Nest Site Locations Research Articles

Age effects on reproductive success, nest-site location, and offspring condition in the Great Cormorant Phalacrocorax carbo sinensis

Breeding performance of many vertebrate species is known to improve over the early stages of the life cycle, which has been commonly attributed to the progressive improvement in competences and increasing investment in reproduction. While there is a large body of evidence for age-related variation in fecundity within bird populations, much less is known on whether and how age affects other traits related to reproduction. The aim of this study was to test for age-related patterns in fecundity, nest-site location, offspring condition and brood sex ratio in a long-lived colonial waterbird, the Great Cormorant (Phalacrocorax carbo sinensis). For this purpose we collected data on 180 breeding attempts of 100 Great Cormorants aged two to 11 years. We found a progressive increase in reproductive output with age and we showed that older individuals nested closer to the colony centre and in higher nesting densities. We also found that parental age was positively related to physiological condition of offspring (measured with whole-blood haemoglobin concentration and plasma glucose concentration). There was no indication for age-related adjustments in brood sex ratio in our cormorant population. Our results indicate a great complexity of the processes which produce age-related improvements in reproductive performance within avian populations.

Sitting in the sun: Nest microhabitat affects incubation temperatures in seabirds

During incubation parent birds are committed to a nest site and endure a range of ambient conditions while regulating egg temperatures. Using artificial eggs containing temperature loggers alongside ambient temperature (Ta) controls, incubation profiles were determined for four tropical seabird species at different nest site locations. Camera traps were used for ad-hoc behavioural incubation observations. Eggs experienced a range of temperatures during incubation and varied significantly between species and in some cases between different microhabitats within a species. Such variation has important consequences in the phenotypic expression of both physical and physiological traits of chicks, and ultimately species fitness. Exposed nest sites were more strongly correlated to Tas. Camera traps highlighted different incubation strategies employed by these species that could be related to trade-offs in predator defence, feeding habits, and temperature regulation of eggs. This study provides evidence that species with similar breeding habits could be affected by environmental stressors in similar ways and that the differences shown in nest site selection could negate some of these effects. We propose that habitats providing suitable nest microclimates will become increasingly important for the successful breeding of seabird species, particularly under predicted climate change scenarios.

A self-organising network model of decision making by the honey bee swarm

Purpose– The purpose of this paper is to carry out a detailed investigation of the mechanisms operating during decision making by the honey bee swarm, which is now considered to be one of the best examples of collective decision making outside the human domain.Design/methodology/approach– This investigation is based on a review of the last 60 years’ published literature about swarm behaviour. It introduces a different perspective to the work by utilising a cybernetic model of a self-organising information network to analyse the findings of this body of research.Findings– Scout bees evaluating potential nest sites accumulated support for their site by differential net recruitment, so the total scout numbers present at each site was a good measure of the total evidence in favour of the site and hence the relative probability of choosing it as the swarm’s new home. The accumulation of evidence continued at a number of alternative nest site locations until a critical quorum threshold was sensed at one of them. The first alternative to reach the threshold was chosen as the preferred nest site. Quorum scouts then prepared the swarm for departure and steered it to its new home.Originality/value– Swarm decision making has not been modelled as a self-organising information network before. This novel approach reveals how a combination of network modifications, self-amplification, self-attenuation, cross-inhibition, integration and quorum mechanisms together contribute towards accurate group decision making.

Sunflower (Helianthus annuus) pollination in California's Central Valley is limited by native bee nest site location.

