Nest Trees Research Articles

Flying through the forest canopy: Movement patterns and habitat selection of rescued and wild Harpy Eagles in the Brazilian Amazon

We tracked six Harpy Eagles (Harpia harpyja) by satellite telemetry from 2011 to 2021 in the Brazilian Amazonia, analyzing the used area, movements parameters and habitat selection functions for three of them: one adult within its breeding site, one translocated adult, and a four-years old floating subadult. We used the first-passage time to assess the scale at which these individuals respond to the environment, and the behavioral change point analysis to determine behavioral states parameters across trajectories. We fitted a logistic linear regression model with used-available locations and environmental covariates: slope, Terrain Ruggedness Index (TRI), Normalized Difference Vegetation Index (NDVI), land cover, and habitat edge as predictor variables. Harpy Eagle locations were highly related with “Forest” land cover and high NDVI values. The subadult and the translocated adult selected for “Secondary Forest” within their home ranges, which highlights the importance of this type of habitat in fragmented landscapes. In addition, we found behavioural differences in the movement paths of rehabilitated individuals of Harpy Eagle that are subsequently released to the wild. In conclusion, we suggest including in conservation management not only the nest tree and its immediately surrounding but also an area over landscape scale to optimize and promote the functional connectivity, with a safe and efficient dispersion of immatures. Linking Harpy Eagle´s movement locations to resources (land cover, NDVI), risks (forested habitat edge) and environmental conditions (slope, terrain ruggedness) is an opportunity to learn about habitat selection by this large canopy predator. The Harpy Eagle movement ecology has a potential relationship with the spatial dynamics of prey in the forest canopy, which needs to be further addressed in future research.

Decay rates of arboreal and terrestrial nests of Easternchimpanzees (Pan troglodytes schweinfurthii) in the Bugoma Central Forest Reserve, Uganda: Implications for population size estimates.

Chimpanzees were once thought to sleep primarily in the trees, but recent studies indicate that some populations also construct terrestrial night nests. This behavior has relevance not only to understanding the behavioral diversity of Pan troglodytes, but also to the conservation of the species, given that nest encounter rates are often used to estimate great ape population densities. A proper estimate of decay rates for ground nests is necessary for converting the encounter rate of nests to the density of weaned chimpanzees. Here we present the results of the first systematic comparative study between the decay rates of arboreal and terrestrial chimpanzee nests, from the Bugoma Central Forest Reserve in western Uganda. We followed the decay of 56 ground and 51 tree nests in eight nest groups between April 2020 and October 2021. For 15 of the ground and 19 of the tree nests, we collected detailed information on the condition of the nests every two weeks; we checked the remaining 73 nests only twice. On average, ground nests lasted 238days versus 276 days for tree nests (p = 0.05). Of the 107 total nests surveyed, 51% of tree and 64% of ground nests had disappeared after six months. Based on our results, we propose a modification of the formula used to convert nest density into chimpanzee density. Our results highlight the importance of taking into account potential differences in decay rates between ground versus tree nests, which will likely influence our understanding of the distribution of ground nesting behavior in chimpanzee across tropical Africa, as well as our estimations of the densities of ground nesting populations.

KARAKTER DAN KERAGAMAN JENIS POHON SARANG ORANGUTAN SUMATERA (Pongo abelii) DI STASIUN RISET SUAQ BELIMBING TAMAN NASIONAL GUNUNG LEUSER

The Sumatran orangutan (Pongo abelii) is an arboreal primate that spends all its daily activities in the trees. Nest-making activities are carried out daily, selecting trees with certain characteristics to make nests. Much research has been done on the character of orangutan nest trees. However, there needs to be more information about the character of orangutan nest trees at the Suaq Belimbing Research Institute, Gunung Leuser National Park. It is known that Suaq Belimbing is a peat swamp forest ecosystem in Gunung Leuser National Park, precisely in Kluet, South Aceh, with quite diverse vegetation composition. Even so, not all vegetation is used as orangutan nest trees. This study aims to obtain data on the characteristics of orangutan nest trees in the Suaq Belimbing peat swamp forest habitat of Gunung Leuser National Park. Data was collected for three months using the line transect method. The results of the study obtained 65 individual trees used as orangutan nests. 45.15% of the nest tree characters had a height of 11-20 m, and 24.46% had a trunk diameter of 31-40 cm. The most widely used crown shape for making nests was cylindrical.

