Nest Trees Research Articles

First photographic record of Brown Bullfinch Pyrrhula nipalensis (Aves: Passeriformes: Fringillidae) from Jammu & Kashmir, India

The Brown Bullfinch (Pyrrhula nipalensis) is a passerine bird within the family Fringillidae. This study reports the first photographic record of the Brown Bullfinch from the Gurez Valley, Jammu and Kashmir, India. The bird was sighted through a camera trap installed in Butamali Tullail, a meadow for herders at an altitude of 3,400 meters. This shy bird typically forages in pairs or small flocks and feeds on seeds, berries, and buds. The Brown Bullfinch thrives in dense temperate forests and breeds from May to July. It constructs well-concealed nests in shrubs or low trees, and both parents participate in raising the young. The Brown Bullfinch is currently classified as Least Concern by the IUCN Red List, but habitat destruction poses potential threats. Conservation efforts should focus on protecting temperate forests in the Himalayan region.

Nest site selection and threats to nesting colonies of white-rumped Vulture (Gyps bengalensis) in Himachal Pradesh

White-rumped Vulture (Gyps bengalensis) suffered the most significant population decline among the three species of Gyps vultures impacted by the South Asia-wide diclofenac toxicity of the 1990s. Although the population lost about 99 % of its individuals, nesting populations still remain in a few pockets in India. One such population is known from the Himalayan foothills in the Kangra region, representing the northernmost nesting population of the species in India. From 2020–2024, we carried out an extensive study on the nesting ecology of the species, identifying 17 colonies with 617 active nests in 553 trees in an area of 5739 SqKm, constituting the highest nesting population reported in India. The smallest colony had ten nests, while the largest had 68. Except for a single nest on a Ficus religiosa tree, all others were on old-growth Chir Pine, Pinus roxburghii, having an average GBH of 254.8 cm (± 49.3 SD). By analyzing 18 variables, we determined vulture preferences for nest tree characteristics. Results indicate that nesting site selection primarily depends on GBH, canopy cover and nearest nest distance. About 80 % of nests were found between 600 and 800 m elevation. The primary threats include forest fire, resin tapping, and tree felling. We recommend protecting larger-sized old-growth forests through awareness campaigns with forest managers and local communities to safeguard the nest sites of the critically endangered bird.

Landscape and habitat characteristics jointly drive the urban distribution of a nuisance species

Identifying environmental variables that affect the distribution of pest and/or nuisance species promotes effective management strategies by improving urban planning and the targeted application of direct interventions like population control. Australian white ibis Threskiornis moluccus are considered a nuisance species throughout Australia, having increased significantly in abundance in coastal urban landscapes following declines in their native inland habitats over the past three decades. Few management interventions thus far have successfully reduced conflicts between ibis and humans, necessitating a better understanding of conditions driving ibis distribution and abundance. We surveyed 26 ibis colonies throughout the Moreton Bay region in central eastern Australia and quantified the effects of a range of spatial (e.g. connectivity with waste management facilities, urban land and wetlands) and habitat (e.g. nesting tree species, density and size) variables on ibis and nest abundance. Ibis and their nests were most abundant at sites within 10 km of waste management facilities, and < 60 m from residential or industrial estates. Ibis were also more abundant at sites with tree canopy height < 10 m and lower tree species richness. Nests were most abundant on water bound islands with tree density > 0.5 trees/m2. Urbanisation had contrasting effects, with nest numbers increasing with higher connectivity (i.e. closer proximity) to urban land, while ibis numbers decreased (relative to waste management facilities). Multifaceted approaches are required for controlling ibis populations, including restricting access to anthropogenic food resources, managing the condition of remnant habitats, and considering population control at sites with high connectivity to foraging grounds.

Large, overlapping home ranges reveal male mating strategies in polygynandrous Eclectus parrots

ABSTRACT The distribution of the resources needed by females for reproduction affects their dispersion in space and time, which in turn influences the number of females a male can defend. When males provide parental care they in turn become a resource for females, and influence where females choose to breed. Combined, these factors explain a preponderance of monogamous and (to a lesser extent) polygynous mating systems in birds. However, less frequently observed mating systems in birds remain harder to explain. Here, we analyse the home ranges of male Eclectus parrots (Eclectus roratus) to investigate how their use of space facilitates an unusual polygynandrous mating system (where multiple males mate with multiple females). Female Eclectus parrots in the rainforests of northern Queensland, Australia, have limited movements. They remain at their nest trees for most of the year and rely on multiple wide-ranging males to bring them their food. We used light aircraft and VHF transmitters to track the movements of four male Eclectus parrots during the breeding season. We combined data on home range size with molecular analyses of a larger sample of breeding birds. Our analyses demonstrate that male home ranges overlap with each other and encompass multiple (3–14) trees with nesting females. We show that some males divide their time between, and gain reproductive success with, females up to 7 km apart. Our tracking and molecular data offer insights into how polygynandrous mating systems relate to space use among males and females.

