Noise pollution is a major component of sensory pollution that can disrupt the well-being and functioning of living organisms, affect a variety of life history traits in animals, and reduce their reproductive success. In this study, we used artificial nest experiments with noise manipulation to investigate the influence of anthropogenic noise on nest predation during the breeding and non-breeding seasons and in different forest habitats. We found that the noise treatment did not alter the predation rates or survival probabilities of birds in artificial nests. However, the diversity and species composition of nest predators in artificial pine forests varied between breeding and non-breeding seasons, which may be explained by season-specific adaption of nest predators to bird nests or the unstable ecosystems of artificial forests. The diversity and species composition of nest predators differed between the different forests, probably because of differences in habitat heterogeneity. Predation time varied with treatment, season, and habitat, although most predators were nocturnal mammals. Niche segregation or changes in optimal foraging time may explain this phenomenon.
- Article type
- Year
- Co-author
Adaptive mate choice has been accepted as the leading theory to explain the colorful plumage of birds. This theory hypothesizes that conspicuous colors act as signals to advertise the qualities of the owners. However, a dilemma arises in that conspicuous colors may not only attract mates, but also alert predators. The "private channels of communication" hypothesis proposes that some intraspecific signals may not be visible to heterospecific animals because of different visual systems. To better understand the evolution of plumage colors and sexual selection in birds, here we studied the chromatic difference and achromatic differences of melanin- and carotenoid-based plumage coloration in five minivet species (Pericrocotus spp.) under conspecific and predator visual systems. We found that either the chromatic or achromatic difference among male or female minivets' plumage was consistently higher under conspecific vision than under predator vision for all five studied species of minivets. This result indicated that individual differences in plumage colors of minivets were visible to the conspecific receivers and hidden from potential predators as a result of evolution under predation risk and conspecific communication. However, males were under a higher risk of predation because they were more conspicuous than females to the vision of a nocturnal predator.
Living and/or non-living animal models are often used as stimuli to observe the behavioral responses of the target animals. In the past, parasites, predators, and harmless controls have been used to test host anti-parasitism defense behavior, and their taxidermy specimens have been widely used as a set of standard methods for the study of avian brood parasitism. In recent years, with the rapid development of 3D-printing technology, 3D-printed bird models are expected to be applied as a standard method in the study of avian brood parasitism. To evaluate the use of 3D-printed models, this study tests the reaction of Oriental Reed Warbler (Acrocephalus orientalis) towards predators, parasites, or controls, and compares the reaction among different nest intruders and between taxidermy specimens and 3D-printed animal models. It was found that the Oriental Reed Warbler responded most aggressively to the parasite, followed by predator, and finally the control; the results were consistent between the reaction to taxidermy specimens and 3D-printed animal models, indicating that 3D-printed models could serve as a substitute for taxidermy specimens. We propose a series of advantages of using 3D-printed models and suggest them to be a standard method for widespread use in future studies of avian brood parasitism.
Here we documented up-to-date information on breeding ecology of Buffy Laughingthrush (Garrulax berthemyi), an endemic species of China, and a sympatric coordinal Red-tailed Laughingthrush (Trochalopteron milnei), in southwestern China. Furthermore, we compared breeding ecology of these two sympatric species. No significant differences were found in clutch size, egg size, nest size, nest height, nest habitat and predation rate between these two species except nests depth, nests cover and eggs color. The Red-tailed Laughingthrush nestlings differed from those of the Buffy Laughingthrush in gape morphology and the extent of down. Observation of breeding behavior showed that cooperative breeding might exist in the population of Buffy Laughingthrush.
Studies on breeding biology enable us to broaden our understanding of the evolution of life history strategies. We studied the breeding biology of the Green-backed Tit (Parus monticolus) to provide comprehensive data on nest and egg characteristics, parental behavior throughout egg laying and nestling periods, and reproductive outcome. Our study reveals adaptive behavioral patterns and reproductive strategies for P. monticolus.
The mutually antagonistic processes producing adaptations and counter-adaptations in avian brood parasites and their hosts provide a model system for the study of coevolution; this topic has long been an area of focus in ornithology and evolutionary biology. Although there is an extensive body of literature dealing with avian brood parasitism, few empirical studies have considered the effects of the coevolutionary processes associated with brood parasitism on the acoustic characteristics of parent–offspring communication. Under the strong selection pressures associated with brood parasitism, parasitic birds may, for instance, produce deceptive songs. The host may in turn evolve the ability to recognize these sounds as deceptive. At present, the mechanisms underlying the different competitive strategies employed by hosts and parasitic birds remain unclear. Here, we reviewed previous studies that investigated acoustic traits in scenarios of brood parasitism, highlighting possible adaptive functions. Using a meta-analysis, we identified no heterogeneity among studies of begging call adaptations in parasitic nestlings. However, our results may have been affected by the small number of applicable papers available for analysis. Our meta-analysis also suggested that studies of acoustic communication and transmission in adult hosts were highly heterogenous, suggesting that research methods were inconsistent among studies. Finally, we identified knowledge gaps and proposed several lines of future research.
The life history of birds dictates their activities and is crucial to population success. However, the life history traits of only one-third of the world's bird species have been described; the rest are poorly understood. We studied the breeding ecology of the Yellow-bellied Warbler (Abroscopus superciliaris) and documented reproductive information throughout the egg and nestling periods. The data included natural nest sites, nest components, nest size, egg laying dates and time, egg morph, egg size, clutch size, egg incubation, nestling brooding and feeding, nestling morph and growth, and reproductive outcome. This study provided particular information of breeding ecology that has not been reported before in the Yellow-bellied Warbler.
In coevolutionary interactions between brood parasites and their hosts, host parents are under strong selection to evolve defenses against parasitism. Egg rejection is an efficient and common defense against parasitism, although some apparently suitable hosts do not reject cuckoo eggs.
Sparrows Ploceidae are widespread throughout the Old World, and they have a suitable diet for rearing cuckoos, but still they are rarely exploited by brood parasites. To solve such puzzle, we conducted artificial parasitism and cross-fostering experiments in Russet Sparrow (Passer cinnamomeus).
The present study showed that Russet Sparrows have no egg recognition ability, but recognize their own nestlings and eject alien chicks or starve them to death. They may use visual cues in chick recognition, although they accept sister species Tree Sparrow (Passer montanus).
By rejecting nestlings of foreign species, Russet Sparrows have succeeded to escape from the brood parasitism by cuckoos and other parasites. Our studies shed light on the puzzle why some species are not utilized by cuckoo parasites as hosts.
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.
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.
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.
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 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.
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.
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.
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.