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WINDOW F R A M E S
NORTH LtDGK Fig. 1 Chart of Kittiwake nest sites in 1985. The numbers beneath the nests are the nest number for that site. The numbers above the nests are the number of young for that nest.
Table 2 shows that the average number of young per nesting attempts is a shade over one per nest. 1t can also be seen that the averages for the newer sites are higher than for the original east ledge site. This is possibly because the birds at the original site are older and coming to the end of their most fertile period. One would have thought, however, thdt this would have been offset by the fact that some of the birds at the newer sites are younger and more inept breeders. This is only hypotheses and could be entirely wrong. The low average for the window frame site is possibly due to it being the least desirable site and therefore attracts more of the younger birds which are just beginning their breeding life. Certainly a greater percentage of nests there never produce young or lose them over the edge (a rare occurrence). Several nesting attempts are started but the nests are not completed, which points to younger inexperienced birds being involved. These nests have never been counted in my figures. I have only included nests which are complete and capable of holding eggs whether they do or not. The periods used in Table 2 are those for which reliably accurate figures exist. A glance at Table one shows that earlier numbers of young are either based on estimâtes, or for some years are not known. Düring the first six years breeding success was so low that its inclusion would have had an unrealistic effect on the Overall averages. Accurate figures for nests and young are produced by drawing an annual chart of each nest site and marking in each nest. Numbers of young are then indicated for each nest, with plus or minus corrections being made at subsequent Visits. Fig. 1 shows the chart for 1985. Breeding Season Nest building begins during March and April. A search below the nest sites reveals a diverse variety of materials which the birds drop. Seaweeds, including hydroids, and grass make up the bulk of the debris, and lengths of plastic string are commonly found. The most outlandish thing I have ever seen actually in a Kittiwake's nest is the brass ferrule, with part of the glass attached, of a broken electric light bulb. I have occasionally watched Kittiwakes pulling up grass near Ness Point. This involved a 69