Juncos are small, sparrow-like birds that are common across much of North America. They are known for their gray and black plumage, with white outer tail feathers that are particularly noticeable when they fly. So do juncos have a white tail? The short answer is yes, juncos do have white outer tail feathers that are visible when their tail is fanned or spread during flight. However, the amount of white varies depending on the species and subspecies.
Description of juncos
Juncos belong to the genus Junco in the sparrow family Passerellidae. There are 7 recognized species:
- Dark-eyed Junco (Junco hyemalis)
- Yellow-eyed Junco (Junco phaeonotus)
- Gray-headed Junco (Junco hyemalis caniceps)
- Guadalupe Junco (Junco insularis)
- Baird’s Junco (Junco phaeonotus bairdii)
- Volcano Junco (Junco vulcani)
- White-winged Junco (Junco hyemalis aikeni)
The most widespread and familiar junco in North America is the Dark-eyed Junco. This species can be further divided into several subspecies or races, which show some regional variations in plumage. The Slate-colored Junco (J. h. hyemalis) is the nominate subspecies and the most common junco found across Canada and the northern U.S.
White tail feathers
In all juncos, the outermost tail feathers (rectrices) are white. When the tail is fanned or spread, as in flight, these white feathers are prominently displayed, creating a distinctive white flash. The amount of white on the outer tail varies between species and subspecies:
- Slate-colored Juncos have the most white – the outer 2-3 tail feathers are completely white.
- Oregon Juncos (J. h. oreganus) have slightly less white on the tail.
- The gray-tailed forms like the Cassiar Junco (J. h. cismontanus) have the least white – only the outer 1-2 tail feathers are partially white.
So in summary, all juncos have white outer tail feathers but the exact amount can help identify the specific type of junco. The white tail flash is most apparent and extensive in the Slate-colored Junco.
Do both male and female juncos have white tails?
Yes, both male and female juncos have white outer tail feathers. The white tail is not a sexually dimorphic trait in juncos and does not differ between the sexes. Both sexes have the same characteristic white tail pattern for their particular subspecies.
Identifying male and female juncos
While the white tail flash is not helpful for telling males and females apart, juncos do show some sexual dimorphism in other plumage characteristics:
- Males tend to be slightly larger and heavier than females.
- Males have darker, more contrasting plumage while females are generally browner.
- Females may have faint streaking on the sides and flanks while males have solidly colored sides.
- Males have a pink bill while females have a yellowish bill with a darker tip.
But despite these differences, both sexes can still be identified as juncos by the conspicuous white tail feathers. The white tail is a species trait rather than a sexually dimorphic one.
Do juvenile juncos have a white tail?
Yes, even juvenile juncos have the characteristic white outer tail feathers. The tail pattern including the white feathers is part of the first plumage adopted by young birds.
Identifying juvenile juncos
While juvenile juncos have the white tail feathers, their overall plumage can look different from adults:
- Both male and female juveniles often resemble adult females in coloration.
- They have browner and more streaked plumage overall.
- The tail may appear darker blackish-brown rather than pure black.
- They have dull flesh-colored bills rather than pink or yellow.
But by examining the tail closely, the white outer tail feathers are still visible even in juveniles. Within a few months, juvenile plumage transitions to adult-like plumage through molting. But throughout this process, the distinctive white tail remains constant.
Why do juncos have white tails?
Several theories may explain why juncos evolved white outer tail feathers:
Signaling flight movements
The flashing white tail could serve as a visual signal to communicate junco movements during flocking or maneuvers. This may help coordinate activity within junco flocks.
Startle defense
When flashing the white tail, juncos can startle potential predators and draw attention away from the more vulnerable head and body. This could allow juncos to escape predation more easily.
Maintenance of dark plumage
The contrast between the dark junco plumage and white tail feathers may also enhance the appearance of darkness throughout the body. This dark plumage helps juncos blend into shadows and low light in forest habitats.
Attraction and courtship
Displaying the flashy white tail feathers could help attract mates and impress competitors during courtship. The tail may serve as an indicator of fitness.
How do juncos use their white tails?
Juncos make active use of their white tails in the following contexts:
Flight
The white tail is most noticeable when juncos are in flight. The tail fanning exposes the white feathers and creates a flashing effect. This likely helps juncos coordinate flock movement and signals changes in direction.
Foraging and feeding
Juncos frequently fan their tails when hopping along the ground foraging for food. This may flush up insects for feeding or startle predators to avoid danger.
Alert calls
When alarmed, juncos fan their tails and expose the white feathers conspicuously as they give high-pitched warning calls.
Social interactions
In conflicts over resources, displaying white tail feathers could signal a junco’s status and right to a contested territory or food source.
Courtship displays
Male juncos in particular use tail-spreading displays with prominent white feathers to attract mates and compete with rivals at leks during the breeding season.
How widespread are white-tailed juncos?
Juncos with white tails can be found throughout much of North America in a variety of habitats. The distribution depends on the particular species and subspecies:
Slate-colored Junco
The nominate and most common Dark-eyed Junco subspecies has an extensive range across the U.S. and Canada. Slate-colored Juncos with conspicuous white tails are common birds in:
- Alaska
- Canada
- Northern U.S. from the Pacific to Atlantic coasts
- Appalachian Mountains
- Northern Great Plains and Rockies
During winter, Slate-colored Juncos migrate southward through most of the continental U.S.
Oregon Junco
This subspecies is found year-round along the Pacific Coast, west of the Rockies from southern Alaska to Baja California. Its range centers on Oregon and Northern California.
Other subspecies
Various regional subspecies with variable white tail plumage occupy other parts of the western and southwestern U.S. including:
- Cassiar Junco – Pacific Northwest
- Gray-headed Junco – Arizona, New Mexico, western Texas
- Red-backed Junco – Black Hills of South Dakota
- Pink-sided Junco – Great Basin region
So juncos with white tail feathers can be observed throughout much of the continent in appropriate habitat. The most widespread subspecies is the white-tailed Slate-colored Junco.
How can you observe juncos and their white tails?
Here are some tips for observing juncos and getting great views of their flashing white tails:
Habitats
Look for juncos in open mixed woodlands, yards with trees, parks, and mountain forests. Seek out habitat edges and areas with bare ground.
Food sources
Provide food like millet and cracked corn on ground feeders or platforms. Juncos will flock to these food bonanzas.
Water
A ground-level birdbath or shallow water source allows juncos to drink while tail-dipping and flashing white tail feathers.
Perches
Low perches give juncos a place to land and display their coloration. Fence posts and rocks work well.
Nesting season
In spring and summer, you may see more tail-spreading displays as juncos try to attract mates near nesting sites.
Cold weather
As winter approaches, juncos form large migratory and foraging flocks, increasing chances to see white tail flashes.
So look for juncos hopping on the ground, perching, or splashing in shallow water to get the best views of their distinctive white outer tail feathers fanning out.
Conclusion
In summary, all juncos have characteristic white tail feathers on the outer rectrices which are especially visible during flight. This feature aids identification. The amount of white varies across the different junco species and subspecies, but some white is always present. Males, females, juveniles, and adults all possess the white tail which serves functions in signaling, defense, and courtship. By providing suitable habitat, food, and perches, observers can readily admire the junco’s flashy white tail in action.
