The London plane is an urban hybrid grown in the UK after two species were brought to Europe from different continents by explorers. How has it adapted to the big city?
BLACKBIRDS’ BIOLOGICAL CLOCKS
The distinctive song of a blackbird can be heard regularly in some parts of the world. It is used to attract a mate during breeding season by male blackbirds, to establish territory and deter rivals. In bustling cities, their melodies can be drowned out by traffic and noise pollution. This has led to evolutionary changes in the song itself and the birds’ body clocks. To avoid the noise of the day, blackbirds are waking up earlier to sing before humans disturb their songs. One study conducted in Germany found that, on average, city blackbirds awaken 29 minutes earlier than forest-dwelling blackbirds and continue to sing six minutes longer at night. City blackbirds also sing at a higher pitch to stand out against the noise of traffic, belting their tunes out at a higher volume.