A Móra Ferenc Múzum Évkönyve, 1972/73-1. (Szeged, 1974)
Jakab Béla: The question of classification of the sea swallow (Sterna hirundo L.) eggs
Dobay L. Madártojás meghatározó. — Budapest, Madártani Intézet. Kézirat. Jakab, B. (1962), An Oological Measurint Method for the Percent Demonstration of the Curvature of Egg Shell. — Acta Zoologica. 8 3—4. Budapest. Jakab, В. (1963), A New Measuring Apparatus to Demonstrate Sectional Curvature of Egg Shell in Per cent. — Acta Zoologica. 9, 3—4. Budapest. Jakab В. (1964), Az új oometriai eljárás tudományos és gyakorlati alkalmazása. — Állattani Közlemények. 51, 1—4. Budapest. Jakab, B.—Tamássy, E. (1968), Oometrically Demonstrated Correlation of Efficient Chicken Hatching and the Grade of Curvature of Egg Shells. — Acta Agronomica. 17, 3—4. Budapest. Jakab В.—Tamássy J. (1969), A madártojások alakmeghatározásának kérdése. — Vertebrata Hungarica. 9, 1—2. Budapest. Kéve, A. (1958), Charadriiformes — Lilealkatúak. — In: Székessy, V.: Fauna Hungáriáé. 21. Aves. 6. Budapest. Mákatsch, W. (1952), Die Vögel an Seen und Teichen. Radebeul-Berlin. Makatsch, W. (1967), Kein Ei gleicht dem Anderen. Radebeul. Prynne, M. (1963), Egg-Shells. London. Schönwetter, M. (1960—1967), Handbuch der Oologie. Berlin. THE QUESTION OF CLASSIFICATION OF THE SEA SWALLOW (STERNA HIRUNDO L.) EGGS by Béla Jakab The sea swallow (Sterna hirundo L.) together with mire-crows (Larus vidibundus L.) live in nests near Szeged, on Fehértó Reservation territory. The material of Fehértó in Móra Ferenc Museum, nests near Szeged, on Fehértó Reservation territory. The material of Fehértó in Móra Ferenc Museum, Szeged, through Beretzk Peter's collection presents a rich picture of the old avifauna of the reservation. We made our research on 91 sea swallow eggs in the egg-collection in order to determine the specific feature of these eggs. Referring to literature and through the eggs of Sterna hirundo L., Sterna paradisea PONTOPPIDAN and Sterna dougallii MONTAGU in the collection of the museum we pointed out how extremely various the colour of these eggs is, within species and among the species of the Sterna genus as well, how considerable the transition between the colouring and the design is, mainly in the hirundo group. That is why the colouring and the design can't serve as a specific feature. The shape of the egg is very similar among the species of the group. The usual size of the eggs is nothing to the purpose, either. The measuring process, however, by means of which the degree of inflexion of the shell segments and shell phases lengthwise can be defined (Jakab 1962,1963,1969), even here yielded a result. The results are given by the cursors of inflexion, measured with shape 25 mm in diamètre, so that we sink the eggs by their sharp ends into the elliptic opening of the shape (HL 25 ). The value of the cursors of inflexion thus measured on the sea-swallow eggs is higher in all the order of magnitude of the eggs, than those measured on the polar tern eggs (wich is the most difficult to distinguish from the sea swallow eggs). It means that the arch of the shell towards the sharp end of the egg is more inflexed on the shell-segment of the tern egg, being at the 25 mm diamètre shape. This part of the eggs is vaster in all respects, opposed to the more pointed and plainer arched formation of the polar tern. The function diagrams shows the indexnumbers of inflexion belonging to different order of magnitude and to different sizes of breadth — and they show clearly their specific correlation of direct proportion. 235
