Nest Cavities Research Articles

Nest Box Bacterial Loads Are Affected by Cavity Use by Secondary Hole Nesters.

Among the environmental factors that affect bird nesting in nest boxes, the influence of microbial communities is relatively poorly understood. In this study, nest boxes used for breeding by secondary cavity nesters were sampled before the start of the breeding season to assess the bacterial loads of the nest box in relation to their previous year status. Different parts of the wooden nest box offer variable conditions for the development of bacteria. During the breeding season, the nest box entrance hole is wiped out by birds, delivering bacteria to their bodies, but during winter, it is exposed to unfavourable external conditions. The interior of the nest box, in turn, is also wiped by birds, but the conditions during winter are more stable there. Therefore, samples from the entrance hole and the interior of the nest box were taken at two different study sites: an urban parkland and a natural forest. We predicted that both the occupancy of the nest boxes during the previous breeding season by birds and the nesting sites would influence the bacterial load of the nest box. To verify this prediction, two categories of nest boxes were sampled at both study sites: nest boxes occupied by any of the two tit species (Great Tit or Blue Tit) in the previous season for breeding and nest boxes that had remained empty that year. The interior bacterial load of the nest box was higher in the nest boxes occupied in the previous breeding season, but only in the forest area. Furthermore, the bacterial load of both the entrance hole of the nest box and the interior was significantly higher in the forest study area in both occupied and unoccupied nest boxes. Our results show that the bacterial load of the nest box is positively related to the presence of nests in the previous breeding season and can vary between different sites.

Notes on Bat Falcon (<i>Falco rufigularis</i>) distribution, nesting, and diet in central-western Mexico

The Bat Falcon may nest in constructions in urban areas. It feeds on bats, birds, and insects. We present records on its distribution, nesting, and diet in western central Mexico. We observed a Bat Falcon couple breeding in 2013 and 2015 in a wall’s cavities from a town’s construction. We collected the remains of the prey consumed by the juveniles in the nest cavities after the juveniles abandoned them in 2013 and 2015, and additionally the remains of prey under the parent’s perches next to the nest cavity in 2015. The nesting period was from March to at least the middle of June. Some of the dietary items during the nesting period were one rodent, four bats, six birds, grasshoppers, and beetles. This study confirms that the Bat Falcon breeds in urban areas and preys upon local species.

Nesting-tree preferences of the black woodpecker—the biggest cavity excavator in a conifer-dominated forests in Poland

The black woodpecker Dryocopus martius is an ecologically disproportionately important forest species owing to its abundance. Its large cavities provide breeding sites and shelter for many species—large birds, mammals, and social insects. I evaluated the nest tree preferences of black woodpeckers in the Augustów Forest, northeast Poland. Approximately 400 black woodpecker cavities were observed. The Scots pine, Pinus sylvestris, was the most commonly selected tree species, accounting for 90%. The cavity trees were 55–225 years old. All trees younger than 90 years were broadleaved tree species. The trees used to excavate the cavities had a larger diameter at the breast height (DBH) than the average of the stand. The trees selected by black woodpeckers were significantly shorter than the average height of the stands. Over 60% of the cavities were excavated 10–16 m above ground level. I found that the DBH and the first branch height were critical factors affecting the cavity entrance height. In pine-dominated forests, black woodpeckers preferred dead trees. Approximately 44% of new cavities were excavated from dead trees. Leaving dead or dying large trees in commercial forests benefits black woodpeckers and large secondary cavity nesters that depend on it and promotes biodiversity conservation. Birds excavate new cavities at a high rate yearly, in contrast with beech-dominated forests.

American Kestrels Compete with European Starlings over Nest Boxes in Eastern Pennsylvania

