(582 Birds of Celebes: Megapodidae. 



for it of the needful heat of the sun absorbed during the day by which the 

 eggs are kept from perishing in the cool of the night. Now black absorbs heat, 

 while white reflects it, and this seems to be the reason why the birds have 

 made a chief breeding-spot of the hot black volcanic sand of Wallace Bay. 

 It is interesting to note that the black gravel on these shores alternates with 

 white sand, as Meyer knows from personal observation, and that the Moleos 

 only select the black as far as is known. A similar observation is made by 

 Dr. Studer on Megapodius freycineti in New Britain: here the bird lays its eggs 

 in black volcanic sand, the temperature of which registered 38" to 40''C. and 

 cooled but little during the night, "as the black sand absorbs very much heat 

 and emits little" (Reise der "Gazelle" 1889, III, 253; Z. wiss. Zool. 1878, 433). But 

 a much more striking display of sagacity in the selection of breeding-spots by 

 the Moleo is recorded by the cousins Drs. P. & F. Sarasin, whose words (37) we 

 translate: In the Bone valley (ca. 250 m) the naturalists came across "a great 

 number of pits, which Maleo-fowls had dug out in order to lay their eggs there. 

 Our people made a search, and we secured to our satisfaction four new-laid 

 eggs. In the same bamboo-thicket, exactly on the spot where the numerous 

 Maleo-pits were scraped out, one against the other like Wolf-pits, was a warm 

 spring . . . The temperature of the water must have been about GO^C . . . The 

 circumstance, that here in the mountains, where the temperature especially in 

 the forest is on the whole low, Maleo-eggs laid simply in the earth should 

 come to due development, had puzzled us here already and led us to suspect a 

 connection between the situation of these diggings and the warm spring". 

 Somewhat further on their journey up to Bone valley (ca. 300 m) "we struck 

 Maleo-diggings again, and just as in the last case we discovered not far from 

 them a warm spring of perhaps 50" C, which formed a little brook Although, 

 on putting the hand in it a sharp smarting sensation of [the skin between the 

 fingers resulted, all the stones of the brook there were padded with a blue- 

 green alga. With regard, then, to the breeding of the Maleo we believe our- 

 selves able to maintain that the bird indeed lays its eggs as a rule in the sand 

 on the hot sea-shore, where the heat of the sun then proves powerful enough 

 to hatch them, but that in the mountains and especially in the shady forest of 

 the interior the warmth of the sun must be substituted by something else, and 

 that for this purpose the Maleo then chooses the water of warm springs, which 

 it searches out, and makes its breeding-pits in the ground warmed by them. 

 Accordingly, where Maleos are encountered in the interior of the country, there 

 warm springs should be not far otF. The Maleo thus makes use of two inor- 

 ganic sources of warmth, by which its eggs are to be hatched, namely, on the 

 one hand the sun, on the other warm springs^). Of the latter condition we 

 found still further confirmation, for near another still hotter spring, in which 



', Other Megapodes make use of the heat produced by the fermentation of vegetable matter placed tJii 

 their eggs. 



