Nest Dimensions Research Articles

Breeding Success of Primary and Secondary Burrow-Nesting Birds on Stream Banks in Central Brazil

Underground burrow nests of three bird species: Amazonian Motmot Momotus momota, Rufous-tailed Jacamar Galbula ruficauda and Swallow Tanager Tersina viridis were monitored for eight years on stream banks, in a Seasonal Semideciduous Forest, to enable determining whether, or not, being a burrow excavator bird is associated with nest predation, and how important the role played by nest dimensions in this nesting system is. Predation was the main cause of nest failures, although there was no significant difference in nest predation between secondary (SCN) and primary (PCN) cavity (burrow)-nesting species. Offspring predation rate was the only one recording significant result; the lowest offspring predation rate was associated with PCN species — Amazonian Motmot but, again, there was no significant difference between PCN and SCN species. On the other hand, SCN species — Swallow Tanager has compensated offspring losses due to its increased fecundity, which enabled two broods per breeding season. No nest parameter has influenced predation rates, although our data suggested the need of further investigating the length of the nest access tunnel.

Further Information about the Nest, Eggs and Nestlings of the Copper-Rumped Hummingbird Saucerottia tobaci from Venezuela

The Copper-rumped Hummingbird Saucerottia tobaci is a polyphyletic hummingbird with seven recognized subspecies. Nonetheless, the most information on its nesting behavior come from the island race S. t. erythronotos. This study aims to describe a nesting event of S. t. feliciae, the most widespread mainland subspecies, in order to provide detailed information on its nest structure, eggs and nestling development, as well as report information related to the nesting success (survival strategies, potential threats), based on observations carried out from August to October 2021 in northern Venezuela. Features of nest (composition, form, dimensions), eggs (appearance, dimensions, mass) and nestling development data from hatching to fledging time (body length, bill, wings, tail, and body mass) were all recorded in detail. The nest was an open saddle-type, cream in color, built of silky vegetable down, silky fibers of moth cocoon, mossy stuffs, pieces of lichen and spider’s web. Nest dimensions (mm): outer-cup depth: 40.7; inner-cup depth: 18.0; base-bed: 22.7; cup-rim thickness: 10.0–12.0; cup-rim length: 40.4; cup-rim wide: 18.4. Two oval-shaped eggs were laid inside, white in color, without spots or blots, smooth in texture, and non-glossy. Egg mass (0.6 ± 0 g; n = 2), egg length (13.95 ± 0.07 mm; n = 2), egg width (9.4 ± 0.14 mm; n = 2). Both eggs were incubated during 16 days. Nestlings were born almost completely naked, dark skin above, reddish beige below; bill yellow with the tip red and blunt; eyes closed. Nestling body mass at hatching (0.6 ± 0 g, n = 2), fledgling period (23 days). First feather barbs (day 10), eyes open (day 10), nestling totally feathered (day 16), and nestling body mass at fledging (4.7 g, n = 1). Survival strategies were nest camouflage, roof protection, female motionlessness, distraction displays and mobbing behavior. The nest was also close to a bumblebee nest and an artificial feeder. Potential threats included nest predators and heavy rains. This study introduces novel information on nesting behavior of a mainland subspecies and suggests that S. t. feliciae resembles S. t. erythronotos with slight differences in terms of nest construction, and eggs mass and length. Data on other nests, including those of other Venezuelan subspecies, are necessary to fully categorize the nesting behavior of this hummingbird in order to identify critical subspecific elements (e. g. nest materials, nestling´s food, human impact, additional nest predators and parasites) needed for its conservation in future.

Management of Centris analis(Hymenoptera: Apidae): Investigating the Ideal Dimensions of Trap Nests for Use in Crop Pollination.

