Breeding biology and novel reproductive behaviour in the Hainan Partridge(Arborophila ardens)

Background: The Hainan Partridge(Arborophila ardens) is endemic to Hainan Island,China,and is listed as vulnerable(VU) because its population size is steadily decreasing due to illegal hunting and habitat loss.Its breeding biology is poorly known.Methods: This study was conducted in three sites in the major tropical primary rainforest in Hainan.Nests of the Hainan Partridge were found by monitoring radio-tracked individuals.Video recorders were set up to monitor reproductive behaviour of Hainan Partridge when nests were found.Results: Here for the first time we report the breeding biology of Hainan Partridge by providing information on its nest site,nest,eggs,and reproductive behaviour.We found that Hainan Partridges laid immaculate white eggs in ground nests which were totally covered by dry leaves and small branches forming arches that provided optimal concealment.A novel and regular behaviour was found in Hainan Partridges since they grasped leaves and small branches and then threw them on or around their nests to provide cover during incubation and after hatching of chicks.Conclusions: Recruitment behaviour in Hainan Partridges benefit from supplementation of nest arch material to nests,cover the nest entrance and thus maintain or increase nest concealment.However,it may also contribute to concealment of the track which could expose their activities and clues for predators.Our finding implies that the Hainan Partridge has evolved such a novel reproductive behaviour under the strong selection of predation pressure.Due to habitat fragmentation and habitat loss,we suggest setting up arch structures and provide small branches and leaves in degraded or fragmented habitats to improve their suitability for partridge reproduction.This method may contribute to increasing the reproductive success of Hainan Partridge and thus compensate for its continuous population decrease.

Comparison of head size and bite force in two sister species of parrotbills

Background: Brain size is associated with morphological evolution and behavioral flexibility because animals with large brain size tend to utilize new resources and colonize novel environments more successfully.Therefore, animals with larger brain size should possess larger distribution ranges.Brain size is strongly positively correlated with head size in birds, but also with prey size and vocalizations, because individuals with large heads eat large food items and produce high frequency calls.Methods: To test if there exists an association between head morphology and bite performance, we compared head size and bite force in two sympatric sister species of parrotbills, Ashy-throated Parrotbill(Paradoxornis alphonsianus) and Vinous-throated Parrotbill(P.webbianus), which both originated from the Himalayan area, but differ significantly in their distribution ranges.Results: In Guizhou, southwestern China, the Ashy-throated Parrotbill with a restricted distribution range had smaller heads whilst the Vinous-throated Parrotbill with a large distribution range had larger heads.However, there were no differences in head size between Ashy-throated Parrotbills and allopatric populations of Vinous-throated Parrotbills(Jiangxi and Hebei).Furthermore, the tendency of variation in bite force was opposite to that in head size with populations with larger head size having weaker bite force.Conclusions: We showed that there are no differences in head size between the Ashy-throated Parrotbill and allopatric populations of Vinous-throated Parrotbill, which provides evidence for the hypothesis that differences in head size in the Guizhou populations of two sister species are probably the result of local adaptation rather than species-specific.Our study has implications for avian dispersal and adaption related to head size such as diet ecology and vocalizations.

The evolution of courtship displays in Galliformes

Species in Galliformes have elaborate ritual courtship displays,often including strutting,fluffing of tail or head feathers,and vocal sounds that serve as excellent examples of sexual selection.According to the male orientation to the female while either posturing or moving,these courtship displays of gallinaceous species can be classified into three categories:1)‘frontal displays’,2)‘lateral displays’,and 3)‘both frontal and lateral displays’.Questions regarding which category of displays is the ancestral state and the evolutionary history of courtship displays in Galliformes remain unanswered.We collected and classified 131 species in terms of their courtship displays into the three categories listed above and carried out a large-scale comparative analysis to reveal the evolutionary trajectory of this trait.We found that the ancestral state of courtship displays of Galliformes involves both relatively short and straightforward frontal and lateral elements(i.e.,the category of‘both frontal and lateral displays’).Furthermore,ancestral trait reconstructions suggest that transitions from‘lateral displays’to‘frontal displays’occurred more frequently than the other way around(i.e.,from‘frontal displays’to‘lateral displays’).In addition,some transitions occurred from‘both frontal and lateral displays’to‘lateral displays’but not from‘both frontal and lateral displays’to‘frontal displays’.Ancestral state reconstruction of courtship displays at the root of the Galliformes phylogeny supports the‘both frontal and lateral displays’first scenario.This original state then evolved towards two extremes,either‘frontal displays’or‘lateral displays’,with more complicated and elaborate display components.Moreover,subsequent transitions occurred from‘lateral displays’to‘frontal displays’much more frequently than the other way around during the evolutionary history,indicating positive selection of‘frontal displays’.

The vocalization of the red junglefowl is a signal of body size and individual health

Bird songs are considered a sexually selected trait that can reflect the individual health of males as well as the vitality of potential mates and their competitors.Vocalization features should,therefore,be related to parasite load and body condition.Here,we performed a thorough acoustic analysis of the display calls of 9-month-old sub-adults and 18-month-old adults of pasture-raised red junglefowls Gallus gallus.We investigated whether the calls of pasture-raised red junglefowls can indicate body size and body condition,in addition to the influence of parasitic infection intensity on the expression of sexual traits.We found that frequency-related syllable parameters were significantly positively correlated with wing length in adults,whereas body weight was independent of both the frequency and temporal parameters of calls.In addition,we correlated parasitic load with the expression of sexually selected traits and discovered a positive association between the intensity of parasite infection and wing length in sub-adults,independent of vocal parameters.Overall,the results suggest that the vocalization of red junglefowls may convey reliable body size information,which will facilitate further studies of different vocal parameters in the transmission of bird vocalizations.