Nest site preferences of the Eurasian Goshawk Accipiter gentilis, an indicator species of conservation concern, in hemiboreal mixed forests

The Goshawk has been recognized as an effective bioindicator sensitive to forest management. We used a comprehensive data set on 75 Goshawk nest sites from Estonia to explore the species’ preferences in relation with forest and landscape characteristics. Goshawk nest sites were regularly distributed with a mean nearest neighbour distance of 6.9 km. The hawks showed a preference for nesting in old (mean age 101 years) coniferous Oxalis-type stands with medium tree density, although the preferred nest tree species was deciduous birch. In surroundings of nest sites, there was a relatively high proportion of old-growth forest (64 %), and nests were closer to mires (1319 m) than expected, while being at a moderate distance from the forest edge (135 m). However, we did not detect any significant effect of the proximity of buildings and roads. Our results suggest that territoriality sets the upper limit to the nesting population, and the ultimate choice of nest location is constrained by the availability of suitable nest sites. We recommend that foresters planning timber harvesting near Goshawk nests avoid clear cutting and maintain sufficiently mature forest nearby. Furthermore, keeping suitable forest patches across forest land support a healthy Goshawk population.

Tree architecture model of Sumatran Orangutan Pongo abelii Lesson, 1827 (Mammalia: Primates: Hominidae) nests at Soraya Research Station, Leuser Ecosystem, Indonesia

The relationship between tree architectural models and the nesting behavior of the Sumatran Orangutan Pongo abelii Lesson, 1827 at the Soraya Research Station, Sumatra, Indonesia was determined by examining the preference for particular nest tree architectural models in relation to the frequency of nest occurrence. This investigation included the study of tree architectural models, tree types, nest profiles, vegetation, environmental factors, and geospatial data, collected within a 20 × 1,000 m (2 ha) observational area during a nest survey. A total of 59 orangutan nests were identified across 47 trees, categorized into 31 species and nine varied tree architectural models. Among these, the most prevalent models observed were Cook, Scarrone, and Attims, which exhibit features assumed to enhance orangutan nesting behaviors. Based on the Neu approach to nest qualities, the analytical test findings show a correlation between the preference ratings for nesting trees. Our results are expected to serve as a reference for selecting tree species in rehabilitation or habitat restoration programs and the development of separated forest block corridors as conservation efforts for orangutans.

Are man-made hives valid thermal surrogates for natural honey bee nests (Apismellifera)?

Honey bees preferentially occupy thick walled tall narrow tree cavities and attach their combs directly to the nest wall, leaving periodic gaps. However, academic research and beekeeping are conducted in squat, thin walled man made hives, with a continuous gap between the combs and the walls and roof. Utilising a computational fluid dynamics (CFD) model of thermoregulating bees in complete nests in trees and thin walled man made hives, with the average size of tree comb gaps determined from honey bee occupied synthetic tree nests, this research compared the metabolic energy impacts of comb gaps and vertical movement of the thermoregulated brood area. This shows their heat transfer regimes are disparate, including: bee space above combs increases heat loss by up to ∼70%; hives, compared to tree nests, require at least 150% the density of honey bees to arrest convection across the brood area. Tree cavities have a larger vertical freedom, a greater thermal resistance and can make dense clustering redundant. With the thermal environment being critical to honey bees, the magnitude and scope of these differences suggest that some hive based behavioural research needs extra validation to be considered non-anthropogenic, and some bee keeping practices are sub-optimal.

