Nest Height Research Articles

Nest characteristics determine nest microclimate and affect breeding output in an Antarctic seabird, the Wilson's storm-petrel.

The importance of nest characteristics for birds breeding in the extreme climate conditions of polar regions, has been greatly understudied. Nest parameters, like nest orientation, exposure and insulation, could strongly influence microclimate and protection against precipitation of the nest, thereby affecting breeding success. A burrow nesting seabird, the Wilson’s storm-petrel (Oceanites oceanicus) is an excellent model species to investigate the importance of nest characteristics, as it is the smallest endotherm breeding in the Antarctic. Here, we investigated the effects of nest parameters such as internal nest dimensions, nest micro-topography and thermal properties of the nest burrow and the influence of weather conditions on breeding output, measured as hatching success, chick survival, and chick growth. We collected data during the austral summers of 2017 and 2018, on King George Island, maritime Antarctica. Our results showed that the thermal microclimate of the nest burrow was significantly improved by a small entrance size, a low nest height, and insulation and tended to be enhanced by a low wind exposition index and an eastern nest site orientation. In addition, an eastern nest site orientation significantly reduced the chance of snow blocking. However, the relationships between nest characteristics and breeding output were complex and might be affected by other parameters like food availability and parental quality. The relation between chick growth and nest air temperature remained especially indistinct. Nevertheless, our results indicate that nest characteristics that enhance the thermal microclimate and reduce the risk of snow blocking favoured both hatching success and chick survival. Due to climate change in the Antarctic, snowfall is expected to increase in the future, which will likely enhance the importance of nest characteristics that determine snow blocking. Additionally, despite global warming, thermally favourable nest burrows will likely still be advantageous in the highly variable and challenging Antarctic climate.

Breeding strategies of open-cup-nesting birds in sub-Antarctic forests of Navarino Island, Chile

BackgroundThere is limited knowledge about the breeding strategies of birds inhabiting in South American temperate forests. This is particularly true for open-cup forest passerines breeding at high latitudes (> 42°). To better understand the ecology of these species, in this study we described and compared the breeding strategies (i.e., nest dimensions, nest height from the ground, egg laying rhythm, clutch size, length of the developmental periods, breeding phenology, and diversity of nesting substrate) of five passerine birds that inhabit sub-Antarctic ecosystems.MethodsDuring three breeding seasons (2014–2017), we monitored 103 nests of the five most abundant open-cup forest-dwelling passerines (Phrygilus patagonicus, Anairetes parulus, Turdus falcklandii, Elaenia albiceps, and Zonotrichia capensis) on Navarino Island (55°S), Cape Horn Biosphere Reserve, southern Chile. Additionally, we compared the breeding strategies of T. falcklandii to another population breeding at lower latitude (39°S).ResultsMost of the species started laying eggs the last week of September; only E. albiceps started 2 months later. During the breeding season of 2016–2017 both E. albiceps and Z. capensis started laying eggs earlier than the previous year. Anairetes parulus and Z. capensis were the most specialized in terms of nesting substrate. Turdus falcklandii had larger clutch sizes and nested closer to the ground on Navarino Island compared to the northern population, which might put this and other ground nesting species of this island at a higher risk of predation by the recently introduced American mink (Neovison vison).ConclusionsOur five study species breed exclusively in open-cups (not in cavities) in sub-Antarctic forests, and some of them built their nests closer to the ground compared to populations breeding at lower latitudes. This may be associated with the lack of terrestrial predators on Navarino Island. Our study opens further questions about the mechanisms driving differences in breeding strategies among populations.

