Quick Answer
No, hummingbirds should not drink oleander nectar. The nectar from oleander flowers contains oleandrin, a toxic cardiac glycoside that can be fatal to hummingbirds if consumed. Even small amounts of oleander nectar can cause heart arrhythmias, hypoglycemia, paralysis, and death in hummingbirds. It’s best to avoid planting oleanders near hummingbird feeders or natural food sources. Other safe flower nectar alternatives include trumpet vines, fuchsias, and coral honeysuckle.
Is Oleander Toxic to Hummingbirds?
Yes, oleander is highly toxic to hummingbirds. All parts of the oleander plant contain toxic cardiac glycosides, including oleandrin, neriine, and others. Oleander is extremely poisonous to many animals, including horses, dogs, cats, and birds. The consumption of oleander nectar, even in small amounts, can be fatal to hummingbirds. The toxins affect the heart, causing cardiac arrhythmias, hypotension, and death. Oleander is considered one of the most deadly plants to hummingbirds.
Toxicity Mechanism
Oleander toxins like oleandrin are cardiac glycosides that inhibit the sodium/potassium ATPase pump in heart muscle cells. This disrupts the normal electrochemical gradient across the cell membrane, preventing effective pumping action of the heart. The heart rate becomes erratic (arrhythmia) and the force of contractions declines, leading to hypotension, circulatory failure, hypoglycemia, paralysis, and death. Even a tiny amount of toxin can be rapidly absorbed and cause toxicity.
Signs of Oleander Poisoning
Hummingbirds poisoned by oleander nectar may exhibit signs like:
- Vomiting
- Diarrhea
- Tremors
- Seizures
- Wing droop
- Weakness
- Collapse
- Coma
- Sudden death
The rapid heart rate and breathing from the toxins can progress to cardiovascular collapse and death. Poisoned birds may die suddenly or be found dead around oleander plants. Prompt veterinary treatment is needed for any chance of survival.
Are Oleanders Toxic to Other Birds?
Yes, oleander is toxic to most bird species. The cardiac glycosides can cause poisoning not only in hummingbirds but also in chickens, parrots, finches, wild turkeys, and other birds that ingest parts of the plant. Cockatiels and parakeets are especially sensitive. Birds that eat the leaves, flowers, nectar, seeds, or drink contaminated water near oleanders risk being poisoned and dying. Oleander should not be planted where birds can access it.
Toxicity in Backyard Birds
Backyard birds like sparrows, robins, chickadees, and thrushes can also suffer oleander poisoning if they eat the flowers or nectar. Care should be taken to prevent backyard birds from nesting in oleanders or feeding on the plant. Bird baths and feeders should not be placed directly under or near oleanders, to prevent toxins leaching into the water or food sources.
Treatment of Oleander Poisoning
There are no specific antidotes for oleander poisoning in birds. Treatment involves trying to remove any remaining plant parts from the GI tract, providing supportive care with IV fluids and electrolytes, administering activated charcoal to bind toxins, anti-arrhythmic medications, sedation, and other measures to try to stabilize the bird. The prognosis is often poor even with aggressive therapy. Preventing access to oleanders is the best way to avoid toxicity.
Do Hummingbirds Naturally Eat Oleander Nectar?
No, hummingbirds do not intentionally seek out oleander nectar in the wild. Oleander is not native to the Americas, where hummingbirds naturally occur. Hummingbirds have not evolved to identify oleander flowers as a food source or have any physiological tolerance to its toxins.
Native Plants vs Introduced Oleander
Hummingbirds obtain nectar from flowering plants that have co-evolved with them in their native habitats, such as columbines, trumpet vines, fuchsias and other native species. Oleander was introduced to the Americas from Asia and the Mediterranean. Hummingbirds do not have an innate ability to distinguish safe flowers from a toxic invasive plant like oleander. If oleander is present in their environment, they may feed from it and succumb to poisoning.
Instincts to Avoid Toxins
Hummingbirds do have some instinctual behaviors to avoid toxins, such as avoidance of extremely bitter taste. However, oleander nectar does not contain deterrents bitter enough to necessarily trigger avoidance. In the absence of generations of evolved avoidance behaviors, hummingbirds will feed on available flowers including toxic oleanders. Preventing access, not relying on deterrence, is the only sure way to stop oleander poisoning.
Where are Oleanders Found?
Oleanders are evergreen shrubs or small trees that are widely planted ornamentally and are invasive in some subtropical areas. They are native to northern Africa, the eastern Mediterranean, and southwest Asia. Regions where ornamental oleanders are common include:
- Southeastern United States
- California
- Mediterranean region
- Southern China
- Taiwan
- Australia
These areas have climates conducive to oleander growth, and plantings for aesthetics which then sometimes spread into the wild. Areas prone to oleander invasiveness tend to have mild winters and warm summers. Oleander distribution overlaps significantly with hummingbird ranges, posing hazards from oleander nectar ingestion.
