Spatial Distribution Of Nests Research Articles

Spatial distribution of nests and nesting trees of colonial birds at Telineelapuram pelicanry using geospatial tools in Andhra Pradesh, India

Spatial distribution of nests and nesting trees of colonial birds at Telineelapuram pelicanry using geospatial tools in Andhra Pradesh, India

Reproductive benefits and reduced investment in parental care behavior associated with reproductive groups of males in Abudefduf troschelii.

Fishes of the family Pomacentridae present a wide diversity of mating systems, ranging from polygyny to promiscuity and from individual territorial defense to the establishment of reproductive colonies of males. The damselfish species Abudefduf troschelii has a reproductive colony mating system, in which males temporarily aggregate in reproductive areas to court and attract females. Males defend an individual territory where they receive eggs and perform paternal care behaviors for their offspring. The present study evaluated the advantages of the colonial mating system in A. troschelii. During an entire reproductive period, in a breeding colony within a rocky reef, we located, marked, geo-referenced, and measured the distances between the territories of all males. We quantified the variance among males in their patterns of paternal care investment, eggs acquired, hatching success, reproductive success, body size, and changes in body coloration. We found that males spatially distributed their nests in groups or independently (i.e., solitary nests). Nesting groups are formed by larger males that show intense nuptial coloration during the entire receptivity period. They are located centrally to the colony and consist of three to six males whose territories overlap. In contrast, small solitary males that fail to acquire or maintain nuptial coloration during the receptivity period establish their nests peripherally to the colony, away from the territories of other males. Our results highlight that the reproductive benefits of colonial nesting are unequal for males, as the spatial distribution of nests within the colony determines the reproductive success of males. Group nesting confers the highest reproductive benefits to males regarding eggs obtained, hatching success, and relative fitness and also enables males to reduce their parental investment in brood care behaviors. The preference of females for oviposition could be associated with greater intrasexual competitiveness, defense ability, body condition, or experience of group-nesting males located at the center of the colony or because their progeny will have a lower probability of predation than they would in solitary nests males.

Good neighbors? Does aggregation of nests in an Arctic-breeding shorebird influence daily survival rates?

Our current understanding of the factors that influence where birds nest is incomplete, yet such information is important for accurate demographic assessments. To address questions related to spatial distributions of shorebird nests and to evaluate factors that may affect nest distribution in these species, during 2017 and 2019, we studied a small population of semipalmated sandpiper Calidris pusilla breeding in the Central Canadian Arctic, near the Karrak Lake Research Station, in Nunavut. The spatial distribution of semipalmated sandpiper nests at this site suggested loose aggregation, with median nearest neighbor distances of 73.8 m and 92.0 m in 2017 and 2019, respectively, while no nests were detected on mainland areas in the vicinity. Evidence for the influence of nesting distribution on the daily survival rate of nests, however, was mixed. Neither nearest neighbor distance nor local nest density had a significant effect on daily nest survival in 2017, but in 2019, the best approximating model included an effect of local nest density, which indicated that nests in areas of high density had reduced survival rates. Contrary to other studies assessing settlement and nest site selection in semipalmated sandpipers, the spatial distribution of nests in this population demonstrates aggregation in an otherwise territorial species, but suggests that aggregated nesting can impose a cost on nest survival under certain conditions.

Spatial and Temporal Monitoring of North African Turtle Doves Streptopelia turtur arenicola (Hartert, EJO, 1894): First Migrants Arrive Early and Select Nesting Trees next to Foraging Resources while Second Breeders’ Wave Breed around Earlier Nests

