Nest-site Choice Research Articles

Individual Nest Site Selection in Hawksbill Turtles Within and Between Nesting Seasons

Abstract We analyzed 410 nest locations from 150 individual nesting hawksbill turtles (Eretmochelys imbricata) on the northeastern Brazilian coast during 8 nesting seasons from 2006 to 2014 to evaluate individual nesting preferences. We determined the consistency of nest site choice within and between nesting seasons for open sand and vegetation nest microhabitats and also for nest site distances from the current waterline, highest spring tide, vegetation line, and position along the beach. We found that behavioral consistency within seasons was more robust than between seasons. This suggests that a decrease in the consistency of nest site choice may be related to progressive landscape changes in the nesting environment, driving behavioral flexibility in nesting preferences.

Communal nesting under climate change: fitness consequences of higher incubation temperatures for anocturnal lizard.

Communal nesting lizards may be vulnerable to climate warming, particularly if air temperatures regulate nest temperatures. In southeastern Australia, velvet geckos Oedura lesueurii lay eggs communally inside rock crevices. We investigated whether increases in air temperatures could elevate nest temperatures, and if so, how this could influence hatching phenotypes, survival, and population dynamics. In natural nests, maximum daily air temperature influenced mean and maximum daily nest temperatures, implying that nest temperatures will increase under climate warming. To determine whether hotter nests influence hatchling phenotypes, we incubated eggs under two fluctuating temperature regimes to mimic current 'cold' nests (mean=23.2°C, range 10-33°C) and future 'hot' nests (27.0°C, 14-37°C). 'Hot' incubation temperatures produced smaller hatchlings than did cold temperature incubation. We released individually marked hatchlings into the wild in 2014 and 2015, and monitored their survival over 10months. In 2014 and 2015, hot-incubated hatchlings had higher annual mortality (99%, 97%) than cold-incubated (11%, 58%) or wild-born hatchlings (78%, 22%). To determine future trajectories of velvet gecko populations under climate warming, we ran population viability analyses in Vortex and varied annual rates of hatchling mortality within the range 78- 96%. Hatchling mortality strongly influenced the probability of extinction and the mean time to extinction. When hatchling mortality was >86%, populations had a higher probability of extinction (PE: range 0.52- 1.0) with mean times to extinction of 18-44years. Whether future changes in hatchling survival translate into reduced population viability will depend on the ability of females to modify their nest-site choices. Over the period 1992-2015, females used the same communal nests annually, suggesting that there may be little plasticity in maternal nest-site selection. The impacts of climate change may therefore be especially severe on communal nesting species, particularly if such species occupy thermally challenging environments.

Effects of salinity on nest-building behaviour in a marine fish.

BackgroundParental allocation and reproductive success are often strongly influenced by environmental factors. In this respect, salinity is a key factor influencing species distributions and community structure in aquatic animals. Nevertheless, the effects of salinity on reproductive behaviours are not well known. Here, we used the sand goby (Pomatoschistus minutus), a small fish inhabiting a range of different salinities, to experimentally assess the effects of changes in salinity on nesting behaviour, a key component of reproduction in sand gobies and many other taxa.ResultsWe found that salinity levels influenced some aspects of male nesting behaviour (i.e. nest entrance size) but not others (i.e. latency to build a nest, choice of nest site, sand on top of nest) and that small and large individuals were differently affected. In particular, the importance of body size in adjustment of nest entrance depended on the salinity level.ConclusionThe results support the prediction that geographically widespread aquatic species, such as sand gobies, are able to perform well under a range of salinity levels. The phenotype by environment interaction found between male size and behavioural responses to salinity can, in turn, help to explain the notable variation observed in nest-building (and other) behaviours closely linked to reproduction.Electronic supplementary materialThe online version of this article (doi:10.1186/s12898-016-0067-y) contains supplementary material, which is available to authorized users.

Habitat choice and female preference in a polymorphic stickleback population

Background: A small pond, c. 90 years old, near Bern, Switzerland contains a population of threespine stickleback (Gasterosteus aculeatus) with two distinct male phenotypes. Males of one type are large, and red, and nest in the shallow littoral zone. The males of the other are small and orange, and nest offshore at slightly greater depth. The females in this population are phenotypically highly variable but cannot easily be assigned to either male type. Question: Is the existence of two sympatric male morphs maintained by substrate-associated male nest site choice and facilitated by female mate preferences? Organisms: Male stickleback caught individually at their breeding sites. Females caught with minnow traps. Methods: In experimental tanks, we simulated the slope and substrate of the two nesting habitats. We then placed individual males in a tank and observed in which habitat the male would build his nest. In a simultaneous two-stimulus choice design, we gave females the choice between a large, red male and a small, orange one. We measured female morphology and used linear mixed effect models to determine whether female preference correlated with female morphology. Results: Both red and orange males preferred nesting in the habitat that simulated the slightly deeper offshore condition. This is the habitat occupied by the small, orange males in the pond itself. The proportion of females that chose a small orange male was similar to that which chose a large red male. Several aspects of female phenotype correlated with the male type that a female preferred.

