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Cochran, W. W., Mouritsen, H., & Wikelski, M. (2004). Migrating songbirds recalibrate their magnetic compass daily from twilight cues. Science, 304(5669), 405–408.
Abstract: Night migratory songbirds can use stars, sun, geomagnetic field, and polarized light for orientation when tested in captivity. We studied the interaction of magnetic, stellar, and twilight orientation cues in free-flying songbirds. We exposed Catharus thrushes to eastward-turned magnetic fields during the twilight period before takeoff and then followed them for up to 1100 kilometers. Instead of heading north, experimental birds flew westward. On subsequent nights, the same individuals migrated northward again. We suggest that birds orient with a magnetic compass calibrated daily from twilight cues. This could explain how birds cross the magnetic equator and deal with declination.
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Dunnett, O.,. (2014). Contested landscapes: the moral geographies of light pollution in Britain. Cultural Geographies, 22(4).
Abstract: This paper considers the concept of light pollution and its connections to moral geographies of landscape in Britain. The paper aims to provide a greater understanding of light pollution in the present day, where the issue connects to policy debates about energy efficiency, crime, health, ecology and night time aesthetics, whilst also engaging with new areas of research in cultural geography. The main sources of investigation are the Campaign to Protect Rural England and the British Astronomical Association’s Campaign for Dark Skies (est. 1990). Using interviews, archival and textual analysis, the paper examines this anti-light-pollution lobby, looking at the lead-up to the formation of the Campaign as well as its ongoing influence. A moral geography of light pollution is identified, drawing on two interconnected discourses – a notion of the ‘astronomical sublime’ and the problem of urbanization. Whilst the former is often invoked, both through visual and linguistic means, by anti-light pollution campaigners, the latter is characterized as a threat to clear night skies, echoing earlier protests against urban sprawl. Complementing a growing area of research, the geographies of light and darkness, this paper considers the light pollution lobby as a way of investigating the fundamental relationship between humankind and the cosmos in the modern age.
Keywords: Light pollution; geography; darkness; moral geographies; urbanization
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Gandy, M. (2017). Negative Luminescence. Ann. Amer. Assn. Geographers, , 1–18.
Abstract: The increasingly pervasive phenomenon of light pollution spans several different fields of concern, including the loss of the night sky, energy wastage, and the effects of artificial light on circadian rhythms and nocturnal ecology. Although the scale of the problem has grown significantly in recent decades, the underlying dynamics remain only partially understood beyond the identification of specific technological pathways such as the rise of light-emitting diodes (LEDs) or the capitalist transformation of the nocturnal realm. It is suggested that current approaches to the study of light, including the identification of “urban atmospheres,†the elaboration of existing approaches to urban ecology, or the extension of “smart city†type discourses, do not capture the full complexity of the politics of light under late modernity.
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Muheim, R., Phillips, J. B., & Akesson, S. (2006). Polarized light cues underlie compass calibration in migratory songbirds. Science, 313(5788), 837–839.
Abstract: Migratory songbirds use the geomagnetic field, stars, the Sun, and polarized light patterns to determine their migratory direction. To prevent navigational errors, it is necessary to calibrate all of these compass systems to a common reference. We show that migratory Savannah sparrows use polarized light cues from the region of sky near the horizon to recalibrate the magnetic compass at both sunrise and sunset. We suggest that skylight polarization patterns are used to derive an absolute (i.e., geographic) directional system that provides the primary calibration reference for all of the compasses of migratory songbirds.
Keywords: Alaska; *Animal Migration; Animals; Calibration; Cues; *Flight, Animal; Geography; *Light; Magnetics; *Orientation; Seasons; Sparrows/*physiology; Sunlight
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Shaw, R. (2015). Night as Fragmenting Frontier: Understanding the Night that Remains in an era of24/7: Night as Fragmenting Frontier. Geography Compass, 9(12), 637–647.
Abstract: Social scientists have previously understood the night through a frontier metaphor. This has pitched night as an empty or lightly inhabited space into which the urban, capitalist day has been expanding. The contemporary increase in nocturnal research has complicated this picture, showing an increasing multiplicity of complexly lived, structured and experienced nights across the globe. This paper looks to retrieve the concept of night as frontier by drawing on postcolonial theories to generate a more subtle conceptualisation of ‘frontier’, while also arguing that recent research reveals that this frontier is now fragmenting. By exploring research into a series of core themes – artificial light at night and darkness; night-lives; and global nights – I then explore what such an understanding of night allows us to say about current research. As nocturnal social science continues to mature, a more critical eye will need to be paid to the complexity of shifting power relations and identities within this fragmenting nocturnal frontier.
Keywords: Society; geography; social science
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