Tiger beetles (named for their ferocity) can be easily recognized by their quick, jerky movements, huge eyes and large, multiple mandibles. Look for these voracious hunters in sunny, open spots where they can easily spot prey and potential predators. The six-spotted tiger beetle is hard to miss, thanks to its iridescent green outer wings, or elytra. Contrary to that which its name implies, this species can have five, two or even no white spots. It is most likely to be found on exposed rocks, logs and tree trunks, whereas the twelve-spotted (may have 12 or fewer spots) tiger beetle tends to prefer moist sandy spots. They both capture and liquefy their prey by masticating it with their formidable mandibles, squeezing it and swallowing the juice. Both of these species of tiger beetles have a two year life cycle, overwintering as adults their first winter, emerging early in the spring, mating and laying eggs during the summer and then overwintering as larvae.
In the fall and winter, fruit makes up about 90% of an American robin’s diet. In the spring, only 10% of a robin’s diet consists of fruit; invertebrates make up the remaining 90%. (Summer is a fairly even mixture of both.) At this time of year, earthworms are a popular food item with robins. Watching a robin foraging for a worm can make you wonder whether the robin is using its ears or its eyes to locate the worm. It turns out that most worms are seen, not heard, by robins. Because the sound of worms burrowing in the soil is of low intensity, they usually cannot be heard by robins because of background noise. Using sight, not sound, the robin first aims one eye toward a spot on the ground in front of it, and after holding this position for a few seconds, rotates its head and draws a bead with its other eye on the same spot– an earthworm in its burrow. The robin then quickly thrusts its bill into the burrow in an attempt to get its next meal.
Killdeer arrived back in northern New England last month and have already begun nesting. Being a ground nester, the killdeer has many mammalian predators from which it needs to protect its eggs, including weasels, skunks, opossums and raccoons. Nesting killdeer have a number of responses to predators, which include several different types of distraction displays which draw attention to the bird away from its nest. One of the most common displays is to feign injury by assuming a position which makes the bird appear vulnerable. When a predator approaches, the bird runs away from the nest, crouches with its head low, wings drooping and tail fanned and dragging the ground to display its rufous rump-patch. The predator typically follows, seeing an easy meal, and as soon as it gets too close for the killdeer’s comfort, the killdeer continues to lead it off by alternate flights and sprints.
Common ravens are known for their aerial acrobatics, often doing rolls and somersaults and other amazing tricks. According to Cornell Lab of Ornithology, one bird was seen flying upside down for more than a half-mile. Young birds are fond of playing games with sticks, repeatedly dropping them and then diving to catch them in mid-air. The pictured raven, however, was much too busy to be doing cartwheels in the sky. It has a nest with eggs nearby, and during its morning patrol encountered a red-tailed hawk which it drove out of sight in a matter of seconds. Although small mammals make up most of a red-tail’s diet, they are known to also prey on smaller birds, including defenseless nestlings, which the ravens will have in the next few weeks. (Because of the angle, the 24-inch-long, 53-inch-wingspread raven looks disproportionally larger than the 19-inch-long, 49-inch wingspread red-tail.)
A cooper’s hawk made short work of a mourning dove near my bird feeder recently, killing and apparently, given the large number of feathers scattered on the snow, plucking the dove on a nearby snow bank. If you look closely you can see whole sunflower seeds in amongst the feathers. These came from inside the mourning dove’s crop. Mourning doves generally feed quickly, filling their crop with seeds which they digest later, when they’ve found a safe spot in which to roost. Unfortunately for this particular dove, it didn’t live long enough to have that opportunity.
A study of coyote prey (through stomach contents) in the Adirondack Mountains of New York revealed that beavers were second only to white-tailed deer. This photograph shows that, possibly for the last time this winter, a coyote recently took advantage of a still-frozen-but-fast-thawing pond by walking across it in an attempt to reach an active beaver lodge. Once there the coyote attempted to dig into it in order to reach the inhabitants. A hard, two-to three-foot-thick wall of frozen mud, logs and sticks kept the beavers well protected, as it was designed to.