Centris analis (Fabricius, 1804) is a solitary, cavity-nesting bee that is often recorded in studies through the use of trap nests. This species is considered to be a good candidate as a manageable pollinator for some orchards. However, further studies are still needed to optimize its rational rearing. This study sought to analyze female preference for different lengths and diameters of trap nests, as well as the effects of nest dimensions on the number of constructed cells, mortality rates, parasitism rates, and sex ratio. We used compact trap nests comprised of tubes with internal diameters ranging from 0.6 to 0.8cm, and lengths ranging from 8 to 12cm. The results showed that females preferred the narrowest (0.6 and 0.7cm) and two of the longest cavities (10 and 12cm). The greatest number of cells built was observed in the most used lengths. The lengths that were tested did not affect the mortality or parasitism rates or the sex ratio. Based on our findings concerning the dimensions examined, we recommend using the narrowest and longest cavities. The combined analyses of the tested parameters (diameter and length) demonstrated new data that can help improve the rearing and maintenance techniques applied to C. analis populations.

Composition of nests constructed by species in the Motacillidae, Sylviidae and Prunellidae

Bird nests can be complex bio-engineered structures constructed from a range of materials to provide a site for incubation, and in many species chick rearing. Reports of the materials used in nest walls and cup linings are typically qualitative and do not assist in understanding the functional properties of the structure as a whole. This paper provides size and composition data for nests from four species of the Motacillidae family: the meadow pipit ( Anthus pratensis), pied wagtail ( Motacilla alba), grey wagtail ( Motacilla cinerea), and the yellow wagtail ( Motacilla flava), three species of the Sylviidae family: willow warbler ( Phylloscopus trochilus), Eurasian reed warbler ( Acrocephalus scirpaceus) and Eurasian blackcap ( Sylvia atricapilla), and the dunnock ( Prunella modularis) of the Prunellidae family. Three hypotheses were tested: do nest dimensions correlate with body mass? Is it possible to distinguish among species based on their nest composition; and for individual species? Is it possible to distinguish between the cup lining and outer nest wall based on the materials used in construction? Nest composition and size varied among species although the degree of intra-specific variation was different. Size of a nest was unrelated to average female adult body mass. Composition relied on similar types of materials but in differing quantities between species. It was possible to distinguish among species in terms of nest construction, and between the cup lining and the outer nest, on the basis of at least one of the component materials. By providing quantitative data on composition, it may be possible in the future to understand better the structural, insulative and hydrological properties of the nest. Such information will be invaluable as we begin to develop an understanding of the factors that have driven evolution of nest architecture.

Nest Dimensions, Burrow-Lining, and Decoration Behavior of Burrowing Owls in the Pampas

Nesting in burrows is uncommon among birds, but one example of a burrow-nesting raptor is the Burrowing Owl (Athene cunicularia). In most areas of North America, where this raptor has been extensively studied, it typically uses burrows of fossorial mammals, but in southern South America this owl digs its own burrows. We studied characteristics of size, lining, and decoration of Burrowing Owl nests located in dunes, rural areas, and urban areas of the Pampas of Argentina, and analyzed whether such characteristics vary according to land cover. We found that Burrowing Owls construct burrows of similar characteristics in the three habitats sampled, although nests in dunes had wider entrances and longer tunnels. Such variation might relate to the soil, which is more compacted in the dunes than at the rural and urban areas. In both rural and urban areas, owls used manure to line the burrow and decorated the nest entrance with visible objects, but the diversity and amount of materials used for decoration was much higher in urban nests. Our results on burrow measurements, burrow-lining, and decoration behavior of Burrowing Owls in the Pampas were consistent with those reported for North American populations, even though burrow construction processes differ at both ranges of the species' distribution.

