Naminės pelėdos (strix aluco l.) mitybos tyrimai Šilutės rajone

• Main Author: Brazaitė, Monika Jurgita
• Other Authors: Dumčius, Algirdas
• Format: Bachelor Thesis
• Language: Lithuanian; English
• Published: Institutional Repository of Siauliai University 2012
• Subjects: Tawny owl; pellet; nutrition studies; Common vole
• Online Access: http://su.oai.elaba.lt/documents/1952107.pdf; http://su.lvb.lt/SU:ELABAETD1952107&prefLang=en_US

Nutrition studies of the towny owl are carried out to ascertain the kinds of prey of the towny owl in Silute region. Such studies have not been done in this region so far. They are important to clear out the nutrition pecularities of the towny owl and one of the best ways to find out the variety of species of small mammals. The aim of the research is to carry out the nutrition studies of the towny owl in Silute region on the ground of the remains of the prey in the owls pellet. There were tasks for the work: to make and put up the bird houses for the towny owl, to collect the litter from the bird houses and the rumination near the bird houses, tree holes and dawn places, to investigate the physical parametres of the rumination, to separate fragments of the prey skeleton from the rumination, to estimate the amount of the prey, to describe the remains of the prey on the basis of the cranometric differences, to make the calculations of the variety of the species. Three bird houses were put up in Silute region. The towny owl was hatching in one of them. The litter from the bird house and 66 rumination parts from the dawn places were collected. The averrage length of the rumination is 3,9±0,93 cm and the weight is 2,4±0,88 g. The averrage amount of the prey in one pellet is 2,1±0,82 units ( max. 4). 141 individuals were identified in the rumination. 166 individuals which belong to small mammals were identified from all nutrition remains. The biggest part in the towny owls nutrition is made of small mammals 89,2% and birds made the smallest influence on the tawny owl΄s nutrition 6%, insects 4,2% and amphibia makes 0,6%. The dominating kind in the towny owl΄s nutrition was the common vole 28,3%, and subdominating species yellow-necked mouse takes 9%, a root vole 8,4%. The biomass of the common vole is 27,3%, the yellow-necked mouse 14,8% , the root vole 14,2%. There was one dominating species in the rumination (a root vole) which domination index is C=0,23. The variety of species in the nutrition of the towny owl is average (H= 2,8). There is no domination o fone kind in the litters (C=0,15), there are several dominating species. The variety of species in the litter is smaller than in the rumination (H= 2,37). A common vole dominates in the nutrition of the towny owl in Silute region (28,3%), but in the other studies in different parts of Lithuania the dominating species is a bank vole (31,4%). From the European investigaters we can see that in the nutrition of the towny owl the dominating species are a yellow-necked mouse, a root vole and a bank vole, but the common vole is seldom dominating.