How big is a female house sparrow?

The house sparrow (Passer domesticus) is a small bird native to Europe, the Middle East, and parts of Asia and Africa. Introduced populations exist in North America, South America, South Africa, Australia, and New Zealand. The house sparrow is strongly associated with human habitation and can live in urban, suburban, or rural settings. Its scientific name means “sparrow of the home”.

Quick Facts

• The house sparrow is one of the most widely distributed and abundant birds in the world.
• Females are typically smaller than males.
• Adult female house sparrows generally range from 14-16 cm in length and weigh around 24-39.5 g.
• Body size can vary across different populations and subspecies.
• As with most bird species, the male house sparrow is larger than the female.

Length

The typical body length of an adult female house sparrow is 14-16 cm (around 5.5-6.5 inches). This measurement is taken from the tip of the beak to the tip of the tail. However, there is some variation across populations:

• European females range from 14-15 cm in length
• American females range from 15-16 cm
• Indian females measure around 15 cm
• Chinese females are the smallest at 14 cm

There are also subtle differences between subspecies. For example, the nominate subspecies Passer domesticus domesticus found in most of Europe is generally larger than the form Passer domesticus indicus found in most of Asia.

In comparison, male house sparrows are larger, typically measuring 16-18 cm in length. The size dimorphism between males and females allows for differentiation between the sexes.

Weight

The average weight of an adult female house sparrow is typically 24-39.5 g (0.8-1.4 oz). However, weight can vary significantly based on geographic location, time of year, and individual health/condition.

Some average female weights by region:

• Europe – 26-32 g
• North America – 24-33 g
• Australia – 24-30 g
• India – 28-33 g

Females are at their heaviest just prior to egg-laying in spring/summer and reach their lowest weights in winter when food is more scarce. Immature females generally weigh less than adults until reaching full size.

For comparison, male house sparrows weigh around 24-45 g on average, with considerable overlap between the sexes. As with length measurements, males are typically heavier than females of the same population.

Wingspan

The wingspan or total wing length of a female house sparrow averages around 23-26 cm (9-10 inches). This is the distance from the tip of one wing to the tip of the other when fully outstretched.

Some key points about wingspan:

• Wingspan is closely correlated with body length and size.
• Longer wingspans allow for more powerful flight over long distances.
• Smaller, shorter wings are more suited for maneuverability in dense habitat.
• As with other measurements, male house sparrows tend to have longer wingspans than females.

Variation Between Individuals

While the averages listed above characterize female house sparrow size well, there can be significant variation between individuals. Factors impacting size include:

• Age – Adult females are larger than immature females less than one year old.
• Health – Parasites, disease, and nutrition impact growth and condition.
• Population – Size averages differ across geographic populations and subspecies.
• Season – Sparrows fluctuate in weight throughout the year based on food availability.

Additionally, females at the extreme small and large ends of the range exist. The amount of variability can differ across populations as well.

Sexual Dimorphism

As in most bird species, female house sparrows are smaller than males. This size difference is known as sexual dimorphism. The evolutionary purpose of dimorphism is not fully clear, but proposed explanations include:

• Larger males are more equipped to defend nesting territories from intruders.
• Smaller females save energy for egg production and incubation.
• Size differences reduce competition between the sexes for food resources.

The degree of size dimorphism varies across populations. In most European populations, male house sparrows are around 10-15% larger than females. However, some introduced populations display greater differences. For example, male House Sparrows in Kenya average about 25% larger than females.

Changes Over Time

Some studies have noted small changes in house sparrow measurements over the past decades. For example, one study of museum specimens found a gradual decline in size of both male and female house sparrows in the UK between 1925 and 1995. The reasons are not fully understood but could be related to climate change, urbanization, pollution, or other factors.

However, changes over time have not been observed consistently across all populations. More research is needed to determine if sparrows are undergoing significant changes in size globally or just in certain locales.

Comparison to Other Sparrows

To provide more perspective, here is how the female house sparrow compares in size to some other common sparrow species:

The Eurasian tree sparrow is very similar in size to the house sparrow, while other sparrows like the chipping and song tend to be smaller on average.

Conclusion

To summarize key points:

• Adult female house sparrows typically range from 14-16 cm in length and 24-39 g in weight.
• Wingspans are around 23-26 cm.
• Exact size depends on the geographic population and individual traits.
• Females are smaller than males, but show overlap in size ranges.
• While subtle changes in size over time have been noted in some studies, more research is needed.

The house sparrow remains one of the most numerous and successful bird species around the world. Their small size, stout build, and adept flying abilities suit them well to a range of human-altered habitats. Gaining a strong understanding of their typical physical dimensions provides insights into their overall ecology and evolution.