This study aimed to evaluate the spatial microdistribution and temporal microdistribution of the North African subspecies of the globally threatened Turtle Doves in Morocco. From the end of February to early September, we monitored the migration dates, counting arrival and departure dates, and breeding chronology, to clarify if the breeding season is divided into sub-breeding phases or not. Equally, the spatial distribution of nests following potential breeding phases was surveyed weekly in Beni Mellal province following a map of a selected orange orchard. Doves arrived in Beni Mellal in the third week of March and left in mid-October, according to the results. The first nests occurred in the second week of April, followed by the first eggs in the third week of April and the first chicks in the first week of May. PCA analysis showed that the nesting and laying stages were achieved principally during the last two weeks of April and the first three weeks of May, the hatching stage between the fourth week of May and the second week of July, and fledging between the fourth week of July and the first week of September. Further, the breeding season was divided into two phases: the first breeding phase, from the first week of April to the first week of June, and the second phase, between the second week of June and the second week of August. The DCA analysis and orchard-created map indicated that the first wave of breeders colonized the marginal trees located on the orchard sides, surrounded by foraging cereals and legumes, and the second breeding-phase nests were constructed in flocks next to the nests of the first breeding phase. According to this strategy, the first breeders prospect the orchard and select nesting trees near foraging resources, while the second breeders’ wave colonizes trees near successfully used prospector sites. These findings are of great importance for comparative investigations and habitat-scale conservation management.

Ecology of Fear in a Colonial Breeder: Colony Structure in Ground-Nesting Great Cormorants Phalacrocorax carbo Reflects Presence of Predators

Ground-nesting Great Cormorants were monitored in three neighbouring colonies at Lake IJsselmeer, The Netherlands. Using aerial photographs taken during peak breeding time, nest density and nearest neighbour distance were determined for four sequential years. In addition, species and number of predators were determined. In total, five mammalian and nine avian predatory species were associated with the Cormorant breeding colonies. Spatial distribution of nests mostly showed dispersed and random patterns rather than a contagious pattern. The latter distribution, with less distance between nests than expected both from a random and equal distribution pattern, was found in the colony of De Ven in 2013 during the last year of its existence. The predator Red Fox Vulpes vulpes arrived at the colony in 2010. In all three colonies, nest density was highest and nearest neighbour distance shortest in colonies with the highest number of predators. At low to moderate predatory pressure, ground-nesting Cormorants left free space between nests that was used by adult birds during take-off and landing. During the last years of its existence the shrinking colony of De Ven showed an almost circular shape, with an extreme nest density and the lowest edge-to-surface area ratio. But with Foxes present, breeding at the fringe still caused greater losses due to direct predation. Breeding success fluctuated synchronously between colonies but was lower in colonies where the number of predators was higher. The arrival of Red Foxes in De Ven caused extreme losses of young and over the years resulted in a strong decline in number of breeders, eventually leading to complete abandoning of the site in 2014. Large gulls formed another important group of predators but did not cause the Cormorants to abandon the breeding site. In the Vooroever colony, bush and tree cover supplied shelter and allowed birds to breed in greater density without causing nearest neighbour density to decrease, as was the case when no cover was available. Greater nest density and reduced nearest neighbour distances are considered to be a pro-active response by individual birds to the presence of predators. When predator numbers increased, the within-colony open spaces that normally exist under circumstances of moderate density were filled up with nests, leaving little or no room for landing and departure. This leads to reduced edge effects and a circular shape of the colony, thereby potentially limiting predation risk. As a consequence of extreme high nest densities, breeding success was lower due to interference by other Cormorants. This study is the first to show that colony structure in waterbirds is affected by forces of attraction and repulsion between founding birds that are predator driven.

Nest characteristics and morphometry of Black Crowned Cranes Balearica pavonina ceciliae in Lake Tana area wetlands

Birds select breeding habitats based on biotic and abiotic environmental factors, resulting in a non-random spatial distribution of nests. This study investigated the onset of nesting, nest location, the relationship between nest height and water depth, nest materials, and the structure and characteristics of Black Crowned Crane nests in the Lake Tana region, Ethiopia. A total of 52 nests were recorded in four wetlands from 2014 to 2015. Nesting activity predominantly took place from September to October. There was a significant difference in the distance from nests to the edge of the wetland (χ2 = 24.843, n = 46, df = 3, p < 0.001). However, in all study areas the distance between nests, which indicates the degree of territoriality, did not show any significant difference (χ2 = 6.016, n = 34, df = 3, p = 0.111). In addition, nests were constructed in the wetland where the water depth ranged from 80 to 220 cm. Nest height (H 2i) and water depth (WD i) at nesting sites were highly correlated, and the regression equation (H 2i = 13.77 + 1.03WD i) indicated that when the water depth increases, the nest height also increases. The shallowest depth where a nest was constructed was 80 cm. Vegetation type varied, but cranes used Leersia hexandra, Oryza longistaminata, and Cyprus rotundus plants as their selected nesting material. The average vegetation height observed at nests with eggs, measured one metre away from the nest rim, ranged from 20 to 90 cm (44.83 ± 2.397), n = 48. The vegetation height at each study site showed no significant difference (F (3) = 2.527, p = 0.07). The mean nest length, width, and height from the surface of the water between nests were not significantly different. Nesting density was variable depending on the size of the wetland, water depth, and vegetation type and cover.

