Food Habitats of the Breeding Long-Legged Buzzard (Buteo rufinus) in Northwestern China

South Polar skua (Stercorarius maccormicki) and Brown skua (Stercorarius antarcticus lonnbergi) have opportunistic feeding habits and are the dominant predators in terrestrial Polar regions. These skuas exploit a wide range of food items, including marine organisms, other birds, and even garbage. In the present study, we compare the diets of these two skua species during the breeding season, using pellets and prey remains collected within their territories. The samples were collected at six sites in Admiralty Bay, on King George Island, Antarctica. We identified eight different items, which we classified as “penguin”, “flying bird”, “skua”, “fish”, “gastropod”, “krill”, “egg” and “marine debris”. In the first breeding season (2008/2009), penguins and flying birds were the food resources more abundant for both skua species, and their diet composition was similar. In the second breeding season (2010/2011) South Polar skua exploited more fish and flying birds than Brown skua; the latter exploited more eggs and penguins. Our findings corroborate those of previous studies, demonstrating that in sympatry South Polar skua exploit more fish than Brown skua. The diet of South Polar skua also varied between breeding seasons, reflecting the opportunistic foraging behavior of these skuas. As in other studies, we recorded that skua is a food resource for both skua species, but it was more common in the diet of South Polar skua. Marine debris was recorded only in the samples of Brown skua. Birds are important food items for both skuas, although significant differences were found in the diets of these sympatric species, with shifts in the composition of the diet probably reflecting fluctuations in the abundance of prey populations, which are known to be common at Admiralty Bay, although more data will be needed to confirm this link.

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Corticosterone secretion in tuatara (Sphenodon punctatus): Influential factors and conservation applications

10.26686/wgtn.17013119.v1 ◽

2021 ◽

Author(s):

◽

Lindsay Erin Anderson

Keyword(s):

Breeding Season ◽

Physiological Stress ◽

Population Variation ◽

Monitoring Tool ◽

Extrinsic Factors ◽

Corticosterone Secretion ◽

Wide Range ◽

Sphenodon Punctatus ◽

Gravid Females

Animals are regularly exposed to environmental, social and physiological challenges. In reaction to these challenges, individuals adjust their physiology and behaviour to maintain essential processes and optimise fitness. The most widely used indicators of physiological stress in vertebrates are glucocorticoid hormones (corticosterone (CORT) or cortisol), which are commonly referred to as ‘stress hormones’. The use of CORT as a tool to understand how individuals respond to natural or human-caused challenges is central to stress physiology research. Here, I investigated intrinsic and extrinsic factors associated with CORT secretion, CORT secretion as an indicator of physiological response to challenges/stressors, and the value of CORT secretion as conservation tool in an iconic protected reptile (the tuatara, Sphenodon punctatus). A capture-restraint time series revealed a significant CORT response over a 24 h period in male and female (non-gravid and gravid) tuatara. Baseline CORT and the CORT response to capture and restraint (i.e. a standardised capture-stress protocol) were similar between sexes; however, female reproductive condition was correlated with CORT secretion in that higher baseline CORT and a lower CORT response were observed in gravid females. An observational study incorporating data across a wide range of ambient temperatures (from four island sites) confirmed that body temperature (Tb) is positively correlated with baseline CORT in gravid females only, and revealed a positive correlation between the CORT response and higher Tb in all adults. A supporting experimental study showed that acute ambient temperature increase (in which mean Tb reached 21.4±0.4°C) elicits a significant CORT response to capture-restraint in gravid females. These results confirmed that gravid females are not secreting CORT maximally during nesting, but actively modulate secretion. An inter-island comparison of CORT secretion (for four populations) revealed that baseline CORT secretion was similar among populations during the non-breeding and breeding seasons; however, the CORT response to capture-restraint varied significantly among populations. Inter-population variation in testosterone (T) was observed in males (but not females) and was positively linked with increased baseline CORT from the non-breeding season to the breeding season, suggesting male reproductive activity may drive seasonal change of baseline CORT. Significant correlations were observed between the CORT response to capture-restraint (but not baseline CORT) and habitat elements of latitude, tuatara density and seabird abundance and 2) demogenetic factors of sex ratio and genetic diversity. The measurement of CORT as a physiological monitoring tool indicated that short- and long- term dynamics of CORT secretion in tuatara are not altered through translocation to a new island, as the acute CORT response remained stable throughout exposure to cumulative stressors and long-term dynamics of CORT secretion in translocated populations simultaneously mirrored those in source populations. These findings deliver the most detailed study of CORT secretion patterns in tuatara to date. Moreover, as the first study to apply CORT secretion data as an conservation physiology monitoring tool in tuatara, these results serve as a baseline reference for future research and monitoring of conservation efforts.

