The migratory birds are central to the epidemiology of many diseases like West Nile virus (WNV), Avian flu, Lyme disease and Salmonellosis. They carry these pathogens with them, either as a reservoir host or by dispersing infected arthropod vectors. Birds contribute to the global spread of emerging infectious diseases in a manner analogous to humans travelling on aircraft. Over the last two decades this problem becomes the main concern for many experimental and theoretical biologists. But still now little effort has been made to study the epidemics caused by the migratory birds using mathematical models. This book is one such effort where the problem is studied through mathematical models. It also provides the methodology to solve such models through different mathematical tools. The book presents simple, but realistic, models involving ordinary differential equations, stochastic differential equations and delay differential equation, to study the relation between the migratory birds and the diseases. The models and their analysis presented here not only help the modelers working in this field but also open new doors to the experimental biologists working in this field.