VENEZUELAN ORNITHOLOGY — FRIEDMANN AND SMITH 473 



to be little evidence in our area of the two separate breeding seasons 

 for any species of birds reported by Davis for British Guiana. It is 

 possible that insufficient field observations may be the cause of this 

 apparent discrepancy for some dozen forms, and it cannot be ruled 

 out as impossible that occasional pairs may nest months before or 

 after the customary breeding season. 



Although there is some breeding activity throughout the year in 

 northeastern Venezuela, it is perhaps significant that the breeding in 

 the minimum months of November-February is confined to species 

 nesting principally in prior or subsequent months. We find only one 

 apparent exception to this "rule," the hummingbird Amazilia jim- 

 briata maculicauda, which breeds from August through January. 

 This confirms Skutch's (1950, pp. 197-204) observation that the 

 hummers' main breeding season was during the months when other 

 birds' breeding activity was at a minimum. Since in Central America 

 those months are the months of maximum abundance of flowers, 

 Skutch postulated a close connection between breeding season and 

 maximum amount of food available. We have too little data to be 

 able to comment in this regard, but we would like to record the 

 following information: 



The trees of our area, many of which have abundant, showy flowers, 

 mainly bloom in the months of March, April, and May, just before 

 the rainy season (fig. 106). Most of the herbaceous plants come into 

 bloom later, with the advent of the rains. While the hummers are 

 strong fliers, those of our area show restrictive preference for the type 

 of flowers at which they feed; Polytmus guainumbi, Glaucis hirsuta, 

 Phaethornis anthophilus, and perhaps to a somewhat lesser extent 

 Amazilia jimbriata are low feeders, whereas Chrysolampis mosguitus, 

 Chlorostilbon canivettii, and Amazilia tobaci prefer to feed at the tree 

 flowers. If the breeding season of these hummers depended more on 

 abundance of food than on other factors, then we should expect the 

 high flying forms to nest in March, April, and May, with the low 

 feeders breeding months later. Hummers as a group would then show 

 a split breeding season, depending upon the food preferences of the 

 forms involved. Field observations in this connection should prove 

 of interest. 



In this connection, further breeding data for tropical races of the 

 horned owl Bubo virginianus would also be of interest. The breeding 

 race of northeastern United States nests well in advance of the general 

 breeding season of other birds. Were tropical races also to be found 

 nesting early in the season, it would suggest that, provided food or 

 other factors are not of prime importance, the breeding season itself 

 may be a phylogenetically conservative character of the group, in 

 common with certain other biological characters such as pair forma- 

 tion and display. 



