Bobcat Caches & Revisits White-tailed Deer Carcass
Rabbits and hares comprise much of a Bobcat’s diet, but when prey is scarce or hard to capture, adult male and large adult female Bobcats will attack bedded, weak or injured White-tailed Deer. Bobcats often cache prey such as a deer that is too large to eat in one feeding. They scrape up leaves, bark, twigs, soil, snow — whatever is available — and cover their prey, returning soon to eat it. When feeding on a deer, Bobcats bite away the hair to avoid eating it, and this discarded hair is frequently mixed with the debris that the cat drags over the kill to cover it.
This photograph was taken 24 hours after the deer was cached, and the site has been visited by several predators. A characteristic sign of Bobcat feeding is the amount of hair strewn around the carcass and the lack of broken long bones (see inset). (Bobcats don’t have the strength to break large bones with their teeth.)(Cache discovered by Lynn & Otto Wurzburg, who observed the Bobcat leaving after caching the deer)
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Coyotes Scavenging
Coyote tracks from three different directions led to an area where a deer’s well-cleaned skull was the only remnant of a communal meal. It had been dug up from a spot nearby where it had been cached, and carried to a more protected area to work on. Coyotes are omnivores, but about 90% of their diet consists of mammals. Coyote scat I’ve examined has included, among other things, the hair of Muskrat, Snowshoe Hare, White-tailed Deer and small rodents as well as feathers, grass and apples.
Coyotes are commonly blamed whenever there is a decline in the White-tailed Deer population. Studies involving the removal of deer populations in a given area have not found any evidence that Coyote removal caused an increase in the deer population, nor did it affect the overall deer population growth. The fact that Coyotes are not causing deer populations to decline can also be seen in the devastating effect White-tailed Deer are having on forest ecosystems throughout the eastern United States as the Coyote population increases.
That’s not to say Coyotes don’t hunt deer – they do, primarily in the spring (fawns) and in the winter, especially when there is enough snow and/or crust to slow deer down but not Coyotes. However, much of their venison consumption is a result of their scavenging deer carcasses, which they do any time of year. Examine Coyote scat and the chances are great you will find deer hair in it; chances are also great that it came from a carcass, not a living deer.
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Drama In The Goldenrod Patch
At this time of year when most flowers have gone by, Canada Goldenrod (Solidago canadensis) is a primary source of pollen and nectar for bees, beetles, butterflies, flies and many other insects. Consequently, goldenrod flowers are a popular place for insect-eating predators to linger.
Recently I spied an Ambush Bug that had captured a fly and had its proboscis inserted into it, contentedly sucking away the fly’s innards while I photographed it. Unbeknownst to me or the Ambush Bug, another predator, a Bald-faced Hornet, had spied the bug with its prey. Although adult hornets consume liquids, usually sugars like the juice of fruits or nectar, their larvae are raised on a diet of insects, so adults are constantly looking for prey. Suddenly, out of nowhere, the hornet flew in, tussled with the Ambush Bug and flew off with the fly in its mandibles, landing on a nearby branch with the object of its thievery.
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Coyotes Investigating Beaver Lodges
Over the past century beaver trapping has declined and beavers have returned to many of their former habitats. Wolves also have come back in a few areas (not the Northeast yet) — but most places where beavers now live remain free of wolves. As a result, the beaver population has continued to increase, limited only by a few predators, primarily humans and Eastern Coyotes.
Coyotes are major beaver predators and have established themselves throughout the Northeast partly because of the abundance of prey and partly because of the absence of wolves, who keep coyotes out of their habitat. During most of the year, coyotes can take advantage of beavers that leave their pond to feed on land. When they are in their lodges, however, beavers are fairly safe from coyote predation, especially if their lodge is surrounded by water. Come winter, when ponds freeze and beavers remain in their lodges, coyotes can easily approach an inhabited lodge by walking over the ice. Thanks to the lodge’s two to three-foot-thick walls of frozen mud and sticks, the beavers within are safe. (Photo: signs showing a coyote’s attempt to access a beaver lodge)
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Some Spiders Still Active
Spiders are ectotherms – warmed and cooled by their environment. In the fall, those outdoor species that remain alive through the winter begin preparing themselves by producing antifreeze proteins that allow their tissues to experience below-freezing temperatures. When a small particle of ice first starts to form, the antifreeze proteins bind to it and prevent the water around it from freezing, thus preventing the growth of an ice crystal. Some species survive in temperatures as low as -5 degrees Celsius.
