killing her caregivers. It was a brave person indeed who went into the aviary to clean it, provide the bird with fresh food and water, let alone capture, weigh and check out her rapidly improving health and strength. She was one intimidating bird.
At the same time we had squirrel patient who needed to be medicated twice a day. A typical adult squirrel from what I can gather. Crazy, hyperactive, given to biting and totally uncooperative. So I was much amused to watch 3 very experienced medical people try to get the squirrel out of his cozy little nest box for his afternoon medications. He screamed, snapped, hissed and bit, hid in his bedding, scrunched out of reach in a corner then finally put his front paws at the top of the box door and his back paws at the bottom and became immovable. Eventually they had to remove his nesting box from the cage and very gently shake him out. One of the med staff confided that she would rather medicate the killer Red-tailed Hawk than the insane squirrel. Understandably.
The impressive animal in the Birdroom this week was a hummingbird. It had been found on the ground, which is not a place where you would typically find a healthy hummingbird, and it was unable to fly. Françoise thought that it had head trauma and she was not optimistic about its recovery. It lay on its tummy with its wings outstretched, or on its side, even on its back in the warm, padded little basket she put it in. None of this was good. Nevertheless we fed it every 20 minutes and it ate like a sumo wrestler. I was secretly hopeful. How could anything with such an appetite not survive?
It is a unique and wonderful thing to hand-feed a hummingbird. We fill a syringe (no needle) with a nutritious and apparently yummy mixture. The tip of the syringe is colored red. (One of my jobs as a novice last year was to color the tips.) You hold the hummingbird, which is a total thrill, and slowly put its beak into the tip of the syringe. You can see that amazing tongue at work in the syringe. A healthier bird will perch on a little twig in the basket and feed itself but this bird needed help. Later that night he went off to foster care with an expert and next week I’ll find out if he made it.
A member of the public brought in some scorpions he found in his yard. The scorpions here aren’t deadly; their sting is like that of a bee, but we weren’t able to convince the man they wouldn’t kill his children. We had to put them back somewhere near where they were captured. Never a dull moment.
more baby season
Seven additional ducklings joined the inaugural duckling. Melanie fed Pig the squirrel, who is thriving, and told us that Little Girl had also made a miraculous recovery. Like Melanie said, “Never underestimate a squirrel.”
Another minor miracle began that afternoon. I overheard Winnie Kelly, one of the really knowledgeable Animal Hotline people, talking on the phone to a woman had walked around the side of her house and come face to face with a fox that was carrying something in its mouth. The startled fox dropped what turned out to be a baby fox and fled. The woman phoned WildCare for advice.
Winnie is nothing if not determined when an animal is at risk. She spoke to a fox rehabilitator at a wildlife organization in Sonoma who told her that she had united many young foxes with their mums. She said that foxes are very secretive, and that no matter where the kit was found, nor at what time, the female fox would always return to the scene between midnight and 1am looking for the baby. Winnie told the very concerned woman to bring the baby to WildCare for evaluation, but if he was found healthy he should be back in the box and out in the yard before midnight. And sure enough, the mother fox retrieved her baby before 1am. Isn’t that a fantastic story? And don’t you wonder what it is about the hour between midnight and 1am that makes for successful fox family reunions?
The last patient to arrive on my shift was a Killdeer chick. Paulette (Assistant Medical Director) thought that it had probably hatched that day. It was tiny, about the size of a ping-pong ball on matchstick legs, and remarkably independent. A member of the public had found it walking down the road by itself. We made it a scrumptious meal of brine shrimp in water and mealworms. The mealworms were almost as big as the chick so Paulette stood by the incubator and tore the mealworms apart and fed the chick bite sized bits. How’s that for customer service?
That’s all from me today, Mum. We’ll really know it’s baby season when there is an onslaught of gorgeous baby raccoons at WildCare. Maybe next Wednesday?