ABSTRACT The American Kestrel (Falco sparverius) has been steadily declining throughout most of its eastern North American range, and the cause of this decline is still relatively unknown. As a cavity nesting species, the American Kestrel often competes with other cavity nesters such as the invasive and abundant European Starling (Sturnus vulgaris) over nest boxes. The relationship between European Starling presence at nesting sites and American Kestrel occupancy and nesting success is understudied. We analyzed data from nest boxes monitored in eastern Pennsylvania, USA, from 1992 to 2021 to identify changes in occupancy of American Kestrels and competitors, and to examine the relationship between competition at nest boxes and American Kestrel nesting parameters. We found that American Kestrel occupancy decreased while European Starling occupancy increased over the study period. All other species occupying nest boxes (small mammals, passerines, owls, and snakes) showed no significant occupancy trends. On average 21% of nest boxes remained unoccupied annually, and 7% of occupied nest boxes were used by both American Kestrels and competitors in the same breeding season. The presence of these competitors had negative associations with American Kestrel occupancy, clutch size, number of fledglings produced, and overall nesting success. Specifically, the rate of nesting success decreased by 26% when European Starlings used the same nest box within the same breeding season. In recent years, nesting productivity of American Kestrels has decreased, with the average number of nestlings, fledglings, and nesting success rate all declining, while the average clutch size remained constant. Our results suggest that American Kestrel nesting parameters in eastern Pennsylvania are negatively associated with competition for nest boxes during the breeding season. The opposing trends in occupancy for the European Starling and the American Kestrel in this study area coupled with the declining productivity of American Kestrel nests raise concerns over the future of this raptor species in eastern Pennsylvania.

Nesting innovations in neotropical parrots associated to anthropogenic environmental changes.

Parrots are among the most diverse and widely distributed groups of birds and one of the most threatened bird orders mainly due to habitat loss and illegal poaching. Most parrots are obligate cavity nesters, so the logging of mature trees and the transformation of natural cliffs represent important threats to their conservation. Here, we report novel observations of Neotropical parrots nesting in previously unrecorded substrates. We show the first documented case of the cliff-nesting burrowing parrots trying to breed at ground level in an abandoned burrowing owl cavity. Additionally, we provide the first documented observations of this species attempting to nest in building cavities in three urbanized areas of Argentina. Moreover, we report data from four countries of 148 pairs of eight species typically breeding in tree cavity using palm tree bracts as nest sites. Behavioral plasticity in nest sites may allow parrots to maximize their nesting success by exploiting alternative breeding substrates. Moreover, these novelties could contribute to cope with habitat loss and further transformation. However, further research is needed to assess the consequences of these nesting innovations in terms of individual fitness and population dynamics as well as potential factors promoting their appearance.

Verification of the peculiarities of the Anthophoridae Family (Insecta: Hymenoptera)

Solitary behavior is characterized by the independence of females in building and provisioning their nests. There is no cooperation, or division of labor, between females of the same generation, or between mother and daughters. Most of the time, the mother dies before her offspring emerges, with no intergenerational relationships. There is a great diversity of nesting habits among solitary bees. Several species of the Megachilidae, Anthophoridae, and Apidae families nest in hollow branches of plants or pre-existing holes in wood. Others nest in cavities on the ground or in ravines or in protected places and few build exposed nests. The objective of this manuscript is to know the peculiarities of the Anthophoridae Family. The study proposed here constitutes bibliographical research in national and international publications that address the Anthophoridae (Insecta: Hymenoptera: Apoidea) in the field of Entomology. The bibliographical research was carried out using the descriptors Hymenoptera, wasps, and bees in the virtual library in Entomology and in the digital library of theses and dissertations of Universidade de São Paulo (BDTD). Concerned with drawing a public profile of quality research in the area, we sought, a literature review in the main journals in the area classified by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES). In order to complement this analysis with other types of documents such as books, scientific journals, and documents.

Cavity‐nesting birds are limited by nesting habitat in Neotropical agricultural landscapes

AbstractMost studies comparing biodiversity between natural and human‐modified landscapes focus on patterns in species occurrence or abundance, but do not consider how different habitat types meet species' breeding requirements. Organisms that use or nest in tree cavities may be especially threatened by habitat conversion due to the loss of their nesting sites. Although cavity‐nesting bird diversity is highest in the tropics, little is known about how tropical birds use cavities, how agriculture affects their reproductive biology, and how effective nest boxes could be as a conservation strategy in tropical agriculture. Here, we explored how habitat conversion from tropical forests to pasture affects the abundance, nesting habitat availability, and nest success of cavity‐nesting birds in Northwest Ecuador. We conducted bird surveys and measured natural cavity availability and use in forest and agriculture. We also added artificial nest boxes to forest and agriculture to see whether cavity limitation in agriculture would elicit higher use of artificial nest boxes. We found evidence of cavity limitation in agriculture—there were many more natural cavities in forest than in agriculture, as well as more avian use of nest boxes placed in agriculture as compared to forest. Our results suggest that it is important to retain remnant trees in tropical agriculture to provide critical nesting habitat for birds. In addition, adding nest boxes to tropical agricultural systems could be a good conservation strategy for certain species, including insectivores that could provide pest‐control services to farmers.Abstract in Spanish is available with online material.

