Notably, the impact on artificial light at night on local bird populations, as opposed to migrant bird populations, is minimal. These "resident birds" are either significantly less affected or unaffected by artificial light in their environments, suggesting that adaptation to the presence of artificial light may be possible (Mouritsen et al., 2005). Regardless of the mechanism behind bird navigation and interference of artificial light, reduction in artificial light emission has been found to be beneficial to bird populations (Miles et al., 2010).
While a fair amount of research has been conducted both to describe and to analyze artificial light at night, many studies have historically maintained only a broad geospatial scale when considering ALAN. Recently, Falchi et al. describe the creation of a worldwide map of artificial sky luminance that considers global regions subjected to different categories of artificial light. The study notes the importance of low-angle, upward-pointing light sources as a primary cause of light pollution with a significant impact on night luminance (Falchi et al., 2016).