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Black-tailed Deer frequently bear twin fawns; in a good year both may survive. Photo by Trish Carney trishcarney.com |
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Fawns lie in the grass so as not to attract predators. Mother is usually within hearing range. Photo by Susan Sasso
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Black-tailed Deer browse on tender shoots and leaves; intestinal microbes help them break down and utilize the nutrients in cellulose. Photo by Trish Carney trishcarney.com
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A startled fawn stotting (also called pronking or pronging) – repeated jumping lifting all four feet off the ground simultaneously. Photo by Trish Carney trishcarney.com
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Safety in numbers— a group of female deer may be more successful at raising fawns. Photo by Trish Carney trishcarney.com |
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A beautiful young doe scratches her lovely coat. Photo by Trish Carney trishcarney.com |
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A handsome young “spiker” showing off his velvet. Photo by Trish Carney trishcarney.com
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Beauty isn’t everything. The boys have to prove themselves. Photo by Trish Carney trishcarney.com
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A portrait of male virility. Photo by Trish Carney trishcarney.com
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mother deer
by Winnie Kelly, photos by Trish Carney trishcarney.com
Spring is baby season for many animal species, including the Black-tailed Deer that inhabit coastal areas of the Pacific Northwest, and abound in suburban Marin County. These deer are a subspecies of the Mule Deer, (Odocoileus hemionus) the larger Western cousin of the White-tailed Deer of the Northeastern forests of North America. Black-tailed does carry their fawns for about six months; evolution has timed the birth so that the most plentiful, nutritious spring growth is available to a deer mother when she needs it the most.
Black-tailed deer almost always bear twins, the deer equivalent of “an heir and a spare.” When the fawns are born, they are extremely fragile, and can’t run to escape predators. Because they are small and relatively immobile, the deer mother separates her twins — an evolutionary safeguard that increases the chances of survival in a prey species. She spends most of her time at least 300 yards away from them – far enough that a predator who sees her won’t see a fawn next to her, but close enough that she can hear and smell danger and come running if needed. The mother deer stays away from her fawns, except to actively nurse them.
The fawn, meanwhile, curls up into the smallest possible space, with his camouflaging spots outward, and sleeps, hoping to stay unnoticed until his next meal with Mom. When the fawn is about three weeks old, he’ll have the speed and endurance to follow his mother. This may be the first time since birth that he meets his sibling as they begin to follow Mom together. The fawns will continue to follow her until what is called "gathering time," when they will form a loose group with other youngsters while their parents begin the year’s social activities. But before that time there's a lot to learn.
Deer are prey animals. Their survival depends on avoiding what’s trying to kill them. Their coat is exactly the color of the average vegetation in the area: lighter in summer, darker in winter. Razor-sharp hearing enables them to pick up the slightest noises, and they can easily distinguish the sounds of an approaching predator from the natural sounds of leaves, wind and other animals. Even better than their hearing is their sense of smell. Deer can scent a predator, or a missing fawn, from half a mile away.
growing up fawn
Although a fawn’s first and most important job is to avoid predators, it must also learn to find water and food. The distant ancestors of Black-tailed Deer lived on open plains or meadowlands, where water wasn’t plentiful or deep, so deer absorb more water from the plants they eat than from other sources. Deer certainly enjoy a quick, cool drink from a stream, but they know that predators love to wait in hiding in the shrubbery that surrounds water sources. In times of drought, when green food and open water are both scarce, deer can smell water two feet below the ground, and will use their sharp hooves to dig a little “deer well.”
Although the eastern White-tailed Deer are grazers, our native Black-tailed Deer are browsers. They will eat a bit of grass, but mostly browse on tender leaves, flowers, or pieces of fruit (and maybe the occasional unlucky snail or insect). This food is plentiful, but pretty low-calorie. Deer have to spend most of their time eating to consume enough energy for all that running. Therefore, like cattle, deer eat in two separate steps: first they browse and then, in a safer, more hidden location, they sit down and chew it to process its nutrition. This is called ruminating, or “chewing the cud”. Ruminants like deer depend upon microbes that break down the fibrous cellulose on which they browse. A four-chambered stomach makes this possible, but fawns need some time to develop the healthy complement of microorganisms that keep the process cooking. Interestingly they receive these microorganisms in their mother's milk.
