52 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I46 



of the species. Blue eggs are known from near Nairobi (Ngong), not 

 too far to the north of Doinyo Narok. Clancey (1960, p. 29) has 

 identified a breeding male specimen of the cuckoo from Lake Magadi, 

 quite close to Doinyo Narok, as of the subspecies pica, a race whose 

 eggs are bluish. 



In South Africa, South-West Africa, Bechuanaland, the Rhodesias, 

 southern Mozambique, and Nyasaland, the known eggs (and there 

 are many) are pure white, except for one blue oviduct egg from 

 Bulaya, 8°33'S., 30°07'E., near Lake Mweru, in northeastern North- 

 ern Rhodesia. It is possible that the local race of the cuckoo there 

 is pica and not serratus, as it cannot be said, on present evidence, 

 that pica may not be the breeding form of Ruanda-Urundi (now 

 the Republic of Ruanda and the Kingdom of Burundi) and the 

 eastern part of the Republic of the Congo near Lake Tanganyika, 

 and that its range may extend south to Bulaya. On the map of 

 the breeding ranges of the races of this cuckoo the egg color has been 

 indicated, B for blue, W for white. 



Several recent authors have considered pica inseparable from ser- 

 ratus, but while close I prefer to keep them distinct, as did Clancey 

 (1960). As far as our immediate problem is concerned the only 

 difference is that if they were merged we would have two egg types 

 in one race, although geographically separate from each other, 

 whereas in our present arrangement, each race has one egg type, but 

 still the species has two. Inasmuch as C. jacobinus is the only species 

 of the genus that has developed two distinct, and constant, egg types, 

 it may be pointed out that the more "advanced" of the two, the 

 pigmented, or greenish-blue, type is apparently the type developed in 

 the stock that gave rise to C. levaillantii and to C. coromandus, both 

 of which lay similar, unmarked bluish or bluish-green eggs. 



The origin of two egg types, or, more precisely, the advent of the 

 pigmented one in a species originally laying only unpigmented white 

 eggs, is a problem for the solution of which no real clues exist, al- 

 though we have already noted that nonparasitic cuckoos lay eggs that 

 are either white or bluish white, and that there may be a tendency in 

 the basic, primordial cuculine stock as a whole to produce some blue 

 eggshell coloring. However, a parallel case has recently been described 

 in a totally unrelated, primitive parasitic cuckoo, the Neotropical 

 Tapera naevia. This bird, parasitic primarily on furnariids and den- 

 drocolaptids, all of which lay white eggs, was known to lay white 

 eggs as well. Haverschmidt (1961, pp. 353-359) has found, in 

 Surinam, that this cuckoo lays two types of eggs, both unmarked, 