It’s often a lot easier to find signs of otters than otters themselves. Recently I discovered two dead crayfish on the shore of a mostly iced-over pond that I knew was inhabited by otters. Nearby otter scat confirmed that these crayfish were probably left by satiated otters. The most important prey item in a majority of otter scat analysis studies is fish, followed closely by crayfish. Otters will take advantage of other prey, such as frogs, salamanders, ducks, muskrats, an occasional young beaver, mice, snakes, insects and even turtles when readily obtainable, but fish and crayfish are first and second choices.
I have never heard of this particular fisher hunting technique, nor have I seen or read about it before, but there’s no denying that a fisher made these marks in the snow and that they tell the story of how it captured a mouse or vole. It’s likely that the fisher could hear or smell that the rodent tunnel in the subnivean layer was occupied. It looks as though the fisher methodically scraped snow towards the center of the circle, going completely around the tree in an attempt to trap and/or expose the mouse or vole within the circle. It succeeded in opening up the rodent tunnel (the hole is in the dead center of the photograph), and if the tiny droplets of blood on the snow near the hole are any indication, was successful in capturing its prey.
River otters are the most aquatic members of the weasel family. They eat the whole gamut of aquatic prey, including fish, frogs, crayfish, salamanders and turtles – not to mention snakes, small birds, mammals, earthworms and insects. It would not be an exaggeration to say that this threesome consumed a minimum of 15 fish and crayfish within half an hour. Look for signs of their sliding in the snow, both down slopes as well as on level ground.
At first glance, this looks like any other kill site, but if you look closely at the hairs, you’ll see that it was a striped skunk that was preyed upon – a rare find, for two reasons. One is that striped skunks spend most of the winter holed up and only amble out during warm spells (which we had recently). Their mating season is also about to begin. The second reason that this find is unusual is that skunks have very few predators, for obvious reasons. Great horned owls and occasionally a coyote, fox or bobcat will risk being sprayed. In this case, tracks were not evident by the time it was discovered. Initially the lack of anything other than hair suggested that the predator was a mammal which carried off the skunk (great horned owls usually eat at the kill site). However, it turns out that the absence of bones, etc. doesn’t actually rule out an owl. According to the Cornell Lab of Ornithology, occasionally when a great horned owl kills more prey than it can eat, it caches the remains for later use. When in need of food, the owl will incubate frozen prey until it thaws and can be eaten. (Discovery and photo by David Putnam.)
If the majority of your diet consisted of one type of food, and that food was concentrated in certain spots, it would make sense to frequent those spots. Bird-eating predators, such as the sharp-shinned hawk, are frequently seen at bird feeders for this very reason. Although not very large — roughly the size of a blue jay (the female is a third again larger than the male) — this accipiter is a formidable predator, and one which causes feeder visitors to either disappear or become motionless for a considerable amount of time. The sharp-shinned hawk is the smallest hawk in North America and derives its common name from the sharp-edged “shin” on the lower part of its legs. Its long tail and short wings make it extremely adept at flying through dense woods in search of small birds.
Dramatic stories are not limited to the snowy woods of northern New England! This photograph was taken in Jamaica Plain, a neighborhood of Boston, Massachusetts. It tells the story of a small bird being killed by a relatively small bird of prey, most likely a Cooper’s Hawk or a Sharp-shinned Hawk – both are accipiters and predators of small birds (as well as other prey). Because their wingspans overlap, there’s no way to unequivocally state which of these raptors left this imprint, but whichever it was, it was successful, judging by the feathers and blood that remain. Both of these hawks are listed as Massachusetts Species of Special Concern, with the Sharp-shinned hawk sighted most often in the western part of the state. (Photograph by Sadie Richards)
Typical fisher scat is anywhere from ¼” to ¾” in diameter, very dark and often quite twisted. It’s not unusual to find just a small amount of scat deposited, as fishers can control the amount of scat they use to mark territory. This scat is a bit atypical, in that it is segmented and not twisted, and there is an ample amount. A close look reveals the dark, stiff hairs and quills of a porcupine, likely the fisher’s most recent meal. Look for fisher scat on raised surfaces such as stumps or at the base of old trees, where fishers occasionally make latrines.
