Toxic Berries To Birds – Do Nandina Berries Kill Birds
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By: Teo Spengler
Heavenly bamboo (Nandina domestica) is not related to bamboo, but it has the same lightly branched, cane-like stems and delicate, fine textured foliage. It is an upright ornamental evergreen shrub with beautiful berries that mature to brilliant red. But are nandina berries poisonous? The answer is yes! The berries contain cyanide and can be toxic berries to birds. In fact, birds eating nandina berries sometimes die.
Are Nandina Berries Poisonous?
Nandina shrubs have many traits that make them appealing to gardeners. These plants have year-round interest with spring flowers, ornamental fruits, and sometimes autumn color. They tolerate drought, shade, and salt and are quite resistant to damage by deer. In addition, they are free of serious pest issues.
However, before planting nandina shrubs, you need to read up on heavenly bamboo berries and birds. One of the most ornamental features of this bush is its shiny red berries, quite similar to holly berries. Unlike holly, however, these can be toxic berries to birds.
Do Nandina Berries Kill Birds?
Nandina berries and foliage can be dangerous for livestock and household pets if eaten. The berries are toxic to birds as well. Thankfully, they are not the first food choice of wild birds but some species, including cedar waxwing, northern mockingbird, and American robin, eat the berries if nothing else is available. Nandina berries kill birds when enough are eaten.
Other factors are believed to be involved as well. Swings in temperatures and lack of sufficient water can cause plant species to produce cyanide in greater concentrations. Combine that type of weather pattern with the voracious eating habits of some migratory birds that gorge themselves on berries. It is no wonder that hundreds can die, especially when the berries are overripe.
Heavenly Bamboo Berries and Birds
Heavenly bamboo berries and birds are also related in another way. One of the downsides of these shrubs is their invasiveness. They propagate readily from the seeds in their berries.
If berries are simply allowed to fall beneath the tree canopy, the gardener can weed out unwanted plants. Heavenly bamboo berries and birds, taken together, can spread the species into wild areas.
If you want to plant nandina while avoiding invasiveness and bird mortality issues, you should plant fruitless cultivars, or at the very least, trim the bush prior to berry production or cut them as soon as they develop.
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Read more about Heavenly Bamboo
Heavenly Bamboo Plant Profile
Despite its common name, heavenly bamboo (Nandina domestica) is not a bamboo at all, but a species of flowering, evergreen shrub native to eastern Asia. Grown as an ornamental shrub, it is characterized by cane-like stems and finely textured leaves that resemble those of bamboo, which is how Nandina domestica got its common name. Heavenly bamboo sports a dazzling show of color all year round, with leaves that turn from pink to green to red as the seasons change. In the spring, dainty white flowers are followed by bright red berries that persist throughout the winter. Looking to add a striking, low-maintenance plant to your garden this year? Look no further than heavenly bamboo!
|Botanical Name||Nandina domestica|
|Common Name||Heavenly bamboo, sacred bamboo|
|Mature Size||7 feet tall, 5 feet wide|
|Sun Exposure||Full sun, partial sun|
|Soil Type||Rich, well-draining|
|Flower Color||Cream, white|
|Native Area||Eastern Asia|
Watch Now: How to Grow and Care for Heavenly Bamboo
Why Nandina Berries Are Bad for Cedar Waxwings
Nandina berries actually have a low toxicity, but they can be lethal to cedar waxwings specifically because their feeding habits differ dramatically from that of other birds, said Rhiannon Crain, project leader for the Habitat Network with The Nature Conservancy and Cornell Lab of Ornithology. "Other birds don't eat as much or as rapidly as cedar waxwings," said Crain. "Cedar waxwings completely stuff every possible part of their body with berries. They will fill their stomach and their crop with berries right up into their mouth until they can't fit another berry inside of them."
Cedar waxwings, which travel in flocks, will fly into a berry-producing bush or tree and strip the branches of every piece of fruit. That can have negative consequences for them even when the plant isn't a nandina. "I've seen them drunk on mulberries," said Crain. "Mulberries, and other fruits high in sugar can turn into alcohol, or ferment, pretty readily on the plant. They will fly into a mulberry tree and eat until they are drunk."