Secondary Shrubby Communities Provide Nesting Habitat for Birds in a Semiarid Agricultural Landscape

Loss and fragmentation of natural and semi-natural vegetation caused by agricultural intensification are related to many declines in shrubland bird populations, but they have received little conservation attention and research effort. In the Llanos de Ojuelos, a semiarid agricultural landscape in Mexico, patches of natural shrubland and nopal (or prickly pear) Opuntia spp. orchards harbour 60% of the regional avifauna, but prior to this study their value as nesting habitat for birds has not been assessed. In 2014 we recorded 143 nests of 25 species, 45% of which were of Mourning Doves Zenaida macroura. The nesting birds recorded account for 38% of all species known to use these habitats in this region and the number of nesting species is larger than in other North American semiarid and arid shrublands. Shrublands and orchards were not different in any habitat attributes measured, nor in the densities of nests found in them, but there were significantly more species nesting in shrublands. Nest height and visibility were not different between habitats, except for Mourning Doves, which nested at a lower height in orchards. Neither attribute affected nest success, except for in Black-chinned Sparrow Spizella atrogularis for whom successful nests were less visible. The assemblages of nesting birds might be explained better by particular plants used as nest substrate than by habitat attributes. Catclaws Mimosa aculeaticarpa var. biuncifera, Huisaches Vachellia farnesiana and V. schaffneri and nopal plants supported 56% of all nests, the latter being particularly important for Mourning Doves, while scarce Central-Mexico Yucca Yucca decipiens trees supported 40% of nesting species. There were interspecific differences in the phenology of nesting, which matched the feeding requirements of the young. Nopal orchards seem to provide abundant complementary food for birds that nest in shrubland patches. Nopal orchards and shrubland patches dotting the landscape may make the dominant agricultural matrix of the southern part of the Central Plateau of Mexico less detrimental to shrubland birds. Our study supports the idea that small patches of secondary shrubland can aid in biodiversity conservation in anthropized landscapes, a role that in this region is provided by shrubland remnant patches as well as nopal orchards.

Multiple factors associated with nest-site selection in a wetland-specialist, the Wren-like Rushbird (Phleocryptes melanops)

ABSTRACTDiverse factors may limit nest-site selection; however, nest predation has long been considered a main factor driving nest-site selection in birds. Marsh-nesting birds face a particularly important trade-off between habitat features that impede their vision of the approach of potential predators and nest concealment from predators. Here, we analyse how different ecological variables influence nest-site selection in the habitat-specialist Wren-like Rushbird (Phleocryptes melanops) breeding in three different wetlands of the Pampas region of Argentina over 3 years. Rushbirds selected nest sites with higher heights and denser vegetation, compared to random sites. Nest height was positively associated with vegetation height and lower visibility from the point of view of aerial predators, and the nest entrance was oriented towards the region with greatest visibility of the nest from the point of view of Rushbirds. Rushbirds seem to flexibly adjust their nest location in response to high predation risk, building their nests under structures built by other birds when breeding colonies of herons and gulls (potential nest predators) are present. Initial nest-site selection is performed by males, which then attempt to attract females to a rudimentary nest. Females sometimes reject such sites and the male then selects a new nesting location. Our study highlights the potential for flexible sex differences in nest-site selection.

Breeding success and population growth of Southern Ground Hornbills Bucorvus leadbeateri in an area supplemented with nest-boxes

SummaryThe provision of artificial nests can improve the conservation status of threatened bird species that are limited by nest-site availability. The shortage of natural cavity nesting sites is one factor limiting the population growth of the Southern Ground Hornbill Bucorvus leadbeateri. In an 1,800 km2 study area in north-eastern South Africa, 31 wooden nest-boxes were installed during 2002–2015. We investigated the relationships between nests, as well as environmental and social factors, with breeding. Generalised linear mixed models were fitted to the observational data and identified positive relationships between breeding attempts and each of home range size and the previous year’s rainfall; as well as positive relationships between breeding success (amongst the groups that attempt breeding) and each of earlier breeding, nest height and thickness of the nest cavity wall. The provision of nest-boxes increased the number of breeding groups and although breeding success also increased initially, it later declined as the density of breeding groups increased above 20 groups. Although nest-boxes alone did not increase overall breeding success, they are an effective conservation tool to enhance the population of Southern Ground Hornbills if spaced optimally, to enhance reproductive output in areas where suitable nest-sites are scarce or lacking.