The pictured hammock spider, still active in late October, is nourishing itself by drinking the dissolved innards of a fall-flying March fly, whose name comes from the predominantly springtime flight period of most March Flies (of the 32 species in the genus Bibio in North America, only three fly in fall).
A common belief is that once cold weather appears, outdoor spiders seek shelter inside houses. In fact, only about 5% of the spiders you find in your house lived outside before coming into your house, according to Seattle’s Burk Museum. The reason people tend to notice them more inside may be because sexually mature male spiders become more active in the fall, wandering far and wide in search of mates.
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Vulnerable Ducklings
There is a reason why ducklings remain with their mother for their first month or two of life. It takes 50-70 days before most ducklings can fly, and survival during this period is highly variable, ranging from less than 10 percent to as high as 70 percent. They are at their most vulnerable during this stage. The most common causes of duckling mortality include predation, adverse weather conditions, starvation, disease, and parasites. The mother offers her young a degree of protection from some of these factors while they are under her care.
Predation is arguably the greatest threat to young waterfowl. Ducklings are sought after by nearly every type of predator, including other birds (eagles, hawks, owls, herons, crows), fish (largemouth bass and northern pike), amphibians (bullfrogs), reptiles (snakes and snapping turtles), and mammals (foxes, raccoons, and mink). Their odds for survival increase dramatically when the ducklings obtain the ability to fly. (Photo: female Wood Duck and ducklings)
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Red Fox Kits Maturing
Time is marching on…the blue eyes of Red Fox kits are turning brown, as they do once a kit is around two months old. Their coat is slowly being replaced by the reddish hairs for which they are named. While kits still spend most of their time close to their den, individuals will take short exploratory walks by themselves. Frequently they accompany their parent on forays during which they are instructed on the finer points of being a successful predator.
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Ambush Bugs Patiently Waiting To Pounce
Ambush bugs, a type of assassin bug, are true bugs, in the order Hemiptera. (Although insects are often referred to as “bugs,” technically only insects in this order are classified as bugs by entomologists.) All true bugs have piercing and sucking mouthparts, and wings which are membranous and clear at the tips, but hardened at the base.
Ambush bugs are usually brightly colored (yellow, red or orange) and have thickened front legs which are used to capture prey up to ten times their own size. They live up to their name, patiently lying in wait for unsuspecting prey, often in goldenrod flowers where they are very well camouflaged. An ambush bug, upon sighting an insect, suddenly seizes the prey in its powerful forelegs and quickly dispatches it with a stab from its sharp beak. It then injects digestive enzymes into its prey, after which it drinks the resulting liquid innards.
Weaning of Red Fox Kits Nearing Completion
When Red Fox kits are about three weeks old they are introduced to solid food. Their mother’s milk continues to provide them with sustenance for several weeks more but it is increasingly fortified by prey that their parents catch. At about five weeks of age, just a week or so after the kits are seen above ground, the process of weaning begins. The mother physically prevents them from having access to her teats by lying down on her stomach or snapping at her kits if they attempt to nurse too often.
The kits in this photograph, taken on April 26 several years ago, are approximately two months old, enjoying what may be one of the last warm milk meals they will ever have. Weaning is completed at about eight weeks or a little more, when the kits’ teeth have all come in.
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Great Horned Owls & Striped Skunks
Striped Skunks do have predators other than Great Horned Owls (bobcats, foxes and coyotes-fishers have been known to prey on skunks, but very infrequently), but these predators have to be pretty desperate before they will prey on a skunk. Automobiles and disease kill more skunks than all of their predators put together, but Great Horned Owls have the distinction of being the primary predator of Striped Skunks.
Being a nocturnal hunter, a Great Horned Owl necessarily consumes prey which are nocturnal. Striped Skunks are active at night and are consumed by Great Horned Owls with regularity, even though a skunk can weigh up to three times as much as a Great Horned Owl (average GHO weighs a little over 3 pounds) and has a potent way of defending itself.