Even when ruminating, deer have to keep on the alert for predators. Within milliseconds of scenting or hearing danger, a deer’s amazingly complex adrenal system floods its muscles with energy, and almost instantaneous reflexes send long, slender legs flying.
Because of unique connective tissues in their shoulder areas, which allow an incredibly wide range of motion, deer are astonishingly agile in rough terrain. Deer are also excellent swimmers, and have been known to cross six miles of open water. Hollow hairs in the deers' coat provide buoyancy, like a very thin, flexible life jacket. Sharp hooves provide traction on any kind of natural terrain, and can cut skin and muscle like a knife, if the deer has to turn and fight.
The same forces that shape these abilities – sensing danger from afar, escaping it quickly, being able to pick up food, and then digest it later – have shaped the way deer live and raise their young. For example, a herd sitting down to chew is less safe (more noticeable) than one deer alone, but one deer alone is less safe (less able to sense danger) than a few deer together. Similarly, a group of female deer alone is better at raising fawns successfully than one that includes both sexes. Therefore, small, single-sex groups – usually brothers with fathers, and mothers with sisters – will spend most of the year roaming, browsing and ruminating together. In late summer, when plentiful food and cover are available, all the family groups in an area begin to mingle, beginning the important process of choosing a good mate (the “gathering”).
cervid social life
Like most animals, deer have a well-developed sense of what is attractive in the opposite sex. Beauty in females is defined by a deep, well-rounded chest and abdomen (to support large fawns); a glossy, well-nourished coat (to support healthy fawns); and strong, agile legs.
Beauty in males is a strong set of well-branched, sharp antlers, the large, well-muscled neck that supports them, and strong hindquarters. Does and their young need protection from predators during gathering time, so they gravitate toward the kind of buck who could use his antlers to throw a coyote twenty feet or so.
Antlers start growing in late spring and early summer, from two points (called pedicles) on the male’s skull. Soft, very sensitive tissue (called velvet) grows up from each side of the skull, and the bone antler is formed inside it. While growing his velvet, a buck will be very cautious about his movements – velvet is fragile and painful if touched or damaged — he may even bleed to death if it is seriously injured. When the antler stops growing, however, the velvet dries up and shreds off, revealing the sharp, tough bone underneath.
Depending on the buck's age, his antlers may stop growing when they’re small bumps (a “button buck”), long spikes (a “spiker”), or branch into two or many points. In California, antlered bucks are usually described by counting the number of points on each antler. For example, a “4x3 buck” would be a buck that had four points on one antler and three on the other.
At gathering time, in late August and September, males shed the velvet from their new antlers, and begin rubbing their antlers against trees and bushes, to get the annoying dried strips of velvet off. This leads into displays of their attractions to prospective mates in mock-battles with bushes, trees, and other males.
During mating season, or the "rut," a male uses his superb nose to sniff out an interested, available female. He begins to follow her around wherever she goes (called “tending” her), usually with head held low in a submissive, courting posture. For the remainder of the fall, the buck tends his doe, alternately protecting and annoying her, fighting off other bucks who might be interested and any unwary predator foolish enough to attack during this season.
living with deer
To live well with deer, we need to remember that deer consider us to be predators. So keep a few important points in mind when you see them:
- In springtime, be cautious around does, who will go to extreme lengths to protect their fawns from predators like you (or your dog).
- Don’t approach a fawn without checking very carefully for a nearby doe.
- In fall, be cautious around bucks, who will go to extreme lengths to protect their does. Don’t approach a doe, either, without looking carefully for a nearby buck.
- Politely ignore fawns that are curled up in their daytime hiding place. Mom is within earshot, and the fawn is fine. Mom will come running, however, if she hears her fawn in trouble with a predator, and you do not want to be that predator!