Factors influencing nesting phenology and nest success of the Rufous-winged Sparrow (Peucaea carpalis) at the center of its distribution in Sonora, Mexico

We determined the effect of the seasonal distribution of summer rainfall and associated seasonal changes in vegetation on the timing of reproduction and reproductive success of the Rufous-winged Sparrow (Peucaea carpalis) in the plains of central Sonora, Mexico, and influence of exotic buffelgrass (Pennisetum ciliare). We monitored 302 nests twice weekly from early July to early October of 2012–2014. We fitted Bayesian logistic-exposure models for nest survival data using covariables year, nest stage, date, normalized difference vegetation index, shrub cover, buffelgrass cover, and nest height. Mean daily nest survival probability equaled 95.9% (95% CRI 95.1%–96.1%), with nest survival probability averaging 36.3% (95% CRI 30.2%–42.5%) during the nesting season.We found evidence that daily nest survival probability differed between nest stages but variation in environmental explanatory variables among nests did not explain variation in daily nest survival probability, despite suggestive evidence of a positive association between NDVI and daily nest survival probability. Daily nest survival probability seemed unaffected by the habitat alteration in buffelgrass prairies, suggesting that the Rufous-winged Sparrow may be resilient to habitat transformation in the center of its distribution.

Breeding in the gray-headed tody-flycatcher (Aves: Tyrannidae) with comments on geographical variation in reproductive traits within the genus Todirostrum

ABSTRACTThe gray-headed tody-flycatcher Todirostrum poliocephalum is a passerine endemic to the Atlantic Forest of Brazil. We describe the nest and nesting behaviour of this species and investigate geographical variation in breeding traits in the genus using data from the literature, museum collections, and citizen science projects. We located 21 nests of the gray-headed tody-flycatcher, 13 of which we monitored. Nest height above the ground averaged 3.3 ± 3.4 m (n = 21). Nests were built over a 16.8 ± 5.6-day period (n = 6) by both adults. Clutch sizes ranged from two to three eggs, with a mean of 2.9 ± 0.3 eggs (n = 10). Eggs measured 16.6 ± 0.5 × 12.0 ± 0.5 mm (n = 23) and weighed 1.1 ± 0.1 g (n = 19). Mean incubation period was 17 days (n = 3) and mean nestling period was 15.5 days (n = 2). Apparent reproductive success was 30.8%, with predation being the primary cause of nest failure (46.1%). Mayfield’s reproductive success was 25.9%, and daily survival rates for eggs and nestlings were 0.957 and 0.971, respectively. Clutch sizes increased with latitude, but temperature and precipitation seasonality had very low importance in explaining clutch size variation.

The Northern Hawk Owl in Montana: A Summary of Breeding Biology, Diet, Habitat Association, and Records (1994–2015)

We studied Northern Hawk Owls in Montana from 1994 through 2015. We report 36 breeding records, 18 of which included a known nest location. Owls reused one nest in subsequent years, but this nest was included only once in our analysis of nest-site characteristics. All nests were in moderate to severely burned forests from 1–11 yr post-burn. Nests were found in black cottonwood (Populus trichocarpa; n = 6), quaking aspen (P. tremuloides; n = 6), Engelmann's spruce (Picea engelmannii; n = 3), and western larch (Larix occidentalis; n = 2). Average nest tree height was 19.6 ± 3.4 m (95% CI, n = 17), average nest height was 14.1 ± 1.6 m (95% CI, n = 17), and average diameter at breast height was 43 ± 4 cm (95% CI, n = 17). Average measurements of nest tree height and nest height were larger than those reported from elsewhere in North America. Diet, based on 274 prey identified from pellets, was 88% voles, most frequently Microtus pennsylvanicus (51%, n = 140). Only 1 of 72 banded owls was recaptured or recovered over the course of this 22-yr study, suggesting a non-sedentary or nomadic population with low site fidelity. The lone recapture represents the first report of a philopatric Northern Hawk Owl in North America. Although this owl is still considered a rare breeder in the conterminous United States, we documented breeding records in 11 of the last 12 yr of this study. All but four known breeding records in Montana occurred within Glacier National Park.