To understand why nandina berries can kill cedar waxwings but not other birds, Crain said to think of an apple seed, which also contains cyanide. "If you eat an apple seed, you would not feel any ill effect. But, instead of eating a single apple seed, if you were to somehow eat a plate of apple seeds, that might start to be a problem for your body." In the same manner, nandina berries are not likely to be a problem for overly curious pets or children, said Crain. They are not likely to eat enough of them for the low toxicity of the berries to cause a health problem.
But the cedar waxwings' small bodies are a mismatch for their gorging habit. "It's really a matter of ingesting enough of the nandina berries that the toxicity in the berries has a measurable impact on their bodies," said Crain.
Although all parts of the Nandina produce toxins, the berries are prompting interest and concern because they are sometimes eaten by fruit-eating birds that don't have the capacity to recognize the non-native plant's chemical risks. The waxwing mortality incident in Georgia prompted study which was reported in the scientific journal Veterinary Medicine International http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3005831/
Jerry Davis, an Extension wildlife specialist in Arkansas, saw that scientific article and wrote a news brief, which I shared with colleagues and stakeholders here in Oregon, in order to raise awareness among people who otherwise wouldn't have seen the article in the Vet Med journal. I also shared both the news release and journal article with our wildlife veterinarian colleagues at Oregon Dept of Fish and Wildlife. In the past, they have not specifically looked for Nandina as a potential cause of death because there wasn't information about the potential toxic consequences for consumers. However they noted that dead birds brought into state labs and classified as "likely alcohol toxicity" (from ingestion of fermented berries, for example) cases could have included Nandina-associated deaths that simply were not identified.
As to why it is included in "wildlife-friendly" yards, etc., Nandina was imported to the Americas as an ornamental plant quite some time ago. It evolved and is native to parts of Asia. Because ancestors of our birds of the Americas did not encounter the plant (or its toxins) historically, there would have been no opportunity for the animals to adapt to the risks (toxins) by evolving recognition or avoidance behaviors. An animal that is "naive" to a new or foreign risk literally gets no chance to learn avoidance behaviors. Imported plants and animals are not subject to testing for potential ecological interactions, such as invasibility or toxicity. Therefore, the Nandina's multi-season features such as foliage and attractive berries have seemed like a natural choice for nature-minded gardeners. Mortality events such as the waxwing incident force us to take a second look at some of these choices, however. Complicating the issue is Nandina's agressiveness and success in spreading from initial plantings to the point that it is becoming widespread in many neighborhoods and potentially invading natural areas. Much remains to be learned as to how we can assess and manage the risk, now that we know. For example, we do not yet know whether berry toxicity (or birds' attraction to the berries) and/or overall plant toxicity varies according to short-term weather events such as our recent snow events. If you want to keep the plants, you might consider clipping off the berries early in their development (prior to ripening).
Finally, other items can be found on the web: Some have advice and concerns for pet owners and owners while others are targeted at managers of plant-eating herbivores that might also have opportunities to consume the leaves or berries of Nandina.
Heavenly bamboo: The red berries on this non-native shrub are deadly for local birds
The nandina bush, also known as heavenly bamboo, has bright red berries in the winter which are toxic when consumed by many birds in the Pacific Northwest.
Such is the case with a plant recently brought to the attention of the Tualatin Soil and Water Conservation District (SWCD) by Dana Sanchez, Oregon State University Extension wildlife specialist, who reports that a common landscaping shrub may threaten local bird populations due to its toxic berry.
The shrub is commonly known as nandina, sacred bamboo, or heavenly bamboo. Nandina is found in the landscaping of yards, parks, hospital grounds, and other locations across the lower 48 states. Planted for its bright red berries and contrasting dark green foliage, the shrub adds color and texture in residential and commercial landscapes.
Some homeowners planted nandina with the intention of providing food for cedar waxwing, American robin, northern mockingbird, and other birds that depend on winter fruits to survive. Nandina berries stay on the bush for months, attracting hungry birds when food is in short supply.
And that can be a major problem for the birds. When dozens of cedar waxwings were found dead in Georgia three years ago, investigators at the University of Georgia found the cause to be nandina berries. Bird autopsies revealed the berries lodged in the birds’ crops, as well as hemorrhaging of several internal organs.