Reproductive Ecology of the Hainan Four Eye-Spotted Turtle (Sacalia insulensis) on Hainan Island, China

From 2000 to 2002, the reproductive ecology of the endangered Hainan four eye-spotted turtle (Sacalia insulensis) was studied on Hainan Island, China. A total of 147 adult females were captured, and their reproductive status was evaluated by palpation, X-ray imaging, and ultrasound. Twenty-two gravid females were under observation when they laid their eggs. We observed gravid females and nesting behavior along stream banks between December and April. Nest dimensions ranged from 5 to 6 cm in diameter and from 2 to 3 cm in depth. No females in our study produced more than 1 clutch per season. Clutch size average was 1.9 eggs (range = 1–3 eggs, SD = 0.56, n = 22) with an average egg mass of 16.05 g (range = 11.8–21.0 g, SD = 2.417, n = 21), an average egg width of 2.36 cm (range = 2.1–2.7 cm, SD = 0.135, n = 21), and an average length of 4.65 cm (range = 3.9–5.3 cm, SD = 0.400, n = 21). Hatching success rate was 53%, and hatchlings emerged after an average of 120.9 d (range = 98–148 d, SD = 14.94, n = 21) in late June to early July. The mean nesting site ground temperature was 24.43°C (range = 15.0°C–30.2°C, SD = 2.712, n = 7).

Comparative nesting patterns and success of Mynas and Starlings (Aves: Sturnidae) inhabiting Jahangirnagar University campus, Bangladesh

Nesting patterns of four species of mynas and starlings, Common Myna (Acridotheres tristis), Jungle Myna (Acridotheres fuscus), the Asian-pied Starling (Gracupica contra) and Chestnut-tailed Mtarling (Sturnia malabarica) were studied in Jahangirnagar University campus from March to September in 2016. Nests were searched systematically throughout the study area and nesting parameters like nest dimensions, nest-site selection, tree species preference, nesting materials, clutch size and nesting success were examined. A total of 101 nests were recorded where 31 nests were of Common Myna, 10 of Jungle Myna, 49 of the Asian-pied Starling and 11 nests were of Chestnut-tailed Starling. Overall, the sturnids preferred nesting on trees (n=84) to anthropogenic structures (n=17). Common myna showed maximum variation in nest-site selection using tree holes (n=12), tree branches (n=10) and building cornices, holes or crevices (n=9) whereas Chestnut-tailed Starling nested only in tree cavities (n=11). Jungle Myna built nests both in tree holes (n=4) and in building holes and crevices (n=6). The Asian-pied Starlings built their domed nests mostly on tree branches (n=47) where 69% nests were peripheral and 31% were central in position. Out of 20 species of trees utilized for nesting purpose, the majority of nests were built on Whites iris Albizia procera (n=18) followed by Neem Azadirachta indica (n=10) and Mahogany Swietenia mahagoni (n=10). The nests were constructed between 2 and 18m (8±3.8m) from the ground level. Among 19 types of nesting materials recorded, twigs, leaves, straws, grasses, feathers, plastics and polythene were frequently used by all four species while the Asian-pied starling used more rubbish materials than other species. Highest nesting success (80%) was recorded in Common Myna whereas the Asian-pied Starling, Chestnut-tailed Starling and Jungle Myna had 77.8%, 75% and 66.7% of nesting success respectively. Adaptions to using different nesting sites in Common Myna and comparatively higher nesting height in the Asian-pied Starling may have facilitated the greater nesting success.
 Bangladesh J. Zool. 48(2): 321-334, 2020

Comparison of Nesting Features and Breeding Success of Turtle Dove Streptopelia turtur between Orchards and Riparian Habitats

The European turtle dove Streptopelia turtur breeds in both farmlands and woodlands, and it is important to explore the difference in breeding ecology of this threatened game in these two ecosystem types. This study, carried out during four years (2015–2018), compares nesting features of this species and its breeding success between apple orchards and riparian vegetation in Midelt Province, Morocco. The main result revealed that the nest placement, including nesting-tree height and nest height, is similar between orchards and riparian trees. However, the nest dimensions (big and small diameters) were larger in orchards. Correlations were variable among nest placement parameters and dimensions. On the contrary, in four breeding seasons, where 566 nests were monitored (467 in orchards and 99 in riparian sites), the average breeding success was different (57% of chicks in apple farms and 53% in riparian vegetation). Moreover, in apple orchards, clutches’ failure is due to both predation (18.89% of eggs and 10.54% of chicks) and temperature lowering (5.03% of unhatched eggs and 5.49% of dead chicks), while in riparian vegetation, the loss is due to nest desertion (21.33% of clutches) and mostly predation (33.16% of clutches).