Invasiveness in Warm Climates
Oleander thrives in frost-free areas with hot summers, moderate rainfall, and well-drained soils. This makes it suited to invade wildlands in California, the Southeastern US, Mediterranean regions, and elsewhere with similar climates. Oleanders spread both by seeds and by root sprouts, allowing them to form dense thickets. These provide copious flowers whose nectar can attract and poison hummingbirds.
Monitoring Invasive Spread
Preventing ongoing habitat invasions by oleanders relies on monitoring and removal of plants or avoidance of using them horticulturally. In areas where oleanders are already established, their flowering and nectar production can be reduced by pruning, or access prevented by netting, fencing, or other barriers. Maintaining oleander-free spaces for hummingbirds is key.
What Flowers Do Hummingbirds Naturally Drink From?
Hummingbirds have evolved to pollinate and feed on nectar from a diverse array of native New World flowering plants. Safe, natural food sources include:
Trumpet Vines
- Trumpet honeysuckle (Lonicera sempervirens)
- Trumpet creeper (Campsis radicans)
- Chilean trumpet creeper (Campsis x tagliabuana)
These vines produce abundant red trumpet-shaped blossoms with high nectar content.
Fuchsias
- Hummingbird fuchsia (Fuchsia magellanica)
- Scarlet fuchsia (Fuchsia splendens)
- Rose-pink fuchsia (Fuchsia arborescens)
Fuchsias are shrubs with colorful drooping flowers perfect for hummingbird feeding.
Sages
- Pineapple sage (Salvia elegans)
- Scarlet sage (Salvia coccinea)
- Autumn sage (Salvia greggii)
Sages produce spikes of tubular red flowers with an attractive aroma.
Columbines
- Western columbine (Aquilegia formosa)
- Crimson columbine (Aquilegia canadensis)
- Rocky Mountain columbine (Aquilegia caerulea)
Columbines have elegant flowers with spurs containing ample nectar.
Penstemons
- Scarlet bugler (Penstemon centranthifolius)
- Foothill penstemon (Penstemon heterophyllus)
- Beardtongue (Penstemon digitalis)
Tubular red penstemon blossoms are a key food source in western North America.
What Flowers Can Be Safely Planted for Hummingbirds?
Many non-native ornamental flowers also provide safe nectar sources for hummingbirds. Some recommended options include:
Coral Honeysuckle
The coral honeysuckle (Lonicera sempervirens) is a popular hummingbird-friendly vine native to the southeastern US. It has bright red tubular blooms.
Bee Balm
Bee balm (Monarda didyma) has distinctive shaggy flower heads in shades of red, pink, and purple. It attracts hummingbirds with its nectar.
Cardinal Flower
Cardinal flower (Lobelia cardinalis) produces tall spikes of scarlet flowers relished by hummingbirds.
Salvias
Ornamental sages like the red sage (Salvia horminum) have tubular flowers in colors that appeal to hummingbirds.
Delphiniums
Delphinium hybrids come in blue, purple, and pink colors. Hummingbirds will drink their nectar but can’t pollinate them.
Crocosmia
Crocosmia produce spikes of reddish-orange blooms on arching stems, providing copious nectar.
Should Oleanders be Planted Near Hummingbird Feeders?
No, oleanders should never be planted near hummingbird feeders. There is too much risk that oleander nectar, leaves, or sap could contaminate the feeder and poison hummingbirds. Even planting oleanders across a yard from feeders poses some risk. It’s safest to avoid oleanders entirely on properties where you want to attract hummingbirds.
Risk of Contaminating Feeders
Oleanders exude sticky, sweet sap that can adhere to hummingbird beaks, feathers, or feet as they perch on flowers. They may then transfer some of that oleander toxin-containing sap to feeders. Nectar dripping from flowers might also contact feeders if oleanders overhang them. It only takes a tiny amount of toxin to sicken or kill a hummingbird. Preventing any oleander contact is crucial.
No Oleanders Within 100 Feet
To minimize risks, oleanders should not be planted within at least 100 feet (30m) of any hummingbird feeders, baths, or preferred natural feeding areas. Wider buffer zones of 0.25 mile (400m) or more are even safer. Have feeders surrounded only by non-toxic flowers and trees. Never place feeders directly underneath oleanders.
Remove Any Nearby Oleanders
If oleanders are already growing close to hummingbird feeding areas, they should be removed. Cutting them back drastically or digging them up altogether will eliminate the hazard. Replace oleanders with safe, pollinator-friendly native plants. Do not let oleanders remain and bloom in proximity to hummingbird attractions.
Conclusion
Oleander is an extremely toxic plant that poses a deadly risk to hummingbirds through its nectar. No part of the plant should be ingested. While oleanders are attractive flowering shrubs, they should never be planted in areas frequented by hummingbirds or other birds due to their toxicity. Safely attracting hummingbirds depends on providing feeders and native plants that offer nourishing nectar without risks from oleanders. The wellbeing of hummingbirds is best served by landscaping with non-toxic flowers and keeping areas totally free of oleanders. This prevents tragic losses of these special birds to such a dangerous invasive plant. With some care in garden design, hummingbird habitats can exclude oleanders and thus protect these vulnerable creatures.
