Developmental life stages of the Pickersgill's reed frog (Hyperolius pickersgilli) in an ex-situ environment at Johannesburg Zoo's captive breeding facility, South Africa.

Globally, the threats of habitat loss and disease on amphibian survival have necessitated the creation of ex-situ insurance populations as a conservation tool. We initiated a captive breeding project to create an insurance population for the endangered Pickersgill's reed frog (Hyperolius pickersgilli Raw, 1982) at the Johannesburg Zoo from parents collected from KwaZulu-Natal Province, South Africa, in 2017. We found that this species has seven developmental life stages, each with unique management requirements. The quiescent tadpoles hatched 6-8 days after the eggs were laid and remained at this stage for 2 days. The next stage, the developing tadpoles, showed no form of cannibalism or carrion feeding. The external appearance of the first leg (the right hind) occurred 5-6 weeks after the tadpoles hatched, and the metamorph stage was reached after 7-8 weeks. The metamorph stage lasted 3-5 days, after which tail resorption was complete and the froglet stage reached. Froglets could not be sexed externally, although body color changed based on the amount of light present at the resting place. Sub-adults were 6 months and older with adult coloration and sex differentiation visible even with color change. Adults were older than 18 months and fully developed and sexually mature, displaying amplexus, oviposition, and external fertilization. A greater understanding of Pickersgill's reed frog's developmental stages and physiological and environmental needs can improve captive breeding and subsequent release of the frogs, facilitate captive breeding elsewhere, and improve the species' conservation status.

Human-wildlife interactions: presence of the ground-nesting Spotted Thick-knee across a South African mosaic urban landscape.

Urbanisation has increasingly encroached on numerous bird species' natural habitats, generally negatively affecting their persistence. Furthermore, increased human-wildlife interactions may benefit or be detrimental to the long term persistence of these species. The Spotted Thick-knee (Burhinus capensis), a ground-nesting species, persists in some mosaic urban landscapes in South Africa. We, therefore, assessed the presence of Spotted Thick-knees and their interactions with humans in the fragmented natural and human-modified landscape of Pietermaritzburg, KwaZulu-Natal. We conducted presence-only surveys at 52 locations between July 2019 and December 2020. 'Presence' locations for Spotted Thick-knee were identified via active surveying and public participation. Newspaper articles were distributed in June 2019, requesting information on Spotted Thick-knee sightings. Questionnaires were also sent to respondents to collect qualitative information regarding their perceptions and observations of this species in Pietermaritzburg. We established that the presence of Spotted Thick-knee's at known locations was not random. They were present at 30 out of 52 sites for 75% of this study's duration. Fewer sites had Spotted Thick-knees present during non-breeding months than breeding months. Respondents' feedback highlighted the pressures associated with Spotted Thick-knees persistence in human-modified mosaic landscapes, particularly predation and disturbance by domestic pets. Our study highlights that some ground-nesting birds, such as Spotted Thick-knees, persist in mosaic urban landscapes, despite the anthropogenic pressures. This study highlights the need to address the paucity of studies on ground-nesting birds in mosaic urban landscapes to determine general trends. Supplementary information: The online version contains supplementary material available at 10.1007/s11252-022-01254-3.

Indigenous knowledge of South African bird and rangeland ecology is effective for informing conservation science.

South Africa's communal rangelands constitute ~25% of the country's land cover and are largely managed for livestock grazing. These habitats play an important role in rural livelihoods and cultural practices. Using semi-structured interviews, we documented indigenous local ecological knowledge (LEK) held by rural dwellers linked to natural resource utilisation, environmental health and cultural keystone indicator species (CKIS) in the grassland communities of southern KwaZulu-Natal, South Africa. Our main objective was to examine the ability for LEK to inform conservation management. We found that people who were heavily reliant on natural resources attained a higher LEK score, indicating a greater breadth of ecological knowledge, which in turn shaped their perceptions of environmental change. Community members confirmed the presence of conservation concern species within this area, highlighting the limitations of only using citizen science databases for conservation management, as their observations within these databases are biased towards major road routes and protected or urban areas. LEK can play an important role in identifying habitats crucial to species' persistence and delineating population trends over time. Our surveys highlighted the importance of the Southern Ground-hornbill Bucorvus leadbeateri as a CKIS that acts as an early warning system of changing weather, notably rain. However, LEK is context-specific, and some CKIS species such as the Southern Ground-hornbill have wide distribution ranges. Consequently, the cultural associations and implications differ based on local belief systems that are often defined by the language spoken and the community's geographical location. Our study demonstrated the importance of including indigenous LEK in conservation planning for threatened species and habitats and the importance of traditional family values responsible for transferring oral knowledge.

