According to Okia et al. 1971, almost 1/2 of bulbuls had Zika. 

My own research has led me to believe that it is more than coincidence that red-whiskered and red-vented bulbuls are introduced species precisely where Zika has hit communities the hardest (including Miami-Dade, Harris County, Houston, and northeastern Brazil).

According to Serpa 2008, Mallet-Rodrigues et al. 2008, Gagliardi 2011, Simon 2010, and Lima 2006, introduced species of red-whiskered bulbuls were sighted and appear to be established in northeastern Brazil—specifically the states of Rio de Janeiro, Espírito Santo, and Bahia.

Zika shares the phylogenetic clade alongside West Nile virus with over 97 percent nodal support. Over 300 birds carry West Nile virus. One bird can infect 100s of mosquitoes. And some of those birds can amplify a virus a billion times more than a human.

With 17 citations: http://www.infobarrel.com/Red-Whiskered_Bulbul_Zikas_Ideal_Reservoir_Host