Culex pipiens

Culex pipiens is the common house mosquito of temperate Europe and North America. It is the primary West Nile virus vector in Europe and across the northern United States, with seasonal peaks in late summer when populations surge after months of warm weather.

It is an unremarkable mosquito visually — medium-sized, plain brown, no distinctive markings — but ecologically dominant in urban and suburban environments. It breeds in virtually any source of stagnant water: drains, catch basins, birdbaths, unused swimming pools, clogged gutters, old tyres.

Biting activity spans from dusk through the night, often indoors as the mosquito follows its blood hosts into houses. Unlike Aedes, Culex pipiens feeds readily on birds as well as humans, which is why West Nile virus (a bird-maintained virus) uses it as a bridge vector to human populations.