The Northern Flicker is a medium-sized woodpecker found widely distributed across most of North America. This bird gets its name from the conspicuous white markings that flash like a flickering light when it flies. Northern Flickers can be identified by their brownish barred plumage, black bib and spotted underparts. But one of the most distinguishing features of Northern Flickers is the coloration of their underwings and tail feathers, which can be either yellow or red. This has led to Northern Flickers being grouped into two distinct subspecies: the Yellow-shafted Flicker which has yellow underwings and tail, and the Red-shafted Flicker which has red underwings and tail. While quite similar in appearance and behavior, there are some key differences between these yellow and red color morphs of Northern Flickers.
Geographic Range
The ranges of the yellow and red Northern Flickers are partitioned across North America along a diagonal line from Alaska to Newfoundland.
Subspecies | Range |
---|---|
Yellow-shafted Flicker | Found in eastern North America from Nova Scotia to Texas |
Red-shafted Flicker | Found in western North America from Alaska to Baja California |
There is a narrow hybrid zone where the ranges of these two subspecies overlap and interbreed in the Great Plains regions. But in general, yellow Northern Flickers occupy the eastern side of the continent while red Northern Flickers occupy the western side. This geographic separation contributes to some of the behavioral and morphological differences between them.
Habitat Preferences
Both yellow and red Northern Flickers inhabit open woodlands, forest edges, parks and suburban areas. They prefer habitats with scattered large trees for nesting and plenty of ground cover where they forage for ants and other insect prey.
However, yellow Northern Flickers are more closely associated with deciduous forests and trees found in eastern North America. These include oak, maple, beech, hickory, birch, ash and poplar.
Red Northern Flickers are more adapted to coniferous forests and trees found in western North America. These include pine, spruce, fir, juniper, redwood and cedar.
So while they occupy similar ecological niches, the habitat preferences of yellow vs. red Northern Flickers correlate with the major forest types found within their respective ranges.
Physical Features
In addition to the difference in underwing and tail color, there are some subtle physical distinctions between yellow and red Northern Flickers.
Feature | Yellow Northern Flicker | Red Northern Flicker |
---|---|---|
Bill Color | Dark gray to black | Light gray to ivory |
Face Pattern | Bold black malar stripes | Subtle brown cheek patches |
Nape Color | Gray to brown | Reddish |
Throat Pattern | Black crescent-shaped bib | Black rounded bib |
Weight | 5.9-8.5 oz (167-241 g) | 4.3-7.5 oz (122-213 g) |
These physical differences reflect adaptations to the habitats and food sources found in their respective ranges. For example, the ivory-colored bill of red Northern Flickers may help camouflage them against lighter conifer bark when feeding. Overall though, the plumage and morphology of these subspecies is very similar despite the geographic isolation.
Vocalizations
One major way to distinguish yellow from red Northern Flickers is by their vocalizations. Both subspecies make a loud repetitive ringing call that sounds like “flicka” or “wicka.” However, their other calls are distinct.
Yellow Northern Flickers have a bright, rolling whistle that speeds up or slows down. Their calls are described as a loud “kee-yer” or “peeah.”
Red Northern Flickers have a slower, drawn-out whistle that stays steady. Their calls sound more like a mellow “cuhh” or “kleeer.”
The differences in their calls may be shaped by the forest acoustics of their habitats. The broader whistles of red Northern Flickers may carry better through coniferous forests. The faster, rolling calls of yellow Northern Flickers may contrast against deciduous leaves. Calls also play an important role in communication, identity and mate attraction for these birds.
Migration Patterns
The migration patterns of yellow and red Northern Flickers also differ in accordance with their ranges.
Yellow Northern Flickers are short-distance migrants that overwinter in the southern parts of their breeding range. They form large flocks when migrating south but generally do not cross the Gulf of Mexico.
Red Northern Flickers are medium-distance migrants that overwinter further south. They form massive migratory flocks that funnel through Central America to wintering grounds in Mexico, Central America and northern South America.
These migration strategies position both subspecies in suitable habitat for the winter months and reduce competition for resources. The migration routes and distances covered by each subspecies match their distinct distributions across North America.
Nest Sites
When selecting nest sites, yellow and red Northern Flickers exhibit some subtle preferences aligned with their habitat differences.
Yellow Northern Flickers often excavate nest cavities in dead limbs of deciduous trees, especially oak and beech. They also readily use nest boxes.
Red Northern Flickers strongly prefer nesting in conifers such as pine, spruce and redwood. They excavate nest holes mainly in dead conifer stubs and snags.
However, both subspecies will opportunistically nest in a wide variety of sites and cavities. These can include fence posts, utility poles, sides of buildings and other manmade structures. Overall they are adaptable when it comes to nest placement throughout their range.
Diet and Feeding Behavior
Ants comprise a major portion of the diet for both yellow and red Northern Flickers. They use their slightly curved bill to probe into ant mounds and lap up ants with their long sticky tongue. This specialized feeding technique is called “anting.”
Yellow Northern Flickers forage primarily on the ground, turning over leaves, debris and bark to find ants on the forest floor.
Red Northern Flickers use their slightly longer bill to probe for ants in trees. They can excavate into dead wood or scale bark to access ant galleries.
Both subspecies supplement their diet with other insects like beetles, termites, crickets, spiders and caterpillars. But ants remain their primary food source across most of their range. These behavioral adaptations around diet optimize their feeding strategies in different forest ecosystems.
Interactions and Hybridization
Where the ranges of yellow and red Northern Flickers meet in the Great Plains regions there is a narrow hybrid zone. In these overlapping areas, yellow and red Northern Flickers interbreed to produce hybrid offspring showing intermediate traits. Hybrids typically have reddish underwings andyellowish tails, a mix of vocalizations and other combined characteristics.
Early naturalists considered yellow and red Northern Flickers to be separate species based on their distinct differences. However, the fact that they readily hybridize helped confirm they are two subspecies of the same species (Colaptes auratus). This interbreeding demonstrates a genetic similarity and evolutionary relationship between yellow and red Northern Flickers.
There is also evidence that the hybrid zone between these subspecies is slowly shifting eastward, with more red characteristics appearing in former all-yellow populations. Some ornithologists think this may be linked to forest changes driven by climate change or pine plantation expansion from the west. This hybrid zone provides a fascinating opportunity to study subspecies evolution and adaptation over time.
Conclusion
In summary, yellow and red Northern Flickers exhibit a classic pattern of subspecies divergence across North America, shaped by geographic isolation. Yellow Northern Flickers adapted to forest habitats in the east, while red Northern Flickers adapted to forests in the west. This led to subtle differences in appearance, voice, behavior, movements and habitat preferences between these two colour morphs. However, they remain very closely related and capable of interbreeding where their ranges now interconnect. The distinction between yellow and red Northern Flickers provides an interesting case study of how subspecies can evolve adaptations tailored to their regional environments while remaining part of a contiguous species. Their future patterns of interaction and hybridization will continue illuminating how subspecies arise and diversify across biological ranges.