Tracking has its rewards, and when you’re following a predator, one of them is to come upon a site where the predator captured prey. After snowshoeing up and down forested Vermont hills following fresh bobcat tracks, I decided that bobcats don’t always mark their territory as often as I had thought, for this bobcat had not paused, nor stopped to spray urine or defecate the entire time I followed it. Eventually, however, on top of a knoll, it sat down behind a tree. There were marks in the snow that indicated that it had gotten up and then leaped down the slope, sliding several feet when it landed and then pounced on a red squirrel. All that was left of this woodland high drama, in addition to bobcat tracks and blood, was a piece of the squirrel’s tail, some squirrel scat and part of the squirrel’s stomach. If you look carefully, you can see where the bobcat sat (bottom of photo) while it enjoyed its meal.
The gray fox (Urocyon cinereoargenteus), although peppery gray on top, has reddish-brown fur on its sides, chest and the back of its head, which explains why it is sometimes mistaken for a red fox. Its tail has a distinct black stripe along the top, and a black tip (red fox tails have a white tip). Gray foxes are shier and more secretive than red foxes, and are seen much less frequently. Probably the characteristic for which the gray fox is best known is its ability to climb trees. The claws of the gray fox’s front feet are more curved than those of the red fox – an adaptation for climbing. They are very skillful climbers, and once a gray fox has shinnied up the trunk of a tree to a limb, it will jump from branch to branch in pursuit of prey, such as squirrels.
Jumping spiders are aptly named as they can spring more than 50 times their own body length to land on unsuspecting prey. They hunt actively rather than catching prey in a web and they have excellent vision, with four big eyes in front and four smaller eyes on the top of their head. Jumping spiders have three-dimensional vision which allows them to estimate the range, direction and nature of potential prey, essential skills for a predator that catches prey by pouncing on it.
This is pure conjecture, but here goes. Barred Owls are known to consume small mammals, birds, reptiles, amphibians, fish and invertebrates. I have repeatedly encountered a Barred Owl lately near a pool of water in a brook that has all but dried up. Fish have become trapped in this pool due to the dryness of the summer, and are easy pickings for predators. Even though studies have shown that fish are a very small percentage of a Barred Owl’s diet (2.5% in owls from New Jersey, New York and Connecticut during the breeding season), I am betting that the owl that I flushed yesterday that was perched right next to the isolated pool in the brook was spending the day (and night?) at his favorite fishing hole. Three times it took off from its perch as I approached, but only flew a few feet away each time. Perhaps fish or frogs kept it from disappearing further into the woods.
The Spined Soldier Bug is a predatory stink bug which preys on a variety of other insects (over 90 species), especially the larvae of butterflies, moths and beetles. It is one insect that farmers actually welcome, as it preys heavily on the larvae of the European corn borer, Mexican bean beetle, cabbage looper, Colorado potato beetle, flea beetles and many other crop pests. The adult Spined Soldier Bug has a prominent spine on each “shoulder.” It also has piercing-sucking mouthparts which it uses to impale prey and suck out their internal juices. The photograph shows a Spined Soldier Bug dining on the innards of a monarch caterpillar.
All spiders are capable of spinning silk, regardless of whether they use it to spin webs and trap prey or not. Egg sacs, drag lines (so they can find their way home), drop lines (to catch them if they fall) egg cases and transportation (young spiders disperse by “ballooning” as the wind catches their silk and carries them off) are some of the other functions silk plays in the life of a spider. Silk is extruded through nozzles called spinnerets located near the tip of the abdomen. Typically a spider has two or three pairs of spinnerets. Each one is the exterior tip of an interior silk gland and has a valve which can control the thickness and the speed with which the silk is extruded. The different glands produce different kinds of silk used for different purposes. The spinnerets work independently for some functions, and together for others. In the photograph, the black and yellow argiope is turning her grasshopper prey around and around as she produces a sheet of silk in which she wraps it. Most, if not all, of the spinnerets are in use.
Although you would think that no predator would think of preying on, much less eating, a striped skunk, there are a few mammals, including coyotes, foxes and bobcats, that do just that, but only if they are in danger of starving. One predator that routinely dines on skunks is the great horned owl. One summer night I made out the silhouette of an owl flying in my direction, and as it flew by me its identity was confirmed by the skunk-like odor that accompanied it.