Direct and indirect effects of ungulates on forest birds’ nesting failure? An experimental test with artificial nests

Increasing deer and wild boar populations in North America and Western Europe are suspected of threatening low-nesting forest birds. Ungulates may directly affect these birds by predating eggs or chicks, or indirectly attract other mammalian or avian predators or reduce nesting site availability and habitat quality. To test some of these various mechanisms in two French forests, 528 artificial nests, 77 of which (14.6%) were monitored with camera traps, were set up in 44 plots which were either unfenced or fenced to respectively include or exclude ungulates. We used generalized linear mixed models to relate the nest failure rate to indices of plot frequentation by ungulates and other nest predators, to vegetation structure and to local bird community richness indices. Nest failure rate was significantly higher in the unfenced plots (39%) than in the fenced plots (32%) but this was related neither to red deer nor to wild boar frequentation of the plots. Furthermore, levels of frequentation for other mammalian and avian predators tended to be positively correlated to ungulate presence but not to nest failure rate. Nest failure rate depended on both nest height and shrub cover: nests on the ground (31% failure rate) were less predated or disturbed than nests in low shrubs (41% failure rate). Nests surrounded by low shrub cover experienced a slightly higher predation risk. We conclude that ungulates have a limited influence on nest failure for low-nesting forest birds; in particular, they seem to contribute very little to egg predation compared to other predators.

Adaptation or ecological trap? Altered nest-site selection by Reed Parrotbills after an extreme flood

BackgroundFloods and other extreme events have disastrous effects on wetland breeding birds. However, such events and their consequences are difficult to study due to their rarity and unpredictable occurrence.MethodsHere we compared nest-sites chosen by Reed Parrotbills (Paradoxornis heudei) during June‒August 2016 in Yongnianwa Wetlands, Hebei Province, China, before and after an extreme flooding event.ResultsTwenty-three nests were identified before and 13 new nests after the flood. There was no significant difference in most nest-site characteristics, such as distance from the road, height of the reeds in which nests were built, or nest volume before or after the flood. However, nests after the flood were located significantly higher in the vegetation compared to before the flood (mean ± SE: 1.17 ± 0.13 m vs. 0.75 ± 0.26 m, p < 0.01). However, predation rate also increased significantly after the flood (67% vs. 25%, p = 0.030).ConclusionsOur results suggested that Reed Parrotbills demonstrated behavioral plasticity in their nest-site selection. Thus, they appeared to increase the height of their nests in response to the drastically changing water levels in reed wetlands, to reduce the likelihood that their nests would be submerged again by flooding. However, predation rate also increased significantly after the flood, suggesting that the change in nest height to combat the threat of flooding made the nests more susceptible to other threats, such as predation. Animals’ response to rare climatic events, such as flooding, may produce ecological traps if they make the animals more susceptible to other kinds of threats they are more likely to continue to encounter.

Nest height is affected by lamppost lighting proximity in addition to nestbox size in urban great tits

Both natural and artificial light have proximate influences on many aspects of avian biology, physiology and behaviour. To date artificial light at night is mostly considered as being a nuisance disrupting for instance sleep and reproduction of diurnal species. Here, we investigate if lamppost night lighting affects cavity‐nesting bird species inside their breeding cavity. Nest height in secondary cavity‐nesting species is the result of trade‐offs between several selective forces. Predation is the prevailing force leading birds to build thin nests to increase the distance towards the entrance hole. A thin nest may also limit artificial light exposure at night. Yet, a minimum level of daylight inside nesting cavities is necessary for adequate visual communication and/or offspring development. Against this background, we hypothesised that avian nest‐building behaviour varies in response to a change in night lighting. We monitored nest height of urban great tits Parus major during six years and found that it varied with artificial light proximity. The birds built thinner nests inside nestboxes of various sizes in response to increasing lamppost night light availability at the nest. In large nestboxes, the nests were also thinner when a lamppost was present in the territory. Whether this relationship between artificial night lighting and nest height reflects a positive or negative effect of urbanisation is discussed in the light of recent experimental studies conducted in rural populations by other research groups.

Seasonal increase of nest height of the Silver-throated Tit (Aegithalos glaucogularis): can it reduce predation risk?