The delivery of ecosystem services by mobile organisms depends on the distribution of those organisms, which is, in turn, affected by resources at local and landscape scales. Pollinator-dependent crops rely on mobile animals like bees for crop production, and the spatial relationship between floral resources and nest location for these central-place foragers influences the delivery of pollination services. Current models that map pollination coverage in agricultural regions utilize landscape-level estimates of floral availability and nesting incidence inferred from expert opinion, rather than direct assessments. Foraging distance is often derived from proxies of bee body size, rather than direct measurements of foraging that account for behavioral responses to floral resource type and distribution. The lack of direct measurements of nesting incidence and foraging distances may lead to inaccurate mapping of pollination services. We examined the role of local-scale floral resource presence from hedgerow plantings on nest incidence of ground-nesting bees in field margins and within monoculture, conventionally managed sunflower fields in California's Central Valley. We tracked bee movement into fields using fluorescent powder. We then used these data to simulate the distribution of pollination services within a crop field. Contrary to expert opinion, we found that ground-nesting native bees nested both in fields and edges, though nesting rates declined with distance into field. Further, we detected no effect of field-margin floral enhancements on nesting. We found evidence of an exponential decay rate of bee movement into fields, indicating that foraging predominantly occurred in less than 1% of medium-sized bees' predicted typical foraging range. Although we found native bees nesting within agricultural fields, their restricted foraging movements likely centralize pollination near nest sites. Our data thus predict a heterogeneous distribution of pollination services within sunflower fields, with edges receiving higher coverage than field centers. To generate more accurate maps of services, we advocate directly measuring the autecology of ecosystem service providers, which vary by crop system, pollinator species, and region. Improving estimates of the factors affecting pollinator populations can increase the accuracy of pollination service maps and help clarify the influence of farming practices on wild bees occurring in agricultural landscapes.

Geographical Effects on the Mass and Dimensions of Finch (Fringillidae, Passeriformes) and Thrush (Turdidae, Passeriformes) Nests

Birds’ nests exhibit a considerable amount of plasticity in their size and construction. Indeed, several studies have shown that geographical location can affect this plasticity because local climatic conditions appear to affect nest-construction behaviours. This study examined nests collected in the UK and housed either at the University of Lincoln or at the British National Nest Reference Collection at the Hunterian Museum, University of Glasgow. Our aim was to increase the species diversity and the sample sizes for each species, over and above published studies. Mass and linear dimensions were recorded from nests of five finch species and two thrush species together with longitude and latitude for the nest site locations. An effect of species was shown for all finch nest dimensions measured but only for particular thrush dimensions. Latitude (range from 50.4 to 57.8°N) had no effect on nest measurements taken for thrush or finch species. However, while longitude (range from 6.8°W to 1.1°E) had no effect on thrush nests, it had a significant effect on the nest mass of finches, with nests constructed in the west being lighter in mass than those from the east. Previous studies examining the effects of latitude have used nests collected from different locations and built in a single year, which suggests that climatic conditions will be broadly comparable between locations. We found that museum collections have nests from a range of years and this rather limits their value in studies trying to ascertain the effects of location. Across different years there may be many unknown factors contributing to the patterns observed. We suggest that any future studies of the effects of climate on nest construction will have to rely on materials especially collected rather than using museum collections.

Spatial patterns of extra-pair paternity in a waterbird colony: separating the effects of nesting density and nest site location.

Centres of avian colonies are usually associated with reduced predation risk and, thus, attract individuals of high quality, while poor-quality individuals are relegated to peripheral zones. Assuming that the incidence of extra-pair paternity (EPP) is dependent on individual quality, we could expect lower incidence of extra-pair offspring in the central parts of colonies. On the other hand, central pairs often nest in higher densities, which might increase EPP rate. To test these hypotheses, we sampled 124 great cormorant Phalacarocorax carbo sinensis chicks from 30 broods from different zones of a colony and genotyped them at seven highly polymorphic microsatellite loci. Sibship reconstruction confirmed the presence of at least one extra-pair chick in 30.0 % of broods. We found that EPP varied significantly between the zones of the colony, with higher incidence of extra-pair broods in the peripheral zone (53.3 vs. 6.7 % of broods). Centre-edge difference in EPP was consistent with the expected distribution of pair quality and suggested that poor-quality peripheral females were more likely to solicit extra-pair interactions, possibly to gain ‘good genes’ for their offspring. By contrast, we found no evidence for density dependence in EPP rate, indicating that likelihood of raising extra-pair offspring was not constrained by limited availability of local males. The results indicate that spatial randomization of sampling within avian colonies is critical to obtain robust estimations of EPP for non-solitary species. To our knowledge, this study provides the first evidence for the centre-edge difference in EPP within a breeding colony of birds.

How does nest-box temperature affect nestling growth rate and breeding success in a parrot?