Aggressive neighbors and dense nesting: nest site choice and success in high-Arctic common eiders

Minimizing the risk of nest predation has led some bird species to exploit the nest defense behavior of other species. At Nasaruvaalik Island, Nunavut, Canada, some common eiders (Somateria mollissima borealis) nest within the boundaries of Arctic tern (Sterna paradisaea) colonies, while others nest elsewhere on the island, away from the terns. We tested the effects of location (within vs. outside the tern colonies), density of common eider nests, and annual variation on the nesting parameters of common eiders. Our results suggest that nesting in association with Arctic terns does not confer an obvious benefit to eiders. Such associative nesting of eiders and terns may be the result of overlapping habitat preferences between the two species, or a general scarcity of suitable nesting habitat for ground-nesting species in the high Arctic. However, eiders nesting in higher densities with other eiders had greater nest success and lower total clutch predation, indicating a positive correlation between nest density and success.

Importance of Inherent Suitability, Behavioural Flexibility and Competitiveness in Occupancy of Urban Parks by an Endemic Honeyeater

Three factors potentially facilitating avian urban colonisation are: (a) inherent suitability for city environments, (b) limited resource overlap with residents, achieved through resource partitioning or outcompeting residents for shared resources, and (c) behavioural flexibility permitting innovative resource exploitation. We examined the foraging ecology and nest site choice of the Noisy Miner ( Manorina melanocephala) in urban parks in Melbourne, Australia to elucidate which of these three factors was likely to be instrumental in facilitating occupancy of this urban habitat by this native honeyeater. The Noisy Miner was relatively unspecialised in its nest site choice in parks, suggesting that the many suburban parks with branching eucalypts probably provide lots of suitable nest sites for this species. Park-dwelling Noisy Miners appeared to be superior competitors for food to most cohabiting bird species. They were never targets of interspecific aggression, but quite often initiated it against 16 other bird species. Most interactions were attacks and/or chases and 74% displaced the target species’ member. In Melbourne's parks, Noisy Miners foraged for invertebrates mainly: (a) in the sub-canopy on foliage, using hanging and reaching behaviours, and (b) on the ground on bark litter and grass, gleaning in a standing posture. Several cohabiting bird species also gleaned invertebrates on the ground in a similar manner, but all also commonly used other behaviours when foraging on this substrate. No cohabiting species that foraged extensively in the sub-canopy fed substantially on invertebrates there. Thus Noisy Miners could successfully inhabit Melbourne's parks apparently at least partly because: (i) nest site choice was relatively unspecialised; (ii) they flexibly exploited food resources at ground level, unlike exurban conspecifics; (iii) they aggressively dominated possible heterospecific food competitors at ground level; and (iv) they probably experienced fairly limited dietary overlap with cohabiting bird species.

The influence of nest-site choice and predator sensory cues on nesting success in the Crimson Finch (Neochmia phaeton)

The attributes of a nest-site that a bird selects may be influenced by the potential predator species present, as different types of predator use different foraging strategies and sensory cues to locate nests. However, in many studies of avian nesting, the identity of the main nest predators and their foraging strategies are not known, limiting our interpretation and understanding of how choice of nest-site and nesting success might be linked. We investigated nest-site choice, nest survival and the nest predators in a population of Crimson Finch (Neochmia phaeton) in tropical Australia. Crimson Finches preferred to nest among foliage of the crowns of Pandanus on stems with aquatic barriers, and near old nests of conspecifics. However, none of these or any other attributes of nest-sites that we recorded significantly affected nest survival. Moreover, neither visual nor olfactory cues influenced nesting success in field experiments with quail eggs. Similar rates of predation of natural and experimental nests, coupled with similar rates of daily predation of eggs and nestlings suggest that predators were not using nest-attendance behaviour of the adult Finches as a cue to find active nests. Identified nest predators were reptiles; our study suggests that Crimson Finches may not be able to choose nest-sites that reduce the ability of these olfactory-driven predators.

