O. Gy. Dely szerk.: Vertebrata Hungarica 20. (Budapest, 1981)
Horváth, L.: Communities of breeding birds in the peaty forest at Tabdi 69-74. o.
uniting lies in the leading species and of the permanent of this community. The River Warbler is the most characteristic species of the Tabdi Forest, as also In the marshy alderwoods of the Hanság and Ocsa. The number of the breeding pairs - computed on the basis of the singing and territorial behaviour of the males - can be estimated at 10-15 pairs. To actually locate the nests would be disastrous for this species, as I have experienced in the 1950' s during my investigations of the life history of the River Warbler, because the disturbance of the vegetation frightens away the birds and results in the destruction of the clutches. I desist therefore from searching for the nests - but merely for those of this species - in my estimation the sole certain method to establish the number fo the breeding pairs. The previous statement is valid also for the Balckcap, the permanent nember of this community, as already set forth in detail in its characterisation (1/7), with the restriction that it has bred in this community also In lesser numbers. In connection with the subordinate members of this community I was able to establish the followinges there have bred in the Tabdi Forest in this year (1979) 3-4 pairs of the Garden Warbler, 2 of the Icterine Warbler, 5-6 of the Greenfinch, 2-3 of the Nightingale, 2 of the Spotted Flycatcher, 1 pair of the Lesser Woodpecker. These numbers are relatively low, and also the following species have bred here in lesser numbers than it might have been expected: 8 pairs of the Turtle Dove, 6 of the Hooded Crow, and 4 each of the Wood Pigeon and of the Short-toed Tree Creeper. The strict protection of the raptors may be the cause of the fact that one pair of the Hobby, two paris of the Buzzard and one pair of the Goshawk have bred in such a small forest. I must mention the nesting of a pair of Willow Warbler despite the fact that the area does not conform with its requirements; furthermore, there were seven pairs of the Red-backed Shrike which found the bushy forest edges highly suitable. Perhaps the following remark should be made after the discussion of the next and last community, nevertheless - to avoid any misunderstanding - I should like to state now that the two communities so far discussed are, though inhabiting the same wood, peculiarly isolated from each other, nearly as much as those of the peaty forest from the turfy meadow. There are contact influences of course (Blackcap, Turtle Dove, Nightingale), but in the case of these species the differences in frequency are also very striking. Such weak influences exist also - naturally - between the forest and the meadow when they are in direct contact and there occurs then the physical possibility for nesting in both areas (e.g. Hooded Crow on a meadow tree, Red-backed Shrike in a meadow bush, Turtle Dove also in a meadow bush, Wood Pigeon on a meadow tree, Hobby also on a meadow tree). In the order of sequence, the third breeding community is that of Buteo buteo bearing the serial number 1/9 In my above cited paper (Horváth, 1956). The short characterization of the breeding area of this community runs as follows: "Boggy woods on plains and mountain old beech forests". On the whole therefore two woodlands of different aspects are united with the Buzzard as the leading species and with the Goshawk as the permanent member determining the community. Apart from two species mentioned above, this community has a number of members in booth kinds of the forest nevertheless some of the species occur only in one or in the other, at least In Hungary. In addition there are certain species whose presence depends on the geographical position and on the extension of the forest in question. But let us see some concrete examples. In the alderwood marshes at Ocsa there occur only the Black Kite (Mil vus migrans ), the Heron (Ardea cinerea ), the Hooded Crow (Corvus c. comix ) and the Tree Sparrow (Passer montanus) beside the leading species and the permanent member, while the big raptors and the large bodied birds - as the Black Stork and the Eagle Owl are in general absent, contrarily to the situation prevailing in the alderwoods of the Hanság; this is due to the smallness of the forest, the proximity of the human settlements and the restricted extension of the neighbouring turfy meadows. What is acceptable in the comparison of the two former investigated marshy forests (Ocsa, Hanság) in increasingly valid for the bird life of the much lesser Tabdi Forest. After such precedents the expectable subordinate members of this community would, in order of their importance (characteristically and not at all quantitatively), be as follows: the Black Kite, the Tree Sparrow, the Heron, the Hooded Crow and the Woodcock (Scolopax rusticola) . Though the Black Kite - a highly characteristic and ommon bird of the galery forests of our larger rivers (Danube, Tisza) is present also in the marshy alderwoods but in small numbers only. It seems a peculiar chance that it has bred only in one pair in the alderwoods at Ocsa (in the NAGY) and also In the peaty alderwoods of the Hanság (in the KAPUVÁRI ÉGER), just as In the Tabdi Forest. The Heron "equalizes" the Hanság and the peaty region between the Danube and the Tisza River, because In both areas there is one small-numbered (8-10 nests) colonies each: one in the "Csikós Éger" at the
