The House Sparrow (Passer domesticus) is a bird that can be found all over the world. It is considered one of the most widely distributed birds globally. But how many different types or subspecies of House Sparrows exist? There are several subspecies that can be distinguished based on variations in their size, coloration, and geographic distribution.
Total Number of Subspecies
In total, there are between 26 and 27 recognized subspecies of the House Sparrow. The exact number is still debated among ornithologists, but most accept around 27 distinct subspecies. This makes the House Sparrow one of the most variably subspeciated birds in the world.
Geographic Distribution of Subspecies
The different subspecies are spread out across Europe, Africa, the Middle East, Central Asia, the Indian subcontinent, and introduced populations in South America, North America, Australia, and New Zealand. Here is a rough breakdown of the geographic distribution of the subspecies:
- Europe – 8 subspecies
- Africa – 5 subspecies
- Middle East – 5 subspecies
- Central Asia – 3 subspecies
- Indian subcontinent – 3 subspecies
- Introduced populations:
- South America – 1 subspecies
- North America – 1 subspecies
- Australia – 1 subspecies
- New Zealand – 1 subspecies
As you can see, the subspecies are concentrated in the House Sparrow’s native range in Europe, Africa, and Asia, with fewer distinct subspecies present in introduced populations.
Key Differences Between Subspecies
What are the key differences that distinguish these numerous subspecies from one another? Here are some of the main variations:
- Size – Some subspecies are larger or smaller on average than others. For example, the subspecies P. d. parkini of North Africa is large, while P. d. indicus of India is small.
- Plumage coloration – Many subspecies show subtle variations in plumage color, such as darker or lighter gray feathers in the males. The black cheek patches and throat may also differ in size.
- Bill size – Bill size, especially depth, can vary among subspecies. Those with larger bills tend to be found in drier, harsher environments.
- Clutch size – Average clutch size (number of eggs) differs slightly among some subspecies. Those in colder climates tend to lay more eggs.
- Migration habits – Some subspecies are more migratory than others based on their native range and climate.
Most Recognized Subspecies
While estimates vary, here are some of the most universally accepted and recognized subspecies of House Sparrows:
| Subspecies | Native Range |
|---|---|
| Passer domesticus domesticus | Western Europe |
| P. d. balearoibericus | Spain, Portugal, Balearic Islands |
| P. d. tingitanus | Northwest Africa |
| P. d. niloticus | Nile Valley |
| P. d. biblicus | Southeast Mediterranean |
| P. d. persicus | Persia and Arabian Peninsula |
| P. d. indicus | India, Sri Lanka |
| P. d. hyrcanus | Central Asia |
| P. d. hufufae | Arabia |
| P. d. bactrianus | Northern Central Asia |
These subspecies give a good overview of the geographic extent of the House Sparrow’s natural range across Europe, Africa, the Middle East, and Asia. The nominate subspecies P. d. domesticus is the original type specimen the species is based on.
Most Distinctive Subspecies
Some of the House Sparrow subspecies stand out as being quite distinctive from the others, showing more pronounced differences in size, coloration, proportions, and behavior:
- P. d. parkini – Large size, pale coloration, long bill
- P. d. indicus – Very small with a short bill and legs
- P. d. malaccensis – Dark chestnut crown and nape
- P. d. nigeriae – Very dark sooty plumage
- P. d. turkestani – Pale sandy coloration
These subspecies often stand out when observed next to House Sparrows of other subspecies. They illustrate the degree of variability and specialization seen across the global range of this species.
Subspecies in Introduced Regions
In areas where House Sparrows have been introduced by humans, usually only one or two subspecies are present:
- North America – P. d. domesticus
- Australia – P. d. domesticus
- New Zealand – P. d. domesticus
- South Africa – P. d. domesticus and P. d. indicus
- South America – P. d. domesticus
The nominate Eurasian subspecies P. d. domesticus has been the most successful at colonizing new environments. Other subspecies were imported to regions like South Africa, but only P. d. domesticus persists in most places.
Subspecies Classification Issues
Classifying House Sparrow subspecies has posed challenges for taxonomists. Here are some issues that make their taxonomy complex:
- Subspecies intergrade with one another across large geographic zones, making the boundaries blurry.
- Some subspecies differences may actually be clinal (gradual), not subspecific.
- Introduced birds hybridize and mix subspecies that wouldn’t normally interbreed.
- Ranges and defining characteristics can vary seasonally as birds move around.
- Older subspecies descriptions were sometimes poor or based on limited study.
These factors mean taxonomic revision of House Sparrow subspecies is still ongoing. More research could reveal fewer, more or different subspecies classifications in the future. Currently though, the 27 or so recognized subspecies provide a good working framework for the diversity seen in this global bird.
Conclusion
The House Sparrow has an extensive native range across Europe, Africa, the Middle East and Asia, within which ornithologists have recognized some 26-27 subspecies. These subspecies exhibit subtle but detectable variation in size, proportions, plumage coloration, behavioral traits, and geographic distribution. The nominate P. d. domesticus has proven most successful outside the House Sparrow’s native range, where it has been introduced around the world. Taxonomy and classification of House Sparrow subspecies remains complex due to intergrading and hybridization of subspecies across large zones. Still, the current subspecies designations provide a useful system for understanding the geographic variability of this multi-faceted bird.