Pied Flycatchers Ficedula hypoleuca prefer ectoparasite-free nest sites when old nest material is present

Nest-dwelling ectoparasitic arthropods may have detrimental effects on avian breeding success and fitness. Birds should therefore be selected to avoid nest sites where the risk of being infested by ectoparasites is high. However, studies testing this hypothesis have produced mixed results. We performed an experiment in south Norway to test whether Pied Flycatchers Ficedula hypoleuca select nest site according to the presence of ectoparasites. We used artificial nest boxes in this experiment which had all been successfully used by conspecifics in the previous breeding season and still contained the old nest material. Five different groups of ectoparasites were recorded in flycatcher nests in the study area, of which the haematophagous hen flea Ceratophyllus gallinae and mites (Dermanyssus sp.) occurred in all examined nests. We offered each flycatcher pair (n = 13) a choice between 1) a box where ectoparasites had been removed by insecticide fumigation and 2) a box in which the old nest had not been fumigated. Flycatchers were highly selective in their choice of nest site, all but one settling in the fumigated, parasite-free nest box. This finding differs from a similar Swedish study (Olsson & Allander 1995) which did not find any evidence that Pied Flycatchers avoided nest boxes with ectoparasites. A likely explanation for this discrepancy is between-population differences in parasite abundance, as the mean number of hen fleas per infested nest was about five times higher in Norway than in Sweden.

Nest-site selection and consequences for nest survival among three sympatric songbirds in an alpine environment

We examined timing of breeding, nest site selection and nest survival of Horned Larks (Eremophila alpestris), Savannah Sparrows (Passerculus sandwichensis) and American Pipits (Anthus rubescens) in an alpine habitat on Hudson Bay Mountain, BC, Canada in 2003–2007. These species partitioned their nesting niches temporally and spatially. We compared nest site characteristics among species using one-way ANOVA and logistic regression. Horned Larks (n = 103 nests) initiated breeding 2 weeks earlier (mean = 1 June) than Savannah Sparrows (n = 52, mean = 14 June) and American Pipits (n = 38, mean = 11 June). Horned Larks and American Pipits nested at similar elevations (means = 1714 and 1719 m, respectively); however, lark nests were more exposed (greater bare ground, rock and lichen/moss cover), with minimal nest concealment, while pipit nests, built into banks and soil mounds, had high concealment. Savannah Sparrows nested at lower elevation (mean = 1649 m) with greater dead vegetative cover. We assessed intraspecific habitat preferences for Horned Larks and Savannah Sparrows using logistic regression; both species chose nest sites with greater availability of their preferred habitat characteristics. We used model selection to evaluate effects of nest site characteristics, nest age, season and year on daily nest survival (DNS). Horned Larks displayed the lowest DNS of 0.954 ± 0.009 (n = 189 nests), which varied with year, season and nest age, but was not influenced by site characteristics. In contrast, DNS was highest for Savannah Sparrows (0.961 ± 0.014, n = 89) with strong responses to nest concealment, year and nest age. American Pipits exhibited an intermediate DNS (0.959 ± 0.009, n = 38), which varied with overhead concealment and elevation. Despite the simple structure of the alpine habitat, there was significant niche differentiation in nest site choices among these species. Preferences for nest concealment were positively related to nest survival in Savannah Sparrows and American Pipits but not Horned Larks, indicating how a common environment can differentially influence behavior and demography.

Do trade-offs between predation pressures on females versus nests drive nest-site choice in painted turtles?

Predation strongly influences reproductive behaviours because reproducing individuals must balance mortality risks to themselves and to their offspring. In many freshwater turtles, the nest predation risk decreases with nest distance from water, whereas the predation risk to females increases farther from water. To determine whether predation pressure influences the distance from water at which female turtles nest, we measured predation pressure on nesting females and on nests, as well as the distances of nests to water, in two populations of painted turtles. Using models, we found that female survival in both populations was high and did not vary with distance from water. Nest survival was also uncorrelated with nest distance to water, although it was significantly lower than adult survival in both populations and was only 1.2% in one population. Our results suggest that nest sites are not predictably safe from predators. Instead, turtles may hedge their bets by nesting over a wide range of distances from water because any distance is risky for nests and no distance is particularly risky for the nesting female. We suggest that other factors, such as suitable incubation conditions and/or post-emergence hatchling survival, probably play a larger role than predation in driving nest-site choice in painted turtles.

Temperature-Dependent Sex Determination under Rapid Anthropogenic Environmental Change: Evolution at a Turtle's Pace?

