[The diurnal activity of starlings (Sturnus vulgaris) and snow-buntings (Plectrophenax nivalis)].

Starlings (Sturnus vulgaris) and snow-buntings (Plectrophenax nivalis) were observed during their period of reproduction. The flying-activity at the nest-hole was automatically recorded.The amount of activity of starlings during feedingtime is dependent on the number of nestlings.The activity-pattern of starlings changes in the course of spring and early summer: 1. At pair-time starlings normally arrive at the nest-holes in the early moring, and one steep peak of activity is characteristic for this time. 2. In the course of nest-building and egg-laying the activity in the morning, decreases; in the afternoon there is an increase. 3. During incubation, the activity is nearly the same the whole day long, though a weak peak of activity is recognizable in the morning and in the afternoon ("bigeminus"). 4. As soon as the young birds are hatched, and as long as they are still small, adult activity is distributed fairly uniformly throughout the day. In the 1./8, 3./8, 5./8, and 7./8 of each day, however, the activity is relatively high (activitypattern with 4 peaks). 5. The older the young birds grow, the more activity the adults show in the morning. There are distinct peaks of activity in the 1./8 and 7./8 of the day, but in the 3./8 and 5./8 they become less marked. 6. The fewer nestlings there are to be fed, the higher and steeper becomes the relative activity-peak in the morning, but not the absolute paek. The beginning and the end of activity of the starlings and snow-buntings change in a characteristic manner in the course of the reproduction-time.During feeding-time, the degree of activity, the middle of the resting-time, the length of the bird-day, and the α:ϱ-quotient of starlings and snow-buntings change in the same manner: 1. The amount of activity, the length of activity-time, and the α: ϱ-quotient have a distinct peak in the course of each reproduction period. 2. The middle of the resting-time shifts to an earlier daytime. Similarities and differences between starlings in Middle-Europe, starlings in the arctic, and snow-buntings of Spitsbergen are discussed.