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Figure 1 | Journal of Circadian Rhythms

Figure 1

From: Natural daylight restricted to twilights delays the timing of testicular regression but does not affect the timing of the daily activity rhythm of the house sparrow (Passer domesticus)

Figure 1

Effects of natural light (NDL) during twilight periods alone on body mass (a), timing of testicular regression (b), and changes in beak color (c). Of two groups of male sparrows (n = 6 each) with large testes housed in the outdoor aviary, beginning in the third week of April 2002 for 8.5 weeks, one group of birds was removed daily from the aviary at the time of sunrise and kept in a room under constant darkness (DD) until sunset, when it was returned to the aviary. The other group remained in the aviary, received NDL all day and served as control. Note testicular regression only in birds that experienced NDL all day.

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Journal of Circadian Rhythms

ISSN: 1740-3391