Organisms become adapted to their environment by evolving through natural selection, a process that generally transpires over many generations. Currently, anthropogenically driven environmental changes are occurring orders of magnitude faster than they did prior to human influence, which could potentially outpace the ability of some organisms to adapt. Here, we focus on traits associated with temperature-dependent sex determination (TSD), a classic polyphenism, in a model turtle species to address the evolutionary potential of species with TSD to respond to rapid climate change. We show, first, that sex-ratio outcomes in species with TSD are sensitive to climatic variation. We then identify the evolutionary potential, in terms of heritability, of TSD and quantify the evolutionary potential of 3 key traits involved in TSD: pivotal temperature, maternal nest-site choice, and nesting phenology. We find that these traits display different patterns of adaptive potential: pivotal temperature exhibits moderate heritable variation, whereas nest-site choice and nesting phenology, with considerable phenotypic plasticity, have only modest evolutionary potential to alter sex ratios. Therefore, the most likely response of species with TSD to anthropogenically induced climate change may be a combination of microevolution in thermal sensitivity of the sex-determining pathway and of plasticity in maternal nesting behavior.

Nesting in a Crowd: Response of House Sparrow Towards Proximity to Spatial Cues in Commercial Zones of Guwahati City

We studied the nest site characteristics features of House Sparrow Passer domesticus in highly crowded commercial zones of Guwahati city, Assam, India. Active nests of House Sparrow were recorded during the peak breeding season—February to April 2013. A total of 106 nests were recorded, out of which 36 % of nests were in colonies having more than two nests with a maximum of 20 nests in a single colony. The shutters were found to be the predominant substrates for nest construction. The average nest height was 3.78 ± 2.18 m. Most of the nests were recorded in less than 5 m height. The habitat patch selection for nesting might be a response to food availability or protection against abiotic factors. The availability or proximity of suitable foraging sites seems to be an important feature for nest site choice. The shopping centers with glass facades (exterior construction of the buildings) do not provide much space for placing the nests. The development of modern buildings is going to be a major threat to the breeding sparrows in near future.

In search of the gap: temporal and spatial dynamics of settling in natal common tern recruits

In colonial birds, criteria used for the first choice of a nest site and its temporal and spatial dynamics are rarely studied. This paper addresses first settlement of natal recruits in common terns Sterna hirundo at a stable colony site subdivided into six islands of equal size and habitat. Using extensive individual-based data of aged and sexed individuals with known recruitment age, I focus on timing of laying, island selection in relation to density and centrality, and movements after first breeding. Recruits’ laying date was timed between that of experienced and replacement breeders. The proportion of early clutches, density, and age of breeders were higher at the islands’ edge (the preferred area), whereas late clutches predominated at the center. Sixty-eight percent of recruits settled at the center and only 32 % at the islands’ edge. With advancing age, breeders shifted nest sites from the island center towards the edge. In 7 out of 18 years, annual recruit numbers were not evenly distributed among the islands. Density did not affect island selection, but in years with low numbers of recruits, their aggregation was more distinct. Recruits’ preference of a specific island rarely lasted more than 2 years. Depletion of the central area in the year after recruitment initially attracted new recruits before succeeding cohorts switched to another island. The dynamics of recruits’ settlement indicate diverging tendencies of attracting or repelling recruits at a specific subcolony, affected by group adherence and cohort size, density, and advancing laying date with age and shifts of nest sites towards the preferred subcolony periphery.

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.

One size does not fit all: Importance of adjusting conservation practices for endangered hawksbill turtles to address local nesting habitat needs in the eastern Pacific Ocean

Conservation biologists frequently use data from the same or related species collected in diverse geographic locations to guide interventions in situations where its applicability is uncertain. There are dangers inherent to this approach. The nesting habitats of critically endangered hawksbill sea turtles (Eretmochelys imbricata) cover a broad geographic global range. Based on data collected in the Caribbean and Indo-Pacific, conservationists assume hawksbills prefer open-coast beaches near coral reefs for nesting, and that individual hawksbills are highly consistent in nest placement, suggesting genetic factors partially account for variation in nest-site choice. We characterized nest-site preferences of hawksbills in El Salvador and Nicaragua, where >80% of nesting activity occurs for this species in the eastern Pacific, and ∼90% of hawksbill clutches are relocated to hatcheries for protection. We found hawksbills preferred nest sites with abundant vegetation on dynamic beaches within mangrove estuaries. Nests in El Salvador were located closer to the ocean and to the woody vegetation border than nests in Nicaragua, suggesting female hawksbills exhibit local adaptations to differences in nesting habitat. Individual hawksbills consistently placed nests under high percentages of overstory vegetation, but were not consistent in nest placement related to woody vegetation borders. We suggest conservation biologists use caution when generalizing about endangered species that invest in specific life-history strategies (e.g., nesting) over broad ranges based on data collected in distant locations when addressing conservation issues.