Effects of nest management methods on hatching success and predation rates of hawksbill turtles on Cousine Island, Seychelles

Sea turtle populations have declined globally and are of conservation concern. We investigated the effects of nest management methods on hatching success and egg/hatchling predation rates of hawksbill turtles Eretmochelys imbricata on Cousine Island, Seychelles. We determined the effectiveness of two different crab-barrier methods (netted and fenced) on hatching success and predation rates. We examined the relative influence of nest-site cover (full sun, partial sun or full shade) and location (zones of high risk or low risk of predation) on hatching success and predation rates. We also examined temperature disparity between netted and control nests to estimate potential effects on sex ratios and measured typical beach-substrate temperatures in the different nesting habitats. We compared data from 40 netted, 40 fenced and 40 control nests during the 2014/2015 breeding season. Overall, hawksbill turtle hatching success was not significantly affected by treatment or cover; however, netted nests and nests incubating in full sun had the highest mean hatching success. Predation rate was generally low but variable, and the rates differed significantly between the three treatments. Nest temperatures differed significantly between the netted and control nests, with netting used to protect nests having a substantial cooling effect. Hatchling sex ratios for natural nests were skewed towards females and those for netted nests skewed towards males. With climate change and increasing ambient temperatures imminent, a better understanding of how the spatial distribution of nests and variations in environmental factors influence hawksbill turtle hatching success and the levels of predation on eggs and hatchlings will assist future conservation measures.

Nest site selection of the Great Bustard (Otis t. tarda) in Körös-Maros National Park, Eastern Hungary

Abstract In the present study we aimed to identify factors influencing the spatial distribution of Great Bustard (Otis t. tarda) nests found between 1998 and 2015 in Dévaványa-Ecseg area in Körös-Maros National Park. During the study period covering 17 years, we obtained information on 536 nests, which shows that Great Bustards used the following grassland crop types for breeding: wheat (43.07%), grassland (23.3%), fallow land (14.45%) and alfalfa (7.67%). These nests were found during the following activities: chemical weed control (33.63%), hay-cutting (25.37%), disking (8.55%) and harvesting (7.08%) and other 18 types of activities. To identify the effects of disturbance and environmental factors on the spatial distribution of nests, such as distances to lek sites, roads, settlements and altitude, we formulated generalized linear models. As a result, we found that nest sites were significantly closer to lek sites and farther from human settlements than expected by random sampling. Our results may contribute to the understanding of Great Bustard nest distributions, which can be helpful in nest detection prior to the initiation of disturbing agricultural activities, which is a key issue in the conservation of this bird. This study opens the way to analyse the effects of other environmental factors such as anthropogenic linear objects.

Population Dynamics of Acromyrmex crassispinus (Forel) (Hymenoptera: Formicidae) and Attacks on Pinus taeda Linnaeus (Pinaceae) plantations

This work aimed to study the population dynamics of Acromyrmex crassispinus (Forel) in Pinus taeda L. plantations, evaluating the density and spatial distribution of nests over time, inferring about the period of the first nuptial flight of A. crassispinus colonies, and evaluating the levels of attack of this leaf-cutting ant on P. taeda plants. Assessments were performed monthly in the first year after planting, every three months until the third year and every six months until the plantation was six years old. The presence of nests was observed only after 15 months after planting. The nest density gradually increased until the planting completed 30 months, and decreased when the forest canopy began to close (after 54 months). Spatial distribution of A. crassispinus nests was random. Probably, the first nuptial flight of an A. crassispinus colony occurs after the third year of the colony foundation. Pinus taeda plants were not attacked by A. crassispinus throughout the evaluation period. Then, when dealing with a replanting area of Pinus plantation, where the previous forest has not been subject to pruning nor thinning, the problem with A. crassispinus is almost null if the clearcutting and the new planting occur during the winter. In this case, leaf-cutting ants control can be alleviated and it is not necessary to carry out systematic control of ants where A. crassispinus is the predominant leaf cutting ant species. Acromyrmex crassispinus control should be done only if nests are located or if attacked plants by ants are detected.