Surgical implantation of radio tags in three eel species (Anguilla spp.) in South Africa.

Studies have reported poor survival of surgically tagged freshwater fishes in warm African waters. This study aimed to assess the applicability of using radio telemetry (and surgical implantation of tags) for Anguilla spp. Nineteen yellow eels (Anguilla bengalensis, A. marmorata and A. mossambica) were surgically implanted with radio tags between October 2018 and January 2019 in the Thukela River, South Africa. Most eels were alive 6 months after tagging, and recaptured eels displayed advanced or complete healing at the incision site. Therefore, this method appears suitable for African freshwater eels.

Implications of the movement behaviour of African tigerfish Hydrocynus vittatus for the design of freshwater protected areas.

African tigerfish Hydrocynus vittatus (n = 35) were tagged with external radio-transmitters in the Kavango River, Namibia, to determine whether freshwater protected areas could be an effective tool for the management and conservation of this species. They were manually tracked in the core study area of 33 km every c. 12 days from July-October 2016 to May 2017 for between 123 to 246 days. In addition, 14 extended surveys were carried out for up to 680 km to determine the total area use of the tagged individuals. Tigerfish displayed at least two behavioural patterns either having high site fidelity with shorter movements or using larger areas with longer movements. Twenty-three (66%) of the tigerfish had high site fidelity using an area of less than 33 km of river, whereas 12 tigerfish (34%) undertook long distance movements of up to 397 km upstream and 116 km downstream from their tagging locations. During the long-distance movements tigerfish crossed the territorial boundaries of Angola, Namibia and Botswana. Of the 35 fish that were monitored, 14 (40%) spent more than 80% of the monitored time in the 33 km study area and 18 (51%) stayed within the study area for at least 50% of the monitored time. These findings suggest that freshwater protected areas may be a useful management tool and we predict that a protected river area of 2-5 km river length could protect 25.9-34.6% of the population for at least 75% of the time whereas protection of 10 km river length could protect at least 50% of tigerfish for at least 75% of the time.

When and where to move: Dynamic occupancy models explain the range dynamics of a food nomadic bird under climate and land cover change.

Globally, long-term research is critical to monitor the responses of tropical species to climate and land cover change at the range scale. Citizen science surveys can reveal the long-term persistence of poorly known nomadic tropical birds occupying fragmented forest patches. We applied dynamic occupancy models to 13 years (2002-2014) of citizen science-driven presence/absence data on Cape parrot (Poicephalus robustus), a food nomadic bird endemic to South Africa. We modeled its underlying range dynamics as a function of resource distribution, and change in climate and land cover through the estimation of colonization and extinction patterns. The range occupancy of Cape parrot changed little over time (ψ = 0.75-0.83) because extinction was balanced by recolonization. Yet, there was considerable regional variability in occupancy and detection probability increased over the years. Colonizations increased with warmer temperature and area of orchards, thus explaining their range shifts southeastwards in recent years. Although colonizations were higher in the presence of nests and yellowwood trees (Afrocarpus and Podocarpus spp.), the extinctions in small forest patches (≤227 ha) and during low precipitation (≤41 mm) are attributed to resource constraints and unsuitable climatic conditions. Loss of indigenous forest cover and artificial lake/water bodies increased extinction probabilities of Cape parrot. The land use matrix (fruit farms, gardens, and cultivations) surrounding forest patches provides alternative food sources, thereby facilitating spatiotemporal colonization and extinction in the human-modified matrix. Our models show that Cape parrots are vulnerable to extreme climatic conditions such as drought which is predicted to increase under climate change. Therefore, management of optimum sized high-quality forest patches is essential for long-term survival of Cape parrot populations. Our novel application of dynamic occupancy models to long-term citizen science monitoring data unfolds the complex relationships between the environmental dynamics and range fluctuations of this food nomadic species.

Altitudinal variation in metabolic parameters of a small Afrotropical bird.