- Call for help if a young fawn with spots is actively running around and crying. This means that Mom is out of earshot – she may have been injured or killed, or the fawn may have been startled or taken out of hearing range by a predator (for example, a well-intentioned human). WildCare’s 24-hour hotline is available for advice at any time 415-456-7283 (SAVE).
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spring insect uprising
Spring heralds the emergence of insect populations in mind-boggling numbers. Many insect species that have been overwintering as larvae or nymphs, emerge with the warmer weather. While we don’t often notice the wide variety and number of insects around us, many animals depend on them for food this time of year. Songbirds, for example, feed their babies almost exclusively on insects for the first few weeks of their lives.
it’s an invertebrate world
What weighs more – all the elephants on earth or all the ants on earth? Scientists estimate that 10% of the animal biomass of the world is composed of ants, and another 10% of termites. This means that these tiny ‘social insects’ could possibly make up an incredible 20% of the total animal biomass on this planet! Insects are arthropods, members of the phylum Arthropoda (from Greek árthron, “joint,” and podós “leg,” which together mean “jointed leg”). Arthropods include the insects, arachnids, crustaceans and others.
Have you looked at your feet when walking through a grassy field? Ever notice how many tiny insects hop out from under your feet? Leaf hoppers, frog hoppers, grasshoppers, crickets, flies, mosquitoes, lady beetles, aphids and more.
Or turn over a compost pile. Some of the invertebrates included in this web are nematodes, mites, springtails, earthworms, slugs and snails, centipedes, millipedes, sow bugs, beetles and ants. There are so many insects, no wonder the animal world feasts in the spring!
Insects have played an important part in the history of human nutrition as well. Because they are high in protein and provide rich mineral content, hundreds of insect species have been used as human food. Some of the more important groups include grasshoppers, caterpillars, beetle grubs and (sometimes) adults, winged termites (some of which are very large in the tropics), bee, wasp and ant brood (larvae and pupae) as well as winged ants, cicadas, and a variety of aquatic insects. After all, these aquatic insects are just small versions of the larger invertebrates we relish— crab, crawfish and lobster.
Insects vary widely in fat (and thus energy) content. Isoptera (termites) and Lepidoptera (caterpillars) rank among the highest in fat. Chitin – a carbohydrate polymer found in invertebrate exoskeletons provides fiber. Numerous applications of chitin and its derivatives (especially chitosan) are found in medicine, agriculture and industry.
lepidoptera: the moths and butterflies
Butterflies and moths make up the Lepidoptera. The name means “scale wing,” and lepidopteran wings are covered with microscopic scales, which are often iridescent and brightly colored in butterflies. The scales are visible as the “fuzz” along the edges of the wing. The larvae and caterpillars are very nutritions and are relished by many birds and some insects. Bats, birds and spiders eat the adults.
hymenoptera: the ants, bees and wasps
Ants belong to the order Hymenoptera which also includes bees, wasps and sawflies. Because they are so plentiful, ants are a large part of many animals’ diets. Some ants have stingers, some bite, and some rely entirely on chemicals that they can secrete or spray as a defense. One of the most common chemicals is called formic acid. Formic acid is sprayed out of a specialized nozzle at the back end of ants in the subfamily Formicinae. This group of ants contains the most abundant and largest ants in much of Europe as well as in North America and northern Asia, and includes the Western Harvester Ant, Pogonomyrmex occidentalis.
Formic acid got its name from “formica,” the Latin name for ant. Scientists have discovered that these ants will usually only spray the formic acid after they’ve inflicted an open wound. An open wound is more sensitive to the formic acid than an undamaged surface. In a behavior called “anting,” some birds have been observed to put ants in their feathers because the ants will squirt formic acid which helps rid the birds of parasites.
