Breeding of the Peregrine Falcon Falco peregrinus: II. Weather, Nest Quality and the Timing of Egg Laying

Summary

Olsen, P.D. & Olsen J. (1989). Breeding of the Peregrine Falcon Falco peregrinux. II. Weather, nest quality and the timing of egg laying. Emu 89, 1–5.

Peregrine Falcons near Canberra bred slightly earlier following a dry winter. The laying season was shorter and ended earlier when there were many raindays between June and September. The number of raindays in July and August accounted for 77% of the variation in the length of the laying period. A warm, dry winter was associated with a lengthened laying season. A longer, slightly earlier, laying season resulted in more pairs laying and therefore more young raised by the population. Late-laying pairs were only slightly less successful than early-laying pairs. Pairs with alternative nest(s), or with a well-drained nest, had a longer egg laying season, and more of them laid, than other pairs. Thus, pairs holding a territory with a high quality nest were advantaged over those that were not, because of the direct effect of rain.