November 5, 2024 at 10:01 am
What’s in a Name?
Predator. It’s a disconcerting word associated with antagonists of dark true crime documentaries, shady corporate deals, and killer creatures from science fiction that “go bump in the night”. As though branded as the bad guy in nature’s story, wildlife’s top predators often carry the weight of this negative connotation on their shoulders despite their irreplaceable and necessary role in regulating healthy and resilient wildlife populations. Taking a step back to look at the bigger picture reveals the positive power of predators in our ecosystem, the surprising variety of forms in which they exist, and the simple ways we can improve our experience living alongside them in Maine. Superheroes don’t all wear capes, and not all stories have a villain.
Aldo Said it Best
"The last word in ignorance is the man who says of an animal or plant, "What good is it?" If the land mechanism as a whole is good, then every part is good, whether we understand it or not. If the biota, in the course of aeons, has built something we like but do not understand, then who but a fool would discard seemingly useless parts? To keep every cog and wheel is the first precaution of intelligent tinkering."
-Aldo Leopold (Round River, 1953, published posthumously)
Have you ever thought about where negative perceptions of some species come from? It’s human nature to fear what we don’t understand, to find comfort in familiarity, and to value what we view as directly relevant to our day-to-day lives. It’s easy to underestimate the value of one piece of the puzzle until we understand how it fits into the whole picture. Consider too, that a poor perception of one species may be the direct result of subjective placement of higher value on a preferred species. Personal preferences for certain species, often those perceived as underdogs, don't change the fact that healthy ecosystems are driven by interactions between diverse and equally vital species. Predator and prey are simply two sides of the same coin.
The Bigger Picture
It’s common sense that predators thrive when prey is abundant, but often overlooked is the positive impact of predation on prey populations. Healthy prey populations are generally not threatened by predation. You read that right. Through the lens of population ecology, prey benefits from predation. In a single interaction, an individual predator wins a meal while the life of its prey is lost, but from the population vantage point, the compilation of all interactions between those species results in healthy and resilient populations of both predator and prey. Let’s look at how this happens.
is tied to snowshoe hare abundance.
Checks and Balances
Carrying capacity is the maximum size of a population that can be sustained in an area based on available resources. Populations cannot increase indefinitely. As prey populations approach the carrying capacity, increased density creates high competition for food, water, and shelter. There simply aren’t enough resources to go around. Dense populations are also significantly more prone to disease and parasites which spread rapidly when individuals living in close proximity frequently cross paths.
Stress on prey populations caused by high density can trigger drastic, large-scale declines until the population reaches a more sustainable level. It’s not always possible to bounce back from such rapid declines. In healthy ecosystems, the instability of this “boom and bust” cycle is mediated by predation.
Pressure from predation allows for regulation of prey populations within the carrying capacity, in some cases limiting prey mortality from disease, starvation, or other factors. In return, the healthy prey population sustains the next generation of predators. The ebb and flow of the predator-prey cycle is a brilliant display of interconnectivity throughout the food web and is a clear reminder about why wildlife management occurs on a broad scale, not the individual level.
Who are Maine’s Predators?
Which species come to mind when you think of Maine predators? If large, terrestrial mammals with big teeth and sharp claws like coyotes, foxes, fisher, and bobcats were among the first you thought of, you’re not alone. They certainly are notorious hunters. But predators include all fish and wildlife that hunt and consume other animals, so they occur in an unbelievable variety of shapes and sizes and can be found in niches across our ecosystem! Even Maine’s native brook trout and landlocked salmon are predators. If they weren’t, your meticulously tied dry flies and favorite smelt patterns wouldn’t do much good. The term predator might feel a bit less scary once you realize that most of Maine’s predators are relatively small in size, many are omnivores, many are diurnal (active during the day), and the majority are both predator and prey!
Predators with Wings
To appreciate some of the most extraordinary predation techniques, you’ll have to look to the bird world. Raptors, which include eagles, hawks, and owls, are also collectively known as birds of prey. The term raptor is derived from the Latin “rapere” meaning “to seize or take by force”. With large talons, powerful beaks, acute eyesight, and the combination of speed and agility in the air, the foundation of their hunting prowess is no secret. But they aren’t the only predators in our skies.
