Happy "National Invasive Awareness Week"! ( Feb 28-March 4 )
We will examine the identification, mediation, and removal of nine common invasive animals in your yard to celebrate. Last season, we focused on common invasive plants on your property. While invasive vegetation is a menace to our ecosystem, its threat is primarily crowding native plants from their natural habitats.
In addition to crowding out native species, invasive animals also:
prey on native wildlife
spawn multiple generations per season
introduce new disease vectors to native plants and animals
Before we begin our list, below are the criteria for identifying an invasive animal.
Invasive animal characteristics:
Not native to an area
Includes Insects, invertebrates, birds, and mammals
Spreads quickly
Destroys and threatens native ecosystems
Causes economic or environmental harm, or harm to human health
Brown Marmorated Stink Bug
Origin: East Asia
Threat: Stink bugs pose an agricultural threat to fruit and vegetable crops. Damage includes pitting and scarring the fruit, rendering the crop unusable for processing. Stink bugs will also cause home infestations during cold months.
Mediation: Seal all cracks and openings around windows, doors, siding, pipes, chimneys, and other access points to your home with caulk.
(stock photo)
Plant native plants which attract stink bug predators.
Removal: For indoor removal, avoid crushing stink bugs. A squashed stink bug emits a pheromone that attracts other stink bugs. Most effective removal methods include vacuuming or knocking insects into a container of soapy water.
Native Stinkbug Predators The wheel bug, a ferocious stink bug cousin, is its main predator. Other natural enemies include Spiders, Parasitic Wasps, Wrens, Bluebirds, Cardinals, Praying Mantis, Bats, and Mice.
Personal Our (indoor) cats enjoy catching and killing stinkbugs for sport!
House Sparrow
Female House Sparrow Male House Sparrow (black throat patch)
Origin: Europe, Asia
Threat: House sparrows disrupt/displace/dominate our native birds by competing for nesting sites, killing adult birds, hatchlings, and eggs. House sparrows bully less aggressive native birds such as bluebirds from their traditional ranges and habitats.
Mediation: To keep house sparrows away from your birdfeeder, avoid millet, milo, wheat, and cracked corn.
Stock your bird feeders with food that does not attract house sparrows. They do not have the bite strength to eat larger shelled seeds such as sunflower and safflower. Also, dried fruit, Nijjer seed, and suet do not appeal to house sparrows.
In early spring, you will often see the male (black throat patch) scouting potential nest sites. When possible, chase the house sparrow away from your nesting boxes. Also, seal bird nesting boxes until March 1 as house sparrows' breeding season is February to March.
Removal: If a house sparrow has claimed your birdhouse, remove the nesting material and plug the entrance hole with duct tape until the bird moves on. If you are not worried about what the neighbors think, run at them with a rake to scare them away!
House Sparrow Predators Domestic cats are the house sparrow's primary predators. However, cats do not discriminate which birds they kill and do more damage to native bird populations than any other predator. Natural predators include small raptors, crows, and jays. In addition, squirrels and chipmunks will raid nests for eggs and hatchlings.
Chinese and European Mantis
Chinese Mantis European Mantis
Origin: Asia, Europe
Threat: The invasive Chinese and European Mantis consume beneficial pollinators and other native insects, including the Carolina mantis.
Mediation: The Chinese Mantis is the only species large enough to prey on hummingbirds. While mantis predation on hummingbirds is rare, you can mitigate the risk by moving hummingbird feeders away from surrounding bushes and branches, making the mantids easier for birds to see.
Removal: A school of thought regards all praying mantises as beneficial insects. Many ecologists consider the introduced mantis species as naturalized. As a lifelong gardener, I appreciate the protection mantids provide. When I find a praying mantis, I admire it and leave it alone- regardless of species.
Spotted Lanternfly
Origin: Asia
Threat: The Spotted Lanternfly threatens several industries, including viticulture, fruit trees, ornamentals, and timberland.
