@jbn, I believe there are over 20 zoos in Europe displaying them (only 2 in UK, which may explain TLD ) and they are pretty common in private hands. But they are also the most common of their family in Europe.... But probably in the US it is the other way around with species being really common in the wild in Europe, being rare in the US.
Hehe, as I alluded above I didn't actually mean they were unusual in captive collections - I literally meant the cardinals are an unusual group of birds being as they display convergent evolution when compared with not one, but two separate groups of Old World passerines, the buntings and the finches - but unlike those two groups, which *are* represented in the New World, there are no cardinals in the Old World.