DAMPAK SIKLON TROPIS SEROJA TERHADAP KETERSEDIAA N PAKAN, TEMPAT BERSARANG DAN PENDAPATAN PETANI LEBAH MADU HUTAN (Apis dorsata)

This study aims to determine the impact of the availability of forest honey bee feed, the impact of forest honey bee nesting sites and the impact of changes in the income of forest honey bee farmers in Uiasa Village, Semau District, Kupang Regency, East Nusa Tenggara before and after the Tropical Cyclone Storm Seroja. This research was carried out around the Pastello Amalato Protected Forest Area, Uiasa Village, Semau District, Kupang Regency, which was carried out for 1 month, from April to May 2022. This research used purposive sampling, interview and roaming methods with data analysis using descriptive qualitative and descriptive analysis. quantitative.The impact of food availability after the Seroja Tropical Cyclone Storm consists of two factors, namely reduced forage for forest honey bees and disruption of the flowering time of forage plants. The impact of forest honey bee nesting after the Seroja tropical cyclone storm was influenced by the movement of forest honey bee hives from their original place to another and the altitude where the forest honey bee nest trees were found was mostly at an altitude of 25-45 meters above sea level compared to other elevations with the number of honey bee trees is 10 trees and 7 trees at an altitude of 0-25 meters above sea level.

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.

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.

Nesting Site Preferences of Ratufa indica indica in the Umblebyle Range Forest, Bhadravathi Division, Shimoga, Karnataka

Malabar Giant Squirrel (Ratufa indica indica) is one of the four subspecies endemic to India (Abdulali 1952), common to northern and central Western Ghats among species Ratufa indica belonging to Subfamily Ratufinae. The study was designed to analyze the nest tree preferences of animals in the dry deciduous forests of the Umblebyle range, Shimoga, Karnataka (South India) during February, March, and April 2021, surveying 20 transects covering a distance of 47.7 km. Nest tree preferences were assessed by observing 406 dreys (nests) on 385 trees covering an area of 8350.89 ha. The nest trees came from 20 families and 41 species, with 12 tree species in the Family Fabaceae and 84 trees in the Terminalia paniculata having the highest preference. The Squirrels showed the highest preference for deciduous trees over semi-evergreen and evergreen trees. The most preferred tree height and nest height ranged between 11-20m, including 87.53% of nesting trees and 83.89% of nests, respectively. The average nest height was estimated to be 14.73 (±3.311) m, with a minimum and maximum height of 7 m and 28 m, respectively. The difference between average tree height and average nest height was 1.512m.

Ordinal Date and Tree Diameter Influence Swallow-Tailed Kite (Elanoides forficatus) Nest Survival

ABSTRACT Swallow-tailed Kites (Elanoides forficatus) continue to rebound from population declines during the late 19th and early 20th centuries, and they are considered a species of concern in several southeastern states in the United States. During 2018–2019, we located and monitored 132 active Swallow-tailed Kite nests in and around the Corkscrew Regional Ecosystem Watershed Wildlife and Environmental Area in southwest Florida, USA, to determine how nest site characteristics affect nest survival. Including both years, the earliest active nest (with eggs or young) was discovered on 12 March and the latest nest fledged young on 23 July. Modeled survival of nests from the onset of incubation to fledging was 57.7% (95% CI: 44.5–68.9) and apparent nest survival was 48.7%. Daily survival rate was negatively correlated with ordinal date. Consequently, nests initiated early in the nesting season (mid-March) were more than three times as likely to fledge young as nests initiated late in the season (mid-May). Daily nest survival was positively correlated with nest tree diameter at breast height, indicating that Swallow-tailed Kites had greater nest survival when using larger, more mature trees. We found 99.0% (n = 102) of Swallow-tailed Kite nests in south Florida slash pine (Pinus elliottii var. densa) trees and one nest in bald cypress (Taxodium distichum). Trees used for nesting in our study area were among the largest nest trees reported for the species. Our results suggest that the large pine trees and large cypress trees formerly available in old growth bottomland hardwoods and lowland pine forests of the United States may have provided superior nesting opportunities for Swallow-tailed Kites.

