Grackles are a group of medium-sized blackbirds found throughout North and South America. Most people are familiar with the common grackle, which has glossy black feathers with purple or blue iridescent tones. However, some species of grackle can have white or light-colored plumage. So can grackles be white?
The short answer is yes, some grackle species and hybrids do have white or light-colored plumage. The great-tailed grackle is one species that can have a light color morph with mostly white feathers. Hybridization between great-tailed grackles and boat-tailed grackles can also result in offspring with white plumage. Additionally, leucistic common grackles with abnormal white feathers have been observed.
While uncommon, the existence of white grackles demonstrates the diversity of plumage that can occur in the grackle family. Below we will explore in more detail the different grackle species and hybrids that can have white or light-colored feathers.
Do great-tailed grackles come in white?
The great-tailed grackle is one of the largest grackle species found in North and South America. Most great-tailed grackles have black plumage like other grackle species. However, approximately 5-10% of the great-tailed grackle population has a genetic color polymorphism that results in white or lighter plumage known as the “white morph.”[1]
These white morph great-tailed grackles have mostly white feathers on their body, wings, and tail. They may still retain some darker feathers like their blackish-gray legs, black bill, or dark feather edges. The iridescent feathers may appear more bronzy or purple-tinted rather than showing the typical blue-green sheen.
The white morph is maintained in the population because the gene causing it is not lethal. While the white color may make them more visible to predators, great-tailed grackles have many defenses like mobbing predators or taking advantage of safety in numbers in large flocks.
So in summary, yes the great-tailed grackle is one grackle species that can naturally have white plumage. It provides an excellent example of color polymorphism in birds.
Range of the white morph great-tailed grackle
The white morph great-tailed grackle can be found throughout their range in the Americas. They occur from the southwestern United States through Mexico and Central America. Their range extends into western and northern South America in countries like Colombia, Venezuela, and Ecuador.[2]
Anywhere great-tailed grackles occur, you may spot the white morph birds mixed among the normal black plumage type. They are not limited to any particular region.
White morph vs. albino grackles
It’s important to note the white morph great-tailed grackle is not albino. Albinism is caused by a genetic mutation that prevents melanin pigment from being properly deposited in feathers. This results in an all-white bird with pink eyes, legs, and bill.
The white morph great-tailed grackle still has dark pigmentation in some feathers and soft tissues. Their eye color is typically dark brown like other grackles. White morph birds also seem to survive as well as the normal black type, while true albino birds tend to have poorer health and survival.
So the white great-tailed grackle’s plumage is better described as a color variant or morph, not a true albino. The genetic difference causing lighter color is not fully understood but is likely a different mutation than albinism.
Do boat-tailed grackles come in white?
The boat-tailed grackle is another large grackle species found in coastal areas of the southeastern United States. It is mostly black with a long keel-shaped tail. Unlike the great-tailed grackle, the boat-tailed grackle does not have a common white color morph.
Boat-tailed grackles with white plumage have been observed but these are very rare. When they do occur, it is usually caused by leucism rather than a distinct color polymorphism like the great-tailed grackle displays.
Leucistic boat-tailed grackles
Leucism is a condition where birds have reduced melanin pigment in some or all of their feathers. It causes irregular white spotting or patches on birds that are normally dark-colored.
Leucistic boat-tailed grackles have been documented showing white patches on the head, body or tail. Rarely, some appear almost entirely white but retain small patches of normal black feathers.[3]
Unlike albinism, leucistic birds have normally colored eyes, legs, and bill. They are also not as weak or unhealthy as true albino birds. However, the abnormal white feathers can still hinder their survival compared to normal plumaged birds.
Leucism seems to occur spontaneously as a genetic mutation and leucistic birds do not comprise a distinct population. Boat-tailed grackles cannot be categorized as having a “white morph” as the great-tailed grackle does.
Do common grackles come in white?
The common grackle is the most widespread and familiar grackle species in North America. Its scientific name is Quiscalus quiscula.
Like the boat-tailed grackle, the common grackle does not have a genetically determined white color morph. Normal common grackles have dark iridescent black plumage with a purplish-blue sheen.