Description and Preferences of Tarsier (Tarsius supriatnai) Nest Trees in Nantu Wildlife Reserve, Gorontalo

Tarsiers (Tarsius supriatnai) were part of the endemic primates in Sulawesi categorized as vulnerable in the IUCN red list. Therefore, this research aimed to describe and analyze the characteristics, preferences, and determinant factors influencing the use of nest trees by tarsiers in Nantu Wildlife Reserve, Gorontalo. This research used a direct observation method to collect data for three months, from September to November 2013, focusing on temperature, humidity, light intensity, tree height, tree diameter, nest height from the ground, and frequency of nest use. Moreovr, the Neu index was applied to determine nest preferences and multiple linear regression analysis was used to analyze the factors influencing nest tree selection. The results showed that the primates preferred eight nest trees, including Ficus altissima (w=1.58) and Ficus benjamina (w=1.50). Multiple linear regression analysis showed that the humidity (4.103±3.674%, P&gt;0.05) and light intensity (126.362±41.149 lx, P&lt;0.05) became dominant factors influencing the frequency of nest use. The results generally showed that vegetation species and microclimate conditions were crucial for tarsiers, indicating the importance of preserving forest areas to ensure the conservation of these primates.

BIOLOGÍA REPRODUCTIVA DEL CHINCHERO ENANO O CHINCHERO EXCAVADOR XIPHORHYNCHUS FUSCUS

Despite recent advances, the knowledge scarcity on Furnariidae forest species reproduction continues to bias ideas and limit the understanding of avian life history. We studied the reproductive biology of the Lesser Woodcreeper (Xiphorhynchus fuscus; Dendrocolaptinae), which nests in tree cavities, to contribute observations toward ideas about evolution and ecology. In the Atlantic Forest of Argentina (2007–2022), we inspected 26 nests (total: 333 visits), color-banded nine adults, conducted 180 h of focal observations at 11 nests, and analyzed patterns of nest survival and parental care using linear models in R. Lesser Woodcreepers laid two or three white eggs (mean±SE = 2.8±0.1; N = 16) on a bed of bark flakes. One adult (possibly female) carried out construction, incubation, feeding, and nest hygiene, but we frequently observed a second adult (possibly male) singing from 'preferred' perches, sometimes approaching the nest tree in response to alarm calls from the nest. Attending adults brought bark to their nests throughout incubation (19 days) and occasionally during nestling (21 days; range: 20–23). In the absence of adults, eggs and young nestlings were left covered with bark. Nest attention (daytime percentage an adult was inside the cavity) was 63±3% during incubation, fell to 38±9% in the first 4 days after hatching, and approximately 0% after nestlings were 10 days old and had open pin feathers. Nestlings were fed almost exclusively arthropods, and the feeding rate increased as brooding declined. Nest survival was 0.984 (95% CI: 0.970–0.992) daily or 0.50 (0.26–0.70) for the nesting period. For four of six broods, when nestlings fledged, a second adult (possibly a male) participated minimally. Our observations cover the mating system and division of parental care in Furnariidae, the advantages of covering eggs and nestlings, and the possibility that males increase parental care during the vulnerable fledgling stage.

Preference of trees for nest building by critically endangered white-rumped vultures (Gyps bengalensis) in Nepal.

White-rumped vultures (Gyps bengalensis) are critically endangered species, and protecting their habitats, particularly the nesting trees, may have a positive impact on their reproductive success. For a better understanding of vultures' habitat needs, the characteristics of nesting trees should be accounted. In this paper, we compare the characteristics of the trees that have vultures' nests and that do not by randomly select a control tree within a 10 m radius of the nesting tree. We extensively searched and monitored the white-rumped vultures' nests, nesting trees, and nesting tree species in Nepal between 2002 and 2022, and measured the characteristics of sampled trees such as their height, girth, canopy spread, branching orders, and whorls. We recorded 1161 nests of white-rumped vulture in total on 194 trees belonging to 19 species over the past two decades. White-rumped vultures preferred the kapok trees (Bombax ceiba) for nest construction than other tree species (χ 2 = 115.38, df = 1, p < .001) as 66.49% of nests were built on them. In the logistic regression model, the number of whorls on a tree, canopy spread, and the height of the first branch determined whether a nest was present or absent on a tree. These results help to prioritize the tree attributes in a habitat conservation plan for vultures.