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Vegetation height and egg coloration differentially affect predation rate and overheating risk: an experimental test mimicking a ground-nesting bird

Canadian Journal of Zoology ◽

10.1139/z2012-035 ◽

2012 ◽

Vol 90 (6) ◽

pp. 694-703 ◽

Cited By ~ 14

Author(s):

H. Gillis ◽

B. Gauffre ◽

R. Huot ◽

V. Bretagnolle

Keyword(s):

Predation Risk ◽

Breeding Season ◽

Nest Site Selection ◽

Artificial Nests ◽

Vegetation Height ◽

Selective Pressures ◽

Wide Range ◽

Nest Microclimate ◽

Egg Coloration ◽

Ground Nesting

Avian eggs need to be laid in protected environments to develop and survive. Nest predation is known as the main cause of breeding failure for many birds, but nest microclimate conditions are also important for embryo development. These two selective pressures are particularly marked in ground-nesting birds. Vegetation height has been shown to be a critical factor for nest-site selection in ground-nesting birds because it can counteract predation and overheating simultaneously. It is therefore difficult to disentangle the respective influences of these risks on selection of a particular nest vegetation height. To develop a conceptual framework for understanding and predicting the relative effects of vegetation on predation and nest microclimate during a breeding season, we used vegetation height to manipulate differentially these two risks. We therefore exposed artificial nests to a wide range of vegetation heights, replicated the experimental tests during spring, and manipulated egg color to estimate predation risk. We confirmed that tall vegetation is relevant to protect unattended eggs against both risks. Whereas predation risk is stable for a given vegetation height, overheating risk presents inter- and intra-seasonal variations. Therefore, over a breeding season, for a given vegetation height, the respective strengths of the two risks are unbalanced and depends on egg coloration. The breeding strategy of ground-nesting birds thus should have been shaped by both selective pressures, but the ultimate choice may depend on the species-specific laying dates and alternative behavioral strategies for protecting the clutch. This study provides new perspectives to investigate avian parental behaviour.

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Black Harrier Circus maurus of the Fynbos biome, South Africa: a threatened specialist or an adaptable survivor?

Bird Conservation International ◽

10.1017/s0959270904000310 ◽

2004 ◽

Vol 14 (4) ◽

pp. 233-245 ◽

Cited By ~ 15

Author(s):

ODETTE CURTIS ◽

ROBERT E. SIMMONS ◽

ANDREW R. JENKINS

Keyword(s):

South Africa ◽

Nest Predation ◽

Breeding Habitat ◽

Future Research ◽

Coastal Plains ◽

Limited Evidence ◽

Direct Observations ◽

Wide Range ◽

Prey Remains ◽

Alien Vegetation

Black Harrier Circus maurus is a rare southern African endemic that may have lost over 50% of its core breeding habitat in the last century as a result of extensive land transformation by agriculture, invasive alien vegetation and urbanization in the Fynbos biome. We partially surveyed both the western (Swartland) and southern (Overberg) coastal plains of south-western South Africa, over 3 years (2000–2002) for breeding Black Harriers, and found a distinctly polarized distribution. Nests were concentrated either along the coastal strip or inland in montane habitats, and generally absent from heavily cultivated and transformed inland plains areas. Limited evidence (direct observations, prey remains) suggests that harriers forage in cereal croplands but generally do not breed in these modified environments. We recorded breeding success at nests in coastal (Dune Thicket) and montane (Mountain Fynbos) habitats. Harriers bred successfully along the coast and nests were aggregated in loose colonies around wetlands. Harriers in montane environments bred poorly, took a wide range of prey, and were subject to high levels of nest predation. We propose that Black Harriers have been displaced from lowland Renosterveld and Fynbos habitats (characterized by better foraging and nesting opportunities), primarily by the advent and spread of cereal agriculture. The conservation and future research implications of this hypothesis are discussed.

