aviurba$mil
contains for each site, 11 habitat attributes describing the degree of urbanization.
The presence or absence of farms or villages, small buildings, high buildings, industry, fields, grassland, scrubby areas,
deciduous woods, coniferous woods, noisy area are noticed. At least, the vegetation cover (variable 11) is a factor with 8 levels
from a minimum cover (R5) up to a maximum (R100).
aviurba$traits
contains four factors : feeding habit (insectivor, granivore, omnivore), feeding stratum (ground, aerial, foliage and scrub),
breeding stratum (ground, building, scrub, foliage) and migration strategy (resident, migrant).