How do scientists know that robins are the preferred host for West Nile virus?

Scientists have determined that robins are the preferred host for West Nile virus through several studies that track the virus's transmission and its effects on different bird species. By analyzing infection rates and observing the virus's replication in various birds, researchers found that robins have a high viral load that facilitates the spread to mosquitoes, which are the primary vectors for the virus. Additionally, field studies and laboratory experiments have shown that robins are more likely to become infected and contribute to the amplification of the virus in the environment compared to other bird species.