The invertebrate fauna of High Arctic seabird nests: the microarthropod community inhabiting nests on Spitsbergen,Svalbard

The invertebrate fauna of the nests of three seabird species, black-legged kittiwakes (Rissa tridactyla), common eider (Somateria mollissima) and glaucous gull (Larus hyperboreus), were sampled in Kongsfjorden, Spitsbergen, Svalbard. The invertebrate community was species poor, consisting predominantly of the flea, Mioctenopsylla arctica arctica (Insecta: Siphonaptera), but with six species of oribatid mite (Acari: Oribatida), Diapterobates notatus, Oribatula tibialis, Ameronothrus lineatus, Hermannia reticulata, Trichoribates trimaculatus and Ceratoppia bipilis, plus an occasional mesostigmatid mite. No Collembola or ticks (Acari: Ixodidae) were observed. With the exception of M. arctica arctica, the fauna of seabird nests consisted of opportunistic microarthropod species rather than specialised nest-dwelling or bird parasitic species. Species diversity of soil oribatid mites was greater in nests of the common eider than compared to nests of the black-legged kittiwake, which may be related to the ground nesting behaviour of the common eiders. No rare or unusual microarthropod species for Svalbard were found in the seabird nests. The contentions that nests may facilitate microarthropod colonisation of High Arctic regions via bird phoresy by providing a high-quality habitat at the point of arrival, or that there might be a specialised microarthropod fauna exploiting this habitat, were not supported in this study. These are amongst the first data on the microarthropod community of seabird nests in the High Arctic.     

Bats in bird nests in Australia: a review

Bats (Microchiroptera) utilize few types of bird nests as roosts. Ten species of bats (Molossidae and Vespertilionidae) were recorded roosting in the enclosed bottle-shaped mud nests of the Fairy Martin Hirundo ariel; two species (Vespertilionidae) were located in the hanging nests of scrubwrens Sericornis spp. and the Brown Gerygone Gerygone mouki; two species (Vespertilionidae) in the enclosed plant material nests of the Grey-crowned Babbler Pomatostomus temporalis and Fernwren Oreoscopus gutturalis; and one species (Emballonuridae) was recorded in the open cup-shaped nest of the White-rumped Swiftlet Collocalia spodiopygius. No information was available on the importance of bird nests as breeding sites and only one species, the Chocolate Wattled Bat Chalinolobus morio, has been recorded hibernating in a nest. Bird nests in Australia provide roosting habitat for four threatened bats and may be important to the conservation of these species.     

Habitat selection,reproduction and predation of wintering lemmings in the Arctic

Snow cover has dramatic effects on the structure and functioning of Arctic ecosystems in winter. In the tundra, the subnivean space is the primary habitat of wintering small mammals and may be critical for their survival and reproduction. We have investigated the effects of snow cover and habitat features on the distributions of collared lemming (Dicrostonyx groenlandicus) and brown lemming (Lemmus trimucronatus) winter nests, as well as on their probabilities of reproduction and predation by stoats (Mustela erminea) and arctic foxes (Vulpes lagopus). We sampled 193 lemming winter nests and measured habitat features at all of these nests and at random sites at two spatial scales. We also monitored overwinter ground temperature at a subsample of nest and random sites. Our results demonstrate that nests were primarily located in areas with high micro-topography heterogeneity, steep slopes, deep snow cover providing thermal protection (reduced daily temperature fluctuations) and a high abundance of mosses. The probability of reproduction increased in collared lemming nests at low elevation and in brown lemming nests with high availability of some graminoid species. The probability of predation by stoats was density dependent and was higher in nests used by collared lemmings. Snow cover did not affect the probability of predation of lemming nests by stoats, but deep snow cover limited predation attempts by arctic foxes. We conclude that snow cover plays a key role in the spatial structure of wintering lemming populations and potentially in their population dynamics in the Arctic.     