For many years scientists assumed that birds had a poor sense of smell because the area of a bird’s brain involved in smell is relatively small compared with the area found in mammals. However, recent research reveals that birds have a high number of active genes that are associated with smell, and many species may have an excellent sense of smell. It’s fairly safe to assume, however, from its consumption of skunks, that the Great Horned Owl’s sense of smell is not very well developed. In addition, if a skunk sprays, much of the odor is absorbed by the Great Horned Owl’s leg feathers, which extend down to its talons.
A favorite memory of mine is walking through a field at dusk and suddenly noticing a strong skunk-like smell coming from above, not below, me. A Great Horned Owl silently flew overhead, with only the tell-tale smell of a recently-captured skunk announcing its presence.
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Small Birds Beware of Sharp-shinned Hawks
Short, powerful, rounded wings and a relatively long tail enable Sharp-shinned Hawks to maneuver in dense cover in pursuit of small birds, which compose 90% of their diet. Small mammals and insects are consumed, but not nearly as frequently as birds. The size of the birds eaten range from hummingbirds to Ruffed Grouse. Long legs and toes (especially middle toes) enable individuals to reach into vegetation and large eyes enhance its ability to catch fast-moving prey.
Sharp-shinned Hawks are familiar sights to those of us with bird feeders – this species is responsible for 35% of 1,138 predation incidents reported at feeders in continent-wide survey. In this photograph, a Blue Jay is successfully warding off an attack by a juvenile Sharp-shinned Hawk. (Photo by Jeannie Killam.)
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Barn Spiders Spinning
If there is a fairly large spider spinning orb webs in a corner of your shed or barn and it has striped gray, brown and white legs, chances are great that it is a Barn Spider, Araneus cavaticus. These spiders are nocturnal, so it’s often the early-rising/late-to-bed folks that observe these arachnids. During the day, Barn Spiders hide in a nearby crevice where birds and other predators cannot easily find them. Webs are freshly constructed every night (or every few nights) and the remains of the old web are eaten in order to conserve the valuable silk. During the night Barn Spiders can be found hanging in the center of their web, awaiting prey.
Male Barn Spiders reach between ¼” and ½” in size and adult females typically are around ¾”. Most males spin webs less frequently and spend much of their lives wandering, attempting to find a female to mate with. Thus, most Barns Spiders you see in webs tend to be females.
The spider in E. B. White’s Charlotte’s Web was based on a Barn Spider. In his inimitable way, White named her Charlotte A. Cavatica, a reference to the Barn Spider’s scientific name. One of Charlotte’s daughters, after asking what her mother’s middle initial was, names herself Aranea.
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Praying Mantises Mating & Laying Eggs
In the fall, after mating, the female praying mantis lays up to 400 eggs in a frothy foam; together the eggs and the foam they are encased in are called an ootheca. This one to two-inch long mass is attached to vegetation, usually about a foot or two off the ground. Eventually the frothy structure hardens, providing a protective case for the eggs.
In the spring, miniature (wingless) mantises, called nymphs, will hatch from this egg case. When hatching, the nymphs appear all at once, crawling from between tiny flaps in the case and then hanging from silk threads about two inches below the case. They are identical to adult mantises, except that they lack wings. Within an hour or two, after drying out, they disappear into nearby vegetation.
A video of a praying mantis laying her eggs and of the young mantises hatching can be seen at https://www.youtube.com/watch?v=1K2BPg7iNZA .
Thanks to Ba Rea, of Bas Relief Publishing (http://basrelief.org/ ) for the use of her West Virginian egg-laying mantis photograph.
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Forest Floor Mystery: Pellets? Old Scat? Cache?
Lying at the base of a large Eastern Hemlock I recently found two piles of bleached bones. One pile consisted of mostly vertebrae; the other pile had numerous tibias, humeri and ribs. All were the appropriate size and shape to have come from several Eastern Chipmunk skeletons – at least four or five. How did they end up in two distinct piles?
The lack of any fur indicated that regardless of how these bones came to be here, they were deposited quite a while ago. The lack of any partial skulls or jaw bones and the large number of bones in each pile led me to believe that these were not the remains of two pellets that had been regurgitated by resident Barred Owls. No wild owl pellet I’ve ever dissected, including the large pellets cast by Snowy and Great Gray Owls, has contained even half this many bones, and most contained at least part of a jaw bone.
