4. RESULTS & DISCUSSION   continued

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4.3 Peregrine elevation cut-out

In the past two years, a reasonable amount of this research has concentrated on cliffs above 1300m. Many cliffs and rocky outcrops above this elevation have been visited with no success in locating eyries. The alpine zone above 1300m tends to be exclusively kestrel habitat. A few brown falcons live above this level as well as wedge tailed eagles. This study has not identified peregrines nesting nor utilising these higher altitudes outside the breeding season. The question is, why are there no breeding peregrines above this elevation? A number of possibilities have been considered:

	4.3.1 Lack of prey In timbered areas up to around 1800m, bird life during the peregrine breeding season is very good as the alpine trees and shrubs are flowering. With this, large numbers of honeyeaters of all types and sizes migrate. Currawongs, crow and other such prey are present at these altitudes, enabling a food supply for peregrines. In most areas studied, the higher altitude cliffs were usually on large hill faces that may start at 600m and rise to 1600m or more. This would give peregrines possibly two thirds of their home range in a zone where peregrines are successfully breeding elsewhere. For this reason, it is considered that lack of prey is not the reason for the lack of peregrines beyond this 1300m altitude. 4.3.2 Climatic conditions (temperature and cloud inversion) It is suggested that it is cloud inversion that is the cause of the non-existence of breeding peregrines above 1300m. Comparison of two meteorological sites, Tantangara and Cabramurra, were used to evaluate weather at altitudes around 1300m.
		4.3.2.1 Temperature Before going into the individual climatic conditions of Tantangara and Cabramurra the geographic differences between the two areas needs to be clarified. Cabramurra is situated on the western side of the Great Dividing Range whereas Tantangara is on the eastern side of the divide. Because of this, on any day there can be a variant in weather. Tantangara is in a cold air drainage area whereas Cabramurra is on top of a mountain. The distance between the two sites is approximately 28km. With Tantangara being a cold air drainage area this is reflected by its lower average minimum temperature compared to Cabramurra which is at 1450m (see chart No 3). It should be noted that peregrines are breeding successfully in the Tantangara area albeit below 1300m. Temperature can be dismissed as being the governing factor for the elevation cut-outs for peregrines breeding. In terms of the peregrines' ability to breed, temperature variations between the two meteorological sites during the breeding months (September, October, and November) are not great (3c).

Chart 3: