Number Of Nests Research Articles

Loss of Mississippi Diamondback Terrapin (Malaclemys terrapin pileata) Nesting Habitat in the Northern Gulf of Mexico

Diamondback terrapins (Malaclemys terrapin) are a species of turtle that occupy coastal tidal marshes and nest on sandy areas above the high-tide line. Within the Grand Bay National Estuarine Research Reserve, Mississippi diamondback terrapin (M. t. pileata) shoreline nesting habitat at Grand Battures (also known as South Rigolets Island) has decreased from a 2.34-km length of surveyable shoreline in 2014 to a 1.45-km length of shoreline in 2021. Depredated nest surveys in 2021 detected the lowest number of nests to date at this location, with increased search effort, and this is likely due to the high rates of erosion described for this area.

Apparent increasing importance of Adriatic Sea as a developmental habitat for Mediterranean green sea turtles (Chelonia mydas)

In the Mediterranean, the green sea turtle (Chelonia mydas) has exhibited increase in the number of nests over the past two decades. While the Eastern Mediterranean is recognized as a high use area, scarce observations of green turtles in Adriatic Sea suggested only low-level utilization of this area. This study presents new findings of green sea turtles in the Adriatic Sea and analyses the importance of the region for the species. In combination with published records, we present 75 findings of the species in the Adriatic including eight new records. The number of records is generally low but shows an intriguing ten-fold increase since 2000. This may be a result of three confounding factors: (i) positive population trend at main nesting sites in Mediterranean; (ii) increased institutional capacity for sea turtle research and conservation in the past two decades, and (iii) raising sea temperatures. Documented increases in the sea surface temperatures may have established suitable and recurring thermal corridors along Ionian-Adriatic developmental pathway and provided environmental cues for immigration of juvenile green turtles into the Adriatic. As the abundance of the species will likely increase in the future, research and conservation efforts will be needed to avoid the Adriatic Sea becoming a sink habitat for the Mediterranean green turtle population.

Long-term management practices successfully reduce bird-related electrical faults in a transmission grid increasingly used by white storks for nesting

Bird nests on transmission lines can cause electrical faults which reduce service reliability. To address this problem, since the mid-90s, the Portuguese Transmission System Operator (TSO) has undertaken management actions to discourage white storks Ciconia ciconia from nesting in hazardous locations of the pylons. Here, we compiled and analyzed an 18-year series of data on electrical faults, TSO management actions to tackle these, and stork nests on transmission pylons in Portugal to: (a) determine the relative importance of bird-related faults over the total number of faults; (b) describe variations in bird-related faults across time (season of the year and time of the day); (c) describe spatial variations in bird-related faults and their association with the occurrence of white stork nests on pylons; and (d) analyze the trends, over the years, of the number of white stork nests on pylons, the TSO management actions and their effectiveness in reducing bird-related fault rates. Overall, birds accounted, on average, for 25.3% of the electrical faults in the transmission network, with the vast majority being attributed to white storks. The seasonal pattern of bird-related faults showed higher rates in April and in October–November. Faults occurred more often during the night period, when storks spend more time on the pylons. We found a positive spatial relationship between the electrical fault rate and the proportion of pylons with stork nests (and the correlated number of nests per 100 km of line). There was, however, considerable variation in the fault rates not explained by the stork nest variables, particularly during the non-breeding season. The TSO management actions (namely removal/translocation of nests in hazardous locations of the pylons, installation of anti-perching devices and provision of alternative nesting platforms) significantly reduced, as a whole, the annual number of bird-related faults between 2001 and 2018, despite the three-fold increase in the number of white stork nests on transmission pylons. A deeper understanding of how white storks use the transmission pylons outside the breeding season is needed, so that targeted management actions can be taken to reduce the remaining bird-related fault rates to residual levels.

Eusociality as a neglected aspect of wild bee α‐diversity and its potential impact on diversity estimation

Abstract Bees provide important ecosystem services and are subjects of extensive studies on their α‐diversity, which is generally calculated with indices that integrate the number of species with their abundances. Variation in social behaviour, though expected to impact genetic diversity, is still largely neglected in such studies. We propose a simple method to show how sociality may affect diversity indices, when a surrogate of genetic diversity is taken into account. This method weighs the number of sampled females (N) to obtain new abundance values (NW), by taking into account relevant biological traits affecting genetic structure of populations, that is, the number of (natal) nests from which the sampled females originated (which depends on brood productivity and sex ratio) and the genetic relatedness among such females. Solitary species tend to have greater NW than eusocial ones especially at larger sample sizes. Across studies on 121 bee communities, we found that Taxonomic distinctness, Shannon–Wiener diversity and Gini–Simpson dominance tended to be greater when based on NW rather than on N. Such differences increased in communities with decreasing number of eusocial species and with increasing proportion of individuals from eusocial species. The results suggest that taking into account the social organisation of wild bees may have important consequences in estimating α‐diversity, thus claiming for future efforts in collecting biological data on as many wild bee species as possible to improve the precision of NW estimations. For example, stressors affecting more solitary bees could impoverish communities dominated by few but abundant eusocial species, more than expected by using unweighted abundances.

Reproductive Ecology and Nesting Site Characteristics of Four-Toed Salamanders (Hemidactylium scutatum) in Natural and Constructed Upland-Embedded Wetlands on the Appalachian Plateau, Kentucky

Many forested freshwater wetlands have been altered or destroyed, and wetlands are constructed to offset loss. However, they do not always replace the function of natural wetlands. It is important to understand how features of the habitat differ between types of wetlands and whether constructed wetlands provide an adequate habitat for species adapted to natural wetlands. Our objectives were to measure the characteristics of Four-toed Salamanders’ nesting habitat and determine which factors contribute to the abundance of eggs and nests in natural and constructed upland-embedded wetlands within a ridgetop ecosystem in eastern Kentucky. We located and examined characteristics for 207 nests in twelve wetlands and measured variables at the nest level and at the wetland level. The best predictor of the number of eggs and number of nests was amount of moss at the wetland. These measures of reproductive effort were similar between types of wetlands, but the number of eggs per nest was higher in constructed wetlands and inversely related to amount of moss, highlighting a deficit in nesting habitat. Research of embryonic and larval survival is needed but based on data from other amphibian species in this system, we predict that the survival of Four-toed Salamanders’ larvae is low in constructed wetlands with permanent hydrology. Restoration of constructed wetlands should address the need for moss as nesting substrate and drying of the wetland to reduce the abundance and diversity of predators of larvae.

Sudden collapse of xylophilous bee populations in the mountains of northern Utah (USA): An historical illustration

A scarcity of studies of the dynamics of wild bee populations hampers conservation efforts by bee ecologists and conservationists. Present limited information suggests that bee populations are highly unpredictable from year-to-year. Here we present an historical data set from nine sites replicated in 1984 and 1985 that demonstrates extreme between-year variability in numbers for 19 xylophilous bee species. Sixteen of those species produced far fewer nests in 1985, and 13 species in 1985 produced less than a third the number of nests produced in 1984. We argue that the 1985 collapse was not due to semivoltinism, i.e., the absence of morphs that require two years to mature, or to excessive sampling in 1984, but to a record cold period from January to March 1985 which likely killed most diapausing bees. Such events illustrate the dynamism of wild bee populations and thereby the large number of years needed to establish statistically significant population trends. We suggest that the current emphasis by bee conservationists to promote widespread surveillance monitoring programs is misguided and that funds are more effectively spent on hypothesis-driven targeted monitoring and on actions to actually reclaim degraded wild bee habitat.

Mediterranean green turtle population recovery increasingly depends on Lake Bardawil, Egypt

To assign conservation status to a population, its size, trends, and distribution must be estimated. The Mediterranean green turtle population has shown signs of recovering over the past decade, likely in response to nest protection, but satellite tracking suggests adult foraging remains largely restricted to only a few key sites in the eastern Mediterranean. Previous research suggested that the majority of green turtles nesting at an important rookery in Cyprus, forage in Lake Bardawil, Egypt making an observed population increase dependent on this important site, which is under a high degree of anthropogenic maintenance. Here we provide new data that further demonstrates the importance of Lake Bardawil to green turtles that nest at other major rookeries on Cyprus, in the Karpaz Peninsula, with 74 % of satellite tracked females (n = 19) migrating to this key site. We also report on the first systematic nest counts for this area in over two decades and identify the inter-nesting habitat used by females nesting at these important beaches on the north and south coasts of the Peninsula. Comparing the oldest available 3-year nest count averages (1993–1995), with nest counts undertaken as part of this study (2017–2019), mean annual nest numbers increased from 186 to 554, an increase of 198 %. Our data confirm the continued importance of these beaches for the Mediterranean green turtle population and underscore the reliance of this endangered population on a man-made lagoon for recent increases in clutch counts at monitored beaches. The results highlight the utility of satellite telemetry to inform conservation status assessments and establishing conservation at both nesting and foraging sites across the population.

Colonization and Extirpation of Great Black-Backed Gulls (Larus marinus) Nesting on Lake Ontario and the Upper St. Lawrence River

Colonies of Herring (Larus argentatus) and/or Ring-billed Gulls (L. delawarensis) on Lake Ontario and the upper St. Lawrence River were searched annually, 1981–2018, for nesting Great Black-backed Gulls (L. marinus). Great Black-backed Gulls nested at nine sites where both Herring and Ring-billed Gulls nested, at seven sites with only Herring Gulls, and at one site where they nested solitarily. Nests per site ranged from 1–21 on Lake Ontario and 1–5 on the St. Lawrence River. On Lake Ontario, nest numbers increased from six nests in 1981 to 51 nests in 2001 (+ 11.3%/yr), then declined to zero nests in 2008, where they have remained ever since. The decline in nesting Great Black-backed Gulls was due primarily to mortality from Type E botulism that affected that species to a greater degree than other gull species, probably because of their superior ability to dominate and scavenge toxin-laden carrion. Temporal changes in routes and efficiency of botulinum toxin transfer likely explain why Great Black-back Gulls were initially able to colonize Lake Ontario, but have undergone extirpation in recent times. Our results illustrate how changes in disease prevalence in the Great Lakes can degrade environmental quality to the extent that some species simply cannot persist.

Timing and mulching frequency affected the number of nests of cavity-nesting wasps that hunt for aphids in forest meadows

Mulching, cutting of the vegetation without plant biomass removal, is a common alternative to mowing. The aim of our study was to find out if the mulching of forest meadows at different time points affects cavity-nesting bees and wasps. We exposed trap nests for cavity-nesting bees and wasps at 24 forest meadows in south-western Germany over 2 years and applied four experimental mulching treatments with six replicates: (i) mulching in June, (ii) mulching in September, (iii) mulching in June and September, and (iv) no mulching as control. Nests were collected throughout the growing period. The insects were sorted and analyzed according to functional groups. Mulching in June and September reduced the nest number of all cavity-nesting insects in the second but not in the first year. The separation of insects into three functional groups (bees, herbivore-hunting wasps and carnivore-hunting wasps) showed that the number of herbivore-hunting wasp nests was reduced by mulching in September in both years and by mulching in June and September in the second year. Specifically, aphid-hunting wasps were influenced by mulching in September or mulching twice in the second year. Aphid-hunting wasps likely find their larval food in the vegetation of the forest meadows, while the other studied groups likely find their main larval food in the surrounding forests and are therefore not negatively affected.Implications for insect conservationFor maintaining the reproductive success of cavity-nesting wasps that hunt for aphids, we recommend mulching once in June rather than mulching in September or twice a year.

