Bird sampling
Point-counts were also implemented to quantify the degree to which birds
affect butterfly populations in urban and rural habitats (Huff et al.,
2000). Using binoculars, two people recorded species and number of
individuals in point-count surveys for 5 minutes in each compass
direction, starting with North, and rotating through East, South, and
West. The total survey time was 20 minutes, whereby five minutes in each
direction within a small sampling site helps to avoid counting the same
individuals twice (Lee and Marsden, 2008). The start and end times were
recorded, as well as the species and number of individuals. Bird
distance to the habitat was also estimated and assigned one of the four
categories: (1) 0 to 50 m from the station centre point: birds up to top
of vegetation or canopy; (2) > 50 m from the station centre
point: birds up to top of vegetation or canopy; (3) Fly-over associated
with the habitat: birds above the top of the canopy; (4) Fly-over
independent of the habitats: birds above the top of the canopy, which do
not seem to be interacting with the environment (Huff et al., 2000).
Observations took place between 05:30 and 10:00 with wind < 30
km h-1 and when there was no rain or fog. The
“Birds of Greece ” was used for species identification (Nason,
2020). This sampling method was conducted at each site in May and June
for a total sample size of n = 36.