Camelthorn and blackthorn trees provide important resources for Southern Pied Babblers (Turdoides bicolor) in the Kalahari

In the southern Kalahari Desert, cooperatively breeding Southern Pied Babblers Turdoides bicolor frequently build their nests and forage in camelthorn trees Vachellia erioloba, a keystone species in the region, and blackthorn trees Senegalia mellifera, a widespread early successional shrub. Using Ivlev's electivity indices (Ei), we show that Southern Pied Babblers preferentially nest in camelthorn trees and preferentially forage in or under camelthorn and blackthorn trees. Southern Pied Babblers primarily forage on the ground; however, they will make use of arboreal resources when these are available. We observed the birds spending the highest proportion of foraging time off the ground during October, when breeding is also most common, compared with all other months within the austral summer breeding season. They are most likely to be observed foraging in camelthorn trees earlier in the breeding season and blackthorn trees later in the breeding season. We demonstrate that Southern Pied Babblers have a strong relationship with camelthorn trees, in which they prefer to both nest and forage. We highlight the importance of protecting camelthorn trees, a keystone species in the region, as part of the conservation and management of endemic Kalahari fauna such as the Southern Pied Babbler. In addition to contributing to the literature on keystone species, our observations raise questions about the ways in which avian reproduction in the arid zone could be decoupled from rainfall via the phenology of deep‐rooted tree species.

Häckningsbiotop och boplatsval hos havsörn Haliaeetus albicilla på Gotland

Nest site features and habitats of the White-tailed Eagle Haliaeetus albicilla were studied in Gotland, Sweden, during 2008–2017. Here, the entire population depended on suitable trees for nesting. The mean age of the nesting trees was 173 years. Only 9% of these trees were younger than 125 years. The mean distance from nests to roads was 400 metres. The mean distance to permanent residences and recreational cottages was 1.5 km and 1.2 km, respectively. Although the nests were not located far from human activities, the eagles were very shy. Therefore, they need protected areas around the nesting trees, especially during the breeding season.

Diversity and Abundance of Breeding Birds, Habitat, and Nesting Substrate Selection in Urban Areas: A Relevant Case from the Southern Slope of the Mediterranean

Urban areas may affect the richness of avian species. The abundance and diversity of urban landscapes offer breeding habitats and nesting resources for urban-adapted species. In our study, we investigated the breeding birds in urban landscapes of Fez’s historical city (Morocco). We used line-transects to search for nests of breeding species, populations, and habitats counting breeding sites and predicting factors (foraging, nesting resources, and urbanization). Furthermore, four habitats counting green gardens, old city walls, urban farms, and urban forests were prospected to search for nests of breeding birds. Among 13 breeding species including 12 resident-breeders, and one breeding migrant, a total of 109 nests were documented. Five species counting Turdus merula, Sylvia atricapilla, Spilopelia senegalensis, Columba livia, and Coloeus monedula were encountered in green gardens; four species counting Athene noctua, Sturnus unicolor, Passer domesticus, and Tachymarptis melba were observed in old city walls. Falco tinnunculus, Fringilla coelebs, and Accipiter nisus occurred in urban forests; and Streptopelia decaocto in urban farms. The recorded nests were divided between cavities (50 nests) and trees (59 nests). In green spaces, nests were distributed among Olea europaea (17), Citrus aurantium (15), Bambusa vulgaris (11), and Eucalyptus globulus (7). In contrast, Olea oleaster and Cupressus sp. hosted only tree nests each, while Populus sp. and Washingtonia filifera hosted only one nest each. Most nests were recorded in habitats rich in nesting trees and close to water sources. On the contrary, the number of nests decreased as the surface and distance of the habitat to the urban center increased. Our data revealed the diversity, habitat use, and nesting substrates of urban breeding bird communities in Morocco and the Southern slope of the Western Palearctic. Future urban plans must integrate measures to provide suitable breeding resources such as cavities of old walls and a high diversity of urban green spaces for birds to enhance their breeding performances, thus promoting the well-being of the population via increasing biodiversity.

Some Observations on the Nest Site Selection, Nesting and Other Breeding Behaviors of Greater Adjutant Stork (Leptoptilos dubios) in the Flood Plains of Kosi River in District Bhagalpur, Bihar, India

