Paternal care and a lack of.

Our resident blackbird is an exemplary father, spending every minute of daylight collecting food for his demanding family in the nest. Being a Scottish blackbird he is very keen on his morning porridge oats.

In total contrast, the local male eider ducks are terrible fathers. As soon as their mates are incubating, the drakes are off, looking for further sexual opportunities, and have no interest whatsoever in feeding their mates or caring for the ducklings when they hatch. The mothers feed rarely during incubation and as a result are in an emaciated and very weak state when the young finally hatch. Once on the river, mothers and failed breeders gather together, to form a creche, and cooperate in protecting the ducklings from marauding gulls. The "extra" shows a very small creche; In good breeding years, which are getting increasingly rare, creches can  be very much larger, containing many tens of ducklings.