Hummingbirds are known for their vibrant, iridescent colors that shimmer in the sunlight. The most common hummingbird species in North America such as the ruby-throated hummingbird and Anna’s hummingbird display flashy reds, greens, blues, and purples on their plumage. Given their reputation for being brightly-colored birds, it may seem unlikely that a pure white hummingbird could exist in nature.
The Leucistic Hummingbird
While entirely white hummingbirds do not occur naturally, there are very rare cases of leucistic hummingbirds that have been observed. Leucism is a genetic condition that causes a partial loss of pigmentation in an animal’s feathers, hair or skin. Unlike albino birds that have no melanin production, leucistic birds retain some pigment in their eyes, bills or feet.
Leucistic hummingbirds have a certain percentage of white feathers mixed in with their normally-colored plumage. They may appear mostly white but still have some normally-colored feathers scattered across their bodies. Typically, leucistic hummingbirds retain their original eye color and do not have the pink eyes characteristic of albino birds.
One such example is a leucistic Anna’s hummingbird that was spotted and filmed in British Columbia in 2020. This particular hummingbird had snowy white feathers covering most of its body except for its bright red crown and throat feathers. The remainder of its plumage including its wings, back and belly was white. Its eyes remained black, indicating it was leucistic rather than a full albino.
In extremely rare cases, a hummingbird may be completely white with no traces of normal coloration due to having two copies of the mutated leucistic gene. However, this has only been documented a handful of times and most reports of white hummingbirds are partially leucistic rather than completely white.
Other Causes of White Feathers
While leucism explains most occurrences of white hummingbirds, there are a couple other reasons a hummingbird may display unusual white plumage:
- Partial albinism – In rare cases, a hummingbird may be partially albino with a mix of white feathers and normally-colored feathers. True albino hummingbirds with pink eyes are exceptionally rare.
- Age-related color loss – As hummingbirds age, their vibrant plumage can fade. Older hummingbirds may appear more white as their feathers gradually lose their pigment.
- Color morphs – Some hummingbird species have regional color morphs where the birds display more white than normal. This is genetic variation within a population rather than a condition like leucism.
Prevalence of White Hummingbirds
While certainly unusual, sightings of white or partially white hummingbirds are documented every year across North America. Some regions seem to report more white hummingbird sightings than others:
- Southern California – This region has a high concentration of Anna’s hummingbirds and observers report multiple leucistic Anna’s hummingbirds each year.
- Southeastern States – States like Louisiana and Florida have documented cases of leucistic ruby-throated hummingbirds and buff-bellied hummingbirds over the years.
- Southwestern States – Leucistic Anna’s and black-chinned hummingbirds are periodically sighted in states like Arizona and New Mexico.
- Pacific Northwest – Both Anna’s and rufous hummingbirds display leucistic plumage in this region on occasion.
While leucistic hummingbirds are rare overall, they seem to occur with the greatest frequency in areas that have large, dense populations of hummingbirds. Still, the percentage of leucistic hummingbirds versus normally-colored birds is extremely small.
Why Does Leucism Occur?
Leucism is the result of a genetic mutation that causes a partial loss of melanin pigment. The exact mutation that causes leucism is not fully understood but it is thought to involve a mutation of the gene responsible for melanin production and deposition.
The leucistic mutation seems to occur randomly and spontaneously in some hummingbirds. Once it occurs, the mutation can be passed down to offspring if the leucistic hummingbird breeds with a normal hummingbird. Depending on how the genes segregate, the offspring may display partial leucism or be totally normally-colored.
The leucistic mutation is extremely uncommon but does persist at a low frequency in hummingbird populations. The exact rate at which the mutation occurs spontaneously is not known.
There are a few theories as to why leucistic hummingbirds occur more frequently in certain regions:
- Founder effect – If a leucistic individual colonizes a new area, it may establish a higher frequency of the leucistic trait in that local population.
- Genetic drift – In small, isolated populations, the frequency of certain genes can increase randomly over time through genetic drift.
- Hybridization – When two different species hybridize, it can shuffle genes and produce unusual phenotypes like leucism.
In most cases though, the occurrence of leucistic hummingbirds seems to be simply due to random chance rather than any identifiable cause.
Survival Challenges
Surviving to adulthood presents some special challenges for leucistic hummingbirds. Without the bright, flashy plumage typical of their species, they face increased risks in certain areas:
- Camouflage – Their white coloration makes them stand out and may compromise their ability to blend in to surroundings.
- Thermoregulation – Missing some of their normal plumage may impact their ability to conserve heat in cool weather.
- Communication – Their unusual appearance may make it harder for them to attract mates or participate in social interactions.
- Predation – Their white coloration makes them highly visible to predators.
On the other hand, adult leucistic hummingbirds appear to be fairly robust and resilient despite these obstacles. Once they reach maturity, they seem capable of successfully defending territories, feeding, and breeding in most cases.
There is limited data, but what evidence exists suggests leucistic hummingbirds have comparable lifespans and survival rates to their normally-pigmented counterparts in the wild.
Interesting Cases
While any sighting of a leucistic hummingbird is special, there are a few particularly remarkable cases worth highlighting:
All White Ruby-Throated Hummingbird
In 2012, a back yard bird watcher in Louisiana spotted and photographed an entirely white ruby-throated hummingbird, representing one of the only documented cases of a completely leucistic ruby-throated hummingbird with no coloration except for its black eyes and bill.
All White Rufous Hummingbird
In 2015, a homeowner in British Columbia captured images of a totally white rufous hummingbird visiting her feeder on multiple occasions. Lacking even the trademark rufous-colored feathers on its back and tail, this was likely one of the only completely leucistic rufous hummingbirds on record.
Partially Leucistic Anna’s Hummingbird
In Los Angeles County, one leucistic Anna’s hummingbird was observed repeatedly over several years displaying a mix of normally-colored green and red feathers blended with white feathers on its head, back and belly. This hummer highlights how leucistic birds may retain some of their normal coloration.
Leucistic Allen’s Hummingbird
Native only to a narrow coastal strip from southern California down into Mexico, Allen’s hummingbirds are one of the rarer West Coast species. In 2012, an individual with white neck feathers was documented in Orange County, representing one of very few known records of leucism in this species.
Key Takeaways
To summarize the answer this question, here are the key points:
- Truly albino white hummingbirds are incredibly rare, but partially white leucistic hummingbirds are observed more regularly.
- Leucism is caused by a genetic mutation leading to partial loss of melanin pigment.
- Leucistic hummingbirds occur more frequently in certain regions like California and the Gulf Coast.
- The leucistic mutation presents some survival challenges but leucistic hummingbirds appear resilient.
- Complete or extensive leucism is rarer than partial leucism where the birds retain some normal coloration.
Conclusion
While not naturally occurring, white hummingbirds do indeed exist in the form of leucistic individuals displaying varying degrees of white plumage. The genetic leucistic mutation causes a partial reduction in melanin pigment, producing hummingbirds that are partly or, more rarely, completely white.
The unusual sight of these mostly-white hummingbirds with a dash of residual color represents a rare but fascinating genetic variation. Leucistic hummingbirds manage to thrive despite their anomalous appearance and provide keen bird enthusiasts with an exceptionally special sighting.
So in summary, while there are no truly albino all-white hummingbird species, rare leucistic individuals display white plumage and provide the only examples of white hummingbirds in nature. These striking yet challenging partial albinos continue to beat the odds and persist as exceptional cases of color aberrancy among their jewel-toned kind.
