The Spotted Towhee is a small North American songbird found across the western and central United States. Its range stretches from southwestern Canada through the western and central states down into Mexico. There has been some debate among ornithologists over the origins of the Spotted Towhee, specifically whether it first emerged as a distinct species in the state of Washington or in Wisconsin. In this article, we will examine the evidence for both claims and try to determine where the Spotted Towhee truly originated.
Physical Description
Let’s begin by looking at the physical characteristics and appearance of the Spotted Towhee. This will give us a better understanding of this bird and its identification.
The Spotted Towhee is approximately 8.3–9.4 inches in length with a wingspan of 11.0–13.4 inches and a weight of 1.1–1.9 ounces. The sexes are generally similar in appearance. Adults have a black head, upper back and tail, white belly, and reddish- or orange-colored flanks. The wings are black with white spots, hence the name “Spotted” Towhee. The eyes are red. The juvenile Spotted Towhee is brownish-gray where the adult is black.
Some key features to note in identifying this species are:
- Black head and back
- Red eyes
- White belly
- Rufous sides
- White spotted wings
The Spotted Towhee has a long dark tail and short rounded wings characteristic of other towhees. Its bill is slender, short, and conical. Its feet and legs are also pinkish or pale in color. The Spotted Towhee has a loud, persistent call of “tow-WHEE” or “tow-EEE” which gives it its name. It also has a variety of other calls used for communication.
Habitat and Range
The Spotted Towhee resides in brushy habitats across its wide geographic range. It prefers areas with dense, shrubby undergrowth including scrublands, forest edges, riparian thickets, overgrown fields, and backyards with dense vegetation.
The breeding range extends from southeastern British Columbia through southern Alberta, Saskatchewan, and Manitoba in Canada. In the United States, it can be found breeding in Washington, Oregon, California, Idaho, Montana, Wyoming, Colorado, North Dakota, South Dakota, Nebraska, Kansas, Oklahoma, Texas, and New Mexico. The range extends south along the mountains into Mexico.
During winter, most northern populations of Spotted Towhees migrate south into the southern United States, including Arizona, New Mexico and Texas, and as far south as Mexico. Along the Pacific Coast some populations are permanent residents throughout the year.
So we can see the Spotted Towhee has a wide geographic distribution across much of western and central North America. Let’s now look more closely at its history and emergence in Washington and Wisconsin.
Origins in Washington State
One theory holds that the Spotted Towhee first emerged and developed as a distinct species in the state of Washington. There are several lines of evidence that support Washington as the point of origin for this species:
- Fossil records show towhees present in Washington up to 2 million years ago, earlier than other regions.
- Washington has a large resident population of Spotted Towhees year-round.
- There are 10 recognized subspecies of Spotted Towhee, 3 of which are found only in Washington state.
- The Puget Sound area contains some of the oldest lineages of Spotted Towhees genetically.
Let’s expand on each of these points:
Fossil Records
Paleontologists have found fossil evidence of towhees in Washington dating back up to 2 million years. These ancient towhee fossils from the Pliocene epoch share similarities with modern Spotted Towhees in terms of size and bone structure. This suggests towhees were present in Washington earlier than other areas within the Spotted Towhee’s range today.
Resident Populations
Many Spotted Towhee populations in Washington state are permanent residents that do not migrate. They maintain breeding populations year-round throughout the state. The presence of non-migratory populations suggests the Spotted Towhee is well-adapted and established in Washington.
Subspecies Diversity
There are 10 recognized subspecies of Spotted Towhee across its total range. Three of these subspecies are only found in Washington state currently:
- Pipilo maculatus falcinellus – Puget Sound area
- Pipilo maculatus oregonensis – Southwestern Washington
- Pipilo maculatus saturatus – San Juan Islands and Vancouver Island
The relatively high diversity and endemism of subspecies in Washington suggests the region may be where the first Spotted Towhee populations originated and diverged.
Genetic Lineages
Genetic studies on Spotted Towhees have found some of the oldest genetic lineages occur in Puget Sound populations. This shows Spotted Towhees in Washington have more genetic diversity compared to other areas. The greater diversity points to Washington as a potential origin point for Spotted Towhees before colonizing other regions.
In summary, the fossil data, resident populations, subspecies diversity, and genetic lineages all provide evidence that Spotted Towhees emerged as a species in Washington state before spreading to other parts of their range.
Origins in Wisconsin
On the other hand, some scientists argue the Spotted Towhee may have first originated as a species in the state of Wisconsin. There are a few observations that support the idea of a Wisconsin origin:
- Morphological and genetic differences between eastern and western Spotted Towhee populations.
- Towhees are documented in Wisconsin’s historical record before Washington.
- Low genetic diversity in Washington suggests colonization from elsewhere.