Greater adjutant stork (Leptoptilos dubios) is the largest and rarest stork belonging to the order Ciconiformes. It is one of the threatened bird species of the world and widely considered to be endangered. The present investigation was carried out to study the nest site selection, nest tree and other breeding behaviours of Greater adjutant stork on the flood plains of Kosi river in district Bhagalpur, Bihar, India in three breeding seasons from 2019 to 2021. Total 12 breeding colonies of Greater adjutant stork were recorded in 2019, 10 in 2020 and 2021 respectively. During these periods, 277 chicks were reared in 123 nests in 2019, 282 chicks in 126 nests in 2020 and 236 chicks in 105 nests in 2021 respectively. Most of the nest trees were located on the road side in and around the villages. Storks mainly selected Kadamb, Peepal, Pakar, Gamhar and Semel trees for the nest building but the Kadamb was the most preffered tree species. Nesting materials used by the GAS were mainly sticks, twigs and fresh leaves of Pigeon wood, Jalebia, Dhaincha, Jamun, Peepal, Gulmohar, Kadamb, and Semal tree. Nests were large spherical structure made of plant sticks mostly on the top of the tree and on the tip of large horizontal branches. Both the sexes alternately shared incubation and protection of the chicks after hatching. The parent birds also collected green leaves from nearby trees for cushioning the nest . The breeding season of Greater adjutant stork was recorded between September to April in Bihar. The incubation period was ranging between 37 to 39 days. Two to three chicks on one nest were common. The adult and juveniles finally vacated the nest before third week of April.

Population change and nest tree longevity of a small-island population of Red-breasted Sapsuckers (Sphyrapicus ruber) breeding in old-growth temperate rainforest

Nous avons enregistré la taille de la population et l'utilisation des arbres de nidification des Pics à Poitrine Rousse (Sphyrapicus ruber) qui nichent dans la forêt pluviale tempérée côtière et ancienne de l'île East Limestone, à Haïda Gwaii, en Colombie-Britannique. La densité des populations sur cette île de 48 ha variait de 10 à 46 nids occupés/km2, avec une augmentation puis une diminution des effectifs de 1991 à 2005, suivie d'une augmentation progressive entre 2006 et 2020. La taille de la population n'a pas été affectée à la suite d'un chablis majeur qui, en 2010, a détruit environ un tiers du type de forêt préféré par l'espèce. Les oiseaux nicheurs ont continué à utiliser les arbres restants dans la zone de chablis, ce qui suggère que la rétention d'arbres morts isolés dans de petites ouvertures forestières peut fournir des sites de reproduction utiles pour les pics. Certains de ces arbres ont été utilisés jusqu'à 10 reprises et ont continué à être sélectionnés jusqu'à 21 ans après leur première utilisation, l'utilisation étant plus prolongée pour l'épicéa de Sitka (Picea sitchensis) que pour la pruche de l'ouest (Tsuga heterophylla). La durée maximale d'utilisation dépasse probablement 23 ans. Il y avait une tendance significative chez ces arbres à être utilisés au cours d'années consécutives. La modélisation de la disponibilité des arbres utilisés au moins une fois suggère qu' il y avait chaque année suffisamment d'arbres adéquats disponibles, et donc que la population n'était pas limitée par le manque de sites de nidification appropriés.

First breeding records of the osprey (Pandion haliaetus) on Jeju Island, South Korea

The first breeding of osprey ( Pandion haliaetus ) on Jeju Island, South Korea, were observed in 2015, and ospreys bred on three sites. We found a total of three nests and observed that A site nest bred on successfully from 2017 to 2020. The number of eggs per clutch ranged from two to four, with a mean ± SD of 3.16 ± 0.75. The nesting period varied from 71 days to 79 days, with an average duration of 76.2 ± 3.18 days. The incubation period ranged from 34 days to 38 days, averaging 35.8 ± 1.72 days. Fledging dates ranged from July 4th to 13th. The nest tree species was Pinus thunbergii , and the average tree height was 16.2 ± 3.12 m. On average, the nest height from the ground was 14.8 ± 2.57 m. The average diameter at breast height of the nesting trees was 36.1 ± 2.02 cm. Of the total 19 eggs produced, the hatching rate was 91.4% ± 10.2%, fledgling rate was 68.6% ± 26.9%, and breeding success was 65.6% ± 25.1%. Little ecological information is available on osprey living in South Korea; therefore, this study makes a meaningful contribution to provide baseline ecological data from South Korea for this species.

