Avian influenza virus (AIV) is an important public health issue
because pandemic influenza viruses in people have contained
genes from viruses that infect birds. The H5 and H7 AIV subtypes
have periodically mutated from low pathogenicity to high
pathogenicity form. Analysis of the geographic distribution of
AIV can identify areas where reassortment events might occur and
how high pathogenicity influenza might travel if it enters wild
bird populations in the US. Modelling the number of AIV cases is
important because the rate of co-infection with multiple AIV
subtypes increases with the number of cases and co-infection is
the source of reassortment events that give rise to new strains
of influenza, which occurred before the 1968 pandemic. Aquatic
birds in the orders Anseriformes and Charadriiformes have been
recognized as reservoirs of AIV since the 1970s. However, little
is known about influenza prevalence in terrestrial birds in the
order Passeriformes. Since passerines share the same habitat as
poultry, they