Of the numerous factors affecting avian metabolic rate, altitude is one of the least studied. We used mass-flow respirometry to measure resting metabolic rate (RMR), evaporative water loss (EWL) and respiratory exchange ratio (RER) in two populations of a small (10-12g) Afrotropical bird, the Cape White-eye (Zosterops virens), in summer and in winter. In total, 51 freshly wild-caught adult Cape White-eyes were measured overnight. Altitude was included as a source of variation in the best approximating models for body mass, whole-animal RMR, RER, whole-animal standard EWL and whole-animal basal EWL. RER was significantly lower in winter, suggesting a greater proportion of lipid oxidation at lower ambient temperatures (Ta). Cape White-eyes were 0.8g heavier at the higher altitude site and 0.5g heavier in winter, suggesting they may have increased their metabolic machinery to cope with cooler temperatures. EWL was generally significantly lower in winter than in summer, suggesting that birds may increase EWL with increasing Ta, as the need for evaporative cooling increases. Our results support the argument that the subtle and complex effects of altitude (and ambient temperature) should be taken into account in studies on avian metabolic rate. WHAT IS ALREADY KNOWN: Of the numerous studies known to affect avian metabolic rate, altitude is one of the least studied. Although trends are not always clear, generally, at higher altitudes, avian metabolic rate increases. WHAT THE STUDY ADDS: There were statistically significant seasonal and altitudinal differences in various physiological parameters of Cape White-eyes. These results highlight the importance of accounting for altitude in studies of avian metabolic rate.

Keeping it regular: Development of thermoregulation in four tropical seabird species.

The thermoregulatory capacity of a species can determine which climatic niche it occupies. Its development in avian chicks is influenced by numerous factors. Furthermore, it is suggested that altricial chicks develop their thermoregulatory capacity post-hatching, while precocial chicks develop aspects of this in the egg. We investigated the development of thermoregulation of four co-occurring seabird species in the Seychelles; namely white, ground-nesting white-tailed tropicbirds (Phaethon lepturus) and tree-nesting fairy terns (Gygis alba); and dark plumaged, tree-nesting lesser noddies (Anous tenuirostris) and ground- and tree-nesting brown noddies (A. stolidus). White-tailed tropicbirds have semi-altricial chicks, while the remaining species have semi-precocial chicks. Cloacal temperatures (Tb) were measured at five day intervals from newly hatched chicks and compared over time, and with adult Tbs. Initial Tbs of all chicks, except fairy terns, were lower than those taken when chicks were older. Brooding cessation generally coincided with feather development, as did an increase in Tb. Mean chick Tb was significantly lower than mean adult Tb for all species, but only white-tailed tropicbird and brown noddy chicks in tree nests differed significantly from mean adult Tb when chick Tb at five day intervals were considered. There was a significant interactive effect of nest site and age on brown noddy chick Tb, but chick colour did not have a significant effect on Tb. However, brown noddy chicks on dune crests maintained a constant Tb sooner than chicks in tree nests. Our results demonstrate that tropical seabird species have a more delayed onset of thermoregulatory capabilities when compared with those in temperate environments, perhaps as nest sites are less thermally challenging. Nest microhabitats and behavioural thermoregulation, are likely more important during early chick development for these species.

Digestive efficiencies of Cape white-eyes (Zosterops virens), red-winged starlings (Onychognathus morio) and speckled mousebirds (Colius striatus) fed varying concentrations of equicaloric glucose or sucrose artificial fruit diets.

Digestive physiology is important for understanding the feeding behaviour of organisms. Specifically, studies on the digestive physiology of frugivorous and nectarivorous birds are important for elucidating their preference patterns in the wild and the selective pressures they exert on fruit pulp and nectar. In this study, digesta transit times and digestive efficiencies of three species of birds, the Cape white-eyes (Zosterops virens), red-winged starlings (Onychognathus morio) and speckled mousebirds (Colius striatus) were investigated on equicaloric glucose or sucrose artificial fruit diets. Three concentrations, approximating the natural range of sugar concentrations in sugary, bird-dispersed fruits were used: low (6.6%), medium (12.4%) and high (22%). Digesta transit times of birds increased with an increase in concentration for all diets but were generally higher on glucose diets. Intake rates, on the other hand, decreased with an increase in sugar concentration. All species of birds failed to maintain a constant assimilated energy intake on glucose diets but mousebirds and white-eyes maintained it on sucrose diets. Apparent assimilation efficiencies of glucose diets for all species were comparable and typical of those found in other frugivorous birds. However, assimilation efficiencies for sucrose diets differed widely with red-winged starlings displaying very low assimilation efficiencies and as a consequence; they lost significant body mass on all sucrose diets. These results demonstrate the importance of digestive physiology in explaining fruit selection patterns in frugivorous birds and how a seemingly trivial physiological trait can have dire ecological consequences.