Each using their own unique method, numerous birds such as the common loon, great-blue heron, belted kingfisher, osprey, and Atlantic puffin demonstrate their expertise as predators of fish in Maine’s waters. And let’s not forget the invaluable services provided by Maine’s agile aerial insectivores! In stark contrast to the patient and secretive nocturnal hunting style of many mammalian predators, swallows, swifts, and flycatchers satisfy their voracious appetites for insects through dynamic daytime predation on the wing. Thankfully, nightjars (eastern whip-poor-wills and common nighthawks) and eight species of bats cover the Maine’s aerial insectivore night shift.
Small but Mighty Hunters
Their small size might make you think that invertebrates are just food for everyone else, but even some invertebrates are predators themselves. Dragonflies for example, better known for their vibrant colors and delicate wings, are some of the most efficient predators on the planet! They have enormous compound eyes for nearly 360-degree field of view, a lightning-fast nervous system to process all the visual information, and an intricate flight system that makes a miss a rare occurrence.
Maine’s amphibians also include a number of miniature hunters. The eastern newt for example, is a carnivorous predator in water and on land throughout its complex life cycle, chowing down insects, worms, and amphibian eggs and larvae. Newts are prey too, but the bright orange color of their eft (juvenile) stage warns bigger predators to find a different meal.
Predation isn’t just reserved for the big and tall in the realm of mammals either. Did you know that Maine is home to a slew of insectivorous shrews? The northern short-tailed shrew is a particularly interesting small underground predator because they use echolocation to detect their prey in the darkness of tunnels and use venom to immobilize their meal. Year-round active hunters with extremely high metabolisms, they eat as much as three times their own body weight in earthworms and other scrumptious snacks every day!
Part-time Predators
Not all predators are predators during all life stages. Did you know that many of Maine’s frogs feed on algae and plants in larval stages, only becoming predators when they reach their adult stage? American bullfrogs grow up on greens, but have a ravenous appetite for invertebrates, fish, snakes, and even other frogs as adults. It just goes to show you that you don’t need a scary mouthful of sharp teeth to be a powerful predator, just a really sticky tongue!
Snapping turtles make a transition during their lifespan too. They are always both predator and prey, but the balance shifts as they age. As eggs and hatchlings, they are an easy meal for birds of prey, snakes, and a wide variety of furbearers, but if they survive this vulnerable time, the hunted becomes the hunter. Adult snapping turtles have very few predators capable of taking them on, and develop into long-lived imposing predators of fish, crayfish, birds, and small mammals.
Even some animals we typically think of as herbivores occasionally show their carnivorous side. Red squirrels, well-known for their resourcefulness and caching of seeds and nuts in their middens, also eat insects, carrion, bird eggs, mice, and nestling birds. The reverse is true too. Many of the top predators thought of as true carnivores have a much broader diet than you might think. In addition to a wide variety of small mammals and birds, red foxes have a seasonally shifting omnivorous diet that includes berries, nuts, seeds, and insects. Coyotes are opportunistic both as hunters and scavengers, and don’t turn their noses up at carrion, grasshoppers, acorns, grasses, blueberries, and apples when they become available.
Repairing Reputations
Even with such a wide range of predators on the landscape, and substantial knowledge of the irreplaceable role of ALL predators in ecological health, a few of Maine’s predators are still burdened with a tarnished reputation. With coyote and fisher taking much of the heat, it’s time to move past the myths, stick to the science, and gain understanding to move from needless fear to healthy respect.
Fisher Facts
Fisher are members of the Mustelid (weasel) family which in Maine, also includes marten, mink, river otter, and short and long-tailed weasels. Like many of their relatives, fisher are agile, slender bodied furbearers with remarkable hunting skills through rough terrain and into the trees. Some Mainers might tell you that there is nothing to fear but fear itself… and fishers. Fisher have an unwarranted, nasty reputation for being particularly ferocious carnivores with an insatiable hunger for domestic cats. Fisher are in fact impressive predators with a serious set of teeth, but as it turns out, the preconceived notion that fishers will wipe out a neighborhood of cats is a pretty big stretch of the imagination.
What is true is that the fisher is notorious for being one of the few daring predators of porcupines, and they are even capable of taking down adult Canada lynx much larger than themselves. Though this fact makes them seem formidable and fearless, the fisher is a shy critter that avoids encounters with people. It is far more likely to spot their two-by-two patterned tracks in the snow or catch a glimpse of a wary fisher on a trail camera than it is to see a one in person. They aren’t dangerous to people, but how about domestic cats?
