Broedvogeltelling op Syltefjordstauran (Finnmark, Noord-Noorwegen) in mei 1989

From the 12th to the 16th of May 1989 the birdcliff of Syltefjordstauran in the north-east of Norway (figure 1) was counted. The cliff is about 4 km long and 150 m. high, facing south-east and consists of mainly sandstone. It hosts Norway’s largest colony of Kittiwakes and the world’s northernmost Gannetry. Thanks to the structure of the cliff and the favourable weather conditions only about 5% remained uncounted by a lack of appropiate observation points. Breeding Shag, Cormorant, Great Black-backed Gull and Black Guillemot were observed but not counted. The results are as follows: 413 occupied nest sites of the Gannet. The error in this figure is negligable, since the colony can be studied at close range. Figure 1 shows the rapid growth of this colony since it was founded in 1961. 139,643 occupied nest sites of the Kittiwake. Samples indicated 5% underestimate due to counting in groups of 5 or 10. Compensation for this and for the 5% uncounted cliff yields an estimate of the real number of breeding pairs between 150,000 and 155,000. In 1964 this number was 140,000. 155 individual Razorbills. Due to their choice of nest sites in crevices or under overhanging rock this number is most probably a rough lower bound on the real number of Razorbills at the cliff. A comparison with the 1,200 Razorbills counted in 1966 is therefore debadable since we do not know by which method this number was established. 3,408 individuals of the Guillemot and the Brunnich’s Guillemot together. Samples taken to investigate the ratio between the two species are presented in table 1. The species seemed to cluster, so that the overall ratio of 1.7 Guillemots/Brünnich’s Guillemots may be a rough approximation of the real ratio. Compensation of the 5% uncounted cliff and application of the ratio 1.7 yields 2,250 Guillemots and 1325 Brunnich’s Guillemots. From table 2 we see that the number of Guillemots has again slightly decreased since 1987, following dramatic decline in the population in that year. No Puffins were observed on the cliff, whereas in 1966 100 pairs were reported.