The root of the birds’ distress is the cyanide and other alkaloids contained in the berries that produce highly toxic hydrogen cyanide, which is extremely poisonous to all animals. Sudden death may be the only sign of cyanide poisoning and death usually comes within minutes to an hour of exposure.
Worse still, nandina is a non-domestic, noxious, and highly invasive weed that displaces the non-toxic, native plants on which local birds normally thrive. Nandina has been imported from China and Japan, and has invaded many natural areas. Homeowners and commercial landscapers are still planting this toxic species, unaware of the risk.
“Over 220 bird species nationwide are in serious decline, including our most common birds. Birds are being killed on all fronts,” said Jerry W. Davis, a certified wildlife biologist from Arkansas. “By working together, we can eliminate this toxic and noxious invasive plant. If you are not doing your part, the job is not getting done.”
Consider these simple steps to help reduce and eventually remove the presence of nandina in the local landscape:
1. Avoid using nandina in landscaping projects and opt for beneficial native plants with a similar appearance, such as Pacific ninebark, red elderberry or red huckleberry.
2. If you have nandina already and aren’t ready to part with it, take care to prune the bushes to remove the berries as winter approaches. Planting a variety of non-toxic food sources such as serviceberry, snowbush, or red twig dogwood will help fill the gap.
3. Currently, there are no control efforts underway in Washington County for nandina, but sharing this article with the landscaping company that handles your home or business may help. And report sightings to the Invasive Species hotline at oregoninvasiveshotline.org.
For more information on identifying invasive plants, or learning about native plants for your landscape, see the SWCD website or contact the SWCD at 503-648-3174.
COMMON NAME: Nandina, Heavenly Bamboo
BOTANICAL NAME: Nandina domestica
PRONUNCIATION: nan-DEEN-ah doe-MESS-ti-ka
TYPE: Evergreen – Sun / Shade
HEIGHT: 1 - 8 feet
SPACING: 2 - 4 feet
HABIT: Pinkish or purplish white flowers in clusters at branch ends in early spring. Red berries in winter. Vertical unbranching shoots, leggy but distinctive. Soft, delicate red-orange foliage. Regular Nandina is 5 - 8 feet tall, Compact Nandina 3 - 4 feet, ‘Harbour Dwarf’ 1 - 2 feet, and ‘Nana’ 1 -2 feet. Grows in any soil, any location. Drought tolerant. Do not shear or box – ever! Withstands an unbelievable amount of neglect. To lower height of plant, cut the tallest shoots off at ground level.
CULTURE: Any soil, anywhere. Drought tolerant. Do not shear or box – ever! Can take an unbelievable amount of neglect. To lower height, cut the tallest shoots off at ground level.
USES: Specimen, container, accent, screen, hedge, Oriental gardens, mass or border plant.
PROBLEMS: Relatively few.
NOTES: Native to China. Nandinas have a curious negative connotation with many people – probably because they are often seen growing wild around abandoned properties. This just shows how tough they really are. All varieties are good except ‘Nana,’ which looks like a chlorotic basketball all summer. Nandina ‘San Gabriel’ has distinctively thin foliage.
Nandinas should be pruned by following the longest shoots to the ground and cutting them off there. This technique effectively lowers the overall height but maintains the natural form of the plants. Shearing or boxing nandinas completely ruins the beauty and injures the health of the plants. It would be okay to do the nandina pruning in the summer but the ideal timing is late winter.
INVASIVE NANDINA DOMESTICA By Linda Higby, Freelance Writer
Nandina domestica, a non-native, woody invasive evergreen shrub from Eastern Asia has insidiously worked its way into the fabric of the Texas landscape. Introduced in the 1800s, it was widely used as an ornamental landscape plant. It escaped and began invading natural areas. As one comes to understand the havoc this pernicious member of the Barberry family wreaks on our state, both environmentally and economically, Nandina's nicknames, heavenly bamboo and sacred bamboo become more and more ludicrous.
As a refresher, let's first define what an invasive species is exactly. A generally accepted definition and one that's used by Executive Order 1311 of the Texas Invasives organization states: "an invasive species is defined as one that is non-native or alien to the ecosystem under consideration and whose introduction causes or is likely to cause economic or environmental harm or harm to human health."
Non-domestic Nandina has found a home in Texas because of its ability to thrive in our dry, sunny clime and because it can readily morph, flourishing in shady, moist areas with no care. Nandina's ability to easily adapt and successfully reproduce has led to its promotion as a landscape plant of choice and its perpetuation continues despite myriad data supporting its eradication. Of course there are many other invasive species the likes of Kudzu, China Berry and Ligustrum, but for now my purpose is to explain why Nandina is an un-welcome guest and is included on every invasives species list in our state.
Nandina occurs under forest canopies and near forest edges and can inhabit several types of plant communities from upland hardwoods to flood plains and mesic slope woodlands. It is a fast-growing plant that spreads by underground rhizomes (nefarious root-like structures) and seeds. It has a substantial taproot. Seedlings can persist for several years before maturing. Animal-dispersed seeds are broadcast into natural areas where they love to naturalize, displace native species and crowd out native plant communities. As is the case with so many invasives, this alien has no known natural enemies, competitors or diseases in the environment to keep it in check.
The Institute for the Study of Invasive Species states that "by interfering with ground covering plants, Nandina is able to alter an ecosystem and impact native animals that use native understory plants." In 2009, USDA Forest Service statisticians reported "in monoculture environments, Nandina establishes itself in high enough densities to block sunlight to native species in rich, diverse slope woodlands." And according to Texas Parks and Wildlife, "Nandina grows very aggressively forming monocultures. It out-competes native plant species in our region. This reduces the diversity of native plants in a given area which creates a lack of food and shelter available for wildlife."
Mark Klym, author and Texas Parks and Wildlife Department (TPWD) Coordinator states that "many of our native plants have adapted specifically to accommodate the feeding habits of many native hummingbirds. Rampant infestations of Nandina interfere with the interdependent, symbiotic relationship which occurs between plants and wildlife, altering the infrastructure of our fragile ecosystem." In another TPWD study, field reporters concluded that Nandina displaces native plant communities with which native wildlife have evolved. It can smother or choke out native habitats and contribute to loss of native pollinators such as honey bees, moths and hummingbirds and the animals which rely on insect fauna that have been affected by these invasions.
All parts of the Nandina plant are toxic. The plump, red berries are attractive but poisonous to birds, dogs, cats, some ruminant farm animals and wildlife. Excessive consumption of the berries is extremely toxic to migratory birds unfamiliar with this food source when found in their foraging flight paths. Lady Bird Johnson Wildflower Center (LBJ) describes Nandina as a "highly invasive weed that displaces non-toxic, native plants on which birds thrive and does more harm by actually poisoning native wildlife."
According to another article referenced by LBJ Wildflower Center "when dozens of cedar waxwings were found dead in Georgia three years ago, investigators at the University of Georgia found the cause to be Nandina berries. Bird autopsies revealed the berries lodged in the birds' crops, as well as hemorrhaging of several internal organs. The root of the bird's distress is the cyanide and other alkaloids contained in the berries that produce highly toxic hydrogen cyanide, which is extremely poisonous to all animals. Sudden death may be the only sign of cyanide poisoning and death usually comes within minutes to an hour of exposure."
"Over 220 bird species nationwide are in serious decline, including our most common birds. Birds are being killed on all fronts," states Jerry W. Davis, Certified Wildlife Biologist from Arkansas. The Native Plant Society of Texas warns that song birds are the first line of defense for pest control.
Can we really afford to promote Nandina when we know it to be a serious threat to the birds on which we so depend?
The USDA Forest Service reports that Nandina seedlings are the first plants noticed to emerge after prescribed fires. They suggest that some aspect of post- fire conditions actually promotes the germination of Nandina. Interestingly, they cannot confirm how long Nandina can live but individual plants found near home sites in the Southern U.S. were greater than 100 years old!
While there is always substantiating evidence on both sides to promote one's cause or belief, I have been unable to find evidence supporting the propagation of this plant. Many scientific reports and frustrated gardeners' blogs later, all I come up with is "it was pretty with its red berries," "I thought I was doing the right thing to feed the wildlife," " I can't get rid of it," "it is taking over my property," "what can I do?
Texas A & M AgriLife Extension confirms that invasive species are negatively impacting ecosystems and that it is costly. Their reports indicate that "it is very expensive to prevent, monitor and control the spread of invasives. The damage to crops, fisheries, forests, and other resources costs the US $137 billion annually. Some of the most harmful species cost in excess of $100 million annually."
