Sparrows are birds of the genus Passer. They are around 15 cm long and just weigh 20 - 40 grams. They can have 3 nests at once with 3 to 5 eggs in them. There are 26 types of sparrows all over the world. The house sparrow is the most common species and you could once see it right in your backyard. However, due to pollution, construction and climate change, they are no longer found in cities.
Here are some pictures of House sparrow, Eurasian tree sparrow and Russet sparrow taken in Pangot, Uttarakhand, India.