BackgroundNest predation is usually the main cause of bird nest failure. ‘Predation avoidance hypothesis’ of nest-site selection predicts that birds should prefer nest-sites with higher nesting success. We investigated the relationship between nest height and nest fate in Silver-throated Tits (Aegithalos glaucogularis) and asked whether the seasonal change of nest height was adaptive by simultaneously analyzing the seasonal variation of predation rates of the nests.MethodsWe monitored nests of the Silver-throated Tit across seven breeding seasons in the Dongzhai National Nature Reserve in Henan Province of China. We compared the difference of nesting success among nests of different heights and analyzed the effect of nesting date on nest height and nest predation rates.ResultsThe overall nesting success rate was 24.1% (n = 623). Among the failed nests (n = 472), 59.75% were predated by birds and mammals, followed by snakes (9.11%). The average height of successful nests was significantly lower than that of predated nests. As the season progresses, the height of the nests increased significantly, companied by the decrease in nesting success. Daily survival rate of the nests also decreased with the progression of the season, regardless of breeding stages.ConclusionsOur findings suggest that nest height is an important factor influencing the nesting success of Silver-throated Tits. However, the seasonal increase of nest height appears inconsistent to the ‘predation avoidance hypothesis’, because it is associated with higher predation rates. The reason for this maladaptive behavior remains to be explored in future studies.

Foraging strategies underlying bird egg predation by macaques: A study using artificial nests.

Bird egg predation is widespread in non-human primates. Although nest predation is often described as opportunistic, little is known about foraging strategies and nest detection in primates. Since it is the prevalent cause of nest failure in the tropics, birds select nest sites within specific microhabitats and use different nest types to increase nesting success. Identifying the nests targeted by the northern pigtailed macaques (Macaca leonina), an omnivorous cercopithecine species, and known nest predator, will shine light on nest foraging strategies in primates. The aim of this research was to reveal if nest predation is a selective or opportunistic feeding behavior. We studied, using artificial nests and camera traps, the influence of nest type (open-cup vs. cavity), microhabitat (i.e., understory density, canopy cover, canopy height, ground cover, and presence vs. absence of thorns and lianas), and nest height, on nest predation by a troop of northern pigtailed macaques in the Sakaerat Biosphere Reserve (Thailand), a degraded environment. In our study, macaque predation on artificial nests was high; out of the 200 nests that were set up, 112 were plundered by macaques. Although predation rates decreased with nest height, nest type, and microhabitat had no significant effect on predation by macaques. Nest detectability and accessibility did not affect predation rates. Macaques actively searched for nests in different microhabitats, suggesting that nest predation by this primate might be considered a selective feeding behavior in this degraded habitat. Consequently, nest predation by this primate might have important conservation implications on the population dynamics of forest-dwelling bird species. Behavior observation methods, such as instantaneous scan sampling, may underestimate nest predation by primates, a furtive and cryptic behavior.

Nesting Characteristics of The Tapanuli Orangutan (Pongo tapanuliensis) in Two Unprotected Forests of Batang Toru, North Sumatra

Tapanuli orangutan (Pongo tapanuliensis) is the new great ape species that only occurred in the Batang Toru forest. The long term survival of this population is threatened due to habitat loss and hunting. Performing a nest survey is important to give a deeper understanding of the ecology and help determine the best protective management measures. We provide a basic data of orangutan nesting characteristics in two unprotected forests of Batang Toru: Sitandiang (West Batang Toru) and Hopong (East Batang Toru). A line transect method was conducted to obtain the nest data and sampling quadrat method was used to analyze the condition and sustainability of the habitat. Our result showed that there were similarities in the choosing of tree diameter and species, while there were disparities in the choosing of tree height, nest height, and nest position for nesting. The species diversity index in Sitandiang and Hopong was categorized high, with values found to be 4.5 and 4.6 respectively which mean that these locations potentially serve nest and food tree for the orangutans. Considering our findings, we recommend to allocating these areas into protected forests for long-term survival of Tapanuli orangutan in Batang Toru.

