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Kniprath, E.

Beobachtungen mit Nestkamera an einer Brut der Schleiereule Tyto alba im Kanton Aargau – Die Zeit bis zum Schlüpfen des ersten Kükens.

2019

116

179–205

Key words
(von 1994 bis 2006 vergeben)

Brutzeit, Verhalten, Nistkasten, Gelege, Brüten, Balz, Brutpause, Kopulation, Ernährung

Schlagwort_Vogelart
(wissenschaftlich)

Tyto alba

Schlagwort_Vogelart
(deutsch)

Schleiereule

Aargau, Schweiz

deutsch

Abhandlung

Observations by nest camera at a brood of the Barn Owl Tyto alba in the canton of Aargau – The time up to the hatching of the first chick. – From a collection of approx. 2 million individual photos from a nest camera of a Barn Owl brood in 2012 in the canton of Aargau, Switzerland, the events from the time before and during the brood up to the hatching of the first chick were analysed. For the pre-breeding period, photos were available from day –43 to –24 before the first egg was laid, and a second series of photos started from day +5. From day –43 to –33 the pair spent the daylight hours in the nest box together. On days –32 and –31, there was a nocturnal visit of a foreign owl in the nest box, leading to aggressive behaviour. Following this incidence, the male did not appear in the box for several days. On day –22, the first complete copula took place in the morning. At the start of the second series of photos, the female already incubated three eggs. While the female sat on the nest, it often loosened the underground material of pellets and faeces by digging and tearing with the beak, sometimes creating a small wall around the clutch. The female left the clutch on average 7.00 min per night and stayed in the entrance or outside the box (not visible for the camera). The first chick hatched after an incubation period of 31 days. Two behavioural elements of the owls played a special role: humping and ducking. Humping was shown mostly by the male in the time before egg laying started, primarily with the appearance of the female; rarely also the female humped. It is therefore interpreted as a gesture of humility towards the partner. Ducking was shown exclusively by the female, expressing her willingness to copulate. During 39 % of its visits at the nest box, the male brought prey. Most arrivals of the male were followed by copulations, independent of whether or not it brought prey. 91.6 % of copulations took place on the clutch. On 15 occasions during the day, the male ate itself from the prey.