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City lights create sexual early birds

Male blackbirds exposed to nocturnal illumination ready to mate sooner in spring

By Susan Milius

- More than 2 years ago

SAN FRANCISCO — City lights can deliver male birds into reproductive readiness weeks ahead of schedule.

EARLY BIRD Male European blackbirds exposed to urban night light levels molted sooner and their sexual development advanced up to a month faster than birds living with dark nights.