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Buckthorn Poisonous Invasive Plant

Buckthorn Poisonous Invasive Plant

Common buckthorn, (Rhamnus cathartica) is a wild-growing deciduous shrub that produces small berries that resemble blueberries. Buckthorn berries are poisonous to both humans and animals, plus it’s an invasive plant. Buckthorn Poisonous Invasive Plant.

The plant is native to Europe and is sometimes called European Buckthorn, European Waythorn, and Hart’s Thorn. Whatever name you know the shrub by, make note not to forage for the berries.

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Buckthorn Wild Poisonous and Invasive Plant

Buckthorn grows into a large shrub or small tree that can reach 20-feet tall when mature. The shrub will have a 3-5 foot spread with multiple branches and bark that easily flakes off. A nick in the flaky bark will reveal orange inner tissue.

The shrub develops small, oval leaves that are dull green with a lighter green underside, and the leaf edges are serrated. Each branch will have small thorns at the end and thorns may also be found at the junction of branches throughout the shrub.

Blooms appear in late spring at the same time the leaves are emerging. Flowers will have 4 petals that will be yellow or green in color. The blooms are fragrant but not much to look at.

Clusters of small green berries appear in the shrub after the flowers fade. As the berries ripen they turn from green to blue, then to purplish-black when fully ripe. Each small berry contains four seeds.

Wild Growing Locations

Common buckthorn is an understory plant and thrives along the edge of woods and waterways. It’s a hardy plant that develops into dense thickets and chokes out other native-growing plants.

The shrub is not picky about soil or light conditions and is able to grow almost anywhere. The long branches of the shrub and dense leaf covering that last well into fall produce so much shade that surrounding green plants quickly die from lack of sunlight.

Do Not Eat

Common buckthorn berries ripen they turn from green to blue, then to purplish-black when fully ripe.

Buckthorn berries look attractive on the shrub when they’re ripe but don’t eat them. In addition to being very low in nutrition and bitter, they also act as a strong laxative. The laxative impact is so strong that small birds and animals will die from the effect. Severe abdominal discomfort and dehydration will occur in humans if eaten.

Even the leaves of the shrub have a negative impact on the soil when they fall from the plant and decompose. The leaves are very high in nitrogen and provide a boost of energy for the shrub to develop more top growth. The increased nitrogen also promotes the fast growth of the hardier species of native weeds that survive around the shrub.


Under certain circumstances, the common buckthorn is useful. In barren areas where erosion control is needed this fast-growing shrub will provide a formidable windbreak and hold soil in place.

Buckthorn will survive in sandy, rocky, clay, or damp soil. It will also live in shady areas, in cold or hot climates. Salty sea air near the coastline or low oxygen levels on high mountains will not stop this invasive shrub from growing. As with any plant, the better the growing conditions the better it will grow, however, bad growing conditions will not stop this plant.

If you have a landscape area, like a rocky cliff or other steep terrain that needs erosion control, buckthorn may be helpful. The shrub does not attract bears, deer, or other wildlife, and in some situations that may be beneficial.

How To Get Rid Of Buckthorn

More people want to know how to get rid of the invasive shrub rather than how to grow it.  Removal is time-consuming and must be done meticulously to prevent the shrub from re-growing.

Small samplings can be pulled out of the soil by the roots and disposed of. The older shrubs that produce berries will need to be removed from the soil, along with all roots, and burned. If the shrubs are not burned and berries are on the uprooted buckthorn, there’s a possibility that birds will come by grab one in their mouth and drop it nearby. Buckthorns are so hardy and adaptable that all it takes is one dropped berry to start a new thicket.

After removal and burning, revisit the area several times to check for newly sprouted seedlings. Since each berry contains four seeds and shrub roots run deep, there’s always a chance that a few seeds escaped the flames or a root got left in the ground. Either occurrence will be the start of a new buckthorn thicket.

If multiple seedlings sprout in an area that has been cleared, mowing the seedlings down is often an effective removal method. Several mowings over the course of a summer may be needed to completely eradicate a buckthorn thicket.

Large stumps can be killed with chemical treatments instead of remmvong them from t he ground. However, if chemicals are used they will remain in the soil and render the soil unfit for growing any vegetations for the following 3-5 years.

Notes Of Interest

* Buckthorn has relatively no pest problems and no predators. The shrub can grow and spread undisturbed by any type of animal due to its poisonous nature.

* A few bird species will eat the buckthorn berries during winter when no other food source is available. Each berry contains four seeds so the invasive shrub is soon re-seeded in various locations through bird droppings.

* Seeds can remain viable in the soil for up to five years.