Blood lead concentrations in free-ranging Nile crocodiles (Crocodylus niloticus) from South Africa.

Generally crocodilians have received little attention with regard to the effects of lead toxicity despite their trophic status as apex, generalist predators that utilize both aquatic and terrestrial habitats, thereby exposing them to a potentially wide range of environmental contaminants. During July-October 2010 we collected whole blood from 34 sub-adult and adult free-ranging Nile crocodiles (Crocodylus niloticus) from three separate populations in northeastern South Africa in order to analyze their blood lead concentrations (BPb). Concentrations ranged from below detectability (<3 µg/dL, n = 8) to 960 µg/dL for an adult male at the Lake St Lucia Estuary. Blood lead concentrations averaged 8.15 µg/dL (SD = 7.47) for females and 98.10 µg/dL (SD = 217.42) for males. Eighteen individuals (53 %) had elevated BPbs (≥10 µg/dL). We assessed 12 general linear models using Akaike's Information Criterion (AIC) and found no significant statistical effects among the parameters of sex, crocodile size and population sampled. On average, crocodiles had higher BPbs at Lake St Lucia than at Ndumo Game Reserve or Kosi Bay, which we attribute to lead sinker ingestion during normal gastrolith acquisition. No clinical effects of lead toxicosis were observed in these crocodiles, even though the highest concentration (960 µg/dL) we report represents the most elevated BPb recorded to date for a free-ranging vertebrate. Although we suggest adult Nile crocodiles are likely tolerant of elevated Pb body burdens, experimental studies on other crocodilian species suggest the BPb levels reported here may have harmful or fatal effects to egg development and hatchling health. In light of recent Nile crocodile nesting declines in South Africa we urge further BPb monitoring and ecotoxicology research on reproductive females and embryos.

Sitting in the sun: Nest microhabitat affects incubation temperatures in seabirds.

During incubation parent birds are committed to a nest site and endure a range of ambient conditions while regulating egg temperatures. Using artificial eggs containing temperature loggers alongside ambient temperature (Ta) controls, incubation profiles were determined for four tropical seabird species at different nest site locations. Camera traps were used for ad-hoc behavioural incubation observations. Eggs experienced a range of temperatures during incubation and varied significantly between species and in some cases between different microhabitats within a species. Such variation has important consequences in the phenotypic expression of both physical and physiological traits of chicks, and ultimately species fitness. Exposed nest sites were more strongly correlated to Tas. Camera traps highlighted different incubation strategies employed by these species that could be related to trade-offs in predator defence, feeding habits, and temperature regulation of eggs. This study provides evidence that species with similar breeding habits could be affected by environmental stressors in similar ways and that the differences shown in nest site selection could negate some of these effects. We propose that habitats providing suitable nest microclimates will become increasingly important for the successful breeding of seabird species, particularly under predicted climate change scenarios.

The potential effects of climate-change-associated temperature increases on the metabolic rate of a small Afrotropical bird.

Studies have only recently begun to underline the importance of including data on the physiological flexibility of a species when modelling its vulnerability to extinction from climate change. We investigated the effects of a 4°C increase in ambient temperature (Ta), similar to that predicted for southern Africa by the year 2080, on certain physiological variables of a 10-12 g passerine bird endemic to southern Africa, the Cape white-eye Zosterops virens. There was no significant difference in resting metabolism, body mass and intraperitoneal body temperature between birds housed indoors at 4°C above outside ambient temperature and those housed indoors at outside ambient temperature. We conclude that the physiological flexibility of Cape white-eyes will aid them in coping with the 4°C increase predicted for their range by 2080.

Seasonal metabolic variation over two years in an Afrotropical passerine bird.

Seasonal trends in metabolic parameters are well established in avian populations from highly seasonal environments, however, seasonal trends in metabolism of birds from lower latitudes (and of Afrotropical birds in particular) are not well understood. We investigated seasonal trends in metabolism for a small (10-12g) Afrotropical bird, the Cape White-eye (Zosterops virens), using flow-through respirometry in two summers and two winters. There was no seasonal difference in body mass between consecutive seasons. The lower critical limit of thermoneutrality was lower in winter (23°C) than in summer (28°C), as expected for a small Afrotropical bird. In the first year of the study, mean whole animal basal metabolic rate (BMR) of Cape White-eyes was significantly lower in winter than in summer, while in the second year of the study this trend was reversed, and in the middle two seasons there was no significant difference in BMR. Differences in mean temperature and mean rainfall between seasons could not account for the seasonal trends in BMR. We conclude that seasonal trends in avian BMR may vary between years, within a population.