Implications of nest relocation for morphology and locomotor performance of green turtle (Chelonia mydas) hatchlings

Sea turtle scute abnormalities are observed in higher proportion in hatchlings compared to adults, suggesting that hatchlings with a non-modal scute pattern (NMSP) have a lower chance of surviving to adulthood. In this study, we collected 732 newly emerged hatchlings from Redang Island, Malaysia, and compared their scute classification, size, and mass to fitness correlates (self-righting ability, crawling speed, and swimming speed). We investigated the proportion of hatchlings from each nest with NMSP to determine if there was a correlation with incubation duration or clutch relocation. We found relocated clutches at Chagar Hutang Turtle Sanctuary had a significantly shorter incubation duration with a higher proportion of NMSP compared to in situ clutches. Hatchlings’ mass were significantly heavier from in situ clutches compared to relocated clutches, although there were no significant differences of hatchling speed based on scute classification or clutch type. The difference of hatchling mass between in situ and relocated clutches could affect predation and mortality rates on recently emerged hatchlings. These findings have important conservation implications, suggesting that relocation should only be implemented on clutches with a high potential to be disrupted or with a low chance of survival if left in situ. Our findings highlight the need for a standard procedure when clutch relocation is used as a conservation strategy. Relocation should replicate natural nest dimensions by duplicating both nest width and depth, and clutches should be relocated to similar shade conditions as the natural nest.

Mass of white stork nests predicted from their size: Online calculator and implications for conservation

Ecologists and wildlife managers require useful tools to reduce the human-wildlife conflict. So far, little attention has been paid to the damage caused by avian nesting on man-made structures. We weighed 145 occupied nests of the white stork (Ciconia ciconia) in eastern Poland and applied general linear models (multiple regressions) to predict a nest’s mass from its measurements. Nests measured showed large variation in size (mean ± SD = 140.9 ± 23.7 cm, range: 80–230 cm in diameter; 59.7 ± 27.8 cm, range: 10–140 cm in height) and weighted 70–1348 kg (mean ± SD: 378 ± 251 kg). We set up a free online calculator which uses model equations to estimate nest masses given nest dimensions. Apart from the management application, it can be used in ecological research, e.g. nests tracked over subsequent seasons, and even into account weather data to assess the effect of climate change.

Nesting features and breeding chronology of the crested coot (Fulica cristata) in two North African high altitude wetlands

The current study aimed to investigate the nesting behavior and breeding chronology of the crested coot (Fulica cristata) in Morocco’s high altitude wetlands. We monitored nesting activities and breeding phenology in two wetlands, Zerrouka and Hachlaf lakes, to achieve our goals. Besides, nesting materials and nest dimensions were analyzed to characterize the crested coot nests. As a result, 52 nests were found in two sites, 18 in Zerouka and 34 in Hachlaf. Nests were built by available twigs on each site, and nest dimensions varied between analyzed wetlands. Nests were larger in Zerrouka compared to Hachlaf Lake. To protect their nests, coots select open waters and submerged vegetation as nesting sites. On the other hand, breeding chronology, including nesting, laying, and hatching dates, was earlier in Zerrouka Lake than Hachlaf. The nesting activities started at Zerrouka during January and February, while at Hachlaf, breeding attempts started during April.

Nest building, dimension, and selection of aromatic and medicinal twigs to repel ectoparasites in the European Turtle dove

Studies incorporating the nesting behavior and ecology of parasite disease in the European turtle dove during breeding periods are rare. This research examined nest features and nesting materials in Turtle doves to characterize nest dimensions, build, and incorporate vegetation, mainly aromatic and medicinal plants. In parallel, we estimated the ectoparasite load on chicks to verify an eventual relation between odorant plants and pathogen loads. The study was carried in apple orchards at Okhaja Ait Ayach, Midelt province Morocco, during 2015 and 2016. The obtained results demonstrate that the Turtle dove constructs a medium nest, compared to its body size, using several plant species, including medicinal and aromatic species known for their toxicity against pathogens. The inhibition capacity of nesting materials is reflected in parasite loads since only 8% of chicks were infested with Columbicola columbae and Dermanyssus gallinae. Repellent materials in nests are a successful behavioral strategy for this declining game to protect nestlings against pathogens.