Considering they can kill lynx, there is no denying that fisher (and many other predators) are capable of hunting domestic cats if the opportunity presents itself, but that doesn’t mean your pet is at the top of their menu. While other animals like raccoons, opossums, and skunks are more likely to take advantage of easy access to resources incidentally provided by humans, fisher tend to stick to areas with natural foods away from people. This propensity for a cryptic existence leaves little to no evidence that fisher pose a noteworthy risk to your feline companion as Maine’s tall tales might lead you to believe. And that eerie cry you sometimes hear at night in the woods? That’s probably a red fox.
Fisher were not always as abundant in Maine as they are today, and we are lucky to have a healthy statewide population that contributes to our ecosystem and is capable of sustaining regulated harvest opportunities.
Coyote Complexities
Coyotes are an abundant predator that rattle the nerves of many, especially during a full moon. They have a lot to say, and just a small number of howling animals can sound like a huge pack. Coyotes pose unique challenges for wildlife managers tasked with maintaining a healthy population with opportunities for both sustainable harvest and viewing while reducing conflict and conserving other wildlife. But coyotes are extremely intelligent and highly adaptable with a fascinating history and unique position in Maine’s ecosystem.
The first myth you may have heard about coyotes is that they are invasive or were intentionally or unintentionally introduced to Maine. It’s true that coyotes did not occur in Maine historically, but they were not introduced. Coyotes are considered a naturalized species that expanded their range through natural dispersal, just like Virginia opossums. Unlike invasive species, most naturalized species, including coyotes, do not have a net negative impact on the environment.
Coyotes gradually spread northeast on their own four feet following significant habitat shifts and extirpation of wolves in the 1800s. Through unmatched adaptability, coyotes made a permanent home for themselves in our state as one of our top predators. They can live just about anywhere from suburban parks to remote wilderness. They were first documented here in the 1930s, became well established by the 1970s, and are here to stay.
Another common concern is that coyotes are reducing Maine’s white-tailed deer population and hunting opportunities. It is true that coyotes are efficient predators and can influence white-tailed deer population dynamics, particularly when deer are restricted by deep snow. However, nature is far too complex to assume that coyote predation always reduces the deer population. In areas where deer are not limited by habitat and winter severity, predation does not limit yearly population growth. In fact, over the last decade, Maine’s deer population has steadily increased. It’s also important to remember that in addition to being skillful hunters, coyotes are opportunistic scavengers. Many deer consumed by coyotes died by other means, such as malnutrition and motor vehicle collisions.
Lastly, like fisher, coyotes are often thought of as a dangerous animal that prowls around and poses a threat to people and pets. Coyote attacks on people are exceedingly rare and are usually associated with a coyote that has been fed and habituated. Management of the coyote population through regulated trapping and hunting is beneficial to keeping coyotes wary of people, limiting future conflicts, and maintaining a population at both ecologically sound and socially acceptable levels. Learning to recognize normal versus abnormal coyote behavior and taking steps to remove common attractants from one’s yard are two ways that Mainers can live more comfortably with coyote neighbors.
Living with Predators
It’s always fun to observe wildlife, but unfortunately, problems can arise when wildlife is inadvertently attracted through provision of shelter in or under human-made structures and food in the form of bird feeders, gardens, compost, grills, pet food, trash, fruit trees, and livestock. Dropped seeds from bird feeders are particularly attractive to rodents which in turn attract predators to backyards.
The good news is that most human-wildlife conflicts are preventable or resolved when attractants are removed. Taking some simple steps such as feeding pets inside, keeping small livestock in predator proof enclosures, removing feeders, and securing your trash can go a long way in keeping wildlife wild. Our Living with Wildlife page is a great resource for additional species-specific tips for avoiding conflict.
If you come across a large predator in your yard or while enjoying an outdoor adventure, keep your distance, keep small pets and children close to you, make loud noises, and leave the area calmly. Rest assured, even Maine’s top predators are just as keen to avoid an encounter as you are. When attractants are removed and they are given plenty of space, healthy predators are all but guaranteed to move on without incident.
From a respectful distance, watching Maine’s predators can be an amazing experience and a meaningful reminder of just how imperative they are to the complex mechanism of nature. We hope you’ll think about the bigger picture the next time you paddle among dragonflies in a wetland, reel in your next landlocked salmon, hear distant coyotes yipping and howling, or catch a glimpse of a fisher on your trail camera. There’s something new to learn and appreciate about predators of all shapes and sizes with every observation!
Learn More:
How to Prevent Wildlife Conflict
Fisher Predation on Lynx in Maine
Maine Furbearer Management Plan