If not pellets, then scat? How likely is it that a predator could catch and consume multiple chipmunks rapidly enough so that they would end up in the same pile of scat? One feasible explanation could be that a fox, coyote or fisher preyed on young, inexperienced chipmunks, but the bones were adult-size bones.
Perhaps these two piles are the remains of a predator’s cache – perhaps a bobcat?
The possibilities are endless as to how this chipmunk graveyard came to be. However, none of the theories proposed here can explain the dissimilarity between the types of bones in each pile. If any naturally curious readers have insight into this phenomenon, your thoughts are welcome!
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Twelve-spotted Tiger Beetles Mating
As their name implies, all species of tiger beetles are ferocious predators. They are equipped with huge eyes, large three-toothed mandibles that crisscross at their tips and the ability to move very fast . Twelve-spotted Tiger Beetles (Cicindela duodecimguttata) are usually found in open, sandy spots, where their larvae can dig and live in burrows. Adult tiger beetles use their formidable mandibles to masticate their prey and then squeeze the bits and drink the resulting liquid.
In May and June, whenever they are not ambushing prey, Twelve-spotted Tiger Beetles are concentrating on reproducing, as the “menage a trois” photo illustrates.
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A Gardener’s Favorite Beetle
Ground beetles (family Carabidae) are fast moving beetles, many of which are predators with specialized diets. One ground beetle (Cychrus caraboides) eats only snails (its head and thorax are very slender, allowing access to the inside of a snail’s shell). Another, Harpalus rufipes, limits its diet to strawberry seeds. Loricera pilicornis uses bristles on its antennae to trap springtails and mites.
The Bronze Carabid, Carabus nemoralis, (pictured) uses its large curved mandibles to crush and slice through prey – it will eat or try to eat just about any invertebrate, but specializes in capturing and eating slugs. Its hardened forewings, or elytra, have a coppery sheen to them, and parts of its thorax and the edges of its elytra are iridescent purple. This nocturnal, introduced, flightless, one-inch-long beetle resides throughout the Northeast and is already actively pursuing slugs.
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Scent Posts
Scent posts can serve as territorial markers as well as a means of conveying hierarchy, breeding status, gender, fitness, etc. When you think of a scent post, where an animal deposits its scent either by rubbing, urinating or defecating, one often thinks of it as being used by one animal to communicate with other individuals of the same species. However, for whatever the reason, a rock, stump or the junction of two trails can prove irresistibly appealing to more than one species. Each chooses to leave messages for other members of its respective species at the same location. In this case, two predators, a Fisher (left) and an Eastern Coyote (right), left their scat at the base of a rotting stump. The tracks of both of these animals were evident throughout the area. In sharing the same scent post, were they vying for the same territory, advertising for a mate (both are at the peak of their mating season), or simply making their presence known? Unfortunately, the human nose isn’t equipped to answer this question.
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The Short Life Span of Ruffed Grouse
Ruffed grouse typically have a short life span; few live to be three years old. By mid-August about 60 percent of the grouse hatched that year are lost to predators, weather extremes, disease, accidents (such as flying into windows) and hunters. Less than half of the surviving young survive through the winter to have a chance to breed in the spring, and less than half of those that survive long enough to breed make it to a second mating season. The hazards for a ruffed grouse are many, with predation at the top of the list.
Birds of prey, especially the goshawk and great horned owl, take many grouse, but terrestrial hunters such as foxes, coyotes, bobcats and fishers also take advantage of this plentiful food source. Along with hares, porcupines, squirrels, mice and voles, grouse are one of the fisher’s preferred foods. A fisher managed to capture a ruffed grouse in the pictured scene, leaving only tracks and a few tell-tale feathers to tell the story.
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Scat Revelations
Predators and scavengers of all stripes are reaping the benefits of deer hunting season. A close look at the composition and form of the pictured scat reveals much more than the fact that a coyote dined on a white-tailed deer. Note that the scat consists almost entirely of deer hair. When a predator such as a coyote comes upon a carcass, it tends to eat the internal organs first, which produce black, moist, soft scats with next to no bones or hair in them. As it continues to feed, the coyote’s scats contain more and more bones and hair, until eventually that is all they consist of.
There are two conclusions one could make when analyzing this scat. One is that the coyote whose scat this is was finishing up the tail end of a deer carcass. It is also possible that this coyote might not have been at the top of its pack’s hierarchy. The alpha pair usually has first dibs on the internal organs, with lower members of the pack having access to the less choice parts, such as hair and bones.
