Urban bird predation on horse chestnut leaf miner Cameraria ohridella in three Swiss cities

We established our study sites in the cities of Basel, Lugano and Zurich. We characterised urban tree cover of each city using a rectangular grid with squares of 100x100 m. Within each square, we measured the area covered by urban trees using the European Union's Copernicus Land Monitoring Service information, Urban Atlas Street Tree Layer 2018 https://doi.org/10.2909/205691b3-7ae9-41dd-abf1-1fbf60d72c8c.

Then we assigned each square to three categories of urban tree cover that roughly represented the main types of urban uses: 1) low cover, industrial/commercial areas, 0-20% tree cover; 2) intermediate cover, residential areas, 20-40% tree cover; 3) high cover, urban parks and cemeteries, 40-60% tree cover. <br/><br/> We measured bird predation rate on the non-native insect larvae of the horse chestnut leaf miner (HCLM) Cameraria ohridella, an invasive moth that lays eggs and completes its larval and pupal development stages within the leaves of the horse chestnut Aesculus hippocastanus.