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Corticosterone secretion in tuatara (Sphenodon punctatus): Influential factors and conservation applications

10.26686/wgtn.17013119 ◽

2021 ◽

Author(s):

◽

Lindsay Erin Anderson

Keyword(s):

Breeding Season ◽

Physiological Stress ◽

Population Variation ◽

Monitoring Tool ◽

Extrinsic Factors ◽

Corticosterone Secretion ◽

Wide Range ◽

Sphenodon Punctatus ◽

Gravid Females

Animals are regularly exposed to environmental, social and physiological challenges. In reaction to these challenges, individuals adjust their physiology and behaviour to maintain essential processes and optimise fitness. The most widely used indicators of physiological stress in vertebrates are glucocorticoid hormones (corticosterone (CORT) or cortisol), which are commonly referred to as ‘stress hormones’. The use of CORT as a tool to understand how individuals respond to natural or human-caused challenges is central to stress physiology research. Here, I investigated intrinsic and extrinsic factors associated with CORT secretion, CORT secretion as an indicator of physiological response to challenges/stressors, and the value of CORT secretion as conservation tool in an iconic protected reptile (the tuatara, Sphenodon punctatus). A capture-restraint time series revealed a significant CORT response over a 24 h period in male and female (non-gravid and gravid) tuatara. Baseline CORT and the CORT response to capture and restraint (i.e. a standardised capture-stress protocol) were similar between sexes; however, female reproductive condition was correlated with CORT secretion in that higher baseline CORT and a lower CORT response were observed in gravid females. An observational study incorporating data across a wide range of ambient temperatures (from four island sites) confirmed that body temperature (Tb) is positively correlated with baseline CORT in gravid females only, and revealed a positive correlation between the CORT response and higher Tb in all adults. A supporting experimental study showed that acute ambient temperature increase (in which mean Tb reached 21.4±0.4°C) elicits a significant CORT response to capture-restraint in gravid females. These results confirmed that gravid females are not secreting CORT maximally during nesting, but actively modulate secretion. An inter-island comparison of CORT secretion (for four populations) revealed that baseline CORT secretion was similar among populations during the non-breeding and breeding seasons; however, the CORT response to capture-restraint varied significantly among populations. Inter-population variation in testosterone (T) was observed in males (but not females) and was positively linked with increased baseline CORT from the non-breeding season to the breeding season, suggesting male reproductive activity may drive seasonal change of baseline CORT. Significant correlations were observed between the CORT response to capture-restraint (but not baseline CORT) and habitat elements of latitude, tuatara density and seabird abundance and 2) demogenetic factors of sex ratio and genetic diversity. The measurement of CORT as a physiological monitoring tool indicated that short- and long- term dynamics of CORT secretion in tuatara are not altered through translocation to a new island, as the acute CORT response remained stable throughout exposure to cumulative stressors and long-term dynamics of CORT secretion in translocated populations simultaneously mirrored those in source populations. These findings deliver the most detailed study of CORT secretion patterns in tuatara to date. Moreover, as the first study to apply CORT secretion data as an conservation physiology monitoring tool in tuatara, these results serve as a baseline reference for future research and monitoring of conservation efforts.

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Theileria, Hepatozoon and Taenia infection in great gerbils (Rhombomys opimus) in northwestern China

International Journal for Parasitology Parasites and Wildlife ◽

10.1016/j.ijppaw.2021.04.002 ◽

2021 ◽

Author(s):

Na Ji ◽

Xueling Chen ◽

Gang Liu ◽

Shanshan Zhao ◽

Wenbo Tan ◽

...

Keyword(s):

Northwestern China ◽

Rhombomys Opimus

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Seasonal and social factors associated with spacing in a wild territorial electric fish

10.1101/2020.01.29.924761 ◽

2020 ◽

Cited By ~ 3

Author(s):

Lucía Zubizarreta ◽

Laura Quintana ◽

Daniel Hernández ◽

Franco Teixeira de Mello ◽

Mariana Meerhoff ◽

...

