How does light pollution affect bird migrations?

Light pollution can significantly affect bird migrations. It very easily catches the attention of birds as far as 5 kilometers away from the source. The birds could then either go towards this light and observe it for a while, using energy that needs to be put towards their migration, or the light could make the birds distracted, causing collisions. This sounds like a minor problem on paper, but hundreds of birds could die in one night from one light source in the right conditions (reflecting in clouds, particularly bright light, etc.). The purpose of this project is to quantify the amount that light can affect birds. This will be done by collecting data on specific bird populations at an earlier point in time (before development) in cities compared to after development and comparing that data to the same species of bird in more natural habitats, looking at the same times that were observed for the other area. For example, if there were lots of bluebirds that died in a city area, that data would be compared to the deaths of that species of bluebird in a less developed area, like in a plains area without any manmade light. The original amount of the species in an area will be compared to the final amount in that area, since if the original city data was compared to the final environment data, then there would be inaccuracies since there could be different original amounts of the species in each area.