Cattle grazing in CRP grasslands during the nesting season: effects on avian reproduction

Bird populations in grasslands have experienced declines coinciding with loss and fragmentation of prairies. The United States Department of Agriculture (USDA)-administered Conservation Reserve Program (CRP) is the most extensive grassland restoration program in North America and it has especially benefitted grassland birds. Grazing by domestic cattle has been restricted in CRP during avian nesting seasons despite the potential improvements in structuring habitat for a greater diversity of grassland bird species. Potential negative consequences of grazing in CRP grasslands include trampling of nests by cattle, reductions in nest concealment from predators, and attraction of brood-parasitic brown-headed cowbirds (Molothrus ater). We designed an experiment to test for effects of cattle grazing in CRP fields during the nesting season on nest survival and brood parasitism of 5 bird species that commonly nest in CRP grasslands: mourning dove (Zenaida macroura), grasshopper sparrow (Ammodramus savannarum), dickcissel (Spiza americana), and eastern (Sturnella magna) and western (S. neglecta) meadowlarks. Grazing was implemented during summers 2017 and 2018 on 17 of 36 fields followed by a year of rest on all fields in 2019. Of the 879 nests on grazed fields, only 4 were likely trampled by cattle (vs. 54% of all nests estimated as failing because of depredation). Experimental grazing (grazed vs. ungrazed fields) had variable effects on nest survival and cowbird parasitism among the bird species analyzed. Negative effects of grazing on daily nest survival of dickcissel and meadowlarks were apparent, at least in some years. We found no direct effects of grazing on nest survival of mourning dove or grasshopper sparrow. Probability and intensity (cowbird offspring/nest) of cowbird parasitism in dickcissel nests was higher on grazed versus ungrazed sites but only in conservation practice (CP) CP2 (vs. CP25 fields). Parasitism probability of grasshopper sparrow nests by cowbirds was higher on grazed fields in the 2 years after introduction of cattle in 2017. Greater vegetative concealment around nest sites was associated with reduced cowbird parasitism of meadowlark and grasshopper sparrow nests and higher nest survival for grasshopper sparrows. Reductions in vegetative height caused by longer-term or high-intensity grazing might therefore have negative consequences for some grassland birds by increasing nest site visibility and exposure to cowbird parasitism. Our results indicate that cattle grazing in CRP fields during the nesting season might have some negative effects on reproductive success of some grassland bird species, at least in the short term; however, the potential improvements of structuring habitat to accommodate more grassland bird species and increasing landowner participation in the CRP are considerable.     

Association of pseudoscorpions with different types of bird nests

The hypothesis of associating pseudoscorpions with bird nest types was tested on the basis of an analysis of 480 specimens. Eleven pseudoscorpion species were found in 171 nests of 28 different bird species collected in Slovakia, Austria and the Czech Republic. The frequent appearance of Cheiridium museorum, Dactylochelifer latreillii, Chernes hahnii, Dendrochernes cyrneus and Allochernes wideri was confirmed. High proportion and association of Pselaphochernes scorpioides in hoopoe hollow nests with decomposed substrate, D. cyrneus in the Eurasian tree sparrow nest boxes and A. wideri in the nests of the tawny owls, the European scops owls and the European roller was proved. In contrast, C. hahnii and D. latreillii were related to the nest fauna of blackbirds and song thrushes, C. museorum to the nests of white wagtails situated on the ground and on buildings and C. cancroides to the nests in synanthropic habitats. Until present, the occurrence of 22 pseudoscorpion species has been confirmed in the bird nests of Central Europe based on the obtained results and published resources. According to the association to bird nests these pseudoscorpions were classified as (1) nidixenous species — Chthonius fuscimanus, C. tetrachelatus, Mundochthonius styriacus, Neobisium carcinoides, N. crassifemoratum, N. inaequale, N. sylvaticum, Chernes cimicoides, C. similis, C. vicinus, Allochernes powelli, Lamprochernes chyzeri, L. nodosus and Larca lata; and (2) nidiphilous species — C. museorum, C. cancroides, A. wideri, D. cyrneus, D. latreillii, C. hahnii, D. panzeri and P. scorpioides.     