Nest and egg description of the Andean Guan (Penelope montagnii, Cracidae)

Chachalacas, guans, and curassows are the most threatened Neotropical birds. However, information about their reproduction has not been well-documented for several species. Here, we provide the first description of nest and eggs of the Andean Guan (Penelope montagnii) in Andean highland forests from Colombia. We also compile nest and egg characteristics in the other 14 Penelope species. An active nest made of dry leaves and ferns was found over a simple platform 1.22 m above the ground on a Daphnopsis caracasana tree. Like other Penelope species, clutch size consisted of three oval and white eggs. The average egg measurements and mass were as follows: 69.66 mm × 46.32 mm, 81.6 g. We gathered the available information on the nest type, nesting materials, phorophyte, nest dimensions, the distance of the nest to the ground, and the clutch size and egg dimensions for all Penelope species. We only found three species with detailed information of eggs and nests, besides the Andean Guan reported here. In general, these species construct their nests over simple platforms, employing plant materials available from the environment. Nests present dimensions with external and internal diameters between 30–60 cm and 18–38.5 cm respectively, and depths ranging from 5 to 25 cm. Importantly, these trends are far to be conclusive due to the remarkable gaps of knowledge in nesting ecology for most of Penelope species. We encourage additional studies on reproductive ecology for these birds.

Assessing climatic and intrinsic factors that drive arthropod diversity in bird nests

Bird nests are specialized structures that act as microrefuge and a source of food for arthropods. Nest arthropod richness and composition may vary according to the nest builder, geographical location and nest size. Because information on nest arthropods is scarce, there are even fewer studies on the drivers of nest arthropod diversity. We characterized arthropod diversity in cup- and dome-shaped nests along a 130 km latitudinal gradient in the mediterranean-type region of Central Chile and, we assessed whether nest dimensions and climatic factors explain richness (alpha-diversity). Then, we evaluated whether climatic differences between sites explain arthropod nest composition (beta-diversity). All collected nests hosted at least one arthropod specimen. We identified 43 taxonomic entities (4.2 entities per nest ± 0.5, mean ± SE, n = 27 nests) belonging to 18 orders and five classes: Arachnida, Diplopoda, Entognatha, Insecta and Malacostraca. We observed differences in nest arthropod richness and composition related to sites but not bird species. Larger nests supported greater arthropod richness. Furthermore, we observed that climatic differences explain the variation in arthropod composition between sites. Nests in the northern region (drier and warmer) mainly hosted Hemipterans and Hymenopterans. Contrary, nests in the southern region (humid and colder) hosted species of Collembola, Dermaptera, and Diplopoda. Positive relationship between nests surface area with arthropod richness suggests us that larger nests may keep more resources. Our study sheds light on a crucial interaction which may have potential consequences for insect assemblage composition and bird reproductive biology.

Nest Dimensions, Burrow-Lining, and Decoration Behavior of Burrowing Owls in the Pampas

Nesting in burrows is uncommon among birds, but one example of a burrow-nesting raptor is the Burrowing Owl (Athene cunicularia). In most areas of North America, where this raptor has been extensively studied, it typically uses burrows of fossorial mammals, but in southern South America this owl digs its own burrows. We studied characteristics of size, lining, and decoration of Burrowing Owl nests located in dunes, rural areas, and urban areas of the Pampas of Argentina, and analyzed whether such characteristics vary according to land cover. We found that Burrowing Owls construct burrows of similar characteristics in the three habitats sampled, although nests in dunes had wider entrances and longer tunnels. Such variation might relate to the soil, which is more compacted in the dunes than at the rural and urban areas. In both rural and urban areas, owls used manure to line the burrow and decorated the nest entrance with visible objects, but the diversity and amount of materials used for decoration was much higher in urban nests. Our results on burrow measurements, burrow-lining, and decoration behavior of Burrowing Owls in the Pampas were consistent with those reported for North American populations, even though burrow construction processes differ at both ranges of the species' distribution.

