With many species of lovebirds, sexing presents no problem. The sexes are clearly differentiated in outward appearance. Lovebirds can be classified on the basis as belonging to the sexually dimorphic group (clearly different); the intermediate group (harder to differentiate by appearance); and the white eye-ring group (no consistent difference).

THE SEXUALLY DIMORPHIC GROUP
Abyssinian lovebird (Agapornis Taranta) males have bright red feather on the forehead and a few more bright red little feathers forming a very narrowing around the eyes. females (hens) have a small, greenish eye ring and a green forehead of the same shade as the rest of the body. The male has brownish black flight feathers and lesser wing coverts; the female's are gray-brown, sometimes with black markings. In young females, these parts are greenish in color, but in young males these parts are black from the start. There is a slight weight differences between the sexes. Males lovebird average about 2.3 ounces (65 grams), and female average about 1.9 ounces (55 grams).

MADAGASCAR LOVEBIRD (Agapornis Cana)
Males have a completely gray head and neck. The underwing coverts are black. The female lovebird is entirely green here is no gray or black on her anywhere. There is no weight difference between males and females.

RED-FACED LOVEBIRD (Agapornis Pullaria)
Male lovebirds have an orange-red forehead and facial area, a light blur rump, and black flight feathers and lower wing coverts. The forehead and facial area are more orange than red.

THE INTERMEDIATE GROUP
Black-collared lovebird (agapornis swinderniana). Male and hen lovebirds are similar in appearance.
Peach-faced lovebird (agapornis roseicollis). Male and female lovebirds are similar in appearance, although many females have a paler head.

THE WHITE EYE-RING GROUP
Nyasa lovebird (agapornis personata lilianae). Male and female lovebirds are similar in appearance, although females often have more substantial beaks and are darker in coloration. There also is a slight difference in weight; males average about 1.3 ounces (37 grams) and females average 1.5 ounces (43 grams).
Black-cheecked lovebird (Agapornis personata nigrigenis). Males and hens are similar in appearance. There is a slight difference in weight; males average about 1.3 ounces (38 grams) and females average 1.5 ounces (43 grams).

Fischer's lovebird (agapornis personata fischeri) Male and female are similar in appearance. There is a slight difference in weight; males average about 1.8 ounces (50 grams), and females average 2 ounces (56 grams).
Note: Only females (hens) of the white eye ring group carry pieces of nesting material tucked under the feathers of the rump and the lower back.