Old World sparrows are small, brown, and grey birds belonging to the family Passeridae, known for their seed-eating habits and brooding in urban environments, particularly buildings. They should not be confused with the New World sparrows of the family Passerellidae or the Java sparrow, which is unrelated. Old World sparrows are widespread, encompassing various species such as the house and Eurasian tree sparrows that thrive in cities. These birds have a stout build, with short tails, strong beaks, and range in size from the tiny chestnut sparrow to the larger parrot-billed sparrow. While their appearance might be similar to finches, they have unique anatomical features like an extra bone in the tongue to aid in seed handling.
First introduced by Constantine Samuel Rafinesque in 1815, the family Passeridae typically comprises true sparrows (Passer), snowfinches (Montifringilla), and rock sparrows (Petronia), among others. Historically, sparrows were often grouped with weavers or finches due to similar characteristics. The family contains various genera, with species adapted to a range of habitats including forests, grasslands, and deserts; for example, the snowfinches inhabit cold, high-altitude regions.
Social creatures, Old World sparrows often form large flocks and breed colonially, with species like the house sparrow assembling in big roosts for non-breeding periods. They engage in dust or water bathing, followed by group preening and sometimes collective singing. House sparrows usually lay 3-6 eggs with an incubation period of around two weeks. Sparrows have had a long-standing engagement with humans, spanning from agricultural pest control to serving as pets. They hold symbolic value in various cultures, often representing commonality or in religious texts as emblems of divine care.
The family's distribution is primarily across Europe, Africa, and Asia, with some species introduced by humans to other regions such as North America and Australia. Attempts to manage sparrow populations due to their impact on agriculture, such as China's Great Sparrow Campaign, have often proven ineffective or counterproductive. Despite a reputation for being mundane or associated with lewdness in historical texts, sparrows maintain a significant place in human history, from being kept as colorful pets in Rome to featuring in religious and literary works as symbols of love or divine watchfulness.