From the Pteropundit (Name used on trial basis)

Bird owners put on alert for Newcastle disease - 10/17/02 - NCTimes.net

While East Coast birds get to worry about West Nile, it's Newcastle in the West. It's a bad one, with a near-100 percent death rate in unvaccinated flocks. And there's an invasive-species angle here: it's thought that the disease was brought to Southern California by Amazon parrots, which are asymptomatic carriers of the disease.