.--Southern
Lapwings (Belanopterus chilensis) in Chile usually begin mating in July (mid-
winter) in open and plowed fields. Four eggs are laid and both sexes share in
the incubation. In the Vanellinae, the incubation period varies from 20 to 30
days depending, in part, on the size of the bird (O. L. Austin, Jr., Birds o/
the world, New York, Golden Press, 1961; see p. 119). The Lapwing, Vanellus
vanellus, of Eurasia, which is similar in size to the Southern Lapwing, needs 24
days for hatching its eggs (E. T. Gilliard, Living birds o/ the world, New York,
Doubleday & Co., 1958; see p. 161). So far as we know, there are no published
records of the duration of incubation of the Southern Lapwing.
On 2 October 1961, four eggs of the Southern Lapwing were taken from a nest
found in an open field 3.5 miles south of Angol, Malleco Province, Chile, at 250
feet elevation. The eggs were hatched in an incubator made of a closed cardboard
box (4 X 4 X 10 inches) with a 60-watt light bulb for warmth. The temperature
inside the box varied between 34øC and 46øC.
We do not know whether the eggs had been incubated prior to 2 October, but
26 days after being placed in the incubator, two of the four eggs hatched. The other
two eggs had failed to develop. The baby birds were heard peeping four days
prior to hatching. The birds emerged from the eggs 30 and 70 minutes after the
onset of pipping. One newly-hatched bird weighed 20.5 g; the egg before hatching
weighed 25.5 g. After two days the birds weighed 18.5 and 17.5 g; and after four
days, 15.0 and 12.7 g, respectively. Neither chick was seen to take food or water
during this time and repeated efforts to elicit a feeding response failed. Both died
on the fourth da.
Lapwings are thought to be exclusively insectivorous, eating worms, beetles, and
other animals harmful to agriculture (J. D. Goodall, A. W. Johnson, and R. A.
Philippi B., Las aves de Chile, vol. 2; Buenos Aires, Platt Establecimientos Gr/tficos
S. A., 1946; see p. 204). A lapwing, taken in the same area on 28 November 1961,
had in its stomach the remains of 2 larval lepidopterans, and 13 larval and 2
adult coleopterans.
A young, downy Southern Lapwing from the same locality, weighing 148 g, was
brought into the laboratory on 4 September 1961. It was fed known quantities of
food about 12 times daily and periodically weighed. The food consisted of earth-
worms, raw ox heart, lung, and spleen, and muscle from fox and lamb. Earthworms
were preferred by the bird, and its activity was greater when it was on an earthworm
diet. At the end of 23 days it weighed 250 g.
Average daily weight increase in the first eight days in captivity was 4.6 per cent
of the body weight. Average daily consumption of food during this period was
126.3 g on a diet of fox, ox heart, and earthworms. In the two 24-hour periods in
which food consumption was greatest, the bird ate 214 g (103 per cent of its
body weight) and 226 g (108 per cent of its body weight) of earthworms. In
the second eight days in captivity, its body weight increased an average of 0.65
per cent daily, on a diet of an average of 58 g daily of ox heart and lungs, and lamb.
We thank George J. Wallace, Department of Zoology, Michigan State University,
who read and commented on this paper.--J. K. GRER ^21/2D M^RjoRm GaEza, The
Museum and Department of Zoology, Michigan State University, East Lansing,
Michigan. Present address: The University of Oklahoma Museum of Science and
History and Department of Zoology, The University of Oklahoma, Norman, Oklahoma.