Disentangling the diversity of arboreal ant communities in tropical forest trees.

Tropical canopies are known for their high abundance and diversity of ants. However, the factors which enable coexistence of so many species in trees, and in particular, the role of foragers in determining local diversity, are not well understood. We censused nesting and foraging arboreal ant communities in two 0.32 ha plots of primary and secondary lowland rainforest in New Guinea and explored their species diversity and composition. Null models were used to test if the records of species foraging (but not nesting) in a tree were dependent on the spatial distribution of nests in surrounding trees. In total, 102 ant species from 389 trees occurred in the primary plot compared with only 50 species from 295 trees in the secondary forest plot. However, there was only a small difference in mean ant richness per tree between primary and secondary forest (3.8 and 3.3 sp. respectively) and considerably lower richness per tree was found only when nests were considered (1.5 sp. in both forests). About half of foraging individuals collected in a tree belonged to species which were not nesting in that tree. Null models showed that the ants foraging but not nesting in a tree are more likely to nest in nearby trees than would be expected at random. The effects of both forest stage and tree size traits were similar regardless of whether only foragers, only nests, or both datasets combined were considered. However, relative abundance distributions of species differed between foraging and nesting communities. The primary forest plot was dominated by native ant species, whereas invasive species were common in secondary forest. This study demonstrates the high contribution of foragers to arboreal ant diversity, indicating an important role of connectivity between trees, and also highlights the importance of primary vegetation for the conservation of native ant communities.

Responses of cavity‐nesting birds to fire: testing a general model with data from the Northern Flicker

Census‐based studies document changes in population size of animal species in response to wildfires, but mechanisms involving behavior of individuals and the effects on reproductive success are usually unknown. I developed a conceptual model explaining the persistence of cavity‐nesting birds on the landscape after fires depending on carrying capacity (food supply) of the habitat and the philopatry and territoriality of the species. The breeding density, nest site characteristics, and reproductive success of Northern Flickers Colaptes auratus was studied before and after low‐ to moderate‐severity fires on replicated plots. The density and spatial distribution of nests did not change in a consistent way after fires, but the rates of cavity excavation increased and characteristics of nest sites changed as such decay class of the tree. Laying dates were delayed and clutches were smaller in freshly excavated vs. reused cavities on the burned sites. Breeding philopatry caused a shift to older age classes in the population. Depredation of nests by small mammals increased during the first three years after fires, reducing the number of young produced per nest attempt on burned plots. The study shows that, even when fire does not reduce the density of breeding pairs, there may be detrimental effects detected only by monitoring the behavior and reproduction of individuals.

Nest-site selection among reintroducedMacrochelys temminckii

Abstract We evaluated nest-site selection in a reintroduced population of Macrochelys temminckii at two locations in southeastern Oklahoma by comparing mean values of variables characterizing microhabitat at nest-sites and random sites. We also analyzed the spatial distribution of nests using a computer randomization procedure. The spatial distribution of nests did not differ significantly from random. However, females nested in areas with significantly greater water depths 2 m from the shoreline and significantly less ground cover compared to random sites. Areas with little ground cover might indicate sites with thermal characteristics appropriate for incubation of eggs laid by M. temminckii, and greater water depth may provide cover for females prior to nesting. The discovery of nest-sites at the same location in consecutive years suggests that some female M. temminckii might return to the same place to nest repeatedly, but further study is required to confirm whether this species exhibits nest-site fid...