Relative importance of vegetation features and intra- and inter-specific interactions on habitat preferences of a raptor guild in eucalypt plantations

Forest plantations are increasingly recognized for their role in providing ecosystem services in agroforestry systems. Understanding the habitat preferences of potentially beneficial birds supports effective forest management. Our study focused on identifying breeding habitat preferences of a raptor guild and assessing exotic eucalypt plantations as potential breeding sites. We explored preferences at various spatial scales considering vegetation features, intraspecific territorial behaviour, and interspecific interactions within the guild to determine their importance. We hypothesized that feeding habits and body mass explain differences in habitat preferences among three diurnal raptors (Northern goshawk, Common buzzard, Eurasian sparrowhawk). We employed random forest models to differentiate breeding sites from control plots, assessing factors' relative importance and unravelling the hierarchical process of habitat selection in southwestern Europe's eucalypt plantations. The studied eucalypt plantations emerged as suitable breeding habitats, harbouring dense breeding populations with uniform spatial distribution. Intraspecific territoriality and vegetation significantly influenced breeding habitat selection, while interspecific interactions held lesser influence. Species-specific variations were attributed to feeding habits and body masses. Tall eucalypt trees and mature-like patches were crucial elements driving breeding habitat selection. Raptors' preference for specific woody elements primarily influences areas within a relatively small radius around their nests (including the nest tree, nest site −10 m radius, and nest stand −50 m), with sparrowhawks showing preferences extending to 125 m. Raptors' inclination for mature woody elements and mature forest patches should steer forest management to bolster these apex predators and their contributions in eucalypt plantations within agroforestry systems.

Nest tree preference by Hornbill Species in Pench Tiger Reserve, Madhya Pradesh

Nest tree preference by Hornbill Species in Pench Tiger Reserve, Madhya Pradesh

Diversity of bee tree (sambit) for Apis dorsata conservation in Membalong, Belitung Regency, Indonesia

The land transformation of forests to monoculture threatened the existence of biodiversity in Belitung, including the bee trees (local name: sambit) for Apis dorsata nesting. Bee farmers are having difficulty finding numerous kinds of bee trees. The objectives of this study were (1) to identify the species of bee trees, (2) to characterize the nesting branches of the bee tree, and (3) to identify the ecosystem of the bee trees in three villages in Membalong, Belitung Regency. Data were collected using: (1) interviewing bee farmers, (2) measurements of nesting branches, and (3) exploring the bee tree ecosystems. We discovered 22 species (13 families) of bee trees, with Myrtaceae was the most frequent. Syzygium cymosum (local name: mengkeling) was a common nesting tree of A. dorsata. The characteristics of bee trees were: height of the nesting branch: 7.85 ± 3.80 m above the ground, length of the branch: 2.74 ± 1.43 m, and the incline of the branch: 20.20° ± 2.57°. We found bee trees in terrestrial ecosystems (primary and secondary heath forests) and wetlands (swamps and mangroves). The last ecosystem was a new finding. We suggest local communities cultivate the native plants and reduce the area of forest land used.

Naturally Occurring Vegetation Connectivity Facilitates Ant-Mediated Coffee Berry Borer Removal.

Vegetation connectivity is an essential aspect of the habitat complexity that impacts species interactions at local scales. However, agricultural intensification reduces connectivity in agroforestry systems, including coffee agroecosystems, which may hinder the movement of natural enemies and reduce the ecosystem services that they provide. Ants play an important role in regulating the coffee berry borer (CBB), which is the most damaging coffee pest. For arboreal ant communities, the connections between trees are important structures that facilitate ant mobility, resource recruitment, foraging success, and pest control ability. To better understand how connectivity impacts arboreal ants in coffee agroecosystems, we conducted an experiment to assess the impact of artificial (string) and naturally occurring vegetation (vines, leaves, branches) connectivity on Azteca sericeasur behavior on coffee plants. We compared ant activity, resource recruitment, and CBB removal rates across three connectivity treatments connecting coffee plants to A. sericeasur nest trees: vegetation connectivity, string, and control (not connected) treatments. We found higher rates of ant activity, resource recruitment, and CBB removal on plants with naturally occurring vegetation connections to A. sericeasur nest trees. Artificial connectivity (string) increased the rates of resource recruitment and CBB removal but to a lesser extent than vegetation connectivity. Moreover, vegetation connectivity buffered reductions in ant activity with distance from the ant nest tree. These results reinforce how habitat complexity in the form of vegetation connectivity impacts interspecific interactions at the local scale. Our results also suggest that leaving some degree of vegetation connectivity between coffee plants and shade trees can promote ant-mediated biological pest control in coffee systems.

