Material and Methods

Birds examined for haematozoa were collected by trapping, by searching beaches after storms, and in the case of unprotected species, by shooting. Useful material was obtained from birds trapped by members of the Ornithological Society of New Zealand during routine banding work. Blood smears were taken from the birds concerned by pricking one of the superficial vessels of the leg, this method being used with large numbers of even small species such as Zosterops lateralis (silvereye) without causing them any ill effects. It should be made clear, however, that this method, although desirable in the case of rare and protected birds, is not productive of the best results. Some Leucocytosoon and Toxoplasma infections are liable to be overlooked unless smears are made from the heart blood, as is suggested by the fact that the only one of 124 specimens of Zosterops lateralis page 3 found positive for Toxoplasma was the only specimen from which heart blood smears were examined.

During the 1947 shooting season, blood smears were taken from game birds by visiting shooters' camps in the vicinity of Lake Wairarapa. The discovery of a very light Plasmodium infection in an example of Anas poicilorhyncha (grey duck) led to the development of a small self-contained collecting outfit, numbers of which were distributed among the members of the various Acclimatization Societies in time for the 1948 shooting season in an effort to obtain more material of the haematozoan. Each set consisted of eight numbered slides, a spreading slide, and a glass rod for transferring blood from specimens to slide, packed together with a printed sheet for field notes and a printed sheet of directions in a small cardboard box. Although no additional positive slides were so obtained, and many of the slides returned to the laboratory were too dirty or too poorly prepared to be of use, sufficient usable smears (some 60 per cent of the total of 640) were returned to recommend the distribution of collecting sets to interested laymen as a useful auxiliary to other collecting methods in haematozoan surveys.

Thin blood and organ smears were made on 3 in. × 1 in. microscopic slides, air-dried, fixed in absolute methyl alcohol, and stained with Giemsa. They were left uncovered and examined under a x5 ocular and a x97 oil immersion objective. All figures were drawn with the aid of an Abbé camera lucida at a magnification of 2,400, a x15 ocular being substituted for the x5 used in searching.