Who eats ants? Other ants, for a start, and anteaters, of course. Sparrows, wrens, flickers, grouse and starlings have all been seen eating ants. Other ant afficionados include spiders, fish such as trout, lizards, snakes, bears and even coyotes will dig up and eat Honeypot (Myrmecocystus) Ants occasionally. Wasps are enjoyed by numerous species of birds, skunks, bears, badgers, bats, weasels, wolverines, rats and mice. The bee-eater birds, crickets, grasshoppers, frogs, and bears eat bees.
coleoptera: the beetles
Beetles, in the order Coleoptera, comprise the largest number of species of all the insect orders. The word Coleoptera is from the Greek koleos, meaning “sheath,” and pteron, meaning “wing,” thus “sheathed wing,” Most beetles have two pairs of wings, the front pair, the elytra, are hardened and thickened into a sheath-like cover over the rear pair of wings that are protected beneath. These hardened wings always meet in the middle, making a straight line down the insect’s back, and making a beetle very easy to recognize.
Darkling beetles, family Tenebrionidae, for example, are black, relatively large and shiny, and can always be found walking on the ground. That’s because their elytra are fused so they can’t fly. They can be found all over the world, and it is estimated that there are more than 20,000 species. These are the beetles most commonly used in WildCare’s hospital to feed many different patients -- in the form of mealworms.
Members of the genus Eleodes have perfected an interesting defense against predators, which include birds, reptiles and amphibians. Nicknamed the “stink” beetle, if threatened, they stand on their heads and elevate their rear ends to spray a foul-smelling black fluid that drives away their adversaries. However, some animals have figured out a way around the beetles' defense, and plant the tail end of the beetle into the ground, so they can eat it head first and avoid the beetles' chemical defense.
There are so many different kinds of beetles that it is virtually impossible to make any general statements about them because they occupy a vastly diverse set of ecological niches. Many of the insectivorous mammals like shrews and moles will, of course, mostly eat beetles since beetles are the most abundant insects available. Ducks love them. Opossums, skunks and bats are also known to eat beetles.
Studies of the remains of insects found in bat guano find a large number of beetle parts. This could be because the hard elytra of beetles tend to survive the trip through the bat’s digestive system better than the soft squishy bits of a mosquito, but it could also be because those hard, stiff elytra tend to make beetles much easier to detect with chiropteran sonar, and also make the beetles less swift and maneuverable in flight, making them easier to catch than hoverflies or midges.
Grubs are the larval stage of beetles, typically found just below the soil’s surface. Japanese Beetles, May or June Beetles, and Asiatic Garden Beetles, are examples of beetles in this group. They are “C” shaped and are a light to white color. Grubs eat organic matter including plant roots. They feed in the upper surfaces of the soil until cooler weather forces them to move deeper into the soil for the winter. During the spring, they move back to the upper soil, feeding and then finally pupating and emerging as adult beetles. Crows and jays, moles, raccoons, opossums and skunks all love grubs.
the buzz
All this insect activity brings up a few interesting points to take away. First, if you think that you have to feed wildlife, you might want to reconsider. There is plenty of food out there for animals to eat. You just may not recognize it as food, but you can rest assured they do.
Second, it’s clear that the larger wild animals like raccoons, skunks and crows – animals some people consider to be nuisances – are working overtime to keep the insect populations in control and maintaining the balance of nature. Insects can carry a lot of diseases, and if they become too numerous, can cause problems for us. West Nile Virus, transmitted by mosquitoes, is just the most recent example.
Third, pesticides to control pests in your garden adversely affect many more animals than the insects you are trying to control. They are often deadly to birds, for example, and not good for us, either. If you need gardening help, an integrated pest management program will help keep pesticides out of our environment.