Chimpanzees select comfortable nesting tree species

Every evening, chimpanzees build sleeping “nests” in trees. In some studied communities, individuals appear to be selective about the tree species used, which has led researchers to hypothesize whether chimpanzees prefer trees that repel troublesome insects or/and that provide comfortable and stable structures. We investigate these hypotheses, or a trade-off between both, though study of tree species preference based on their biomechanical and/or biochemical properties in the Sebitoli chimpanzee community in Kibale National Park, Uganda. The ten tree species most frequently used for nesting were compared with ten abundant in their environment but not preferred for nesting. For these 20 tree species, we determined their biomechanical and morphological characteristics such as foliar density, foliar units form (shape and size) and branch rigidity. Their spatial repellent activity, previously tested against Anopheles gambiae was incorporated into the analysis. Chimpanzees chose tree species with medium-sized and elongated foliar units, high foliar density and branch with stiffer wood. In addition, most tree species with such mechanical and morphological properties also have mosquito repellent activity. These tree properties may provide a comfortable sleeping environment enhancing sleep quality. Finally, a comparison across chimpanzee communities would be relevant to understand whether these choices are not only ecological but also cultural.

Forest management, forest vegetation, and climate influence nesting ecology of a focal bird species in the western USA

Landscape-scale forest restoration aims to restore ecological structure and function and provide habitat for wildlife. However, forest management likely has varying impacts across wildlife life stages, with consequences for population persistence. Using 10 years of nest (n = 294) survey data for a focal bird species, white-headed woodpecker (Dryobates albolarvatus), we assessed how forest management (tree removal and prescribed burning) at two spatial scales (stand [2.25 ha] and landscape [314 ha]), forest vegetation variables at three spatial scales (nest tree, local [0.4 ha], and landscape [314 ha]), and climate influenced nest initiation date, egg production, egg survival, and nestling survival. We applied Bayesian hierarchical mixed effects models to these data to identify and compare drivers at each life stage. None of the variables we considered influenced egg production; white-headed woodpeckers laid an average of four eggs. As the extent of the landscape with tree removal increased, nests initiated later. Egg survival was higher in nests with prescribed burning at the stand scale. Nestling survival was higher in sites that had been managed with burning and tree removal at the stand scale, but the relationship with burning switched to negative at the landscape scale. Only nestling survival was shaped by attributes of the nest cavity itself. Egg survival increased with increased variation in forest patch sizes at the landscape scale. Woodpeckers initiated nests earlier under warmer conditions, with previous August and September temperatures being particularly influential. Both egg and nestling survival increased with cumulative precipitation. While increased temperatures decreased egg survival, nestling survival peaked at an optimal maximum temperature (∼32 °C). This study illustrates how forest management, forest vegetation, and climate factors affecting nesting ecology vary throughout the nesting season. Additionally, effects that switch directions (positive versus negative) across spatial scales indicate spatially dependent ecological processes (e.g., nest suitability versus adult foraging). This study provides a model for assessing the effects of forest management on bird population persistence by considering the nesting season as stages with distinct ecological limitations linked to spatially-dependent factors.

Resource selection and home range size variation of Atlantic Forest woodpecker species: Implications for selective logging and conservation

Understanding the habitat requirements of forest-dependent species, such as woodpeckers, is crucial for effective management strategies in environments facing significant anthropogenic pressures. During 2013–2019, we investigated the variation in the availability of forest structural attributes in two unlogged forests, one forest with active selective logging, and one forest 33 years after it had been logged, in the Upper Paraná Atlantic Forest in Misiones, Argentina. Then, we studied the selection of the forest attributes by co-occurring populations of Helmeted Woodpecker (Celeus galeatus), Lineated Woodpecker (Dryocopus lineatus), and Robust Woodpecker (Campephilus robustus), along with their correlation to variations in home range sizes of woodpeckers. We found that the density of potential nest trees of the three woodpecker species, the density of potential Helmeted Woodpecker roost trees, the basal area ha−1 of live trees ≥ 30 cm DBH, the density of live large trees ≥ 30 cm DBH, and the volume of dead wood ≥ 30 cm diameter differed among study sites. Home range sizes of Helmeted Woodpeckers decreased with higher potential roost tree density and greater understory bamboo cover. The home range sizes of Robust Woodpeckers decreased with a higher density of dead trees, while home range sizes of Lineated Woodpeckers were not influenced by any of the variables we measured. The three woodpecker species selected diameter classes and tree species for foraging and nesting disproportionally to their availability. Helmeted Woodpecker preferred guatambú (Balfourodendron riedelianum) over other trees for roosting. We recommend considering key attributes associated with smaller home range sizes of the threatened Helmeted Woodpecker in sustainable forest management, as these attributes are also important for the other two woodpecker species. To ensure the availability of the resources selected by these woodpeckers, we recommend increasing the legal minimum cutting diameter to 60 cm for grapia (Apuleia leiocarpa), guatambú, rabo duro (Lonchocarpus leucanthus) and palo de canga (Symplocos uniflora), and to 50 cm for laurel negro (Nectandra megapotamica) and laurel amarillo (N. lanceolata). We found similar quantities of most of the tree resources we measured in unlogged forests and a forest undergoing a natural recovery for 33 years after the cessation of selective logging, and we recommend that more logged forests be restored in this manner.