Keyword(s):

Body Size ◽

Dissolved Oxygen ◽

Breeding Season ◽

Electric Fish ◽

Behavioral Plasticity ◽

Gonadal Hormones ◽

Social Contexts ◽

Weakly Electric Fish ◽

Territory Size ◽

Wide Range

AbstractThe expression of territorial behavior in wild species is especially suited to explore how animals integrate individual traits with dynamic environmental and social contexts. In this study, we focused on the seasonal variation of the determinants of territory size in the weakly electric fish Gymnotus omarorum. This species is a seasonal breeder that displays year-long territorial aggression, in which female and male dyads exhibit indistinguishable non-breeding territorial agonistic behavior and the only significant predictor of contest outcome is body size. We carried out field surveys across seasons that included the identification of individual location, measurements of water physico-chemical variables, characterization of individual morphometric and physiological traits, and their correlation to spatial distribution. Although Gymnotus omarorum tolerates a wide range of dissolved oxygen concentration, territory size correlated with dissolved oxygen in both seasons. In the non-breeding season, we show that territory size is sexually monomorphic and explained only by body size. In the breeding season, while body size no longer correlated with territory size, evidence of sexual differences in territory size determinants emerged. First, the overall spatial arrangement adopted a sexual bias. Second, territory size depended on gonadal hormones in both sexes, which was expected for males, but not previously reported in females. Third, females’ territory size correlated with gonadal size and females showed relatively larger territories than males, probably to meet sexually dimorphic energetic requirements. This study provides evidence of seasonal changes in factors correlated with territory size and contributes to the understanding of the mechanisms underlying behavioral plasticity.

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Morphological and molecular analyses of Taenia and Mesocestoides species from red foxes (Vulpes vulpes) in northwestern China

10.21203/rs.3.rs-885658/v1 ◽

2021 ◽

Author(s):

Gang Liu ◽

Na Ji ◽

Sándor Hornok ◽

Yu Zhang ◽

Shanshan Zhao ◽

...

Keyword(s):

Life Cycle ◽

Vulpes Vulpes ◽

Red Fox ◽

Novel Species ◽

Northwestern China ◽

Red Foxes ◽

Predator Species ◽

Molecular Analyses ◽

Sequence Identity ◽

Rhombomys Opimus

Abstract Background The red fox (Vulpes vulpes) is a geographically widespread predator species, occurring across the northern Hemisphere. It has high veterinary-medical significance, in part owing to its definitive host role in the life cycle of several tapeworm species, including zoonotic ones. However, there have been only few reports on cyclophyllid tapeworm (Cestoda: Cyclophyllidea) infection in red foxes from China. Methods In this study, 263 tapeworms were collected from eight road-killed red foxes in Xinjiang Uygur Autonomous Region (XUAR, northwestern China). The tapeworms were analyzed based on morphological characters and mitochondrial cytochrome c oxidase subunit 1 (cox1) gene sequences. Results 83 Taenia and 180 Mesocestoides tapeworms were identified according to the presence or absence of rostellum, and the number, the length and the shape of the large rostellar hooks. The morphological and molecular analyses revealed that i) 180 Mesocestoides tapeworms, here named as Mesocestoides sp. Vulpes vulpes, showed 99.21% (378/381 bp) identity to Mesocestoides sp. reported from red fox in Mongolia; and ii) 83 Taenia tapeworms belonged to three species. The first Taenia species (n = 16, named as Taenia sp. Vulpes vulpes), based on the length of large rostellar hooks (337–342 µm) and its cox1 sequence, was identified as a potentially novel species, which is phylogenetically close to Taenia laticollis. The second species (n = 54, named as Taenia sp. Vulpes vulpes & Rhombomys opimus), was morphologically similar to Taenia endothoracicus according to the number (n = 52), the length (319–332 µm) and the shape of the large rostellar hooks. This species, infecting three red foxes, shared 100% cox1 sequence identity with Taenia sp. Rhombomys opimus genotype C found previously in great gerbils (Rhombomys opimus) in the same region. The third species (n = 13, named as Taenia polyacantha-like), had shorter large rostellar hooks (178–180 µm) and showed 96.27% (361/375 bp) sequence identity to Taenia polyacantha reported from red fox in Italy. In addition, co-infections with two Taenia species and with Taenia and Mesocestoides species were also demonstrated. Conclusions The “great gerbil-red fox” life cycle of Taenia sp. Vulpes vulpes & Rhombomys opimus, belonging to the mitochondrial lineage of T. endothoracicus, is confirmed. The T. polyacantha-like species and Mesocestoides sp. Vulpes vulpes were found for the first time in red fox in China. Taenia sp. Vulpes vulpes is a potentially novel species, which is close to Taenia laticollis based on its phylogenetic properties. The life cycle of Taenia sp. Vulpes vulpes and Mesocestoides sp. Vulpes vulpes should be further explored.

