Most bird species in North America mate for a single breeding season. Some may team up again the following year, just because both stay in - or return to - the same territory. Fewer than one-fifth of Song Sparrow pairs, like these
, are reunited. Hawks, eagles, and ravens have wide territories, thus few contacts with the opposite sex. Maintaining a relationship through the winter may assure breeding in the next season. Learn more this week on BirdNote
, Saturday morning before the 9 o'clock news.