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Night lighting of cities makes them adults before blackbirds

Night lighting of cities makes them adults before blackbirds The light from the street lamps, traffic lights and the light streaming from the windows of our homes displaces the darkness of the city. The lack of darkness at night, of course, impacts on plants, animals and humans. For example, researchers have documented the impact of a night light on a black scythe. Conclusion ornithologists is that urban blackbirds lighting for shifting their natural biorhythms.

Birds living in lighted areas are sexually mature earlier than their peers from rural areas. Also singing in the morning start earlier and earlier moult.

For many species, the seasonal change in the length of one of the key signals that come from the environment and to help manage their rhythms. And not just the day (ie, when it is time to wake up and when it's time to go to sleep), but also the seasonal (ie, when it is time to begin to mate). People that know very well indeed and handling time use lighting to enhance snášek in laying hens in factory farms.

Researchers from the Max Planck Institute for Ornithology in Germany Radolfzell focused on animals exposed to strong urban lighting. Several captured urban blackbirds black light meter equipped to see what light these birds are exposed overnight.

Meters experienced any extreme values. "Light intensity was actually very low, around 0.2 lux. It is thus one thirtieth of what shines from ordinary street lamp, "says Jeske Parteck data.

But despite the blackbirds move only in an environment with such a low level of illumination, and it disrupts their adolescence. Light and tied him to cause the production of hormones that sexually mature birds earlier.

Scientists exposed the birds caught in the wild and urban lighting intensity of 0.3 lux for ten months. "Result impressed us," says Parteck. "Sexual organs of birds exposed to light was ripe about a month earlier than in birds, who had night darkness. "Researchers also measured levels of testosterone: birds exposed to light began to produce this hormone earlier. Light exposure also started in the morning birds singing earlier, one hour.

"From these findings it can be inferred that birds exposed to nocturnal light, are usually able to start to reproduce earlier than birds, who are dark at night," says Parteck. The other side of the coin is that their breeding season also ends earlier. "Night lighting of cities in these birds can lead to dramatic changes in their seasonal biorhythms."



Source: Ekolist.cz



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