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Seasonality of Food Use and Caching in New Zealand Robins (Petroica Australis)

10.26686/wgtn.16922902.v1 ◽

2021 ◽

Author(s):

◽

Jamie Ernest Sherred Steer

Keyword(s):

New Zealand ◽

Breeding Season ◽

Food Resource ◽

Time Of Day ◽

Competitive Response ◽

Food Caching ◽

Food Scarcity ◽

Wide Range ◽

In The Wild ◽

Environmental Instability

Foraging behaviour in birds is strongly determined by temporal factors such as season and time of day. Most birds show a limited number of food use methods such as consuming, feeding to conspecifics, or discarding. A relatively small number of birds also cache food for later use. The expression of caching in birds has been attributed to numerous factors. However, noting the environmental instability experienced by most caching species, researchers tend to cite survival of future food scarcity as the predominant advantage. Recording the food use behaviour of wild birds is typically difficult and time consuming, and many studies of north-temperate food-caching birds are limited by long caching distances, protracted caching durations, and a lack of year-round data. Additionally, food-caching in Australasian passerines has received limited quantification. The naïveté of the New Zealand robin (Petroica australis) makes it ideal for behavioural observations in the wild. Robins express a wide range of food use behaviours within close proximity of observers, and cached food is retrieved within a few days. Food use can be observed year-round in a temperate environment that is relatively stable. Thus, food use decisions in robins can be assessed in a wider context. In this study, behavioural data were collected from robins inhabiting the Karori Wildlife Sanctuary in Wellington. Robin behaviour was quantified by presenting monogamous, paired birds an ephemeral food resource and observing their responses. Seasonal variation in food use differed with sex and season. Birds mediated their food use in response to the presence of conspecifics. Males dominated food use year-round. During the breeding season, males cached little, mostly feeding familial conspecifics. However, non-breeding males selfishly cached food. Conversely, female caching propensity was mediated by courtship feeding during the breeding season, and the threat of male pilferage outside of it. Birds did not appear to anticipate future food scarcity. Instead, food was cached in the season in which retrieval would be least necessary. In robins, food is opportunistically cached, mainly as a competitive response to excess food.

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Molecular detection and genotyping of Enterocytozoon bieneusi in pet dogs in Xinjiang, Northwestern China

Parasite ◽

10.1051/parasite/2021057 ◽

2021 ◽

Vol 28 ◽

pp. 57

Author(s):

Yangwenna Cao ◽

Qinglin Tong ◽

Chenhao Zhao ◽

Aikebaierjiang Maimaiti ◽

Liwen Chuai ◽

...

Keyword(s):

Pcr Amplification ◽

Enterocytozoon Bieneusi ◽

Northwestern China ◽

Nuclear Ribosomal Dna ◽

Health Concern ◽

Pet Dogs ◽

Parasitic Fungi ◽

Type Iv ◽

Wide Range ◽

Significant Difference

Enterocytozoon bieneusi is an obligate intracellular parasitic fungi that infects a wide range of mammalian hosts. However, the literature is lacking information regarding the presence and diversity of E. bieneusi genotypes in domesticated dogs in Northwestern China. Fecal samples from 604 pet dogs were obtained in 5 cities (Urumqi, Korla, Hotan, Aksu, and Shihezi) in Xinjiang. Screening for E. bieneusi was performed, and isolates were genotyped via nested-PCR amplification of the internal transcribed spacer (ITS) of nuclear ribosomal DNA. The infection rate of E. bieneusi was 6.3% (38/604). The prevalence of E. bieneusi infections in adult animals (>1 year, 10.3%, 15/145) was higher than that in younger (≤1 year) dogs (5.0%, 23/459), which was statistically significant (p = 0.021). No significant difference was observed between the different collection sites or between sexes. Eight distinct genotypes were identified, including 5 known genotypes (PtEb IX, EbpC, D, CD9, and Type IV) and 3 novel genotypes (CD11, CD12, CD13). The most prevalent was genotype PtEb IX, being observed in 50.0% (19/38) of the samples, followed by EbpC (31.6%, 12/38), D (5.3%, 2/38), and the remaining genotypes (CD9, Type IV, CD11, CD12, and CD13) were observed in 1 sample (2.6%, 1/38) each. These findings suggest that genotypes PtEb IX and CD9 are canine host-adapted, and likely pose little risk of zoonotic transmission. Moreover, known zoonotic genotypes EbpC, D, and Type IV represent a public health concern and should undergo further molecular epidemiological investigation.

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