Climate change is predicted to affect many species by reducing range, habitat suitability and breeding success. Cavity-nesting species, already threatened by deforestation and declining natural hollows, may be particularly at risk because they are limited in nest-site location, and climatic alterations may further reduce usability of natural cavities. It is therefore essential to determine how cavity-users may be affected. We recorded internal nest-box temperatures and modelled the relationships of four temperature parameters (relating to mean temperature, variability in temperature, low temperature extremes and high temperature extremes) with breeding success and nestling growth in an Australian cavity-nesting parrot, the Crimson Rosella (Platycercus elegans). We found that less extreme low temperatures resulted in heavier nestlings; however, higher mean temperatures tended to result in lighter nestlings. Greater temperature variability tended to reduce fledging success; however, no temperature variables had a clear effect on clutch size or hatching success. Our findings indicate that there may be a complex relationship between nestling growth and temperature, and although less extreme cold temperatures may benefit nestlings, continued increases in mean temperature and variability may have negative consequences.

Sunflower (Helianthus annuus) pollination in California's Central Valley is limited by native bee nest site location

The delivery of ecosystem services by mobile organisms depends on the distribution of those organisms, which is, in turn, affected by resources at local and landscape scales. Pollinator-dependent crops rely on mobile animals like bees for crop production, and the spatial relationship between floral resources and nest location for these central-place foragers influences the delivery of pollination services. Current models that map pollination coverage in agricultural regions utilize landscape-level estimates of floral availability and nesting incidence inferred from expert opinion, rather than direct assessments. Foraging distance is often derived from proxies of bee body size, rather than direct measurements of foraging that account for behavioral responses to floral resource type and distribution. The lack of direct measurements of nesting incidence and foraging distances may lead to inaccurate mapping of pollination services. We examined the role of local-scale floral resource presence from hedgerow plantings on nest incidence of ground-nesting bees in field margins and within monoculture, conventionally managed sunflower fields in California's Central Valley. We tracked bee movement into fields using fluorescent powder. We then used these data to simulate the distribution of pollination services within a crop field. Contrary to expert opinion, we found that ground-nesting native bees nested both in fields and edges, though nesting rates declined with distance into field. Further, we detected no effect of field-margin floral enhancements on nesting. We found evidence of an exponential decay rate of bee movement into fields, indicating that foraging predominantly occurred in less than 1% of medium-sized bees' predicted typical foraging range. Although we found native bees nesting within agricultural fields, their restricted foraging movements likely centralize pollination near nest sites. Our data thus predict a heterogeneous distribution of pollination services within sunflower fields, with edges receiving higher coverage than field centers. To generate more accurate maps of services, we advocate directly measuring the autecology of ecosystem service providers, which vary by crop system, pollinator species, and region. Improving estimates of the factors affecting pollinator populations can increase the accuracy of pollination service maps and help clarify the influence of farming practices on wild bees occurring in agricultural landscapes.

Diet and reproductive success of an Arctic generalist predator: Interplay between variations in prey abundance, nest site location, and intraguild predation

ABSTRACT Under varying prey abundance, generalist consumers should be less affected than specialists due to their more diverse diet. Nonetheless, when prey availability declines, interspecific competition among consumers should increase and could lead to increased intraguild predation. We examined these potential effects in a generalist predator of the tundra, the Glaucous Gull (Larus hyperboreus), over a 7-yr period characterized by large fluctuations in lemming abundance, a potential prey item for gulls. We studied diet by analyzing regurgitated pellets collected at nests and blood nitrogen and carbon stable isotopes, and we monitored annual nesting density and reproductive success on Bylot Island, Nunavut, Canada. Stable isotopes revealed a relatively similar contribution of terrestrial and marine food sources to the gull diet, although the terrestrial contribution increased in the year of high lemming abundance. According to analysis of pellets, diet during incubation was dominated by geese and lemmin...

Commonness and ecology, but not bigger brains, predict urban living in birds.