Circannual rhythm of resting metabolic rate of a small Afrotropical bird.

Seasonal variation in avian metabolic rate is well established in Holarctic and temperate species, while trends in Afrotropical species are relatively poorly understood. Furthermore, given the paucity of data on circannual rhythm in avian metabolism, it is not known whether seasonal measurements made in summer and winter correspond with annual peaks and troughs in avian metabolic rate. Thus, we investigated how mean body mass, resting metabolic rate (RMR) and evaporative water loss (EWL) of a small Afrotropical bird, the Cape white-eye (Zosterops virens), changed monthly over the course of a year at 20°C and 25°C. Mean body mass was 12.2±1.0g throughout the study period. However, both EWL and RMR varied monthly, and peaks and troughs in RMR occurred in March and October respectively, which did not correspond to peaks and troughs in mean monthly outdoor ambient temperatures. These results suggest that measuring RMR at the height of summer and winter may underestimate the flexibility of which birds are capable in terms of their metabolic rate. We encourage further studies on this topic, to establish whether the lag between environmental temperature and RMR is consistent in other species.

Does sugar content matter? Blood plasma glucose levels in an occasional and a specialist avian nectarivore.

Nectar composition within a plant pollinator group can be variable, and bird pollinated plants can be segregated into two groups based on their adaptations to either a specialist or an occasional bird pollination system. Specialist nectarivores rely primarily on nectar for their energy requirements, while occasional nectarivores meet their energy requirements from nectar as well as from seeds, fruit and insects. Avian blood plasma glucose concentration (PGlu) is generally high compared with mammals. It is also affected by a range of factors including species, gender, age, ambient temperature, feeding pattern, reproductive status, circadian rhythm and moult status, among others. We examined whether sugar content affected PGlu of two avian nectarivores, a specialist nectarivore the Amethyst Sunbird Chalcomitra amethystina, and an occasional nectarivore the Cape White-eye Zosterops virens, when fed sucrose-hexose sugar solution diets of varying concentrations (5%-35%). Both species regulated PGlu within a range which was affected by sampling time (fed or fasted) and not dietary sugar concentration. The range in mean PGlu was broader in Amethyst Sunbirds (11.52-16.51mmol/L) compared with Cape White-eyes (14.33-15.85mmol/L). This suggests that these birds are not constrained by dietary sugar concentration with regard to PGlu regulation, and consequently selective pressure on plants for their nectar characteristics is due to reasons other than glucose regulation.

A genomic basis of vocal rhythm in birds.

Vocal rhythm plays a fundamental role in sexual selection and species recognition in birds, but little is known of its genetic basis due to the confounding effect of vocal learning in model systems. Uncovering its genetic basis could facilitate identifying genes potentially important in speciation. Here we investigate the genomic underpinnings of rhythm in vocal non-learning Pogoniulus tinkerbirds using 135 individual whole genomes distributed across a southern African hybrid zone. We find rhythm speed is associated with two genes that are also known to affect human speech, Neurexin-1 and Coenzyme Q8A. Models leveraging ancestry reveal these candidate loci also impact rhythmic stability, a trait linked with motor performance which is an indicator of quality. Character displacement in rhythmic stability suggests possible reinforcement against hybridization, supported by evidence of asymmetric assortative mating in the species producing faster, more stable rhythms. Because rhythm is omnipresent in animal communication, candidate genes identified here may shape vocal rhythm across birds and other vertebrates.

Seasonal thermoregulation in the burrowing parrot (Cyanoliseus patagonus).

Birds exposed to seasonal environments are faced with the problem of maintaining thermogenic homoeostasis. Previous studies have established that birds native to the Holarctic increase their Resting Metabolic Rate at different ambient temperatures (RMRTa) and Basal Metabolic Rate (BMR) in winter as an adaptation to cold temperature since winters are more severe, while their non-Holarctic counterparts generally decrease their winter BMR as an energy saving mechanism during unproductive and dry winter months. In this study, we examined seasonal thermoregulation in the burrowing parrot (Cyanoliseus patagonus), a colonial psittacine native to the Patagonian region of Argentina, a region with an unpredictable environment. We found significantly higher mass specific RMRTa and BMR in summer than in winter. Both summer and winter BMR of the species fell within the predicted 95% confident interval for a parrot of its size. Body mass was significantly higher in winter than in summer. The burrowing parrot had broad thermo-neutral zones in winter and summer. The circadian rhythm of core body temperature (Tb) of burrowing parrots was not affected by season, showing that this species regulated its Tb irrespective of season. These results suggest that the burrowing parrots' seasonal thermoregulatory responses represent that of energy conservation which is important in an unpredictable environment.