My first encounter with noxious Nandina occurred when I discovered it on a property I was working on in Shavano Park, San Antonio. A seemingly friendly looking evil-doer, planted close to the house by an unknowing homeowner, had spread into the woods. I found rigorous plants popping up everywhere, literally invading the beautiful native wooded habitat! It was impossible to completely follow the extensive, pervasive root system to eradicate it, even with the help of two men. Three days into the project we were still doing our best to just somehow manage the situation. Maybe that is what spurred this article. I can certainly testify to the seriousness of the situation, having attempted to deal with it personally. My research for this article only confirms my firsthand observations that this plant is systematically upsetting our fragile ecosystem, limiting natural biodiversity and messing with the natural balance of things. It is ubiquitous and appears to be unstoppable!
It is interesting to note that the City of San Antonio's Appendix E Recommended Plants List does not include Nandina among its plants of choice to grow. And, while San Antonio Water System (SAWS) does include this plant in its recommended plant list, it states that Nandina is "very difficult to eradicate avoid berry-producing varieties which have proven invasive in central Texas and the Southeastern U.S."
Apparently unaware of the risks, homeowners and landscapers are still planting this toxic, aggressive species. How can we halt this criminal? With facts in hand, passionately spread the word! Educate your friends and neighbors as to why invasive Nandina is not the plant of choice. Don't buy this stuff or plant it! Refuse to support big box stores and nurseries that sell it. Instead, plant a variety of friendly natives to replace lost habitat because diversity increases the chances that an animal can find food. Here are some excellent plant options: Flameleaf Sumac, Bush Germander, Texas Sage, Possum Haw Holly, American Beauty Berry, Salvia greggi, Yaupon Holly, Carolina Buckthorn, Barbados Cherry, or my favorites Agarita and its cousin, Texas Barberry.
Homeowners determined to plant Nandina are encouraged to plant sterile, dwarf varieties such as Nana and Harbor Dwarf, which rarely set seed. Yet, because these varieties still spread profusely by rhizomatic action, it is recommended that dwarfs be kept in pots and monitored. Because Nandina is very difficult to remove manually, care must be taken when this invasive is potted as rhizomes escaping the bottom of the pot tend to "travel" quickly, with even the smallest piece of root re-sprouting! Didn't I see a Nandina's mug shot at the Post Office yesterday?
Remove prior plantings and control sprouts and seedlings. Collect and bag or burn all fruit to prevent spreading. Pullerbear Tree and Root Puller makes an invasives weed remover tool which may help or just dig, dig, dig the roots by hand. Develop an on-going maintenance program to stay on top of re-growth and resident newcomers. Investigate chemical treatment options but with any chemical use follow the directions carefully and be aware that several chemical applications will be necessary with varying degrees of success. Please refer to LBJ Wildflower Center or The Institute for the Study of Invasive Species regarding chemical products targeted for invasives and their proper application.
As scientists and researchers continue to search for answers to the "invasives dilemma," there are glimmers of hope. Dr. Kelly Lyons of Trinity University states "experimental studies suggest that more diverse vegetative communities are more resistant to new species introductions, in particular non-indigenous species invasions." Great news! And, in growing numbers throughout the state, groups of citizens are forming "Invaders of Texas" chapters. These grass roots chapters which are overseen by LBJ Wildflower Center, are committed to a three-pronged approach with regards to dealing with the invasives challenge. Through outreach programs, education and eradication, their mission is to inform the public of the seriousness of the situation and to actively work towards the control of the invasion of this species in our great state. We applaud these "citizen scientists," as they are called, and if you would like to support their efforts you may reach them at www.texasinvasives.org/ invaders .
- City of San Antonio
- Institute for the Study of Invasive Species
- Lady Bird Johnson National Wildflower Center
- Madrone Native Nursery, San Marcos
- Native Plant Society of Texas
- Personal, firsthand experiences in the trenches!
- San Antonio Water Authority
- Texas A & M Agrilife Extension
- Texas Forest Service
- Texas Invasives
- Texas Parks and Wildlife Department
- Trinity University
- USDA Forest Service