The blue heron is a large wading bird found throughout much of North America. As their name suggests, blue herons typically have an overall blue-gray plumage. However, some variations in color can occur. So can a blue heron ever be all white? Let’s take a closer look at the facts.
Typical plumage of a blue heron
Blue herons (scientific name Ardea herodias) are most commonly identified by their blue-gray feathers covering the head, neck, body, and wings. Their plumage can range from a blue-gray to a more slate-gray.
The sides of their neck have long white plumes used for courtship displays. Their bellies are typically whitish, providing camouflage when viewed from below against the sky. The plumage on their chest is more of a reddish-brown. Their legs are yellowish in color. Juvenile blue herons have duller plumage overall.
So while white feathers can be present on a blue heron, especially on the belly and neck, their overall coloration is predominantly blue-gray. An entirely white blue heron would be highly unusual.
Origins of the blue heron’s coloration
The blue-gray plumage of the great blue heron likely evolved as camouflage to help this large bird blend in amongst shoreline vegetation as it wades and waits to ambush prey. The blue and gray hues match well with the waters and skies they hunt near.
White feathers on a heron’s belly blend with the sky when viewed from below. Dark feathers on the crown and back blend with vegetation above and behind. This camouflage helps blue herons stealthily stalk prey.
Albinism and leucism
So how could a blue heron end up all white? Two genetic conditions, albinism and leucism, can result in abnormal, all-white plumage.
Albinism is caused by an absence of melanin pigment throughout the body. Albino birds have pink eyes, skin, and scales on their legs and feet. Their feathers are completely white. True albino blue herons are extremely rare, but they have been documented.
Leucism is a partial loss of pigmentation. Leucistic birds retain some pigment in their eyes, skin, and body extremities. But their plumage appears completely white because of a lack of melanin in their feathers. Leucistic blue herons are also uncommon, but not quite as rare as true albinos.
Prevalence of albinism and leucism
Researchers have estimated the prevalence of albinism in wild bird populations at 1 in every 1800 individuals. Rates of leucism are only slightly higher, around 1 in every 1500 to 1600 birds.
So while uncommon, albinism and leucism do naturally occur. An all-white blue heron could simply be an albino or leucistic individual.
Color morphs
Another possible explanation for an all-white blue heron is an unusual color morph.
Some bird species exhibit color morphs – permanent color variations that can differ from the usual plumage. The white morph of the great blue heron has been documented. These all-white individuals are not albinos or leucistic birds. Rather, they represent a naturally occurring color variant.
Condition | Cause | Features |
---|---|---|
Albinism | Lack of melanin throughout body | All white feathers, pink eyes, skin, and scales on legs/feet |
Leucism | Partial lack of melanin in feathers | All white feathers, but colored eyes, skin, and scaled extremities |
White morph | Genetic color variant | All white feathers, normally colored eyes, skin, legs, and feet |
Case reports of white blue herons
There are a handful of reports involving all-white blue herons that provide some real-world examples:
Mississippi, 2006
In 2006, an all-white great blue heron was spotted and photographed at a wildlife refuge in Mississippi. Based on its normally colored eyes, skin, and legs, experts identified it as an example of a white color morph, rather than an albino or leucistic bird.
Texas, 2013
An entirely white juvenile heron was spotted on the coast of Texas in 2013. The young bird’s pink bill and legs suggested it was likely an albino heron.
Ontario, 2019
Birdwatchers in Canada reported seeing an all-white heron at a marsh in 2019. Its colored skin and eyes indicated leucism as the cause of its unusual white plumage.
Wisconsin, 2021
In 2021, a Wisconsin wildlife photographer captured images of an adult white heron with normally-colored eyes and skin. This was likely a white color morph.
So while most blue herons sport their trademark blue-gray colors, over the years a number of abnormally white individuals have been documented across North America.
Reasons for white colorations
So what would cause a blue heron to be all white when their species normally displays blue-gray plumage? Here are some potential explanations:
- A genetic mutation resulting in albinism – absence of melanin pigmentation
- Leucism – a partial loss of the pigment melanin in feathers
- A rare white color morph – a long-lasting color variant
- A combination of aged plumage and bleaching from sunlight
- Hybridization with other white heron species
Of these possibilities, albinism, leucism, or a white morph seem the most likely explanations in the absence of other unusual features.
Impacts on survival
What are the potential impacts of being all white for a normally blue-gray heron? Here are some considerations:
- Greater vulnerability to predators due to lack of camouflage
- Increased sun exposure leading to skin damage and bleaching of feathers
- Possible social exclusion from other blue herons
- Potential disadvantages hunting due to increased visibility
- No major impacts on mating success
The unusual coloration may draw extra attention from predators. But otherwise, an all-white heron could remain reasonably healthy in the wild, especially if it can find more secluded habitats. Overall impacts on survival may be minimal in some cases.
Conclusion
While extremely rare, blue herons have been documented displaying all-white plumage on occasion. This abnormal coloration is likely due to albinism, leucism, white color morphs, or a combination of factors. An all-white heron would stand out starkly from a typical blue-gray individual. But with minimal detrimental impacts on health and mating prospects, these unusually-colored birds can still thrive in the wild in some habitats. So while highly uncommon, it is indeed possible for a blue heron to be completely white.