BackgroundSeveral life history and ecological variables have been reported to affect the likelihood of species becoming urbanized. Recently, studies have also focused on the role of brain size in explaining ability to adapt to urban environments. In contrast, however, little is known about the effect of colonization pressure from surrounding areas, which may confound conclusions about what makes a species urban. We recorded presence/absence data for birds in 93 urban sites in Oslo (Norway) and compared these with species lists generated from 137 forest and 51 farmland sites surrounding Oslo which may represent source populations for colonization.ResultsWe found that the frequency (proportion of sites where present) of a species within the city was strongly and positively associated with its frequency in sites surrounding the city, as were both species breeding habitat and nest site location. In contrast, there were generally no significant effects of relative brain mass or migration on urban occupancy. Furthermore, analyses of previously published data showed that urban density of birds in six other European cities was also positively and significantly associated with density in areas outside cities, whereas relative brain mass showed no such relationship.ConclusionsThese results suggest that urban bird communities are primarily determined by how frequently species occurred in the surrounding landscapes and by features of ecology (i.e. breeding habitat and nest site location), whereas species’ relative brain mass had no significant effects.Electronic supplementary materialThe online version of this article (doi:10.1186/s12898-015-0044-x) contains supplementary material, which is available to authorized users.

Selección de sitios de anidación de Lepidochelys olivacea (Testudines: Cheloniidae) en el Pacífico Sur de Costa Rica

La selección del sitio de anidación en tortugas marinas es determinante para la sobrevivencia de la progenie, sin embargo para Lepidochelys olivacea existe poca información al respecto. Este trabajo se enfocó en determinar si L. olivacea selecciona sus sitios de anidación de acuerdo a un patrón o preferencia espacial determinada, o si por el contrario distribuye sus nidos aleatoriamente en la playa. La recolección de datos se realizó entre julio y setiembre del 2011, en las playas de Piro y Pejeperro, Península de Osa, Costa Rica. La ubicación del nido se evaluó midiendo las distancias entre la línea de marea y el nido, entre el nido y la vegetación, y determinando la posición del nido con respecto a los sectores marcados cada 100m en la playa. En ambas playas, las tortugas mostraron una marcada preferencia por anidar lo más lejos posible de la línea de marea, lo cual protege a sus nidos de inundación pero los expone a un mayor riesgo de depredación. Además, en playa Piro se detectó una mayor concentración de nidos cerca de la desembocadura del río, y en las cercanías de un estero en el caso de Pejeperro. Si estas zonas están asociadas a un mayor éxito de eclosión, es posible que las tortugas estén regresando y seleccionado esos sitios por impronta o filopatría. Futuras investigaciones deberán enfocarse en determinar si en eventos de anidación sucesivos, L. olivacea muestra repetibilidad y mantiene sus preferencias de anidación a nivel de individuo.

Resource configuration and abundance affect space use of a cooperatively breeding resident bird

ABSTRACT Movement and space use of birds is driven by activities associated with acquiring and maintaining access to critical resources. Thus, the spatial configuration of resources within home ranges should influence bird movements, and resource values should be relative to their locations. We radio-tracked 22 Brown-headed Nuthatches (Sitta pusilla) and related their space use and home range sizes to available resources while taking nest site locations into account. We developed utilization distributions (UDs) from nuthatch locations, and treated the area of each 95% isopleth as home range size and the height of the UD as relative probability of use. We fit models relating home range size to mean resource measures within home ranges, and used lognormal regression to relate intensity of use to resource metrics at random points by ranking linear mixed models. Nuthatch home ranges typically had two centers of activity. Areas of high use were associated with the density of recently killed snags (likely a for...

Nesting Characteristics and Habitat Use of the Endangered Hawaiian Petrel (Pterodroma sandwichensis) on the Island of Lāna'i

Abstract. The endangered Hawaiian Petrel (Pterodroma sandwichensis) is endemic to the main Hawaiian Islands where it nests in underground burrows surrounded by vegetation that varies greatly from island to island. Information regarding island-specific nest site selection and habitat characteristics is important when considering the management needs of the species, including control of invasive plants and protection from introduced predators. Extensive search efforts, using nocturnal vocalization and visual surveys, resulted in locating 71 nesting burrows on the Island of Lāna'i. Logistic regression was used to examine the influence of elevation, planar curvature, percent slope, canopy cover, and vegetation type on nest site locations. The top model in predicting Hawaiian Petrel nest site selection was influenced by increasing slopes, an understory dominated by native vegetation, and open canopy. The top model was supported by a model weight (wi) of 0.53, with the second model holding most of the remaining...