A bird’s eye view of ecosystem conversion: Examining the resilience of piñon-juniper woodlands and their avian communities in the face of fire regime change

Climate change and land-use legacies have caused a shift in wildfires and post-fire growing conditions. These changes have strong potential to diminish the resilience of many ecosystems, with cascading effects and feedbacks across taxa. Piñon-juniper (PJ) woodlands are a diverse and widespread forest type in the western US and are home to many obligate and semi-obligate bird species. As such, this system is ideal for understanding wildfire resilience, or lack thereof, in terms of both vegetation and wildlife associations. This study evaluated post-fire vegetation structure and associated avian communities following three wildfires; one that burned one year prior to sampling (recent fire), and two that burned approximately 25 years previously (old fires). Vegetation characteristics and the habitat use of PJ-associated bird species were compared across severely burned patches, unburned refugia, and unburned sites outside of the burn perimeter. We expected wildfire to alter vegetation and bird usage for the first few years post-fire, which we observed in our recent burns. However, even 25-years post-fire, little recovery to PJ woodland had occurred and the associated bird communities had not returned, compared to unburned areas. No piñon regeneration was observed in any burned areas and no juniper regeneration in the recent fire. Piñon seedling densities in unburned sites and refugia averaged 80 ha−1 and 151 ha−1, respectively, while juniper seedling densities were 220 ha−1 in both habitat types. Habitat use for thirteen PJ-associated species were modeled, three of which (Woodhouse’s Scrub Jay, Ash-throated Flycatcher, and Virginia’s Warbler) used all habitats. Four species (American Robin, Gray Vireo, Black-throated Gray Warbler, and Gray Flycatcher) were essentially absent from the old burn habitat, reflecting species-specific need for mature piñon or juniper trees and/or greater canopy cover. Conversely, birds that were present in the old burn habitat (including Virginia’s Warbler, Blue-gray Gnatcatcher, Woodhouse’s Scrub-jay, Ash-throated Flycatcher, and Spotted Towhee) are typically associated with habitat edges, high shrub cover, or cavity nests. Altered vegetation structure and bird habitat use in burned areas 25 years post-fire are evidence for enduring conversion to non-forest vegetation types. However, unburned refugia embedded in burned areas maintain forest attributes and support obligate bird communities, supporting ecological function and biological diversity.

The requirements of three co-existing woodpecker species Picidae in relation to forests' features in the agricultural landscape of SE Poland

The occurrence of woodpeckers in European forests depends on many forest stand characteristics. During the study conducted in 2013 in the agricultural landscape of SE Poland (in an extremely deforested area with a 5% share of forest area), the habitat requirements of Middle Spotted Woodpecker Dendrocoptes medius, Great Spotted Woodpecker Dendrocopos major and Syrian Woodpecker Dendrocopos syriacus were described. For this purpose, the degree of occupation by individual species of 73 forest patches was assessed over an area of 355 km2. To determine the habitat requirements of the woodpecker species, a set of 7 parameters characterizing the studied forests and their surroundings were determined, viz. forest patch area, average age of the tree stand, etc.). Generally, the Syrian Woodpecker inhabited small forest patches surrounded by a significantly larger proportion (2.3–5.6%) of orchards, compared to forests uninhabited by this species. The most important factors that positively influenced the occurrence of the Middle and Great Spotted Woodpeckers were the forest patch size, average age of the forest patch stand, and area of forest stands aged older than 80 years. The Great Spotted Woodpecker preferred forest patches with an area exceeding 15 ha, but the Middle Spotted Woodpecker occurred only in forest patches over 42 ha. Such minimum forest patch areas should be considered essential for protecting the two mentioned species in a heavily deforested landscape. Small-sized forest patches should also be protected, enabling refuge for the Syrian Woodpecker. Keywords: bird conservation strategy, forest management, habitat selection, primary cavity nesters, rural landscape, woods, woodpeckers, SE Poland

Cavity-breeding birds create specific microhabitats for diverse arthropod communities in boreal forests

