Breeding Ecology And Vocal Behaviour Of Fire-tailed Myzornis At Gaoligong Mountain, China

Alpine breeding birds were expected to evolve a series of particular behaviors, allowing them existing in the high altitude extreme environment with unpredictable conditions. We studied the breeding biology, nest selection, and vocal behavior of an alpine breeding species: Fire-tailed Myzornis(Myzornis pyrrhoura) in the Gaoligong Mountain of China during the breeding seasons in 2013, and 2014. Our aim was to explore the behavior adaptation of M. pyrrhoura to the alpine extreme environment.Nineteen global nests with side entrance of M. pyrrhoura were found by systematic searching. The nests were built by both sexes and mainly contained mosses and Rhododendron flakes. They were located on vertical bank or rock face, ~20–152 cm height above ground. Socially monogamous and sexual dimorphism was found both in size and plumage of Fire-tailed Myzornis. Egg-laying was initiated in middle April and ended in early July. The clutch size was(mean ± SD) 2.91 ± 0.54(n = 11) and fresh egg weighted 1.84 ± 0.19 g(n = 11). Males and females contributed nearly equally to all the breeding activities including incubating, provisioning, brooding, and cleaning. The incubation lasted for 15 d(n = 1) with a notable high percentage of nest attendance(99.48%) by the parents. The total provisioning rates were 6.52 ± 1.82(range = 3.29 – 10.29)trips per hr that increased with the increasing of nestling age, while the percentage of time adult spending on brooding decreased. Nestlings fledged at 19.67 ± 0.33(n = 3) days of age, when they were 19.03% heavier than the adult. Growth of all nestlings followed logistic model except the tail length. Overall reproductive success was 42.86%. Compared with other lower-elevation congeners, M. pyrrhoura had bigger and heavier nests, fewer but bigger eggs, longer nestling period, higher provisioning rates. Such a life history strategy enables their persistence in the alpine environment.We measured 17 variables of the nest sites of M. pyrrhoura using sampling spots. According to the result of PCA(Principle Component Analysis) on 20 nest sites of M. pyrrhoura, there are 5 principle factors were conformed. Orientation, nest coverage, food resources, topography, and human disturbance were influenced the nest-site selection of M. phrrhoura. Both the scope of the nest site and the direction of the entrance were tend to south direction. Our results suggested that Fire-tailed Myzornis preferred to warm site for nesting in high altitude environment with low temperature. Nest-site selection pattern of Fire-tailed Myzornis tended to support the thermal-refuge hypothesis. Comparing 15 variables of the nest site characteristics within the three sympatric alpine breeding babblers including Fire-tailed Myzornis(n = 20), White-browed Fulvetta(Fulvetta vinipectus)(n = 53), and Black-faced Laughingthrush(Garrulax affinis)(n = 19), five variables were overlapped while other 10 variables were differentiated. This nest-site selection mechanism is the bias for these three babblers could coexist and breed in the alpine environment with low primary productivity.We recorded the birdsong of Fire-tailed Myzornis from 30 different adults, juveniles from 3 families, and 3 nestlings from 1 clutch(No. 2013-2), and 384.4 min recordings were collected. At the same time, the behavior were also recorded. Analyzing the characteristics of the spectrograms, seven different types of the birdsong of M. pyrrhoura including contact call, single-syllable call, alarm call, male song, parental-juvenile communication call, fuveniles’ call, and nestlings’ call were classified. The notable difference were found within individual on contact call, single-syllable call, and alarm call, each of them were collected from at least 10 individuals. Only 280 verses from 6 males were record, indicating that the male song of Fire-tailed Myzornis was related rare. Comparing with the spectrograms of the song of the close-related species, the spectrograms of M. pyrrhoura have more complex syllable types and higher frequency than that of Garrulax spp., Leiothrix spp. Yuhina spp., Minla spp., Fulvetta spp., and Paradoxornis spp., but were similar with that of Sylvia spp.. The complexity of its male song may determined by heredity, while the absent of that may influenced by its stable mating system. Because monogamy may reduce the energetic expenditure by the absent of the male song. This song mechanism of Fire-tailed Myzornis is beneficial to adapting to the alpine extreme environment.