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Fishers Eating Fruit & Marking Territory
When one thinks of fishers, meat-eating predators come to mind. While it is true that the fisher is a generalist, opportunistic hunter and scavenger, and feeds on any prey it can catch and kill (snowshoe hares, rabbits, squirrels and other small rodents, birds, bird eggs, smaller weasels, shrews, porcupines, raccoons, amphibians, reptiles, carrion and a very occasional cat or chicken), it also consumes fruit and nuts, especially when prey is scarce.
Given the amount of apples that are available this fall, even if prey isn’t hard to find, it is not too surprising to see fisher scat composed solely of apples at the base of this scent marking post (confirmed by fine fisher hairs at the very tip of the stump as well as scat).
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Darners Laying Eggs
Females of different species of dragonfly have different techniques for laying their eggs. Most skimmers, cruisers and clubtails dip the tip of their abdomen to the surface of the water while hovering or flying, and release their eggs. Most darners, such as the Shadow Darner (Aeshna umbrosa) pictured, have a sharp-edged ovipositor with which they slit open a stem or leaf of a plant on or near the water. They then push their egg into the plant tissue exposed by the slit. Because they are stationary during this process, female darners are vulnerable to predation by fish and frogs at this time. A close look at the bottom third of cattail leaves this time of year will tell you whether or not darners are in the vicinity, as the slits they make are very apparent, appearing as thin, tan, 1/2″ vertical lines.
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button.
Black and Yellow Mud Daubers Collecting Mud & Building Cells
There are many species of mud daubers — wasps that build mud cells in which they lay eggs and in which their larvae develop. The female Black and Yellow Mud Dauber gathers mud at the edge of a pond or puddle, rolls it into a ball, grasps it in her mandibles and flies it back to her nest site, a spot protected from rain, often on a man-made building. Here she constructs several mud cylindrical cells.
Like most wasps, mud daubers are predators, and they provision their mud cells with select spiders (including jumping spiders, crab spiders and orb weavers) which they locate, sting and paralyze before stuffing them into a cell. The female lays an egg amongst the spiders, so that when the egg hatches the emerging larva will have a supply of spiders (that haven’t decomposed, because they’re not dead) to eat. She seals the cell with mud, and repeats this process several times after which she covers the small group of cells with more mud. The Black and Yellow Mud Dauber larvae pupate in the fall, overwinter inside the cells and emerge as adult wasps the following spring.
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Rose Chafers Busy Eating & Being Eaten
All of a sudden we are besieged by Rose Chafers, those tan beetles that feed on roses and peonies, as well as the foliage of many trees, shrubs and other plants. The reason for their sudden appearance has to do with their life cycle.
Adult Rose Chafers emerge from the ground in late May and early June. (Because the Rose Chafer prefers sandy soil to lay eggs, plants located on sandy sites are most likely to be attacked.) Adult beetles feed on plants for three or four weeks, generally until late June when they mate, lay eggs in the soil and then die shortly afterwards. Two to three weeks later, the eggs hatch into small, white grub‑like larvae which feed on the roots of grasses and weeds. The larvae spend the winter in the soil below the frost line before pupating and emerging as adults in the spring.
Rose Chafers contain a toxin that can be deadly to birds, but apparently not to crab spiders, at least the one that was photographed drinking the innards of a Rose Chafer it had caught. As testimony to their drive to reproduce, a Rose Chafer, minutes after this picture was taken, mounted and attempted to mate with the Rose Chafer that was being consumed by the crab spider.
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Predator Eating Predator
The Six-spotted Fishing Spider, Dolomedes triton, is an arachnid in the nursery web spider family Pisauridae. As its name implies, the Six-spotted Fishing Spider does occasionally eat small fish, but also consumes other invertebrates and tadpoles. The hunting techniques of fishing spiders are varied. Often they sit patiently during the day, waiting hours with their legs stretched out for an unsuspecting insect (such as the pictured Dot-tailed Whiteface dragonfly) to land on the same lily pad or leaf that the spider is sitting on. They can and do walk on water as well as dive up to seven inches deep in order to catch aquatic prey. The Six-spotted Fishing Spider in this photograph has removed the head of its prey and is drinking its liquefied innards.
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