42 U.S. NATIONAL MUSEUM BULLETIN 223 



sistent and definite this behavior may have been. The term "sizzhng" 

 is not too informative. 



The mating and territorial behavior of these finches are still in- 

 adequately understood, and the descriptive data do not all point to 

 the same picture. Thus, in Mozambique, J. Vincent (1936, pp. 102- 

 103) found a flock of about 30 cuckoo finches, all of which looked alike. 

 He collected three of them and found all to be males in full breeding 

 condition, like birds that one would expect to find established on indi- 

 vidual breeding territories. Similar observations have come to me 

 from Rhodesia (C. J. Vernon, in litt.). 



In 1950 Neuby-Varty wrote me of his experience with these finches 

 in Rhodesia. His experience led him to conclude that they did not 

 form pairs, as he saw them in groups of three, four, or five individuals 

 all through the breeding season, and once he found one male with 

 several females. Since these birds were not collected, however, some 

 of the "females" may actually have been immature birds of either sex. 



More recently (in litt., June 24, 1956), Neuby-Varty informed me 

 that he found cuckoo finches apparently paired off, with marked terri- 

 torial behavior and apparent monogamy. He found one pair (A) in a 

 stretch of vlei (grassland) along the river on his ranch; further up 

 the same river was a second pair (B); and about IK miles away he 

 discovered a third pair (C) in a vlei on the boundary of his land. 

 He carefully combed other open spaces on his property but found no 

 others. Thej'^ seemed to confine themselves to a limited stretch of 

 country and definitely to prefer country with wet vleis and shortish 

 grass. He found that they were very pugnacious and that there was 

 only one pair in an area; they would not tolerate any invasion from 

 nearby birds. One day he tried to drive pair A into pair B's territory 

 by slowly walking up the river. They flew nearly up to B, but B 

 chased them down river again. He then tried to get pair B into A's 

 territory with the same result. They could go just so far when the 

 other pair would intercept them and drive them back. They seemed 

 to range over a large bit of country, and so he came to the conclusion 

 that they require an enormous amount of territory. He estunated 

 that A had about 350 acres; B slightly less, about 300; C had about 

 the same as B. However, I think that this excessive spacing is a 

 reflection of low numerical numbers rather than an expression of 

 actual need. In response to further questioning, Neuby-Varty in- 

 formed me of pair A that the male and female were very easily dis- 

 tinguishable, and that their resting spot of dried reeds was about 30 

 yards from a road traversed by him every day except Sunday. He 

 used to see this same pair every day. 



In keeping with these observations of Neuby-Varty, the fact should 

 also be noted that other writers have commented on the pugnacious 



