Monospecific Flocks:
Group sizes for parrots were counted from a canoe in the oxbow lake and
from the bank of the Manu River, primarily at dusk as groups flew to
roosting sites. These group sizes were averaged by species and combined
with spot-mapping locations along the trail system to estimate the
number of individuals per species on the plot. As per the original
study, we derived the average encounter rate of birds perched on the
plot per species per census route. We subsequently used these encounter
rates and multiplied by the average group size per species by the
fraction of the plot covered by each census route to derive density
estimates of each parrot species on the plot.