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More than 50 wildlife rehabilitators from central California met in Grass Valley on March 24 to learn more and share information about raccoons. Photo by JoLynn Taylor |
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Raccoons come to rehabilitation centers for many reasons, including injury, orphaning and diseases. Photo by JoLynn Taylor |
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Distemper can present as apparent tameness and unusual behavior. Photo by JoLynn Taylor |
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Dr. Pesavento presented her process and research project to the group of raccoon rehabilitators in Grass Valley. Photo by JoLynn Taylor |
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Raccoons are procyonids, a relatively generalized terrestrial carnivore that share characteristics with dogs, bears and weasels. Veterinary treatments are often based on what we know about cats and dogs. Photo courtesy of Patricia Pesavento |
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Scent receptors in mammals map directly to the olfactory center of the brain. Photo from Nature Reviews Neuroscience |
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A microscopic view of the neural pathways in the nasal and sinus area. Most mammals are hundreds of time more sensitive to olfactory information than are humans. Photo courtesy of Patricia Pesavento |
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Polyomaviruses are widespread in nature. In animals with healthy immune systems, the viruses remain latent after primary infection. Illnesses associated with these viruses may occur when the immune system is compromised The Raccoon polyomavirus identified by Dr. Pesavento and her team is similar to polyomaviruses from other species. Photo from Landes Bioscience |
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A high cancer incidence is reported in wildlife populations in environments that are heavily contaminated with chemicals from human sources. |
project in pathology
On March 24, Jan Crowell of Wildlife Rehabilitation and Release in Grass Valley hosted a raccoon class and a roundtable discussion which were attended by a number of people from neighboring wildlife rehabilitation centers. The class and roundtable were also attended by two researchers from UC Davis who have worked on several of WildCare’s recent raccoon cases.
WildCare’s Raccoon Team Leader JoLynn Taylor presented the class she is preparing for the International Wildlife Rehabilitation Council’s (IWRC) online education program. At the end of the class, Patricia Pesavento, DVM, PhD, dip. ACVP, an Associate Professor of Anatomic Pathology at the University of California at Davis Veterinary Medicine, presented an update of the work she has been doing on raccoon pathology with WildCare and asked for participation from other centers.
wildcare’s raccoons
Raccoons are admitted to WildCare for a variety of reasons. Basic injuries like broken bones and bacterial infections usually respond well to treatment, but when a viral infection such as distemper or parvovirus is suspected, the prognosis is very poor, as there is no effective treatment for these diseases. In general, there is little research available about wildlife diseases, because most of what scientists have studied and published is based on dogs, cats or animals of agricultural interest. Veterinarians who treat wildlife must base their treatments on those used in similar domestic species. Raccoons are a very modern and generalized species that shares characteristics with the dog, cat, weasel and bear families.
In the last couple of years, WildCare's wildlife hospital has admitted a number of raccoons whose symptoms seemed to come from distemper, a disease they share with canines. Those symptoms include nervous system disorders, from apparent tameness at one end of the spectrum, to seizures at the other
end. But Medical Staff experience and intuition said that, although many of the symptoms matched up, not all of them led to a clear diagnosis of the distemper virus. It was possible the distemper virus had mutated, or that the animals were dying of something else. To see if we could learn more about how to treat these cases, we began routine testing of these raccoons. Two years ago, after receiving a generous funding grant for the purpose from Microsoft on behalf of Clinic volunteer Stephen Shaw's many hours of volunteer work, WildCare began to send these suspected distemper cases to the California Animal Health and Food Safety (CAFHS) laboratory at UC Davis.
As the lab reports came in, the findings surprised us as well as the pathologists. Many of the cases that seemed so similar to distemper turned out to be a form of brain cancer localized in the olfactory lobes— one that had never before been documented. Suddenly, this was no longer a routine process for the people at the lab— Drs. Leslie Woods and Federico Giannitti from the CAHFS lab wanted to learn more. Dr. Deana Clifford, a wildlife veterinarian from the Wildlife Investigations Laboratory of the California Department of Fish and Game (CDF&G) became involved with advice and some financial support, and as a professor of pathology, Dr. Patricia Pesavento engaged her graduate students in a research project to learn more. She described the project at the roundtable in March.
the roundtable
After listening to the raccoon natural history and rehabilitation talk and the ensuing discussion, Dr. Pesavento expressed her appreciation for the opportunity to learn more about raccoons from a perspective different than her usual clinical one, and the value of looking at a problem from other angles.