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.

The use of drone to study the nesting behavior of milky stork: Some preliminary observations

Abstract. Mardiastuti A, Mulyani YA, Akbar A, Wicaksono B, Rahmawati T, Wulandari YP, Warsajaya. 2023. The use of drone to study the nesting behavior of milky stork: Some preliminary observations. Biodiversitas 24: 4549-4557. The use of a drone to census waterbirds has been increasingly popular. However, study on the waterbird’s behavioral response to the drone was still limited. The objective of this study is to reveal the response of the breeding milky stork Mycteria cinerea to the drone as a new and safer tool for collecting breeding behavior data. Factors that influence the success of the observation by using a drone were also identified and a set of recommendations was formulated. The research was conducted during the breeding season of the milky stork in Pulau Rambut, a small island in Jakarta Bay, between December 2022 and March 2023. Three types of drones were tested in the pilot study, and eventually, a small manually piloted drone (Syma X25 Pro) was found to be more appropriate for behavioral study. The bird response to the drone (no, neutral, temporary, negative response) was observed through a combination of various distances and angles of the drone to the nest trees. Despite the weather obstacles, this study suggested that the milky stork mostly (17 out of 20 trials) showed no response or neutral response to the drone. Some temporary responses were detected due to some accidental events, including a sudden launch of the drone. In conclusion, a small-size, easy-to-maneuver drone that produces low noise and mild wind can be used by using a manual pilot mode to study the breeding behavior of milky storks or other similar waterbird species.

Landscape factors influencing bird nest site selection in urban green spaces

IntroductionUnderstanding the birds’ breeding strategies in urban habitats is vital for ensuring their continued existence. Therefore, more research must be conducted on bird breeding and urban adaptation strategies in urban green spaces. This study aimed to address this gap by investigating the influence of landscape factors on the selection of bird nest sites. MethodsData on the presence and absence of magpie (Pica pica) and gray magpie (Cyanopica cyana) nests were collected through field surveys conducted in the campus of Nanjing Forestry University during the 2023 breeding season. Generalized additive models (GAMs) incorporating landscape variables were employed to assess the effects of these predictors on nest occurrence. The model with the lowest Akaike’s information criterion value was selected among the candidate GAMs.ResultsBelow is a summary of the main results. Nest tree height (TH), distance from the central lawn (D), and tree coverage (TC) within the sampled area were identified as the primary landscape factors influencing nest site choice. Conversely, factors such as the shortest distance to the water source, herb coverage, shrub coverage, percentage of buildings, and percentage of hard pavement did not significantly impact on nest site selection. Furthermore, the nesting potential of magpies and grey magpies initially increased with tree height, reaching a maximum at ca. TH=25 meters after which it began to decline. The nesting occurrence rate showed an initial decrease tendency with increasing distance from the central lawn, reaching a minimum at D=400 meters, and then increased with further distance. Additionally, nesting potential decreased initially with increasing of TC in the range of 0–20%, fluctuated evenly between 20–60% TC, and decreased rapidly when TC exceeded 60%.DiscussionThis study provides valuable insights into the selection of nest sites by birds in urban habitats, specifically with respect to landscape factors. The understanding of the impact of urban green spaces on urban birds and the underlying mechanisms of their behavior contributes to the conservation of wild birds and promotes the harmonious development of urban areas.