Nest Site Location and Success Rates of an Urban Population of Woodpigeon Columba Palumbus in Ireland

:ABSTRACTRecent decades have seen an increase in the number of woodpigeon frequenting cities and urban areas. Relatively few studies have assessed the nest site location, predation and breeding success rate of urban woodpigeons, and no such study exists in Ireland. The current study found that nest site location had a significant impact on the nest predation rates of an urban population of woodpigeon. Urban woodpigeons had a selective preference for nesting in evergreen trees, despite the fact that these nests suffered a significantly higher rate of predation than nests located in deciduous trees. Furthermore, woodpigeons nesting higher above the ground (at a height greater than five metres) suffered significantly lower rates of predation than those nesting closer to the ground (below five metres).

Nest Site Location and Success Rates of an Urban Population of Woodpigeon <em>Columba Palumbus</em> in Ireland

Recent decades have seen an increase in the number of woodpigeon frequenting cities and urban areas. Relatively few studies have assessed the nest site location, predation and breeding success rate of urban woodpigeons, and no such study exists in Ireland. The current study found that nest site location had a significant impact on the nest predation rates of an urban population of woodpigeon. Urban woodpigeons had a selective preference for nesting in evergreen trees, despite the fact that these nests suffered a significantly higher rate of predation than nests located in deciduous trees. Furthermore, woodpigeons nesting higher above the ground (at a height greater than five metres) suffered significantly lower rates of predation than those nesting closer to the ground (below five metres).

Landscape heterogeneity drives intra-population niche variation and reproduction in an arctic top predator.

While intra-population variability in resource use is ubiquitous, little is known of how this measure of niche diversity varies in space and its role in population dynamics. Here we examined how heterogeneous breeding environments can structure intra-population niche variation in both resource use and reproductive output. We investigated intra-population niche variation in the Arctic tundra ecosystem, studying peregrine falcon (Falco peregrinus tundrius, White) breeding within a terrestrial-marine gradient near Rankin Inlet, Nunavut, Canada. Using stable isotope analysis, we found that intra-population niches varied at the individual level; we examined within-nest and among-nest variation, though only the latter varied along the terrestrial-marine gradient (i.e., increased among-nest variability among birds nesting within the marine environment, indicating higher degree of specialization). Terrestrial prey species (small herbivores and insectivores) were consumed by virtually all falcons. Falcons nesting within the marine environment made use of marine prey (sea birds), but depended heavily on terrestrial prey (up to 90% of the diet). Using 28-years of peregrine falcon nesting data, we found a positive relationship between the proportion of terrestrial habitat surrounding nest sites and annual nestling production, but no relationship with the likelihood of successfully rearing at least one nestling reaching 25 days old. Annually, successful inland breeders raised 0.47 more young on average compared to offshore breeders, which yields potential fitness consequences for this long-living species. The analyses of niche and reproductive success suggest a potential breeding cost for accessing distant terrestrial prey, perhaps due to additional traveling costs, for those individuals with marine nest site locations. Our study indicates how landscape heterogeneity can generate proximate (niche variation) and ultimate (reproduction) consequences on a population of generalist predator. We also show that within-individual and among-individual variation are not mutually exclusive, but can simultaneously arise and structure intra-population niche variation.

Minor fitness benefits for edge avoidance in nesting grassland birds in the Northeastern United States

ABSTRACT. Grassland birds are often affected negatively by habitat fragmentation. Outcomes include greater nest predation and brood parasitism, decreased colonization rates of small, isolated patches, and greater nest density in remnant core habitats. These effects have been well documented in the Midwest, but little is known about fragmentation and edge effects on grassland birds in the fragmented agricultural fields within the forested landscapes of the northeastern United States. From 2002 to 2010, we assessed how edges and edge types affected nest-site location and daily nest survival (DNS) of Savannah Sparrows (Passerculus sandwichensis) and Bobolinks (Dolichonyx oryzivorus) breeding in 11 fields (range: 13.2–38.3 ha; mean = 21.1 ha) within a large agricultural region of Vermont. Mean (± SD) distance to edge was 80.3 ± 39.6 m for Savannah Sparrows (n = 995) and 94.5 ± 56.5 m for Bobolinks (n = 652). Both species nested significantly less than expected within 50 m of the edge. For Savannah Sparrows ne...