She then followed with her own presentation of the process she and her team followed, in which they discovered a polyomavirus that is associated with the brain cancer identified by Drs. Woods and Giannitti at CAFHS. Her talk began with a quick basic lesson in the biology on which she and her team base their research.
quick lesson in biology
Viruses and cancers: Dr. Pesavento noted the American Cancer Society statistic that an infectious disease is associated with 15-20% of cancers. Examples include Epstein-Barr Virus, JC virus, cytomegalovirus, Merkel cell polyomavirus and the papillomavirus which is associated with cervical cancer in women. Virus-associated cancers are also linked to immunosuppression such as those in Kaposi sarcoma and AIDS. But, she reminded us that just because a viral association is identified, it doesn’t mean there aren’t also environmental factors as well. A high cancer incidence is reported in wildlife populations in environments that are heavily contaminated with chemicals from human sources.
Cancers are more often seen in older animals, but viruses are very commonly found in young ones. That's true of humans too— think of children passing cold and flu viruses to each other. She pointed out that while the raccoon polyomavirus (RaPyV) is genetically similar to polyomaviruses that infect other species, each virus is unique to its species.
Olfactory neural pathways: scent receptors in the nasal/sinus area are directly linked to the olfactory area of the brain (one of the reasons that our sense of smell is often so difficult to describe). These olfactory neurons are unique in this sense. Because they’re neurons, olfactory cells are “excitable,” i.e., capable of responding to changes in the environment around them. Because the raccoons' tumors were consistently located in the olfactory brain center, the immediate thought was, “Were the raccoons smelling something that might be causing this?”
With her graduate students, Dr. Pesavento is initiating a project to try to get a better picture of what the findings might mean.
the project
WildCare receives a large amount of information from CAHFS, including microbiological, parasitic, virological and serologic data, and detailed reports of samples and diagnoses. Our records are retained and searchable, so that information can be compiled from our cases, both for ourselves and through CAHFS. This data is a great start, but it is too narrow for scientific purposes.
First of all, of course, is the fact that most (not all) of the raccoons diagnosed with this specific malignant brain tumor lived in Marin County. But that may just be a result of the fact that we are the only center currently engaged in this type of diagnostic testing. The first step is to obtain more samples from other areas. As suggested above, young animals are important in viral shedding. Dr. Pesavento is requesting samples from healthy raccoons at about the age of eight weeks or older from WildCare and other centers to find the answers to the following questions:
- How common are tumors in raccoons, and are they consistently
associated with virus?
- Who is shedding the virus and where is it being shed?
- Does polyomavirus cause tumors?
- What is the route of infection?
- Are raccoons immunosuppressed?
- Is raccoon behavior important to the data?
- Is there something in the environment that contributes to tumor
formation?
one health
To date, eight confirmed cases of this malignant brain tumor, specific to raccoons in Marin, have been documented. These interesting cases represent another example of a one-health issue. As such, it is one that the CDF&G is very interested in, and to the extent its budget constraints allow, it has contributed financial support to keep the project moving forward. The “One Health” principle is central to Dr. Deana Clifford’s work at the CDF&G Wildlife Investigations Laboratory. She commended WildCare’s efforts, noting that, “Without the generous support of WildCare’s donors, these cancers may have gone undetected.”
While a polyomavirus from a raccoon may not cause a tumor in another species, what we can learn from wildlife will have implications for other species, including ourselves.
Maybe these cases will confirm what we already know: it isn’t healthy to eat garbage.
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great gift ideas for may
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WildCare logo-wear also makes a great gift! Choose from a cool selection of caps, tees and sweatshirts on our Shop page, or visit WildCare and choose from an even larger selection!
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What a perfect gift!
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