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.

OTHER LOVEBIRDS
With lovebirds that have no clear external sex differences, sexing is more difficult. People have used a number of methods, such as those listed below.
Body build. Females tend to be sturdier and heavier in build than males. This is not an absolute, however. With variations in nutrition, selective breeding, and other environmental factors, lovebirds of the same sex may differ considerably in build.

Coloring. Male lovebirds often are thought to have somewhat more intense coloring than females. Again, this is no sure thing. Feed, breeding, climate, and geographical variations can significantly affect coloring.

Nest building. construction activities of the female are more intensive than those of the male. The hens gnaw out nest holes in thick branches and trunks, and they collect strips of bark for nest building. Perhaps as a result, they have a stronger grip than males, and if you handle them, they'll bite harder. Males tend to leave most building activities to the female, and they support the process mostly by feeding their female partner. Again, don't take this as an absolute. I have known several males that took an extremely active role in nest building, both in captivity and in the wild. Some people say that females tend to sleep inside the nest block and the male on top of it, but I think that's far from true.

Perching. Females sit more broadly on their perch. Their legs are spread apart more than those of the males if they are relaxed and healthy.

Tail flaring. The tails of the sexes flare differently when they meet for mating and other social activities. The flare is slight, but distinct by sex. A female gives you the impression that all the tail feathers are the same length; a male holds the tail feathers slightly nipped. The male, therefore, seems to have a rounded tail, and the female appears to have a tail that is trimmed straight across. I consider this a fairly reliable indicator.

Anal inspection. Lovebirds have two thin, long, small bones, called ossa pubes, on the ventral side of the pelvis. These bones slant downward and to the rear. In grown females that have come into breeding condition, these two bones become more elastic and spread outward more, due to the effect of estrogen hormones. The bones are clearly further apart, and you can feel this with your fingers. In males, by contrast, the space between the two bone remains quite narrow; it seems as if the  two bones lie right up against each other. This technique works only while females are sexually active. Hens that are not in breeding condition have their bones tightly joined, just like males.

Endoscopic examination (laparoscopy). Under local anesthetic, a qualified veterinarian makes a small (few millimeters) incision in the left side of the lovebird's belly just bellow the ribs and inserts an optical fiber instrument. The left side is used because, in the hen, the one functional ovary is just left of center. With the instrument, which is known as a laparoscope, the veterinarian can look inside the lovebird. The instrument consists of a long, narrow, flexible tube with a system of small mirror, and an optical fiber to transmit light. It is thus possible to determine the sex of the lovebird. The male testicle looks cylindrical or elliptical, whereas the single functional ovary in an adult female looks like a little cluster of grapes.

This technique works best for large birds; it is also satisfactory with masked lovebirds. Others are too sensitive to shock and stress to tolerate the laparoscope.

Scientific examination. relatively recently another method of sexing monomorphic bird species has been developed. Zoogen Inc. has isolated a recombinant DNA probe (pMg1), which is associated with the sex chromosomes of diverse groups of lovebirds. The probe is a small segment of DNA made up of the same sequence as the target sample. By analyzing the DNA sequence revealed by using the pMg1 probe, the sex of the lovebird being tested can be accurately ascertained. As the DNA of an individual lovebird is constant throughout its life, this technique is not dependent on age or reproductive cycle.

The blood sample collection process is quite simple; a thin needle is inserted in a blood is collected. That, as far as the lovebird is concerned, is all! No anesthetic is necessary and the whole process takes less than ten minutes. The test is less expensive than laparoscopy, and is a noninvasive procedure with no postoperative requirements. Further information may be obtained from your veterinarian or direct from Zoogen Inc.