2.5. Estimating the abundance of vespid species in the field
During 2020 and 2021 we installed baited traps (Avispa’clac®) to
estimate the abundance of vespid species in the nesting territories of
honey-buzzards. We surveyed 6 nesting territories in 2020 and 4 in 2021.
Seven baited traps were installed per territory as follows: 1 trap at 0
m from the nest, 3 traps at 500 m from the nest, and 3 traps at 1000 m
from the nest (Supplementary Figure 2 ). The traps were always
restricted to forest patches as it is the main hunting habitat of
honey-buzzards (van Manen et al . 2011). We used water, sugar and
yeast (5 / 2 / 0.06 kg, respectively) as a bait. Traps remained active
for 7 days in each survey. In 2020 we performed one survey in mid-July
and one in mid-August. In 2021, we performed two surveys in July and two
in August. Trapped insects were preserved in 70% ethanol until
identification.