The nests of secondary cavity-nesters located in tree cavities may form specific microhabitats of conservation importance due to their limited accessibility and availability. Species-specific nesting materials in nests of different secondary cavity-nesters may furthermore provide very different microhabitats for arthropods. The potential differences in arthropod communities inhabiting nests of different bird species in excavated cavities or nest boxes have, however, rarely been studied despite their relevance for conservation. Here we investigated the diversity and composition of arthropod communities in these different cavity types and bird species’ nests in managed boreal forests. We identified morphologically and by DNA-metabarcoding arthropods in nest materials that were collected in and compared between (i) woodpecker-size cavities from seven different combinations of cavity type (nest box or excavated cavity), tree species (aspen or pine) and accumulation history of nest materials (single-season cleaned or uncleaned nest boxes that accumulated nests of passerines or an owl species); and (ii) nests of two different passerine species in small nest boxes. We identified 64 arthropod taxa in ten orders, from which Diptera, Coleoptera, Siphonaptera, and Lepidoptera were the most abundant. Shannon diversity index was similar among the cavity-nest-type combinations, but taxa richness was the highest in the owl nests. The arthropod communities (especially Histeridae beetles) deviated most from the other types of nests in owl and aspen cavity nests with more advanced decomposition of nest material (soil or wet environment related taxa). The differences in arthropod communities between the different nest types point out the importance of the ecological chain “tree cavities—bird nests—arthropod communities”.

Biological and Hydrodynamic Aspects for the Design of Artificial Reef Modules for Cephalopod Molluscs in the Ares-Betanzos Estuary

The design of an artificial reef (AR) module for improving the fishing productivity of cephalopod molluscs in the Ares-Betanzos estuary (Galicia, NW Spain) is addressed in this study. At the time of deciding on a suitable AR design, it is first necessary to assess how the different marine species use ARs so that it is possible to define the complexity of the design: its size and shape, as well as the number of nest cavities it should present and the dimensions of these cavities. Thus, two different cubic modules are proposed, both with an edge of 1500 mm. One of them can be considered as the standard design, while the other has been modified to include four open cylindrical holes. Several tools are employed to assess both proposals. Moreover, a CFD (computational fluid dynamics) model is performed. The results suggest that the flow in the interior of the tubes provides a suitable environment for cephalopod molluscs, given that circulation is produced, guaranteeing nutrient renewal. As further contributions, the present work determines how the capture of cephalopods and other species in Galician fish markets has evolved and reviews the habitat preferred by cephalopods in Galicia. It also proposes and compares two AR modules.

Parasites, depredators, and limited resources as potential drivers of winter mortality of feral honeybee colonies in German forests.

Wild honeybees (Apis mellifera) are considered extinct in most parts of Europe. The likely causes of their decline include increased parasite burden, lack of high-quality nesting sites and associated depredation pressure, and food scarcity. In Germany, feral honeybees still colonize managed forests, but their survival rate is too low to maintain viable populations. Based on colony observations collected during a monitoring study, data on parasite prevalence, experiments on nest depredation, and analyses of land cover maps, we explored whether parasite pressure, depredation or expected landscape-level food availability explain feral colony winter mortality. Considering the colony-level occurrence of 18 microparasites in the previous summer, colonies that died did not have a higher parasite burden than colonies that survived. Camera traps installed at cavity trees revealed that four woodpecker species, great tits, and pine martens act as nest depredators. In a depredator exclusion experiment, the winter survival rate of colonies in cavities with protected entrances was 50% higher than that of colonies with unmanipulated entrances. Landscapes surrounding surviving colonies contained on average 6.4 percentage points more cropland than landscapes surrounding dying colonies, with cropland being known to disproportionately provide forage for bees in our study system. We conclude that the lack of spacious but well-protected nesting cavities and the shortage of food are currently more important than parasites in limiting populations of wild-living honeybees in German forests. Increasing the density and diversity of large tree cavities and promoting bee forage plants in forests will probably promote wild-living honeybees despite parasite pressure.

