- They are large birds with a distinctive forked tail
- Their wing- span is up to 150 centimetres (5 feet)
- Including their long tail, their body length is approximately 60 cms (2 feet)
- Their average weight is around one kilogram (2.20lbs)
- Females are slightly larger than males
- The plumage of both sexes is identical, adults being identifiable by their silvery- grey head and generally richer, reddish- brown, colouration- particularly noticeable on the upper tail
- Younger birds are a more uniform brown colour and the fork in the tail is less pronounced

Image by Mark Hughes