HABITAT STRUCTURE AND HETEROGENEITY DETERMINE A SUCCESSFUL BREEDING PROBABILITY OF THE LONG-EARED OWL (<i>ASIO OTUS</i>, STRIGIDAE, STRIGIFORMES)

In 2001 to 2020, for each Long-eared owl nest in the Crane Homeland Nature Reserve territory with an area of 48 km2, the following microhabitat parameters were determined using standard field methods: the nest type built by different bird species, the presence of a nest roof, the nesting tree species, and the nest height above the ground. In most cases, for nesting the Long-eared owl reused magpie nests (Pica pica) (77%), and half of the nests were found on willow trees (family Salicaceae) (50%). The nest height above the ground varied from 1.5 to 22 m. Vegetation on the nesting area with a radius of 500 m was determined using the “Semi-Automatic Classification Plugin” automatic vegetation classifier of QGIS software. Five habitat types were so classified: forests, shrubs, meadows, arable land, and satellite image mistakes. Village areas were allocated separately. The average shares of the largest habitat types for over 20 years on the nesting sites included meadows (51.1%) and shrubs (16%). From 2001 to 2020, a habitat change in the breeding area was observed: forest and shrub areas decreased, while the meadow, village and arable land areas increased. An analysis of the effect of habitat types on the nesting success was evaluated by means of the “gbm” and “dismo” modules in the R program using the Boosted Tree classifier algorithm. The presence of such habitat types in the nesting area as villages (24.2%), shrubs (19.3%), meadows (11.8%), and habitat heterogeneity (11.6%) most strongly affected the probability of owl successful nesting. That owls tend to use anthropogenic and agricultural territories is associated with the diversity, easy foraging and more effective protection from predators during the breeding season.

Characteristics of The Introduced Orangutan Nest at Jantho Orangutan Reintroduction Station, Aceh Besar

Sumatran orangutans (Pongo abelii) learned the process of building nests from their mothers and started building nests around the age of 0.5 years. Orangutan nests have the most intricate arrangement of other primate nests. Orangutans built the nest as a place to rest, play, and protect themselves from predators and insect bites such as mosquitoes. Orangutan nests have different locations tailored to the needs and context of the nest trees. The shape of the nest and the position of the nest usually have differences due to differences in sex, age level, and body weight. The research had conducted at the Jantho Orangutan Reintroduction (JOR) Station, Aceh Besar Regency, Aceh Province. It had carried out from January to August 2021. The research method used is purposive sampling. The selected transects are existing (permanent) with FB, RI, and IS coding, which is part of mammalian transects scattered in the Jantho Pine Forest Nature Reserve. Observations were carried out as many as two repetitions in different months. The results showed several classes and nest positions found at the JOR Station. The nest classes found were 1, 2, and 3, while the others were not found. Nests in position 2 were the most founded at the study site, and position 5 was not found. It indicates no orangutan at the study site liked to play on the ground. This study gets four nest shapes, namely single round, flat oval, tiered, and irregularly widened

Swainson’s Hawk Nesting Population in the Antelope Valley of the Western Mojave Desert, California

The Swainson’s Hawk (Buteo swainsoni) has a long history of breeding in California, but a severe decline in the statewide breeding population was identified in 1979, when in all of southern California only two pairs were found, one in the Antelope Valley of the western Mojave Desert. That area was little studied until we began banding Swainson’s Hawks there in 1997. Over 20 breeding seasons between 1979 and 2022, we documented in the Antelope Valley 124 attempts to nest, in which the mean clutch and brood sizes were 2.49 and 2.37, respectively. From 2004 through 2006, we observed two to four breeding pairs annually; from 2009 through 2022, three to 14 breeding pairs. The rate of success of the 91 nests revisited to determine if any young fledged was 64%. Nest trees consisted of 81.5% non-native species, 13.7% native species, including Joshua trees (Yucca brevifolia), and 4.8% unidentified deciduous trees. Between 1997 and 2022, in 50 nests, we recorded 170 vertebrate prey items, of which 90 were gophers (Thomomys bottae). Though the Antelope Valley population has grown since 1980, its nesting and foraging habitat now face multiple threats. To conserve occupied nesting territories, we recommend creation of nesting and foraging habitat reserves that include both native desert and cultivated alfalfa close to existing conserved land.

Степной орёл в Алтае-Саянском регионе – результаты исследований 2019–2023 годов

Степной орёл в Алтае-Саянском регионе – результаты исследований 2019–2023 годов

Орёл-могильник на юго-востоке Казахстана в 2022–2023 годах: распространение, численность, угрозы

Орёл-могильник на юго-востоке Казахстана в 2022–2023 годах: распространение, численность, угрозы

Результаты мониторинга гнездовых популяций солнечного орла в Дагестане (Россия) в 2022–2023 гг.

Результаты мониторинга гнездовых популяций солнечного орла в Дагестане (Россия) в 2022–2023 гг.