Red-eared Slider (<i>Trachemys scripta elegans</i>) nests in the Greater Toronto Area

Red-eared Slider (Trachemys scripta elegans) is a non-native turtle found in abundance in Toronto’s wetlands as a result of pet releases. Although this species is known to reproduce successfully in southwestern Ontario, Canada, there is yet no evidence to suggest successful reproduction in the Greater Toronto Area (GTA). As part of a native turtle nest protection program, volunteers inadvertently placed nest protector boxes over four slider nests in 2021 and 10 nests in 2022. This gave us the opportunity to determine whether nests produced viable offspring and whether these hatchlings would emerge in the fall. The exact nesting date for each nest was recorded. In 2021, eight of the 41 eggs from the slider nests showed very late-stage arrested embryonic development. In 2022, one of the nests had four hatchlings out of their eggshells but still inside the nest cavity. It is unclear whether the hatchlings would emerge later in the fall or overwinter in the nest cavity and emerge the following spring. If the small population sampled accurately reflects what occurs in the GTA, complete egg development may be possible for this species in some years, in some locations, with the right local micro-climate and micro-habitat. We discuss implications for turtle nest protection in Toronto.

Nest-Site Features and Breeding Ecology of Chestnut-Vented Nuthatch Sitta nagaensis in Southwestern China.

The breeding ecology of birds is the cornerstone of bird life-history theory, and breeding success directly affects the survival and development of populations. We studied the breeding ecology of a secondary cavity-nesting bird, the chestnut-vented nuthatch Sitta nagaensis, in southwestern China from March to June in 2020, 2021, and 2022. In total, 16 nests in nest boxes and 19 nests in natural cavities were studied. The nesting habitat was mainly Pinus yunnanensis forest (68.4%), and the nest trees were mainly P. yunnanensis and pear Pyrus spp. Cavities made by woodpeckers and knot holes were used as nest sites, and the nuthatches plastered the hole entrance with mud. The nesting material was mainly pine bark. The clutch size was 3.47 ± 0.56 (range 2-4, n = 30), with an incubation period of 16.06 ± 0.91 days (range 15-19 days, n = 18). The nestling period was 20.88 ± 1.90 days (range 18-23 days, n = 23), and both parents fed the nestlings.

Snake-like hissing calls made by nestlings of the open nesting zitting cisticola Cisticola juncidis

Mimicry is widespread in the animal kingdom, with sound/or acoustic mimicry remaining less studied than visual mimicry. Some incubating female birds in cavity nests emit a hissing call when encountering nest predators, which sounds like a snake hiss and serves to scare off predators; this is considered a form of acoustic Batesian mimicry. Similarly, for nearly defenseless bird nestlings, using a hissing call to scare off predators can improve their survival; however, few studies have reported nestlings making hissing calls. In this study, we report on the hissing calls of nestlings of the open-nesting zitting cisticola (Cisticola juncidis) and compare their hissing calls with those of other animals, such as birds and snakes. The results showed that the hissing calls of C. juncidis nestlings closely approximate the sounds of snakes. This study is the first report of sounds that mimic snakes made by the nestlings of any open-nesting passerine bird species.

Fire‐mediated tree cavity reduction needs to be considered in reintroduction strategies for a critically endangered bird

Fire is an important agent of tree cavity creation and loss in some forest ecosystems. Even though cavity‐bearing trees may be replaced over decades post fire, cavity‐nesting animals depend on uninterrupted access to suitable nesting sites. Balancing the impacts of fire on the availability and recruitment of suitable tree cavities for wildlife is important. We studied fire effects on trees with suitable nests for Critically Endangered Orange‐bellied Parrots Neophema chrysogaster to evaluate how to optimize suitable cavity availability both now and into the future. We used field surveys to quantify the age‐class distribution of trees across the species' historical range, and climbed them to reveal that only 16% of Smithton peppermints Eucalyptus nitida supported a potentially suitable nest cavity. We incorporated this information into a simulation that explored the impacts of fire on the occurrence of nest trees over a century under different fire regimes. We predicted that more frequent and severe fires resulted in lower probabilities of persistence of nesting sites for Orange‐bellied Parrots. Management of the foraging habitat of Orange‐bellied Parrots requires regular burning of moorlands adjacent to the forests where they nest. Our simulations show that preventing regular burning of these forests is important to maximize the probability of persistence of nesting habitat for Orange‐bellied Parrots. We show that by incorporating field data on the true availability of habitat, it is possible to simulate the uncertain impacts of fire on future perpetuation of suitable nesting cavities for wildlife.

