Its vocalisations carry better in natural environments than those of the house sparrow. The Spanish sparrow's vocalisations are similar to those of the house sparrow. The Spanish sparrow's other calls are almost the same as those of the house sparrow. The taxonomy of the house sparrow and its Mediterranean relatives is complicated. Invasive species include the European hare, wild boar and house sparrow. The Italian sparrow's behaviour is similar in many ways to that of the house sparrow. Dvorak celebrated many other kinds of bird, including the stock dove, skylark, and house sparrow. The house sparrow is closely associated with humans. The house sparrow is a very social bird. The plumage of the house sparrow is mostly different shades of grey and brown. In mass, the house sparrow ranges from . In London, the house sparrow almost disappeared from the central city. On the ground, the house sparrow typically hops rather than walks. It possesses a streaked back, somewhat resembling a small house sparrow. The house sparrow is typically about long, ranging from .