The spatial distribution of nests of the harvester ant Messor barbarus in dryland cereals

The harvester ant Messor barbarus can be responsible for substantial losses of weed seeds in arable fields in NE Spain. The spatial distribution of nests can have consequences for biological weed control, because foraging intensities decline with distance from the nest. The probability that seeds will escape harvesting will be lower if nests occur regularly distributed. We here investigated ‘large’-scale variability (up to 150 m), caused by habitat heterogeneity, and ‘small’-scale spatial variability (up to 12 m), caused by interactions between colonies, in nest distribution in a 50 × 150 m area in a cereal field in NE Spain, in 2009 and 2010. Large-scale variability was present in the data, but could not be explained by elevation, distance to the nearest field edge, or interpreted as simple trends across the area. Small-scale interactions could successfully be described by a multi-type/hard core Strauss process model, indicating territoriality among nests. Exclusion and interaction zones were identified, with radii that were smaller for small than for large colonies, and smaller for 2009 than for 2010. There was close resemblance between the observed and fitted spatial structure up to a radius of 3–4 m. Large-scale spatial variability, but not small-scale interactions, may be responsible for the existence of areas with few or no nests, where weed seeds have a higher probability of escaping the ants and entering the seed bank. Identifying and understanding the factors that influence the large-scale trends is, therefore, essential for optimizing weed control.

An invasive gull displaces native waterbirds to breeding habitats more exposed to native predators

AbstractThe effect of invasive opportunistic predators may include population changes in both native prey and native predators as well as alteration of predator–prey interactions. We analyzed the activity of native magpie Pica pica and changes in population, nest sites and nesting success probability of native waterbirds (namely: grebes, ducks, rails and native gulls) in response to the population growth of the invasive Caspian gull Larus cachinnans. The study was carried out at a reservoir in southern Poland and at a similar control reservoir where the Caspian gull was absent. Both the invasive gulls and the native magpie are opportunistic predators of nests of native waterbirds. The population increase of the invasive gull led to a decline in the population of native black‐headed gulls Larus ridibundus only. However, the invasive gull displaced all the native species from the breeding islets located in the central part of the reservoir to islets located close to the shoreline. The latter were frequently visited by magpies, which depredated on nests along the shores, leading to an up to threefold decrease in nesting success as compared with nests located in the central area of the invaded reservoir. Predation by Caspian gulls was rarely observed. Thus, the invasion of Caspian gull caused complex direct and indirect effects on the waterbird community that included competition for breeding sites, changes in the spatial distribution of nests and alteration of predation rate by native predators. Moreover, the effects of invasion may not be reflected by changes in population size of native species.

Polydomy in the ant Ectatomma opaciventre.

Tropical ants commonly exhibit a hyper-dispersed pattern of spatial distribution of nests. In polydomous species, nests may be satellites, that is, secondary structures of the main nest, where the queen is found. In order to evaluate whether the ant Ectatomma opaciventre Roger (Formicidae: Ectatomminae) uses the strategy of building polydomous nests, the spatial distribution pattern of 33 nests in a 1,800 m 2 degraded area located in Rio Claro, SP, Brazil, were investigated using the nearest neighbor method. To complement the results of this investigation, the cuticular chemical profile of eight colonies was analyzed using Fourier transform infrared photoacoustic spectrosco-py (FTIR-PAS). The nests of E. opaciventre presented a hyper-dispersed or regular distribution, which is the most common in ants. The analysis of the cuticular hydrocarbons apparently con-firmed the hypothesis that this species is polydomous, since the chemical profiles of all studied colonies with nests at different sites were very similar to the chemical signature of the single found queen and were also different from those of colonies used as control.

Sea level rise, land use, and climate change influence the distribution of loggerhead turtle nests at the largest USA rookery (Melbourne Beach, Florida)