Bird functional and taxonomic diversity in xerophytic forests: contributing to balance bird conservation and livestock production

Biodiversity is increasingly dependent on the ecological state of agricultural and livestock systems. Here, we assess the relationship between bird functional and taxonomic diversity and forest structure along a gradient in grazing intensity in xerophytic forests in Central-East Argentina. We found that bird functional diversity responds more to forest structure variables than taxonomic diversity. Further, we found a non-linear response of functional and taxonomic richness to grazing intensity, peaking at intermediate intensity. Mature forests with older trees and low grazing intensity favored a wider range of bird traits, such as seed dispersal and cavity nesters. In particular, taxonomic and functional diversity significantly increased with increasing canopy cover and DBH. In contrast, shrub encroachment, high grazing intensity, and the decrease of tree density and cover were associated with reduced functional diversity, affecting various nesting, foraging, and habitat requirements of birds. We recommend preserving high canopy cover and older trees and maintaining low grazing intensities to create a synergy between livestock production and biodiversity conservation.

Breeding ecology, population size and nest site preferences of Red-billed Tropicbirds at St Helena, South Atlantic Ocean

ABSTRACT We describe the population size and breeding ecology of the Red-billed Tropicbird, Phaethon aethereus, a poorly studied pantropical seabird, at St Helena, South Atlantic. The population size of 81–246 pairs and 272–564 individuals identifies the study population as the largest colony of Red-billed Tropicbirds in the South Atlantic, but also an internationally important part of the global population. We estimated the survival from laying to fledging of 158 nests between 2004 and 2017 at only 33%, among the lowest values reported globally for the species. Most nest failures occurred during incubation, with predation identified as the predominant cause of fledging failure. Intervals between breeding attempts were longer after successful nesting attempts than failed attempts. Previous breeding interval and nest cavity fidelity further influenced the interval between breeding attempts, while the presence of replacement clutches did not. Multiple nest site and cavity characteristics were important predictors of cavity use, nest site selection and productivity. Management options for reducing mammalian predators to ensure the long-term viability of this important population at St Helena are discussed.

Fast visual adaptation to dim light in a cavity-nesting bird

Many birds move fast into dark nest cavities forcing the visual system to adapt to low light intensities. Their visual system takes between 15 and 60 min for complete dark adaptation, but little is known about the visual performance of birds during the first seconds in low light intensities. In a forced two-choice behavioural experiment we studied how well budgerigars can discriminate stimuli of different luminance directly after entering a darker environment. The birds made their choices within about 1 s and did not wait to adapt their visual system to the low light intensities. When moving from a bright facility into an environment with 0.5 log unit lower illuminance, the budgerigars detected targets with a luminance of 0.825 cd m-2 on a black background. When moving into an environment with 1.7 or 3.5 log units lower illuminance, they detected targets with luminances between 0.106 and 0.136 cd m-2. In tests with two simultaneously displayed targets, the birds discriminated similar luminance differences between the targets (Weber fraction of 0.41-0.54) in all light levels. Our results support the notion that partial adaptation of bird eyes to the lower illumination occurring within 1 s allows them to safely detect and feed their chicks.

Nest-dwelling Mites of Selected Common Bird Species in Sri Lanka

Bird nests primarily function to protect and incubate eggs and nestlings. However, nests are also host to a broad diversity and abundance of arthropod associates, primarily mites (Acari). Our knowledge of nest dwelling mites of common bird species in Sri Lanka is quite limited and necessitates further study. Five different types of nests of selected common bird species (18) in Sri Lanka in urban, suburban, wild, and captive populations were sampled opportunistically using a portable mini vacuum trap. ANOVA: single factor test was used to evaluate statistical significance at p<0.05. A total of 1493 mites were collected from 180 nests. The mites belonging to order Mesostigmata had the highest relative abundance (58.6%) and prevalence (74.4%) of all mite orders collected, followed by the Sarcoptiformes (41.1%, 72.8%), and Trombidiformes (0.3%, 2.2%). Mite diversity of host bird species was measured using the Shannon-Weiner diversity index (H’). Pycnonotus cafer nests had the highest diversity of mites. Cup-shaped nests were host to the highest average abundance value (13.4) of mites, while cavity nests had the lowest value (5.7). Nests from captive populations had the highest average abundance (24.6) of mites and the nests of suburban populations had the lowest value (7.2). These findings can be used as a baseline data set for further detailed research studies on nest-dwelling mites of birds, focusing on avifaunal conservation and the impact on human health by nest-dwelling ectoparasites, built-in human habitations in Sri Lanka.