Ground-nesting bees prefer bare ground areas on calcareous grasslands

Although most of the wild bee species are ground-nesting, little is known about their nesting requirements and the conservation measures to promote ground-nesting bees. Calcareous grasslands are one of the most species-rich habitats in Central Europe and therefore essential for protecting bee diversity. The management practices of calcareous grasslands are so far often focused on plant populations, but in order to support declining insect populations, additional measures have to be considered for nature conservation. As wild bees depend on the availability of nesting sites, we studied the effects of locally increased bare ground availability on ground-nesting bees on four large and four small calcareous grasslands in Central Germany. Vegetation cover of 24 experimental plots (1 m²) was removed. The number of bee nests as well as the presence of bees on these plots (here: nesting activity) were compared to 24 control plots during six sampling runs. Results showed that the number of bee nests on experimental plots was fourteen times higher compared to control plots, positively related to the surrounding flower cover and higher on steeper slopes, independent of grassland area. Moreover, the observed nesting activity on experimental plots was 2.5 times higher compared to the control and positively related to the currently prevailing soil surface temperature. Bee abundance quantified during transect walks increased on grasslands with a generally higher bare ground availability and a higher flower cover. In conclusion, our study emphasizes the need to consider the availability of nesting resources to promote the vast majority of wild bees, which are ground-nesting. They benefited from bare ground availability as well as adjacent floral resources, and experimental removal of the vegetation cover appeared to be a major, so far underestimated conservation practice. • Ground-nesting bees prefer artificially created vegetation free patches on calcareous grasslands. • The abundance of (ground-nesting) bees is enhanced by a higher bare ground availability. • Nearby floral resources and steeper slopes increase the nest number of ground-nesting bees. • Higher soil temperatures increased the nesting activity of ground nesting bees. • Habitat size has no influence on bee abundance, the proportion of ground-nesting bees or colonization.

Optimisation of spot-welding process using Taguchi based Cuckoo search algorithm

The present work evaluated the efficiency of a Taguchi-based Cuckoo Search (CS) algorithm for optimizing the spot-welding process. The L9 orthogonal array of the Taguchi method is used for the conduction of required experiments. During the study input parameters are welding current (kA), hold time (cycles), welding time (cycles), and electrode pressure (kPa) while Peak Load, kN has been considered as an output parameter. The required objective function is developed through regression model formulation. Initially, CS operating parameters such as maximum number of iterations, number of nests, and probability to discover a cuckoo egg by the host bird is optimized through the Taguchi method and are found as 40, 20, and 0.5 respectively. That optimized CS further optimizes the spot-welding process. The maximum peak load of 34.5 kN is obtained if the welding current is 30.7 kA, welding time is 32 cycles, hold time is 20 cycles, and electrode pressure is 480 kPa respectively. Experimental validation yields a very low % error of 1.93% during optimization with an optimized CS method and the error is substantially high if optimization is conducted using a non-optimized CS method.

Hydrological Effects on the Reproduction of the Giant South American River Turtle Podocnemis expansa (Testudines: Podocnemididae)

Understanding the relationship between species and the environment is crucial to predicting their responses to human-induced global changes, i.e., habitat conversion, biological invasions, and global warming. Precipitation and river level are relevant factors that regulate the populations of aquatic organisms. We used long-term data to assess the effects of climate on nest number, clutch size (number of eggs per nest), hatching success, and unviable eggs of the Giant South American River Turtle (Podocnemis expansa) in a protected area of Brazilian Amazonia. We found a positive relationship between the number of nests and precipitation on headwaters in May. We also observed that clutch size increased when the local river level rose; hatching success increased with rising local river level, mainly during October and November; and egg failure increased with rising headwater river level. We show how precipitation and river level (at local and headwater) can influence reproductive success in P. expansa, highlighting the perils of human-induced environmental changes.

Monk Parakeet’s (Myiopsitta monachus) Ecological Parameters after Five Decades of Invasion in Santiago Metropolis, Chile

Monk Parakeets are considered one of the most invasive bird species given its unique capacity among psittacines to build their own communal nests. Originally introduced as pets in houses from where they escaped or were released, they are currently considered invasive in more than 20 countries worldwide. This is the case in Chile, where Monk Parakeets were introduced during the 1970s. Between 2016 and 2019 we searched Monk Parakeets’ nests structures in the Santiago metropolis region. We identified 1458 Monk Parakeets’ communal nests on 546 trees belonging to 34 tree species. Ninety-one percent of the occupied trees were also introduced. Paraná pine and cedar of Lebanon were the tree species with highest abundance of nests, averaging more than four nests/tree/species, with 23 and 18 maximum number of nests, respectively. Tasmanian blue gum and black locust were selected by parakeets more often than expected, based on availability. From all trees, 24.6% denoted health problems and 47.3% were pruned. The average nest height was 14.2 m and nests were observed mainly in secondary branches (59.3%). The occupancy rate was 89.7% and was associated to nest height and type of branch. During two reproductive seasons we quantified eggs and nestlings in chambers averaging 4.5 and 4.2, respectively. We provide a rough population size estimate and the characteristics of Monk Parakeets nest and tree selectivity, aiming to characterize several decades of a neglected urban invasion to warrant strategies for improved management measures.

