I've only captured Eagles in BI and when I got the acknowledgement it said that the eagle was taken to a nearby city I owned and the Romans would make great efforts to get it back.

Recently I took down 3 1st Cohorts in one battle but nothing was said (I couldn't believe it). This time I wasn't near any city I owned so could this be a factor? Does there need to be a place for the eagle to go? Has anyone else noticed this or is it just an odd coincidence?