Arthropods (Pseudoscorpionidea,Acarina, Coleoptera,Siphonaptera) in nests of the bearded tit (<Emphasis Type="Italic">Panurus biarmicus</Emphasis>)

In the period 1993–2006, during investigation of reproduction biology of the bearded tit, 106 deserted nests of the species were collected in Slovakia, Austria and Italy and their arthropod fauna was analyzed. Occasionally introduced individuals of the pseudoscorpion Lamprochernes nodosus, a frequent species in Central Europe, were recorded in the nests. Altogether 984 individuals and 33 species of mesostigmatic mites (Acari) were found in 46.2% of the nests examined. The ectoparasite Ornithonyssus sylviarum was most abundant and frequent; it represented almost 68.3% of all individuals. Due to it, the parasitic mites predominated (69.4% of individuals). Other ecological groups were less represented: edaphic detriticols − 11.6%, coprophils − 10.7%, species of vegetation stratum − 8.2%, and nidicols − 0.2%. Beetles (40 species, 246 individuals) were present in 57 nests. Most of the beetles were strongly hygrophilous species inhabiting soil surface in the reed stands or other types of wetlands and the shore vegetation. Predators represented 59% of all individuals. They might find food in the nests, but none of the species had a close relationship to bird nests and represented 35% of species. All beetle species penetrated the nests occasionally, when ascending on the vegetation or searching cover during periods of increased water level. Occasionally, larvae and nymphs of the Dermacentor marginatus tick were found. They were most probably introduced by insectivores of the genus Neomys. Only one species of fleas, Ceratophyllus garei — a parasite of birds nesting in humid environment, was recorded in the nests.     

Egg predation in forest bird communities on islands and mainland

Summary To examine if differences in egg predation rates could explain differences in bird community composition, egg predation was studied in two years on small islands in a South Swedish lake and on the nearby mainland using both natural and artificial nests.In plots with similar vegetation, the combined density of ground- and tree-nesting bird species did not differ between the islands and the mainland. Egg predation rates were similar on islands and the mainland for natural Turdus nests in two years, and for artificial Turdus and Phylloscopus nests. Unmarked and unvisited experimental nests suffered similar rate of egg predation as marked and visited nests. Egg predation rates were higher on natural nests when artificial nests were also put out, increasing the total nest density. Initial egg predation rates in artificial nests were also higher than later when nest density had decreased by 75%.The egg predators involved differed for artificial Phylloscopus nests between the islands and the mainland. Small mammals were apparently responsible for 29% of the predation on the mainland, but none on the islands. Artificial Turdus nests near crow nests suffered from a higher egg predation rate than nests further away from crow nests. Daily survival rates of Turdus nests increased from the laying to the incubation and further to the fledging state.Egg predation can not explain differences in bird community composition between islands and mainland in the present case.     

Mesostigmatic mites (Acari: Mesostigmata) in nests of the Eurasian griffon vulture (<Emphasis Type="Italic">Gyps fulvus</Emphasis>) in Croatia

We examined the species composition and community structure of mites of the order Mesostigmata (Acari) in nests of the Eurasian griffon vulture (Gyps fulvus Hablizl, 1783) in Croatia. Material collected from 18 nests included 565 mites belonging to seven species. The most abundant species were Leiodinychus orbicularis (C.L. Koch, 1839) (Trematuridae) and Androlaelaps casalis (Berlese, 1887) (Laelapidae). The results were compared with the community structure and frequency of dominant species of Mesostigmata in nests of 32 other bird species. Leiodinychus orbicularis occurred in the nests of 13 species of birds. It is a typical nidicolous species which occurs most frequently in the perennial nests of birds of prey. In contrast, A. casalis rarely occurs in the nests of birds of prey.     