INFORMATION ON THE BIOLOGY OF PICA PICA BACTRIANA

Abstract The article shows the relevance of the topic, the distribution of Pica pica bactriana, meeting characteristics and its study, the duration of the research and the methods used in the work, the number of nests found, nesting places, meeting places and their number, singing, mating. behavioral responses to breeding, number and location of nests, nesting interspecific relationships, nesting duration and use, nest shape, dimensions, nest location, nest construction, nest components and morphometric dimensions, oviposition and duration and brood care during incubation, changes in the egg, hatching, chick size, growth and development, images of reproduction, relation to the nest of the new generation Its biological characteristics and importance, such as its habitat, information about its nighttime, relationship with historical monuments, nutrition and food types, have been studied

Reuse of nests in the Great Reed Warbler Acrocephalus arundinaceus: A behavior to save time and energy and to deter nest parasites?

The reproductive period in animals is a demanding part in their life history. In birds, environmental factors, such as adverse weather, predation, or brood parasitism; and/or anthropogenic disturbance, can limit breeding success, resulting in failure of clutches. The nest loss in open‐cup nesting passerines is usually replaced with a new nest with a new clutch, however, in some cases the clutch replacement may occur in unusual forms. In this study, we report on three cases of within‐season nest reuse in the Great Reed Warbler. In the first case, a nest was reused for two times in the same season after unsuccessful nesting attempts (two‐time nest reuse). After the nest was depredated the first time, the female laid new eggs that were depredated again, then again the female laid new eggs that produced four fledglings. In the second case, the first clutch was depredated, after which the female laid a new clutch in the same nest that was again depredated. In the third case, the female laid new eggs among the eggs that failed to hatch previously. Our observations tend not to be consistent with the predator avoidance hypothesis because the depredated nests were reused by the parents. The time/energy saving hypothesis or possible deterrence of nest parasitism could explain nest reuse in this study, but because of low number of nests reused compared to the total number of nests found, this phenomenon needs further clarification.

Cheek‐to‐cheek: Communal nesting in an ephemeral pool‐breeding frog

AbstractCommunal nesting is a behaviour exhibited by some oviparous species, the adults of which deposit their eggs over the same time period in a common area and possibly in direct physical contact. While this may occur inadvertently, it is proposed to be an adaptive trait in some species. Herein, we describe both solitary and communal nesting behaviours in the sandpaper frog (Lechriodus fletcheri). Field observations over two consecutive breeding seasons revealed that adults of this species frequently deposit their eggs in frothed nests alongside those of other mating pairs to form floating communal rafts or “masses” on the surface of the water. The presence of communal masses despite; (i) the relatively small number of nests deposited within each breeding episode and (ii) the space available for nests to be deposited separately within a pool, both indicate that some adults are deliberately choosing to lay their nests together. We propose that adults are thus engaging in a form of social behaviour and that communal nesting may be highly advantageous for improving offspring survival by complimenting the anti‐predator properties of the froth nest. This is because the communal mass further isolates embryos from the external environment during development prior to hatching, given a reduction in the surface area relative to volume of each nest that composes the mass. While future research is required to determine why both solitary and communal nesting behaviours are exhibited in this species, it could suggest that there are certain costs associated with communality that occasionally outweigh the benefits.

Population status of house sparrow (Passer domesticus L.) and its association with native bird species in and around Dehradun City of Uttarakhand, India

Recent studies have indicated a significant decline in the population of the house sparrow (Passer domesticus L.) at the global level. In India also, the house sparrow population is being drastically decreased. Considering the issue, an attempt has been made to monitor the current status of house sparrows across Dehradun City of Uttarakhand from 2017 to 2019. The line transect method was used for bird surveys in the three habitats (high-density urban area, low-density urban area, and suburban area). The results showed that the population of house sparrows was significantly higher in the suburban area (84.19 ± 8.05) as compared to those in high-density (12.75 ± 2.02) and low-density (42.97 ± 4.74) urban areas. Similarly, the number of active nests was also found higher in a suburban area as compared to other areas. Additionally, a total of 87 co-occurring avian species were observed in the study area with maximum avian diversity reported in low-density (H = 2.85) followed by suburban (H = 2.67) and high-density urban areas (H = 2.12) respectively. This study suggested that the regular monitoring of house sparrows and co-occurring avian species is important to understand the population trend of the house sparrow in the study area.