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 493:259-274 (2013) - DOI: https://doi.org/10.3354/meps10531 Sea level rise, land use, and climate change influence the distribution of loggerhead turtle nests at the largest USA rookery (Melbourne Beach, Florida) Joshua S. Reece1,*, Davina Passeri2, Llewellyn Ehrhart3, Scott C. Hagen2, Allison Hays3, Christopher Long3, Reed F. Noss3, Matthew Bilskie2, Cheryl Sanchez3, Monette V. Schwoerer3, Betsy Von Holle3, John Weishampel3, Shaye Wolf4 1Valdosta State University, Department of Biology, 1500 North Patterson Street, Valdosta, Georgia 31698, USA 2University of Central Florida, Department of Civil and Environmental Engineering, 4000 Central Florida Boulevard, Orlando, Florida 32816, USA 3University of Central Florida, Department of Biology, 4000 Central Florida Boulevard, Orlando, Florida 32816, USA 4Center for Biological Diversity, 351 California Street, Suite 600, San Francisco, California 94104, USA *Email: jreece@valdosta.edu ABSTRACT: Anthropogenic climate change adds to the existing suite of threats to species, such as habitat degradation, by increasing extinction risk and compromising the ability of species to respond adaptively to these stressors. Because threats from anthropogenic climate change often interact synergistically with other threats, integrated assessments of the factors and processes that affect species persistence and distribution are required. We assessed the influence of coastal land use and climate change (specifically sea level rise) on the spatial distribution of nests within the largest loggerhead Caretta caretta marine turtle rookery in the Atlantic Ocean, at Melbourne Beach, Florida, from 1986 to 2006. We generated a multiple regression model based on climate change, sea-level rise and land use that describes 47% of the spatial variation in loggerhead nesting. Nests have shifted northward (likely in response to warming temperatures), away from intensive coastal development, and, surprisingly, toward areas of increased erosion. Using the Bruun Rule (an approximation of the response of the shoreline profile to sea level rise), we modeled the impacts of sea level rise of 0.25 and 0.5 m in conjunction with extrapolations of coastal development and a continued northward shift in nest distribution. We project up to a 43% decrease in beach area from 1986 to a future with 0.5 m of sea level rise and predict that loggerhead nesting will shift northward and become increasingly crowded on narrowing beaches. An implication of this study is that areas currently protected for large rookeries may not overlap with their future distributions. KEY WORDS: Caretta · Climate change · Sea level rise · Beach erosion · Sea turtle · Coastal development · Bruun Rule Full text in pdf format Supplementary material PreviousNextCite this article as: Reece JS, Passeri D, Ehrhart L, Hagen SC and others (2013) Sea level rise, land use, and climate change influence the distribution of loggerhead turtle nests at the largest USA rookery (Melbourne Beach, Florida). Mar Ecol Prog Ser 493:259-274. https://doi.org/10.3354/meps10531 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 493. Online publication date: November 20, 2013 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2013 Inter-Research.

Spatial segregation of four coexisting processional termites (Termitidae: Nasutitermitinae) in tropical rainforest

AbstractIn Lambir Hills National Park, Sarawak, Malaysia, there are four species of processional termites that coexist: Hospitalitermes hospitalis, H. lividiceps, H. rufus and Longipeditermes longipes. This paper presents the results of our investigation on the spatial distribution of nests and the foraging activities of the four species in coexistence. The results show that there are fairly marked differences in nesting sites, as well as in foraging activities, among the four species. It is noteworthy that H. rufus inhabits only the canopy area over 20 m above ground, apparently segregated from the other three species, and that their foraging activities are limited also to tree canopies over 10 m above ground. In contrast, L. longipes nests underground and forages exclusively on the forest floor. Hospitalitermes hospitalis and H. lividiceps inhabit and forage over wide areas, from the forest floor to tree canopies. The upper parts of the tree canopy (over 10 m) are also foraging territories of the secluded H. rufus, but there were no observations of simultaneous foraging of the three Hospitalitermes species in the same canopy areas.

Nest site habitat selection and nesting performance of the Great Bustard Otis tarda in southern Portugal: implications for conservation