Thermophilous fungi of birds' nests

Summary Twenty seven species of thermophilous fungi were found on plant debris in the nests of twelve passerine bird species in Nottinghamshire of whichDactylomyces thermophilus, Humicola insolens, Penicillium duponti, Stilbella thermophila andTorula thermophila are new records for Britain.Certain species, such asAspergillus fumigatus, Chaetomium thermophile, Coprinus delicatulus, Humicola insolens, Thermoidium sulphureum andThermomyces languinosus were present in most of the 54 nests surveyed, usually at a high frequency.The species populations of thermophilous nest fungi are similar to those on plant debris on the soil surface and in the grassland vegetation. They are closely related to thermophilous floras known from various composts. The relatively high frequency of strictly thermophilic species found on organic debris of the various nests indicates that nests are warmed up by the birds while using the nests, and, probably, also by the sun and air during the summer months.The number of thermophilous species and their frequency on the plant debris of the nests varies considerably in the twelve bird species. The number of species as well as their frequency was exceptionally low in Sandmartin's nests but the nests of Blackbird, Hedge Sparrow and of the Thrushes were rich in thermophilous fungi.All the 27 thermophilous fungi recorded from the birds' nests may be regarded a) as saprophytes with no known harmful relationships to birds and other animals, such asAllescheria terrestris, Botryotrichum species,Chaetomium thermophile, Coprinus delicatulus, Humicola insolens, Penicillium duponti, Sporotrichum thermophile, Stilbella thermophila, Thermoidium sulphureum, Thielavia sepedonium andTorula thermophila, or b) as saprophytes on the plant debris of the nests but with known potential pathogenicity to birds, other animals and man, e.g.,Absidia ramosa, Aspergillus fumigatus, A. terreus, Dendrostilbella boydii (=conidialAllescheria boydii),Emericella nidulans, Endomyces lactis, Mucor pusillus, Paecilomyces varioti, Rhizopus arrhizus, R. cohnii andThermomyces lanuginosus.     

Herbaceous ground cover reduces nest predation in olive groves

Capsule Bare ground increases artificial nest predation in olive groves.

Aims To assess the effect of different soil management regimes on nest predation rates in olive groves.

Methods We performed nest predation experiments with artificial nests during the breeding season in 2013, in two areas of southern Spain. Each artificial nest (n?=?300) contained three quail Coturnix eggs, two of which were unmanipulated and the third one was emptied and injected with plaster. Predators were identified by marks on eggs filled with plaster.

Results Ground nests were significantly more depredated, irrespective of the presence of ground cover; tree nests were less depredated in fields with ground cover. There was a clear difference in nest predators of ground and tree nests. Rodents were the most frequent predators of tree nests.

Conclusion Lower predation rates of tree nests in orchards with ground cover are probably linked to a change in the foraging behaviour of rodents, which in these more complex habitats might be restricted by rodents' own risk of predation. This study underscores the important role of agricultural practices in preserving farmland bird communities, particularly tree-nesting species, suggesting that for this group, implementation of ground cover in olive groves might enhance breeding success by reducing nest predation rates.     

Interactions with Great Skuas Stercorarius skua as a factor in the long‐term decline of an Arctic Skua Stercorarius parasiticus population

Many of the UK’s seabird species have displayed high variation in breeding success since the 1980s, largely due to changes in the availability of Lesser Sandeels Ammodytes marinus, their main prey. During this time, Arctic Skuas Stercorarius parasiticus experienced a rapid decline in the UK and the species has subsequently been placed on the Red List of birds of conservation concern. Although shortage of Lesser Sandeels is likely to be an influential factor, the Arctic Skua’s breeding range overlaps with that of the Great Skua Stercorarius skua, a larger bird with a more varied diet, and interspecific interactions for nesting habitat may exert an additional pressure on Arctic Skua breeding populations. Results from four censuses, spanning 21 years, were used to model habitat use and analyse distributional change in nesting Arctic Skuas at a major colony located on Fetlar, Shetland, Scotland. The decline in Arctic Skuas was not uniform across the island and competition with Great Skuas for nest‐sites appears to have influenced localized breeding distribution. By 2006, Arctic Skuas had been almost entirely excluded from shrub heath, blanket bog and coastal heath habitats, which were identified as preferred habitat in 1986. In 2006, Arctic Skua breeding territories were mainly restricted to one core area of preferred habitat where over 90% nested in high density as this habitat became increasingly occupied by Great Skuas. The more generalist foraging habit of the Great Skua allowed the population to grow rapidly as numbers of the more specialist Arctic Skua decreased during times of low sandeel availability. Our model suggests that both interspecific competition for territories with Great Skuas and food limitation have played important roles in the decline of Arctic Skuas on Fetlar.     

