Breeding biology of the Sardinian warbler

Abstract

The Sardinian Warbler Sylvia melanocephala is generally a bird of high maquis and other thorny scrub as well as gardens, fruit plantations, parks and light oak woods. Its status in the Maltese Islands has already appeared elsewhere.

This paper summarizes data from 343 nest record cards for the Sardinian warbler. Nest record cards, modeled on those in use by the British Trust for Ornithology, were introduced by the Malta Ornithological Society in 1967 but hardly any cards were filled before 1975 when, with the number of active ringers increasing, an effort was made to induce ringers to take an interest in them. Most ringers, however, still found it difficult to locate nests and apart from cards filled by the authors, very few were submitted by other members. In the breeding seasons of 1978-80 a special effort was made to complete as many cards as possible. 75 cards were submitted in the period 1967-77, 67 in 1978,128 in 1979 and 73 in 1980. This number is small; nevertheless, because of the detail the cards contain, it has been possible to produce an informative dossier.

Nests were mainly located by systematically searching bushes and its is likely that in the areas searched in 1978-80 very few nests were missed. Normally each area was covered every fortnight to search for new nests. Once located, nests were checked at least once weekly. The main areas searched were Ta' Qali, Buskett, Xemxija, and a few rocky valleys such as Wied l-Isperanza. Ta' Qali is a disused airfield and large parts of it were recently converted to agricultural land. Other extensive areas were planned with conifers - mainly Aleppo Pine Pinus halepensis and Cypress Cupressus sempervirens the latter acting as wind breaks. In spring 1980 most of the pine plantation, which had reached an average height of 1.5m, was inexplicably cleared. Buskett is a small area of mixed woodland, while Xemxija is a small plantation of Acacia Acacia cyanophylla, Tamarisk Tamarix gallica and Eucalyptus Eucalyptus amygdalinus. The acacia and tamarisk, in which the Sardinian warblers breed, had reached an average height of 4.5m by spring 1980. The rocky valleys were mainly low maquis and the vegetation was extensively damaged after the floods of October 1979.