Bird Functional Traits Respond to Forest Structure in Riparian Areas Undergoing Active Restoration

Monitoring wildlife responses is essential to assess restoration projects. Birds are widely used as bioindicators of ecosystem restoration, but most studies use only taxonomic descriptors to compare categories of reference and restoring sites. Here, we used forest structure as a continuous predictor variable to evaluate avifaunal taxonomic and functional indicators in riparian forest reference and restoration sites on southeastern Brazil. Reference sites were riparian forest remnants, and restoration sites were pasture before seedling reintroduction. Forest structure variables (mean tree height, canopy depth, mean diameter at breast height, basal area, tree layering, tree density, and grass cover) were reduced into two axes using a Principal Component Analysis (PCA), Forest Axis 1 (tree biomass vs. grass cover) and Forest Axis 2 (canopy depth vs. tree density). Bird species were classified in relation to five functional categories (i.e., diet, foraging stratum, nest height, cavity dependence for nesting, and forest dependence). Forest Axis 1 influenced the functional diversity of bird assemblages and the relative abundance within levels of each functional category (except for nest height). The relative abundance of all functional categories combined was also affected by Forest Axis 2. Therefore, forest structure affected the predominant functional traits of bird species in riparian sites under restoration. Sites with higher tree biomass were the richest, with canopy birds that were insectivores and frugivores of high forest dependence, whereas more open sites were associated with birds of low forest dependence and ground-foraging insectivores. Forest structures of similar-aged sites were strongly variable, due to natural and anthropic disturbances, so restoration age was a poor indicator of forest development. These unpredictable disturbances can change the development of sites under restoration, so that forest structure can be a better descriptor of the trajectory of these ecosystems.

The effects of reed density, surface and management on the probability of cuckoo (Cuculus canorus) parasitism on great reed warbler (Acrocephalus arundinaceus) nests

While some previous investigations have been made into the effects of vegetation structure on the probability of brood parasitism in reed passerines, the effects of vegetation management remain unclear. Furthermore, we possess little information on how vegetation density influences the probability of brood parasitism in wide-surfaced reed-beds. The aim of this study was to test how vegetation density and reed management by burning influence the probability of cuckoo (Cuculus canorus) brood parasitism in great reed warbler (Acrocephalus arundinaceus) nests in a wide-surfaced reed-bed with pure reed stands. We found that the probability of parasitism was highest in nests constructed in low reed density, with low annual variation of reed density and low annual variation of nest height. Reed management had no effect on the probability of parasitism. Our results suggest that, in wide-surfaced reed-beds with pure reed stands, nests in sparser reed are more exposed to brood parasitism than those concealed in dense reed. Furthermore, low spatio-temporal variation in reed density and nest height benefit brood parasitism, as it provides a relatively constant number of host nests in a similar spatial distribution in the reed-bed from year to year. Vegetation structure was suggested to have an important role in adaptation of hosts’ defence against brood parasites.

High, low, or familiar? Nest site preferences of experienced laying hens

ABSTRACT1. The aim of this study was to investigate which nest heights are preferred by laying hens in the absence of familiar nest locations and whether preferred nest heights are more attractive than a familiar location. In two experiments, a total of 108 hens of four different layer breeds, which were at least 50 weeks of age, were studied.2. In the first experiment, hens were given individual free choice between nests for 1-week at four different heights (0 cm, 39 cm, 78 cm, and 117 cm above ground). Hens of the four breeds differed in their nest height preferences (P = 0.0013). However, hens of three breeds preferred ground level nests (P < 0.007) and the fourth line showed an equal preference for the ground level and level three, the latter level corresponding to the height of the nests in their home compartments.4. In the second experiment, hens from the four breeds were given a choice between ground level nests and nests at a familiar location, i.e. at the same location as in their home compartment. Hens of all strains preferred the familiar nest location (P = 0.002) and preferences did not differ between strains (P = 0.77).5. Laying hens seem to prefer nests at ground level in the absence of a familiar nest. However, if possible, experienced 50 week old hens continue to use a familiar nest location instead of a ground nest location. The results are discussed with respect to a potential primary preference that may be modifiable by experience and with respect to possible relevance in commercial housing.