Avian species functional diversity and habitat use: The role of forest structural attributes and tree diversity in the Midlands Mistbelt Forests of KwaZulu-Natal, South Africa.

Forest transformation has major impacts on biodiversity and ecosystem functioning. Identifying the influence of forest habitat structure and composition on avian functional communities is important for conserving and managing forest systems. This study investigated the effect of forest structure and composition characteristics on bird species community structure, habitat use and functional diversity in 14 Mistbelt Forest patches of the Midlands of KwaZulu-Natal in South Africa. We surveyed bird communities using point counts. We quantified bird functional diversity for each forest patch using three diversity indices: functional richness, functional evenness and functional divergence. We further assessed species-specific responses by focussing on three avian forest specialists, orange ground-thrush Geokichla gurneyi, forest canary Crithagra scotops and Cape parrot Poicephalus robustus. We found that bird community and forest-specialist species responses to forest structure and tree species diversity differed. Also, forest structural complexity, canopy cover and tree species richness were the main forest characteristics better at explaining microhabitat influence on bird functional diversity. Forest patches with relatively high structural complexity and tree species richness had higher functional richness. Different structural characteristics influenced habitat use by the three forest specialists. Tree species diversity influenced C. scotops and G. gurneyi positively, while P. robustus responded negatively to forest patches with high tree species richness. Our study showed that site-scale forest structure and composition characteristics are important for bird species richness and functional richness. Forest patches with high tree species diversity and structural complexity should be maintained to conserve forest specialists, bird species richness and functional richness.

The histology and growth rate of Nile crocodile (Crocodylus niloticus) claws.

The histology and growth of reptilian and crocodilian claws (ungues) have been extensively studied; however, Nile crocodile (Crocodylus niloticus) claws have not received adequate attention. Furthermore, age estimations for reptilian claws remain unexplored, despite Nile crocodile claws being used in long-term dietary reconstruction studies, assuming certain age-related patterns. In this study, we investigate the histology and growth patterns of Nile crocodile claws, aiming to infer axes for sampling cornified material for radiocarbon dating and establish age estimations for crocodilian claws. Our findings reveal that Nile crocodile claws exhibit growth patterns similar to other reptilians, presenting as modified scutes/scales with an age profile along the sagittal plane. This profile starts at the basal germ matrix and progressively expands in thickness and age dorsoventrally towards the apex or "tip." Consequently, the oldest corneous material is concentrated at the most dorsal point of the claw's apex. To validate previous dietary reconstruction assumptions, we conducted radiocarbon dating on this region of the claw, which supported the idea that retained corneous material in the claws is typically relatively young (5-10 years old) due to abrasion. Our study contributes insights into the histology and growth dynamics of Nile crocodile claws, shedding light on their use in dietary reconstruction studies and emphasizing the significance of considering age-related assumptions in such investigations.

Long-term concentration of tropical forest nutrient hotspots is generated by a central-place apex predator.

Apex predators typically affect the distribution of key soil and vegetation nutrients through the heterogeneous deposition of prey carcasses and excreta, leading to a nutrient concentration in a hotspot. The exact role of central-place foragers, such as tropical raptors, in nutrient deposition and cycling, is not yet known. We investigated whether harpy eagles (Harpia harpyja) in Amazonian Forests-a typically low soil fertility ecosystem-affect soil nutrient profiles and the phytochemistry around their nest-trees through cumulative deposition of prey carcasses and excreta. Nest-trees occurred at densities of 1.5-5.0/100 km2, and each nest received ~ 102.3 kg of undressed carcasses each year. Effects of nests were surprisingly negative over local soil nutrient profiles, with soils underneath nest-trees showing reductions in nutrients compared with controls. Conversely, canopy tree leaves around nests showed significant 99%, 154% and 50% increases in nitrogen, phosphorus and potassium, respectively. Harpy eagles have experienced a 41% decline in their range, and many raptor species are becoming locally extirpated. These are general examples of disruption in biogeochemical cycles and nutrient heterogeneity caused by population declines in a central-place apex predator. This form of carrion deposition is by no means an exception since several large raptors have similar habits.