3. STUDYING PEREGRINES   continued

3.1 Locating cliffs and nests - NOT PUBLISHED HERE   3.2 Accessing cliffs   3.3 Collecting data   3.3.1     Prey remains   3.3.2     Clutch sizes   3.3.3     Eyrie   3.3.4     Adult birds   3.3.5     Photography and remote camera work   3.4 Equipment used

3.3 Collecting data

3.3.1 Prey remains As many prey remains and casts as possible were collected at all sites. These were collected from either the nest ledge or from around the cliffs where remains were strewn. Fledglings tend to congregate on the top of the cliff above a nest site. Many prey remains and casts can be collected here after the breeding season. It is also an indication that the falcons may have bred that year. The amounts collected ranged from just a few feathers to, at one nest ledge, several hands full. All remains were placed in zip lock plastic bags and labelled, indicating date and site. These were then sent to a biologist/environmental consultant, Alison Rowell, to be analysed to determine the species hunted by the peregrine. Some sites were visited both early and later in the breeding season. Remains and casts were collected each time to enable a comparison of prey species at different times of the season. Generally, the male is the sole food provider earlier in the season whereas later in the season both parents provide food. It was expected that by collecting data at different times during the season, any differences between the prey species sought by males and females would be revealed. 3.3.2 Clutch sizes At each site, where possible, the number of young and eggs, including addled eggs (infertile or rotten eggs) were recorded. An estimate was made of the age of young, based on their stage of development. From this, lay dates were estimated. Some eyries were visited several times to determine the success ratio. back to top 3.3.3 Eyrie For each eyrie, the elevation and aspect was determined. Elevation was calculated by using both an altimeter and contour lines on topographical maps. Both methods were used to ensure accuracy. Aspect was determined from topographic back to top 3.3.4 Adult birds General information about adult birds was recorded, such as individual markings, the number of adult birds present, behaviour of the birds, and gender. back to top 3.3.5 Photography and remote camera work At various sites, photographs of cliffs, adult peregrines, eyries, eggs and young were taken. During 1997 a remote camera outfit was built and used to photograph peregrines on nest ledges. The equipment used included an Olympus OM10 camera with motor drive, a Trailmaster TM500 passive infrared unit, and a radio transmitting link between the two, so separation of the units was possible. The camera could also be placed on site and remotely operated from approximately 200m away via a transmitter.

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