Buckthorn is a problem

  • Out-competes native plants for nutrients, light, and moisture
  • Degrades wildlife habitat
  • Threatens the future of forests, wetlands, prairies, and other natural habitats
  • Contributes to erosion by shading out other plants that grow on the forest floor
  • Serves as host to other pests, such as crown rust fungus and soybean aphid
  • Forms an impenetrable layer of vegetation
  • Lacks “natural controls” like insects or disease that would curb its growth

Buckthorn Poisonous Invasive Plant

USDA Plant database

House Sparrow Information

House Sparrow Information


The House Sparrow (Passer domesticus) is one of the most common bird species in North America, although it is a non-native species. These sociable and tame birds can be spotted in backyards hopping along the ground pecking at seed as well as on city streets feeding on crumbs. This species has a long running relationship with humans and has come to rely heavily on human populations for survival. House Sparrows have healthy and stable populations across a wide geographic range and are listed as Least Concern on the IUCN Red List.
House Sparrows are generally tame and sociable birds, within their flocks and with people, especially during the winter. Because these birds live in social communities, methods of communication have been developed to relay dominance, submissiveness, nervousness, courting and aggression. They often feed together to minimize predation and their flocks have social structures that are similar to that of chickens. Male House Sparrows with larger black throat  House Sparrow can most often be seen hopping on the ground rather than walking.patches tend to be dominant over males with smaller bibs. During the courting and breeding season females tend to be more assertive, but males are the dominant sex in the flock throughout the rest of the year. Nervousness is indicated by a flick of the tail. Aggression is communicated by a crouched posture with thrust-forward head, spread wings, erect tails and ruffled feathers (in extreme situations.) In a courting display, a male will puff up his chest and open his wings and tail, hopping stiffly and bowing up and down in front of the female4. In addition to social dominance and behavioral communication, House Sparrows are a noisy species that uses a number of simple vocalizations to verbalize warnings, threats and defense, or to attract a mate. The most common sounds include a chatter (often used by females toward her mate or to chase away competing females,) a cheep (used in a series to attract mates and in a flock to communicate submissiveness,) wheezy calls, and chirps.

House Sparrows tend to have more direct and higher flight than native species of sparrows. Their flight is continuous and lacks periods of gliding5. Because of their stature and short legs, House Sparrows can most often be seen hopping on the ground rather than walking.
House Sparrows tend to have life spans of just a few years. However, there are recorded instances of wild individuals living as long as 13 to 15 years.



House Sparrows are unrelated to other species of sparrows that are native to North America, such as the white-crowned sparrow, and therefore, differ in appearance. They may be identified by their shorter, stockier appearances, accentuated by full chests, shorter tails and legs, large round heads and shorter, thicker beaks. House Sparrows reach a mature size of 5.9” to 6.7” in length and 27g to 29g in weight. Their wingspan, when full grown, is 7.5” to 9.8”1. Geographic variations exist due to the House Sparrows immense range. Colder climates tend to produce larger birds with shorter wings and legs, whereas populations with darker plumage tend to be found in humid climates2.

Coloration may differ between sexes and during different seasons. Both sexes generally have buff, brown and black stripes on their backs, although males tend to be more brightly colored, with gray heads, black patches or “bibs” on their necks and white cheeks. Females are generally dull tan-gray, with gray undersides, buff eye-stripes, and a bill that is more yellow than males. During the summer, breeding males will display a black bill, mask, throat and chest, a gray cap, and a white stripe on their shoulders. Their main coloring is a reddish-brown with black streaks. Non-breeding males lack the vibrant reddish-brown coloration because those feathers become obscured by gray feather tips. Non-breeding males also have less black on their throats and chests, and yellow at the base of their bills3. This seasonal variation is due to an annual molt. Juveniles are plain in color, in appearance to females.


House Sparrows tend to be found in areas inhabited or affected by humans, including cities, towns, suburbs, farms, and parks. Because of their dependency on humans, House Sparrows are unable to survive in areas such as uninhabited woodlands, alpine forests, grasslands, or deserts. In extreme climates House Sparrows must maintain a close proximity to human populations for survival.

In their habitats House Sparrows (and their eggs and young) are vulnerable to a number of predators, such as hawks, owls, cats, dogs, raccoons and snakes. Their tendency to forage in flocks increases their awareness and survival rates.


They are year round residents of their native environments of Eurasia and North Africa. Introduced, invasive populations are also non-migratory and thrive in South Africa, South America, New Zealand, Australia, and North America. Their lack of migration increases survival rates because of a diminished demand for energy and exposure to predators.
The House Sparrow was introduced to Brooklyn, New York in 1851, when 100 birds from England were released. This may have been done to control certain insect populations or to make the area more familiar to European immigrants. By the turn of the century, their populations had spread to the Rocky Mountains. Additional populations were released in San Francisco and Salt Lake City in the 1870’s, expanding this species range across North America (excluding Alaska and northern parts of Canada6.)


The house sparrow is an omnivorous ground forager that spends much of its time hopping along the ground pecking at food. They have also been known to steal food from larger species of birds and drink nectar from flowers. Their diets consist mainly of grain and seed (corn, oats, sorghum, wheat,) crumbs and food waste, ragweed, grasses, buckwheat, commercial birdseed, and insects.


House Sparrows are monogamous and form breeding pairs each season, with nesting beginning in late winter and courtship occurring in early spring. Nesting may begin only a few days before the first egg is laid. They prefer to build their nests in man made structures such as the walls of buildings, on streetlights, in nest boxes or in the eaves of houses. They have been known to evict other birds from their nests, destroying existing eggs and physically attacking the opposing birds. House Sparrows tend to reuse their nests. And have been known to aggressively defend their nesting areas.

Both males and females construct the nests by stuffing their nesting cavities with dry vegetation until the hole is nearly full and then lining the interior with softer materials such as string, paper, and feathers. House Sparrows often nest in close proximity to each other, the nests sometimes sharing a common wall.

A House Sparrow may lay up to 4 broods in a year, each containing between 1 and 8 white/light-green/blue-white eggs, speckled with gray or brown and approximately 7/8” in length. Parents alternate incubating the eggs for a period of 10 to 14 days. Young chicks are born naked and uncoordinated, with closed eyes. During the nestling period of 10 to 14 days both parents feed the chicks through regurgitation. House Sparrows reach sexual maturity by around 9 months of age.

Notes of Interest:

House Sparrows enjoy dust baths and can often be spotted coating their bodies with dust and dirt. They also take baths in puddles or shallow water, using a similar flicking motion to coat their feathers.

Because the house sparrow is so numerous and tame, they are often the subject of avian biological studies and have been the subject of nearly 5,000 scientific papers7.

Although House Sparrows are common and numbers are stable, some populations have experienced a sharp decline, possibly due to farming practices, and changes in land-use. Despite this, they are not considered threatened and are not protected under any laws or regulations.


1. http://www.allaboutbirds.org/guide/house_sparrow/id
2. http://animals.nationalgeographic.com/animals/birding/house-sparrow/
3. http://www.allaboutbirds.org/guide/house_sparrow/id
4. http://www.allaboutbirds.org/guide/house_sparrow/id
5. http://animaldiversity.ummz.umich.edu/accounts/Passer_domesticus/
6. http://www.allaboutbirds.org/guide/house_sparrow/id
7. http://www.allaboutbirds.org/guide/house_sparrow/id


Common Starling – Sturnus vulgaris

Common Starling


The Common Starling, European Starling, is native to most of temperate Europe and western Asia. It was introduced into the New York in 1890 when only 100 birds were released. (1) Since then they have spread throughout the US and Canada. Large flocks of Starlings (easily made up of thousands of birds) can be seen in farm areas in upstate NY. This has proven to be both beneficial and detrimental at the same time. They do eat many crop damaging insects yet they also eat grain seeds and have replaced native species. Frankly, I believe this a classic example of the unintended consequence of introducing an “invasive species”.

common starlingThe breeding season begins in early spring and summer. Males choose the nest site and use it to attract females. (2) I have had numerous issues with Starlings becoming stuck in vent grates and have friends that had them entering the house via the fireplace. Starlings also occasionally nest in burrows and cliffs. The female lays 3 to 6 light blue – green/white eggs. The incubation period is approximately 12 days. The chicks are helpless when hatched. They fledge in approximately another 21 days. Pairs may have three broods per breeding season.

The Common Starling is a great vocal mimic: individuals can learn the calls of up to 20 different species. Their normal calls are rather raspy calls with no real rhythm.

As a note – in NY there is no closed hunting season on Starlings (at least now).

common starlingIdentification: Starlings are chunky and blackbird-sized they are 8”–9” long with a wingspan of approximately 13”-16”. They weigh between 2–4 oz. The bill is narrow conical with a sharp tip. In flight their wings are short and pointed as are their tails. At a distance, starlings look black. In summer they are purplish-green iridescent with yellow beaks; in fresh winter plumage they are brown, covered in white spots. Their legs are stout and as can be seen are pink/red.

Juveniles are grey-brown, and by their first winter resemble adults though often retain some brown juvenile feathering especially on the head in the early part of the winter.


European Starlings prefer urban or suburban areas. They also commonly reside in grassy areas such as farmland, grazing pastures, open forests and woodlands.


Starling range from Alaska, through much of Canada, all the contiguous US.


Starlings do not engage in any significant migration.


Starlings are omnivorous but they eat mostly insects and other invertebrates such as grasshoppers, beetles, flies, caterpillars, snails, earthworms, millipedes, and spiders. They also eat fruits and grains and will frequent bird feeders.

(1)    The Audubon Society Field Guide to North American Birds

(2)    Cornell University