Are there more ground-dwelling invertebrates inside than outside Grashopper Warbler Locustella naevia territories?

Abstract

I investigated differences in the number of ground-dwelling invertebrates inside as compared with just outside Grasshopper Warbler Locustella naevia territories, using glue traps. No statistical difference was found in the total number of invertebrates caught. There was, however, a significantly higher number of spiders within territories. This may indicate that spiders are an important food source for Grasshopper Warblers, or that spider density indicates other territory qualities for Grasshopper Warblers.