Mediation: Remove the spotted lanternfly host plant "Tree of Heaven" from your property.
Photo by Lawrence Berringer
Removal: The adult SLF has one evasive maneuver- jump forward. Knowing their jump pattern makes them easy to catch. My preferred method is to place a wide-mouth plastic jug filled with an inch of soapy water directly in front of the SLF, and they will dutifully jump in to meet a merciful end in the soapy water.
Spotted Lanternfly Predators Bluebirds, wrens, spiders, wheel bugs, frogs, chickens
Spotted Lanternfly appears on the menu of several predators, including fellow invasives European and Chinese Mantis! (stock photos)
See our blog Spotted Lanternfly Battle Tactics, for more information on managing spotted lanternflies!
Starling
Origin: Europe
Threat: Starlings cost U.S. agriculture hundreds of millions of dollars in annual crop damage by pecking holes in fruits, making them vulnerable to fungal diseases. They are a fierce competitor for nesting sites which hinders native birds' ability to reproduce. Starlings also carry and transmit avian diseases. In addition, their droppings provide a growth medium for a fungus that causes lung infections in humans.
Mediation: Starlings travel in large flocks. Fortunately, the flock is easily frightened; one step in their direction will scare the entire horde off your property. Starlings are omnivorous; keep your compost pile well-turned and avoid leaving edible items where starlings will gather. Keep your bird feeders in a wire cage topped with a squirrel baffle. Unlike our native birds, starlings have weak legs and cannot hang upside down or hold their balance leaning forward to negotiate the barriers to the seed. Starlings are cavity nesters, remove their nesting material and seal potential nesting areas in your home.
For severe infestations, bird spikes on roosting areas, predator decoys, sonic devices, and netting are also effective.
Removal: Starlings are considered invasive pests and, therefore, not a protected species. However, please consult your local laws guidelines before attempting to trap or kill them.
Starling Predators: Raptors, cats, nest raiding rodents, and raccoons.
Domestic Cats
Stanley- our card-catching cat!
Origin: Asia
Threat: According to a 2013 study published in the journal Nature, domestic cats are responsible for the deaths of 4 billion birds and 22 billion small mammals in the United States every year. Scientists estimate that domestic cats produce ten times the deadly impact vs. native predators.
Mediation: Cats are fabulous indoor pets. The best approach for your pet and the local wildlife is to keep your cat indoors. Statistics show that indoor cats' lifespan increases 5x over outdoor cats.
Other solutions include:
Training your cat to walk with you outside on a harness
Creating or purchasing a 'catio' or mesh cat enclosure (you can find a ton of roomy and secure outdoor cat enclosures online).
Always supervise your cat's outdoor time, and never let them roam unattended.
Japanese Beetles
Origin: Asia
Threat: Japanese Beetles are a destructive pest of turf, landscape plants, and crops. Adults feed on the foliage and fruits of several hundred species of trees, shrubs, and vines, while larvae feed on the roots of grasses and other plants.
(Stock Photo)
Mediation: Several native/pollinator-friendly plants are known to repel Japanese beetles. I grow these plants in my yard and flower beds, and I have yet to experience a Japanese beetle infestation.
Catnip
Larkspur
Onions
Leeks
Chives
Garlic
White Chrysanthemum
White Geraniums
Marigolds
Tansy
Redbud
Red Maple
As a bonus, these plants also attract insect predators!
Replacing areas of your lawn with garden beds reduces the habitat that Japanese beetle grubs need to thrive. More gardens/less lawn also increases the biodiversity of your property!
Attracting birds to your property also keeps the Japanese beetle populations in check. For example, I have witnessed cardinals munching Japanese beetles feeding on my basil plants. See our blog on attracting native birds to your property for more information.
In addition, biological treatments such as nematodes and milky spore applications target Japanese beetle grubs without harming native birds and bees.
Removal: Resist the urge to launch chemical warfare on Japanese beetles. The fight against Japanese beetles is a war of attrition; you will not eliminate them from your property. However, if the numbers are manageable, knocking the beetles into a soapy container is the best place to start.