Driving forces behind the fluctuating growth of the number of successful nests in an inland population of white‐tailed eagles in Hokkaido, Japan

AbstractThis study aimed to describe the change in the number of successful nests of the white‐tailed eagle, Haliaeetus albicilla, for 25 years (1997–2021) along the Teshio River (100 km), Japan, which is a new habitat for this endangered species and identify factors driving the number of nests. The number of nests grew from two to nine. The logistic function fitted in well with the growth, and the capacity of the study area sustaining the successful nests was estimated at 6.5. The precipitation in January and April explained the deviation of the observed values from the model prediction. In particular, heavy rain in April was associated with low numbers. Forty‐six nest remains were collected from 17 nest locations. Twelve genera of birds, six genera of mammals, and four genera of fishes were identified. Fish and bird items occupied 93.6% of prey individuals. The fish proportion was similar between high‐performance years when the observed number of successful nests was higher than the model prediction and low‐performance years with a lower number than the prediction (55.2% and 51.0%). However, it was higher in the nests with two fledglings (63.0%) than those with a single fledgling (41.5%). The nearest neighbor distance (NND) of the successful nests declined with the increase in the number of nests. Based on territory size (the mean NND = 7.8 km), the study area can hold 13 nests. The process and mechanism of the dynamics of the number of nests were discussed, focusing on territoriality and weather effects.

Predictors of psychological stress and behavioural diversity among captive red panda in Indian zoos and their implications for global captive management

At high elevations, biodiversity is at elevated risk from extinctions due to rapid environmental changes. In the most of its range in Himalayas, the red panda, an endangered species, is struggling to survive in the wild, and a global captive breeding programme has been launched to conserve the species. Because captivity can have negative impacts on animals, reducing the chance of successful reintroduction, we investigated the predictors of stereotyped behaviour and behavioural diversity of red panda (n = 26), and the effect of stereotypy on their behavioural diversity in three Indian zoos. Multivariate analysis showed that stereotypy increased with density of logs on the ground, age and higher among pandas in zoo 3 compared to zoo 2, but decreased with number of nests, sociality, tree density and tree height used. Similarly, behavioural diversity increased with log density, but decreased among pandas in zoo 2 compared to zoo 1, during summer compared to winter, and also with ambient temperature, stereotypy, tree density, and tree height used. The relationship between stereotypy and behavioural diversity was negative, but not significant. Provision of a greater density of trees was associated with higher levels of daytime inactivity. Findings from this study have global relevance, as the captive red panda experiences similar welfare issues around the world, and our data provide empirical support for some existing guidelines for red panda husbandry.

Reproductive Dynamics of an Isolated Population of American Crocodiles (Crocodylus acutus) Based on Long-term Monitoring Data

The American Crocodile (Crocodylus acutus) is still considered Vulnerable, with some populations remaining depressed and showing little evidence of recovery. An understanding of the reproductive dynamics and parameters of C. acutus is essential for its conservation and management. Although the knowledge of C. acutus reproductive ecology has greatly increased during recent years, some critical parameters such as breeding effort (i.e., proportion of adult females that nest each year in a population) remain poorly known. Herein we analyzed 14 yr of reproductive data from a C. acutus population in a Mexican atoll to better understand its reproductive dynamics in space and time. We estimated the number of reproductive females in the population and in each nesting area, compared nest characteristics and clutch parameters among nesting areas, and determined female breeding effort and breeding frequency (i.e., proportion of years that an adult female nested). We estimated that 35 reproductive female C. acutus inhabit the main island of the atoll, distributed among 12 nesting areas. The annual female breeding effort ranged from 27.3–60.6% and the breeding frequency of 15 selected females ranged from 57.1–92.3%. Breeding effort depends on the breeding effort in preceding years. We also found significant differences in reproductive attributes (i.e., number of nests, nest–water distance, nest depth, clutch size, and nesting success) among nesting areas that we explain by the quality of those habitats for crocodile nesting and by territorial behavior of females.