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.

Geographical location affects size and materials used in the construction of European Pied Flycatcher (Ficedula hypoleuca) nests

BackgroundNest construction is a key element of avian reproductive behaviour and the result is often a complex structure that is used for incubation of eggs, which represents an extended phenotype. It is known that nest construction is a plastic behaviour but the extent to which plasticity is observed in a single species with a wide geographical distribution is largely unknown. This study sought to better understand variation in nest size and composition across a very wide geographical area. The hypothesis suggested that location would affect size but not composition of nests of the European Pied Flycatcher (Ficedula hypoleuca).MethodsNests and reproductive data were collected from seventeen study sites, spread over 6° of latitude and 3.3° of longitude on the island of Great Britain. Dimensions of nests were measured before they were deconstructed to determine the masses and types materials used in the outer nest and the cup lining.ResultsGeographical variation was observed in base thickness of nests but not many other dimensions. Nests varied in composition but were mainly made of leaf, moss, bark, grass, root and fern. Moss was used more to the north and east of the study area compared with more leaf mass towards the south and west. The species of leaf and bark used in the nests varied between geographical locations. Additionally, the use of leaves or bark from a particular tree species did not reflect the incidence of the tree species in the immediate territory.ConclusionsThis study showed that nest composition was affected by geographical location over a wide area. Variation between nests at each location was high and so it was concluded that differences in nest composition reflect individual selection of materials but evidence is such that it remains unclear whether this is deliberate to fulfil a specific role in the nest, or simply opportunistic with birds simply picking up materials with the appropriate characteristics as they find them outside their nestbox.

The Study of Bioindicators Possibilities of Ants (Hymenoptera: Formicidae) Under the Conditions of Industrial Pollution

Ant assemblages were studied under the influence of chemical, coal and cement dust, lead-zinc and metallurgical industry wastes in Kuzbass, Russia. The distribution of nests of various ants’ species, types of nests, dimensional characteristics and their share by areas were analyzed. It has been revealed that with the increase of anthropogenic impact, the size of the ground parts of the ant nests decreases, and the number of underground nests grows. The predominance of L. niger and M. rubra nests in the ant assemblages indicates a high degree of anthropogenic stress, and a decrease in their share appears to be an indicator of a decrease in anthropogenic impact. We conclude that the number of nests of the genus Lasius, the ratio of underground and dome (in the form of earthen mounds and mounds from plant residues) nests, and the linear dimensions of nests can be used as a bioindicator of the industrial emissions’ impact on biocenosis.

Stimulus Preceding Negativity in Trauma Survivors to Negatively Valenced Pictures

Parasite populations are never evenly distributed among the hosts they infect. Avian nest ectoparasites, such as mites, are no exception, as their distribution across the landscape is highly aggregated. It remains unclear if this pattern is driven by differences in transmission events alone, or if the environment that parasites inhabit after transmission also plays a role. Here, we experimentally examined the influence of the post-transmission microclimate, nest characteristics, and host condition on ectoparasite population growth in a bird-ectoparasite system. We infested barn swallow (Hirundo rustica erythrogaster) nests with a standardized number of Northern Fowl Mites (Ornithonyssus sylvarium) and analyzed both biotic (nestling mass, wing length, number of other arthropods present in the nest, and brood size) and abiotic (temperature, humidity, nest lining, nest dimensions, and substrate upon which the nest was built) predictors of mite population growth. Our results suggest that mite populations were most successful, in terms of growth, in nests with higher temperatures, lower humidity, few other arthropods, and hosts in good condition. We also found that nests built on wooden substrates support larger populations of mites than those constructed on metal or concrete. These findings lend insight into the factors that drive large-scale patterns of ectoparasite distributions.