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THE BEHAVIOUR AND GENERAL BIOLOGY OF THE GRACEFUL WARBLER PRINIA GRACILIS.
Author(s) -
Simmons. K. E. L.
Publication year - 1954
Publication title -
ibis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.933
H-Index - 80
eISSN - 1474-919X
pISSN - 0019-1019
DOI - 10.1111/j.1474-919x.1954.tb04128.x
Subject(s) - avian clutch size , courtship , seasonal breeder , biology , zoology , ecology , reproduction
Summary.1 A study was made of Graceful Warblers Prima gracilis in Lower Egypt during 1949 and 1950, particularly of a community of five pairs in a nursery garden at Fay id (Canal Zone). 2 The Graceful is a bird of low vegetation and feeds on or near the ground. Adults remain paired throughout the year and live in the same plot of ground which is defended against other Gracefuls only during the reproductive cycle. There are two moults a year, before and after reproductive activities which extend from late January to November. During this time at least three broods may be reared. 3 At the beginning of the reproductive cycle the male's mouth and bill darken and he begins regular song, the territories now become re‐established by song and, when necessary, by display and attack. The average size of territory at Fayid was 2750 sq. yards. 4 The common displays of the male in the reproductive season are “bowing” and “wing‐snapping”, both being probably derived from locomotory intention‐movements. Song, a threat‐note (“jilting”) and a pure intention‐movement (“flicking”) are associated with the two displays, which are thought to be primarily aggressive. “Wing‐fanning” is a less frequent male display. 5 Sexual behaviour is described. The female “retires” from the male's company just prior to the copulation period. In her absence he builds. She assists later, and both birds continue throughout incubation. 6 Three to five eggs make up a clutch in Lower Egypt. A seasonal rise and fall in clutch‐size is indicated. Both sexes incubate in short spells (longest recorded 16½ minutes). In very hot weather at one nest the eggs were covered only 9% of observed time. The incubation‐period is about 11–12 days. 7 Some numerical data on parental attention are given. The nestling‐period is about 13–14 days. The development and behaviour of the young are outlined. Often the male tends the juveniles alone when the female is, presumably, preparing for another brood. 8 Reactions towards man and other predators are outlined and discussed in relation to the aggressive drive and tameness.