Tichodroma (Dec 2018)
Sojky vytvárajú vnášaním dubov do pásov krovín nové habitaty pre lesné vtáky v poľnohospodárskej krajine / European jays create new habitats for forests birds in agricultural land by spreading oaks into shrub belts
Abstract
The European jay (Garrulus glandarius) is a very efficient acorn disperser, and most of the Quercus seeds, especially at medium to large distances, are jay-dispersed. Jays disperse acorns effectively also into shrub belts in agricultural land, and thus they create new habitats. Such new structures enable to some forest birds, that do not nest within treeless shrub belts, to penetrate into shrub belts with oaks and to spread in open agricultural land. We compared the species composition of breeding bird assemblages in three hazel-blackthorn shrub belts with different proportion of oaks (belts B–D) with those in a shrub belt without trees (belt A) and at an oak forest edge (belt E). From 21 bird species nesting in shrub belts A–D, eight ones were forest birds (Parus major, Sturnus vulgaris, Jynx torquilla, Coccothraustes coccothraustes, G. glandarius, Oriolus oriolus, Phylloscopus collybita, Streptopelia turtur) which did not nest in the shrub belt A without trees. Only one forest bird species (P. major) nested in the shrub belt B with low proportion of oaks, and 6–8 ones in the shrub belts C and D with higher proportion of oaks. On the other hand, up to 11 bird species nesting at the oak forest edge (belt E) did not nest in the shrub belts with oaks in open agricultural land.
