Breeding biology of the golden-faced Tyrannulet (Zimmerius chrysops) in venezuela

Wilson Journal of Ornithology
By:  and 



We present the first detailed information on the breeding biology of the Golden-faced Tyrannulet (Zimmerius chrysops). Information was gathered from 96 nests in Yacamb National Park, Venezuela during the 2002 to 2008 breeding seasons. The enclosed nest was similar to descriptions of nests of other species in the genus. Eggs were laid on alternate days with mean (?? SE) clutch size of 1.98 ?? 0.02 (n 45) and fresh weight of 1.616 ?? 0.020 g (n 48). Only the female incubated and the incubation period averaged 16.9 ?? 0.3 days (n 10). Nest attentiveness ( time on the nest) averaged 66.0 ?? 1.6 (n 40) and increased from early to mid- and late-incubation. Incubation behavior yielded an average 24-hr egg temperature of 34.88 ?? 0.45?? C (n 7 nests, 43 days). The nestling growth rate constant for body mass (k 0.285 ?? 0.011) was slow even for tropical tyrannids. The nestling period for nests where exact hatch and fledging days were observed ranged from 17 to 19 days with an average of 18.0 ?? 0. 2 days (n 9). Both females and males fed nestlings at a rate that increased over the nestling period with a mean of 4.41 ?? 0.65 trips/hr (n 10) during days 1 and 2 after hatching, and 14.93 ?? 2.36 trips/hr (n 6) at pin-break (days 1011). Daily predation rates were similar in egg-laying (0.052 ?? 0.025; n 76.5 exposure days) and incubation periods (0.068 ?? 0.010; n 575.5 exposure days), but were lower during the nestling period (0.039 ?? 0.010; n 377.0 exposure days). The total daily predation rate (0.057 ?? 0.007; n 989.0 exposure days) indicated only 12 of nests were successful. These breeding biology parameters for Z. chrysops differ substantially from other tyrant-flycatchers and temperate species, further highlighting the diversity within the Tyrannidae. ?? 2010 by the Wilson Ornithological Society.
Publication type Article
Publication Subtype Journal Article
Title Breeding biology of the golden-faced Tyrannulet (Zimmerius chrysops) in venezuela
Series title Wilson Journal of Ornithology
DOI 10.1676/09-196.1
Volume 122
Issue 4
Year Published 2010
Language English
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Wilson Journal of Ornithology
First page 689
Last page 698
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