However, leucistic common grackles have been documented. These have irregular white spotting or patches caused by the leucism condition. Very rarely, a common grackle may be almost all white but it cannot be considered a true “white morph.”
Additionally, a few albino common grackles have been recorded over the years. These are distinguished by the complete lack of melanin pigment, resulting in pink eyes and soft tissues. They usually do not survive long in the wild.
In summary, while not typical, leucistic and albino common grackles can result in white plumage. But the species does not have a white color variant like the great-tailed grackle does.
Can grackle hybrids be white?
Yes, there are records of white or leucistic grackle hybrids occurring. When two grackle species interbreed, the resulting hybrid offspring can sometimes exhibit abnormal white plumage.
Great-tailed x Boat-tailed grackle hybrids
Where their ranges overlap in Texas and Louisiana, great-tailed grackles sometimes hybridize with boat-tailed grackles. The hybrid offspring show a mix of traits from both parent species.[4]
Occasionally, these hybrids have been observed to display leucistic white spotting or patches on the head, body, or wings. When the leucism is extensive, the hybrid grackles can appear nearly all white.
While leucistic pure species grackles are rare, the hybridization process seems to produce leucism at a higher rate. The mixed genetics of two species combining may help explain why white hybrids occur more frequently.
Common x Great-tailed grackle hybrids
Hybridization between common grackles and great-tailed grackles has also been documented in areas where their ranges overlap such as Texas. Hybrids show intermediate physical and behavioral characteristics.
There are a number of reports of leucistic Common x Great-tailed grackle hybrids being sighted.[5] These hybrids display irregular white spotting or patches on their plumage, caused by the leucistic condition.
It seems the hybridization process can allow for increased expression of genes causing leucism to result in white hybrid birds. The mixed genetics lead to more variability in plumage coloration.
Conclusion
While most species of grackle are black, white grackles can sometimes occur due to color polymorphisms, albinism, leucism or hybridization. A few key points to summarize:
– The great-tailed grackle exhibits a genetically determined white color morph across its range, comprising around 5-10% of its population. This white morph is not albino, leucistic, or unhealthy.
– Boat-tailed grackles and common grackles do not have a distinct white morph. Rare leucistic or albino individuals may occur, displaying irregular white spotting or complete lack of melanin.
– White hybrid grackles can be produced when great-tailed grackles interbreed with boat-tailed grackles or common grackles. The mixed genetics often increases expression of leucistic traits.
So in conclusion, yes some grackle species and hybrids can display white plumage. The existence of white morphs and hybrids demonstrates the diverse variation in coloration possible in the grackle family.
Frequently Asked Questions
Why are some great-tailed grackles white?
Some great-tailed grackles are white due to a genetic color polymorphism that causes a “white morph” to occur regularly in about 5-10% of the population. The exact gene causing this morph is not confirmed but is likely a mutation unique to the great-tailed grackle.
Are white grackles rare?
The white morph great-tailed grackle is not rare and can be found throughout their range. However, leucistic or albino grackles of any species are quite rare. The abnormal white plumage likely hinders their survival compared to normally colored birds. Hybridization allows for more common occurrence of leucistic white grackles.
Are white grackles albino?
The white morph great-tailed grackles are not albino. True albino grackles with zero melanin pigment are very rare. However, leucistic grackles display irregular white spotting or patches on their plumage. The leucism is caused by a reduction of melanin.
Can common grackles be white?
Common grackles do not display a white morph but rarely individuals may be leucistic or albino. White specimens occur incidentally not as a normal color variant. Hybridization with other grackle species can sometimes produce leucistic white common grackle hybrids.
Do boat-tailed grackles have a white morph?
No, boat-tailed grackles do not have a distinct white morph like the great-tailed grackle does. Occasionally individual boat-tailed grackles display leucistic plumage abnormalities but white coloration is not typical of the species.
Species | White morph | Leucistic | Albino |
---|---|---|---|
Great-tailed Grackle | Yes (5-10%) | No | Extremely Rare |
Boat-tailed Grackle | No | Rare | Extremely Rare |
Common Grackle | No | Rare | Extremely Rare |
Hybrid type | Reference |
---|---|
Great-tailed x Boat-tailed Grackle | [4] |
Common x Great-tailed Grackle | [5] |