SummaryWe present results on breeding parameters, nesting performance and nest habitat selection of the globally threatened Great Bustard Otis tarda, gathered during a 3-year study in Castro Verde (southern Portugal). A total of 107 nests were located. The estimated average onset of laying was 22 April (SD = 12 days, n = 8). The incubation period ranged from 25 March to 15 June. Nearly 95% of females incubated between 1 April and 31 May. Mean clutch size was 2.12 (SD = 0.69, n = 86), showing no significant inter-annual differences. There was no significant relationship between clutch size and average nest finding date, although, on average, nests were found later each year. Hatching occurred between 21 April and 26 June. The estimated proportion of eggs hatched per nest (hatching percentage) was 87.5% in 2002 (n = 8), 64.0% in 2003 (n = 33) and 75.8% in 2004 (n = 33). Overall nesting success for the three years was 71% (n = 107). The main causes of nesting failure were agricultural activities, mainly ploughing and harvesting, followed by corvid predation. Nests were spatially aggregated up to 800–1,500 m. At larger scales, the spatial distribution of nests can be considered random or uniform. Females showed a clear preference for nesting in cereal fields, followed by young fallows, old fallows, ploughed fields and then other habitats, although the intensity of selection of particular habitats varied between years. Nests were associated with both cereals and fallows, thus aggregating where those habitat types occurred within the study area. These results provide the first complete description of the nesting process in a Great Bustard population, as well as important cues to the assessment of conservation measures implemented in Castro Verde, an area holding around 80% of the Portuguese population of this species (application of EU agri-environmental schemes, power line signalling, water-point provision in dry years).

Nest groups of wild bonobos at Wamba: selection of vegetation and tree species and relationships between nest group size and party size

We examined the location of nest groups, spatial distribution of nests within a nest group, and attributes of individual nests of wild bonobos at Wamba, Democratic Republic of Congo. We also examined the seasonal factors influencing nesting behavior and compared the nest group size with the 1 hr party size during daytime. We defined a nest group to be a cluster of nests that were built in the same evening and found within 30 m from the other nearest nest. Examination of the largest gap within a nest group suggested that 30 m was an acceptable cutoff value. Monthly rainfall or fruit abundance did not significantly influence the monthly mean nest group size. Nests were built in the swamp forest for as many as 13% observation days, suggesting the need for reevaluation of the use of swamp forest by bonobos. The use of swamp forest was influenced not by seasonal rainfall or fruit abundance, but by the fruiting of specific species. Preferred tree species for building nests accounted for 19.8% of standing trees, which suggested that the selection of sleeping sites was not largely restricted by the distribution of specific species. The mean 1 hr party size was almost identical through the day and was similar to the mean nest group size. Parties of bonobos sometimes split into smaller nest groups, especially when feeding on non-preferred fruits during fruit scarcity. By contrast, when feeding on preferred fruits while ranging in large parties, they often aggregated to form even larger nest groups. When sleeping in small- or middle-sized nest groups, they tended to aggregate the next morning. These tendencies may reflect the gregarious nature of bonobos who prefer to range or sleep together as far as circumstances allow.

Abundância, distribuição espacial de ninhos de abelhas Meliponina (Hymenoptera, Apidae, Apini) e espécies vegetais utilizadas para nidificação em áreas de cerrado do Maranhão

O trabalho objetivou identificar as espécies de abelhas sem ferrão (Hymenoptera, Apidae, Apini, Meliponina) presentes em três áreas de cerrado no Maranhão, nordeste do Brasil, por meio do levantamento de seus ninhos. Também foi objetivo do trabalho identificar e caracterizar os substratos vegetais utilizados como locais de nidificação. Pretendeu-se averiguar a abundância e a distribuição espacial de ninhos, bem como padrões de uso dos substratos para nidificação. Foram encontrados 73 ninhos pertencentes a 15 espécies. As espécies mais abundantes foram Partamona chapadicola Pedro &amp; Camargo, 2003 (34,25%) e Oxytrigona sp. 2 (20,55%). Identificaramse 11 espécies vegetais utilizadas para construção dos ninhos. O substrato de nidificação mais freqüente foi Qualea parviflora (Vochysiaceae), na qual encontrou-se 38,36% do total de ninhos (n=28), seguido por Salvertia convallariodora (Vochysiaceae) (n=17; 23,29%). O intervalo de confiança de 95% para o DAP situou-se entre 36,21 cm a 41,68 cm. Este intervalo representaria árvores mais velhas que teriam mais cavidades disponíveis para nidificação, o que poderia ser o caso de S. convallariodora e Q. parviflora. O padrão de dispersão dos substratos com ninhos mostrou-se aleatório nas áreas 1 e 2 e uniforme na área 3. Padrões de distribuição aleatórios seriam um indício da ausência de competição e padrões uniformes indicariam competição.