Japanese Beetle Predators: Robins, Crows, Catbirds, Woodpeckers, Cardinals, Wheel Bugs, Assassin Bugs, Skunks, Raccoons
Gypsy Moth Caterpillars
(stock photo)
Origin: Western Europe
Threat: The Gypsy Moth Caterpillar causes severe, periodic infestations that defoliate native trees such as oak, maple, apple, crabapple, hickory, basswood, aspen, willow, birch, pine, spruce, hemlock, and more. Oak is their pre erred species.
Mediation Most healthy trees can endure a gypsy moth infestation. The best prevention is maintaining the health of your trees. Proper watering, fertilization, and pruning are your best defense against gypsy moth infestation.
Removal: Physical barriers such as tree banding effectively prevent gypsy moth caterpillars (and Lanternfly nymphs and adults) from reaching the tree's leaves.
Photo by University of Wisconsin-Madison
Materials for tree banding include burlap, duct tape, or fiberglass.
For severe gypsy moth infestation, a biological pesticide containing "Bt" (Bacillus thuringiensis var. kurstaki) kills gypsy moth caterpillars. Spray the leaves where the caterpillar is feeding, and they will be dead in about a week. This approach is most effective early in the infestation.
The active biological agent in "Bt" occurs naturally in the soil. Therefore, it is not harmful to bees or birds. However, it does harm native caterpillars, which are a primary food source for birds and their nestlings.
Gypsy Moth Predators: Shrews, mice, voles, chipmunks, skunks, raccoons, blue jays, orioles, and rufous-sided towhees. The black-capped chickadee will also feed on egg masses. Parasitic wasps, beetles, ants, and spiders are effective gypsy moth predators.
Emerald Ash Borer
Native range: East Asia
Threat: The emerald ash borer is among the most destructive invasive insect invasions in U.S. history. Their larvae bore into the vascular system of the Ash tree, killing millions of trees in 25 states each year.
(stock photo)
Mediation:
Buy firewood where you burn it. Hauling firewood is the most common way emerald ash borers establish new infestation sites.
Do not plant ash trees. As the emerald ash borer expands across the country, planting alternative tree species is recommended for residential landscaping.
Learn the symptoms of infestation. Monitor your ash trees for signs of emerald ash borer. Watch for the D-shaped exit holes that the beetles leave in the bark. Woodpeckers eat emerald ash borer larvae, and heavy woodpecker damage on ash trees indicates an infestation.
Consult an arborist for annual inspection of ash trees
Removal: There are several insecticides and applications for treating and preventing ash borer infestations. In a healthy tree, where the infestation is not advanced, applications such as soil/root drenches, trunk injections, and bark and foliage sprays are 85% effective. The best course of action in applying these methods for homeowners is to consult/hire a certified arborist.
The USDA has introduced a parasitoid wasp from the ash borer's native range as a biological control. After years of testing, the USDA confirmed the wasps would not damage U.S. ecosystems. These wasps are reared in laboratories and distributed to three northeastern states. Early results have shown Ash borer parasitization up to 49 percent within two years of the wasp's introduction in the wild.
Emerald Ash Borer Predators: Woodpeckers, nuthatches, bluebirds, spiders, parasitoid wasps.
All photographs, unless otherwise noted, were taken on our one-acre property in eastern P.A.
Photographs by SuperNaturalist.net
Helpful links
Get Rid of Stink Bugs | Are Stink Bugs Dangerous (whenyougarden.com)
How to Get Rid of House Sparrows in Your Yard (thespruce.com)
The Invasive Mantis Species | Brandywine Conservancy and Museum of Art
How to Control Japanese Beetles in Your Lawn and Garden (thespruce.com)
Gypsy Moth Caterpillar - Proper Identification and Control - Garden Myths
Domestic Cats - An Overlooked Threat to Local Wildlife - Louise Gund
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