Assessment of Chimpanzee Nest Detectability in Drone-Acquired Images

As with other species of great apes, chimpanzee numbers have declined over the past decades. Proper conservation of the remaining chimpanzees requires accurate and frequent data on their distribution and density. In Tanzania, 75% of the chimpanzees live at low densities on land outside national parks and little is known about their distribution, density, behavior or ecology. Given the sheer scale of chimpanzee distribution across western Tanzania (&gt;20,000 km2), we need new methods that are time and cost efficient while providing precise and accurate data across broad spatial scales. Scientists have recently demonstrated the usefulness of drones for detecting wildlife, including apes. Whilst direct observation of chimpanzees is unlikely given their elusiveness, we investigated the potential of drones to detect chimpanzee nests in the Issa valley, western Tanzania. Between 2015 and 2016, we tested and compared the capabilities of two fixed-wing drones. We surveyed twenty-two plots (50 × 500 m) in gallery forests and miombo woodlands to compare nest observations from the ground with those from the air. We performed mixed-effects logistic regression models to evaluate the impact of image resolution, seasonality, vegetation type, nest height and color on nest detectability. An average of 10% of the nests spotted from the ground were detected from the air. From the factors tested, only image resolution significantly influenced nest detectability in drone-acquired images. We discuss the potential, but also the limitations, of this technology for determining chimpanzee distribution and density and to provide guidance for future investigations on the use of drones for ape population surveys. Combining traditional and novel technological methods of surveying allows more accurate collection of data on animal distribution and habitat connectivity that has important implications for ape conservation in an increasingly anthropogenically-disturbed landscape.

The breeding biology of endemic Spectacled Parrotbill (Sinosuthora conspicillatus) in Lianhuashan National Nature Reserve, Gansu Province, China

BackgroundLife history traits play critical roles in population survival and evolution. Breeding information should be particularly detailed in order to provide significant insights into the population status and the evolution of other traits. To our knowledge, there is still no information about the breeding biology of Spectacled Parrotbill (Sinosuthora conspicillatus), an endemic parrotbill in China.MethodsWe searched the nests, checked all nests found and recorded the information of eggs, nestlings and nest sites of the Spectacled Parrotbill from 2013 to 2015 at Lianhuashan National Nature Reserve in Gansu Province, China.ResultsA total of 16 nests were found. Nest trees were artificial young spruces and honeysuckles. Mean nest height was 0.89 ± 0.47 m (n = 16) above the ground level. All nests were cup-shaped and constructed using leaves, fine strips of barks and grasses by both parents. The mean clutch size was 4.42 ± 0.79 (n = 12). The eggs were oval in pale blue without speckles, and the mean egg mass was 1.25 ± 0.07 g (n = 27). The egg length was 15.56 ± 0.46 mm (n = 27) and the width was 12.46 ± 0.29 mm (n = 27). Incubation period was 13 days and nestling period was 13–14 days. The breeding success rate was 46%, and among those failed nest, 71% were depredated and 29% were deserted.ConclusionDetailed life history information about parrotbill is still limited. The breeding biology of Spectacled Parrotbill reported in the present study should be helpful for further research about population, breeding behavior and conservation of this bird.

Breeding biology and behaviour of a pair of Pacific Bazas Aviceda subcristata in central-coastal Queensland over 10 years

Over ten breeding seasons (2007–2008 to 2016–2017) the nesting of a pair of Pacific Bazas Aviceda subcristata on the central Queensland coast was observed, including nest-site selection, nest building, breeding behaviour and success. Nest success was 73%, giving an average of 1.7 ± standard deviation 1.3 young fledged per attempt and 2.5 ± 1.2 raised per year. The breeding season (nest building to fledging) was from mid September to 21 April with a consistent start date from year to year (laying in October, with replacement clutches in November–February). The incubation and nestling periods averaged 32 ± 1 days and 35 ± 1 days, respectively. Nests were positioned in the fork of a tree in a similar general location (within ~3 ha) each year. Several factors contributed to nest-site selection: tree species (mostly eucalypts), height of tree (15.5–21.5 m), height of nest above the ground (12.5–17.0 m), and the use of old nests of other species. New findings included the influence of predation on extending the length of the breeding season, feeding frequency (mean 10.6 minutes between deliveries), types of prey items (phasmatids 81%, tree frogs 19%; n = 63), food preparation, and pre- and post-fledging behaviour.