Magellanic Woodpecker (Campephilus magellanicus) sap feeding and its role in the Tierra del Fuego forest bird assemblage

Several woodpecker species feed on phloem-sap flowing from pecked trees. We report sap consumption by the magellanic woodpecker (Campephilus magellanicus) inhabiting beech (Nothofagus) forests of Tierra del Fuego island (Chile). Magellanic woodpeckers drilled sap wells in N. betuloides trees close to their nests and also when they were moving in family groups. Three other bird species were observed foraging and competing for sap: the austral parakeet (Enicognathus ferrugineus) and two small passerines, the patagonian sierra-finch (Phrygilus patagonicus) and the white-crested elaenia (Elaenia albiceps). The abundance of these three bird species was greater in sites around sap wells than in other forest sites, suggesting that magellanic woodpecker is an important species in maintaining the Nothofagus forest bird assemblage.     

Nest losses of cavity nesting birds caused by dormice (Gliridae, Rodentia)

Mammals are common predators on bird nests. However, their species identity frequently remains unknown. Here we present long-term data (1975–2005) from a central European woodland on the predatory effect of three dormice species (Rodentia, Gliridae) on cavity-nesting birds. Dormice are mostly frugivorous during the active late-summer season, but shortly after they terminate hibernation, they frequently depredate cavity-nesting-bird nests. The seven bird species studied, lost on average between 2.9 to 18.4% of their broods. MigratoryFicedula flycatchers suffered the highest brood losses, while the residentParus titmice and the nuthatchSitta europaea had much lower brood losses. The three dormice species differed significantly in their predatory effect during different avian breeding stages. The edible dormouseGlis glis (Linnaeus, 1766) depredated both eggs and nestlings equally, while the common dormouseMuscardinus avellanarius (Linnaeus, 1758) and the forest dormouseDryomys nitedula (Pallas, 1778) destroyed more nests during egg laying and the incubation period. Among adult birds, females were taken more frequently by dormice than males. Among avian species, adultFicedula flycatchers were more often depredated than the titmice and nuthatch. Our study provided further evidence, that among the traditional studies on the costs of reproduction, parental mortality at the nests needs to be considered and that incubating or brooding females might be under higher predation risk than the males.     

Nest boxes for Cape Parrots Poicephalus robustus in the Hogsback area,Eastern Cape,South Africa

Breeding propensity of tree-cavity nesting bird species are often limited by a shortage of natural nesting sites. Artificial nests can be used to provide alternative nest sites. Cape Parrots Poicephalus robustus are nationally endangered and nest in existing tree-cavities in high-altitude fragmented Afromontane forests in South Africa, assumed to be in short supply due to historic and current logging practices. To increase nest site availability, 179 wooden bird boxes and 28 bee boxes (to ‘pull’ bees) were erected during 2011–2012 in Hogsback, Eastern Cape. In 2016, no bird boxes were occupied by Cape Parrots. A total of 43% were used by other species, 51% were unused and 6% could not be inspected due to tree instability and inaccessibility. Two bird boxes were inspected by two pairs of Cape Parrots, but were never occupied. Occupancy of boxes by birds was not associated with nest, tree or habitat characteristics. However, occupancy of boxes by bees was associated with habitat type and tree species. Future conservation efforts will include locating natural Cape Parrot nesting sites and reforestation efforts to ensure the long-term availability of natural nesting sites.     

Population increase and nesting patterns of the black noddy Anous minutus in Pisonia forest on Heron Island: Observations in 1978, 1979 and 1992

Abstract Estimates of the population size of black noddy Anous minutus on Heron Island were made by counting nests in permanently marked plots in Pisonia grandis forest in 1978, 1979 and 1992. The results, and published data, indicate that the population has been increasing at ca 7% per annum since early this century and currently is ca 63 000 ± 7000 pairs. The continued exponential increase in bird numbers poses interesting ecological questions and potential management problems, as more of the island is occupied by the birds and interaction with the vegetation intensifies. Pisonia is by far the most common tree on the island and most nests are in this species. However, there is evidence that Ficus opposita is preferred over Pisonia and the high mortality of this species in the marked plots may be due to excessive use by noddies. Pisonia trees which reach the forest canopy and are in the 40–60 cm stem diameter class have more nests than smaller trees. Larger stems (>60 cm diameter) are also underutilized relative to their size, and it is suggested that this is because they are more liable to windthrow in cyclones.     