Home Range and Habitat Selection of Eastern Gray Squirrels (Sciurus carolinensis) in a Small Urban Hardwood Forest

This research investigated the home range and habitat selection of three eastern gray squirrels (Sciurus carolinensis) in 2010 and two in 2011 (one a recapture from 2010) in a mixed hardwood forest adjacent to Park University, Parkville, Missouri. We tracked squirrels on foot, using hand held receivers and antennas, acquiring an average of 41 diurnal locations and 5 nighttime nest site locations for each individual. Kernel home range contours were created using the software program Home Ranger. Home range areas of males (x = 3.41 ha) were larger than female ranges (x = 2.39 ha). Home ranges and locations were displayed in Google Earth imagery where habitat selection analyses were performed. Individuals showed significant selection for habitat types within their ranges, some preferring upland hardwood forest and others riparian forest. Open grassy or developed areas were consistently avoided by all squirrels. Squirrels nested in a variety of trees and snags, the nesting habitat reflecting forest types used during daily activity periods. Both riparian and upland forest habitats appeared to provide needed resources and differences in individual habitat selection may have been influenced by social interactions or other factors. Google Earth Pro proved to be a useful background for displaying animal location and range data as well as a tool for performing habitat selection analyses.

Is it always beneficial to breed in the centre? Trade-offs in nest site selection within the colony of a tree-nesting waterbird

In most of colonial avian species, central parts of the colonies offer higher safety in terms of predatory pressure. However, in heterogeneous habitats, nest sites of high physical quality are likely to offer effective protection against predators or adverse weather conditions regardless of their location within the colony. The aim of this paper was to investigate whether nest site selection in a tree-nesting waterbird, the Great Cormorant Phalacrocorax carbo sinensis, depends on the within-colony location of sites, their physical quality or a combination of these components. The study was conducted during 2010–2011 in a cormorant colony in central Poland. We found that early-breeding individuals preferred nest sites in the central parts of the colony and located high off the ground. The high quality of pairs nesting in these locations was confirmed with good body condition of nestlings, measured by their body masses and plasma concentrations of glucose and urea. A similar spatial pattern was found for the daily nest survival rate and reproductive success. It was found that the central nesting sites associated with high nesting densities were better protected against predators, while the physical quality of nesting sites determined the probability of nest collapse before the conclusion of breeding activities. The two-way process of assessing nest site attractiveness (nest site location vs. physical quality) suggests that, under the limitation of the most attractive nesting sites (good-quality central sites), tree-nesting waterbirds may trade central nesting locations for the high-quality sites at the peripheries of the colony.

Honey bee waggle dance communication: signal meaning and signal noise affect dance follower behaviour

Returning honey bee foragers perform waggle dances to inform nestmate foragers about the presence, location and odour of profitable food sources and new nest sites. The aim of this study is to investigate how the characteristics of waggle dances for natural food sources and environmental factors affect dance follower behaviour. Because food source profitability tends to decrease with increasing foraging distance, we hypothesised that the attractiveness of a dance, measured as the number of dance followers and their attendance, decreases with increasing distance to the advertised food location. Additionally, we determined whether time of year and dance signal noise, quantified as the variation in waggle run direction and duration, affect dance follower behaviour. Our results suggest that bees follow fewer waggle runs as the food source distance increases, but that they invest more time in following each dance. This is because waggle run duration increases with increasing foraging distance. Followers responded to increased angular noise in dances indicating more distant food sources by following more waggle runs per dance than when angular noise was low. The number of dance followers per dancing bee was also affected by the time of year and varied among colonies. Our results provide evidence that both noise in the message, that is variation in the direction component, and the message itself, that is the distance of the advertised food location, affect dance following. These results indicate that dance followers may pay attention to the costs and benefits associated with using dance information.