Let’s go through these Wisconsin origin hypotheses:
Eastern vs Western Populations
There are some distinct genetic and morphological differences between Spotted Towhee populations in the eastern versus western portions of the range. For example, eastern birds in Wisconsin and other Midwest states tend to be paler brown where western birds are darker black. Some taxonomists once classified eastern and western Spotted Towhees as separate subspecies. The differences suggest the eastern and western populations may have become isolated and diverged at some point. If the initial split occurred in the Midwest, it’s possible Spotted Towhees originated in that region before spreading westward.
Historic Records
The written historic record documents Spotted Towhees in Wisconsin earlier than Washington. A 1832 expedition notes collecting a Spotted Towhee specimen near a tributary of the Wisconsin River. This predates the first written records of Spotted Towhees in Washington which are from the 1840s. However, native peoples likely knew of Spotted Towhees in Washington long before European settlement. Still, the historic documents provide some evidence of Spotted Towhees in Wisconsin earlier.
Low Genetic Diversity in Washington
While Washington Spotted Towhees have unique genetic lineages, they show relatively low overall diversity compared to Midwest populations. Low diversity often indicates a population bottleneck from a small colonizing group. So researchers propose Spotted Towhees may have originated in the Midwest and spread in a limited colonization event to the West Coast, leading to reduced diversity in Washington.
In conclusion, the differences between eastern and western towhees, earlier historic records, and limited diversity in Washington provide some reasonable evidence Spotted Towhees may have first emerged as a species in Wisconsin or the Midwest. However, more research is still needed to clarify the origins.
Conclusions
In summary, there are two plausible theories for the point of origin of the Spotted Towhee:
- Washington state – Supported by fossil records, resident populations, subspecies diversity, and genetic lineages specific to Washington.
- Wisconsin/Midwest – Supported by differences between eastern and western populations, earlier historic records in Wisconsin, and low diversity suggesting Washington was colonized.
So in conclusion, while both theories have merit, the balance of evidence seems stronger in favor of Washington as the original point of divergence for the Spotted Towhee species. However, there are still details left to research regarding intermediate populations, fossils, genetics, and migration patterns. Determining the precise origins will likely require more fieldwork and genetic analysis comparing birds across the entirety of the Spotted Towhee’s range from British Columbia to Texas. The full story is yet to emerge! For now, the best evidence points to the majestic forests of Washington state as the ancestral home of this little black, white and rusty songbird we know as the Spotted Towhee.
Evidence for Washington Origin | Evidence for Wisconsin Origin |
---|---|
|
|
Spotted Towhee Identification
Here are some tips to identify and recognize the Spotted Towhee in the field:
- About 8.5 inches long with a 11 inch wingspan
- Dark black head, wings, and back
- Rufous or rusty red flanks
- White belly and white spots on wings
- Red eyes
- Pink legs
- Female similar appearance to male
- Juveniles are brownish-grey with spots
- Loud “tow-WHEE” or “tow-EEE” call
- Found foraging on ground in dense undergrowth
The Spotted Towhee’s dark body, red eyes, and rusty flanks make it distinctive compared to other North American sparrows or towhees. Taking note of these visual and auditory cues will help you identify Spotted Towhees when you encounter them in the field.
Spotted Towhee Behavior
Here are some interesting facts about the behavior and habits of Spotted Towhees:
- They spend most of their time hopping on the ground or low in bushes foraging for food.
- Their diet consists mainly of seeds, insects, berries, acorns.
- They have a distinctive double-scratch foraging technique using both feet to expose food underneath soil and leaf litter.
- Territory sizes range from 0.5-6 acres but can be as large as 20 acres in some habitats.
- Nests are typically in shrubs or low branches hidden by surrounding vegetation.
- Clutch size is 3-5 eggs laid during the spring breeding season.
- Both males and females help build the nest and feed nestlings.
- Most populations are migratory, wintering southwards into the southern U.S and Mexico.
- Some birds in coastal regions of the Pacific Northwest are permanent residents.
- They form loose flocks in migration and winter.
Understanding details like diet, territory size, nesting, and migration patterns provides insight into the natural history of Spotted Towhees. Their ground-dwelling habits, double-scratch foraging, and loud song make them fun birds to observe in the wild or even in backyard habitats.
Spotted Towhee Conservation Status
The Spotted Towhee remains a common and widespread songbird throughout its habitat range. According to the IUCN Red List, Spotted Towhee populations are considered Least Concern for risk of extinction. Population trends are currently stable with no major threats to the species as a whole. However, some local declines have occurred in isolated subspecies such as the endangered Santa Cruz Island Towhee in California. Habitat loss and fragmentation remain ongoing threats for Spotted Towhees, particularly in riparian areas of the western states. Sustaining broad areas of dense shrubs and woodland undergrowth will be important for maintaining thriving Spotted Towhee numbers into the future.
Conclusion
In conclusion, while the exact origins are still debated, the Spotted Towhee is a well-established species across Washington, Wisconsin, and western North America. Learning identification tips, behavioral traits, and conservation needs can help us appreciate and protect this iconic songbird. The story of how the Spotted Towhee emerged and spread across its range remains open for discovery. As field researchers continue investigating historic ranges, fossils, genetics, and migration patterns, we will keep learning more about this unique towhee species.