Opportunistic Predation of Wild Turkey Nests by Wild Pigs

Wild pigs (Sus scrofa; i.e., feral hogs, feral swine) are considered an invasive species in the United States. Where they occur, they damage agricultural crops and wildlife habitat. Wild pigs also depredate native wildlife, particularly ground-nesting bird species during nesting season. In areas inhabited by wild turkeys (Meleagris gallopavo), nest destruction caused by wild pigs may affect recruitment. There is debate whether wild pigs actively seek ground-nesting bird nests or depredate them opportunistically. To address this debate, in 2016 we examined the movements of wild pigs relative to artificial wild turkey nests (i.e., control [no artificial nests], moderate density [12.5–25 nests/km²], and high density [25–50 nests/km²]) throughout the nesting season (i.e., early, peak, and late) in south-central Texas, USA. We found no evidence that wild pigs learned to seek and depredate wild turkey nests relative to nest density or nesting periods. Despite wild pigs being important nest predators, depredation was not a functional response to a pulsed food resource and can only be associated with overlapping densities of wild pigs and nests. Protecting reproductive success of wild turkeys will require reducing wild pig densities in nesting habitat prior to nesting season. © 2019 The Wildlife Society.     

Blow fly Trypocalliphora braueri parasitism on Meadow Pipit and Bluethroat nestlings in Central Europe

The larvae of blow fly (Trypocalliphora braueri) are known to cause a subcutaneous myiasis in bird nestlings mainly in Nearctic species, while only a few records are available from the Palaearctic. Here, we report on infestations of this insect ectoparasite in two passerine species, Meadow Pipit (Anthus pratensis) and Bluethroat (Luscinia svecica), breeding in the Central European mountain range Krkonoše. The infestation of T. braueri parasite was relatively low in studied bird species (3.0% of infested nests in Meadow Pipit and 4.2% in Bluethroat) but varied strongly between years (0–33% of infested nests/year/species). The presence of the parasitic blow fly larvae was apparently controlled by temperature; they were found only during warm summers. The combination of parasite infection and heavy rainfalls in a critical period significantly reduced nestling survival.     

Evidence for Effective Seed Dispersal by the Sulawesi Red-Knobbed Hornbill,Aceros cassidix1

The Sulawesi red-knobbed hornbill (Aceros cassidix) is a large-bodied, frugivorous bird that nests in high densities in the Tangkoko-DuaSudara Nature Reserve, North Sulawesi, Indonesia. I measured seedling abundance and species richness, diversity, and dominance in plots placed below and immediately behind 20 active nest sites to evaluate the role of red-knobbed hornbills as agents of seed dispersal. Comparisons of treatment (below nests) and control plots (behind nests) show that hornbills affect the abundance and distribution of diet-species seedlings. Nondiet and nest tree seedlings did not differ between control and treatment plots suggesting that differences in diet species were the result of additional input by hornbills rather than by random or other dispersal events. Significantly greater numbers of diet seedlings germinated below nests, and the diversity of diet species was greater than that of nondiet species. Dominance of a few species in the treatment plots is consistent with the hypothesis that hornbills are effectively dispersing seeds of some, but not all, of their diet species. Although seedlings under nests may eventually experience density-dependent mortality, seedlings survived at least 12 months, indicating that red-knobbed hornbills were effectively dispersing seeds and influencing the initial fate of seeds of several tropical forest tree species.     

Nest-site selection and its impact on breeding success of the Lesser Kestrel,Falco naumanni,in the North of Iran (Aves: Falconiformes)

The Lesser Kestrel (Falco naumanni) is a small migratory falcon which nests coloni- ally on inland cliffs and ruined buildings. Bandar Turkman city holds one of the most important breeding colonies in Iran. It nests in holes in roofs, walls or on ledges of buildings throughout of the city. We tried to find out whether there is a relationship between nest-site selection and breeding success. Although height from the ground is the most important factor in nest-site selection by F. naumanni, height from the floor and distance to the nearest neighbour are other main factors which affect breeding success. This could be the result of accessibility by human and natural predators such as domestic cats which threaten nests. The number of possible nest-sites in the study area is limited as many old, ruined buildings are being replaced by new construc- tions; this colonially breeding bird species therefore suffers from a lack of highly suitable nest-sites and this directly affect breeding success.