Flexibility of collective decision making during house hunting in Temnothorax ants

Many social animals cooperatively process information during decision making, allowing them to concentrate on the best of several options. However, positive feedback created by information sharing can also lock the group into a suboptimal outcome if option quality changes over time. This creates a trade-off between consensus and flexibility, whose resolution depends on the information-sharing mechanisms groups employ. We investigated the influence of communication behavior on decision flexibility in nest site choice by colonies of the ant Temnothorax rugatulus. These ants divide their emigration into two distinct phases separated by a quorum rule. In the first phase, scouts recruit nestmates to promising sites using the slow method of tandem running. Once a site's population surpasses a quorum, they switch to the faster method of social transport. We gave colonies a choice between two sites of different quality, and then switched site quality at different points during the emigration. Before the quorum was met, colonies were able to switch their choice to the newly superior site, but once they began to transport, their flexibility dropped significantly. Close observation of single ants revealed that transporters were more likely than tandem leaders to continue recruiting to a site even after its quality was diminished. That is, tandem leaders continued to monitor the quality of the site, while transporters instead fully committed to the site without further assessment. We discuss how this change in commitment with quorum attainment may enhance the rapid achievement of consensus needed for nest site selection, but at a cost in flexibility once the quorum is met.

Alternative eyrie use in peregrine falcons: is it a female choice?

AbstractAll animals face the decision of where to breed, a decision that exerts a strong impact on fitness. We examined changes in choice of nest site in peregrine falcons (Falco peregrinus) over a 17‐year period in northern Spain. Falcons had a mean of 3.1 eyries per territory, each location used for a mean of 3.0 consecutive years. Surprisingly, change in eyrie location was not predicted by breeding productivity. However, breeding success decreased with the number of consecutive years that eyries were reused. Ectoparasitic infestation was not a significant predictor in the models. The number of fledglings in the previous season was the main factor explaining the eyrie‐switching decision, with successful pairs being more prone to move. Newly established females showed a higher tendency to switch (59%) than older territorial females (38%) but males did not exhibit the same tendency. High rainfall in April had a negative effect on productivity. In the case of females, changing the eyrie from one season to the next had a positive effect on productivity. In the case of models run with males as a random factor, rainfall in April and eyrie shelter reached significance. So, contrary to the ‘win–stay, lose–switch’ rule and in direct contrast with general literature, peregrines changed eyries after successfully raising large broods and eyrie switching increased the breeding success of females but not of males.

Reduction in site fidelity with smaller spatial scale may suggest scale-dependent information use

Animals change the strategy that they use to select breeding sites at the spatial scales of habitat, patch, and microhabitat. In this regard, breeding site fidelity is expected to vary according to environmental predictability, which, in turn, is expected to differ between each spatial scale. However, whether or not animals change their degree of site fidelity at different spatial scales remains unclear. We captured and released males of the terrestrial frog Pseudophryne bibronii into alternative patches within a breeding habitat and determined the extent to which site fidelity influenced individual nest-site choice. We found that males tended to return to their original patch rather than resettle in an alternative patch. However, males were unlikely to return to their original nest sites within the patch. We suggest that site fidelity in this species may be scale dependent because information from previous breeding seasons can predict the quality of patches, but not nest sites. This behavioral variation is consistent with a hypothetical relationship between spatial scale and environmental predictability, which may have important implications for decision-making processes that extend over multiple spatial scales.

Nest site selection of white-naped crane (Grus vipio) at Zhalong National Nature Reserve, Heilongjiang, China

White-naped crane (Grus vipio) is a globally threatened species. It is very important to analyze its nest site selection in circumstances where there are multiple disturbances, and also helpful to accumulate valuable information about this threatened species and supply scientific suggestions for conservation and management. We studied nest site selection and the effects of environmental variables on nesting habits of white-naped crane at Zhalong National Nature Reserve, Qiqihar City, Heilongjiang, China, during March-May of 2002–2008. White-naped crane responded and adapted to changes in the quality of the spatial environments of landscape and microhabitat under multiple environmental disturbances. Nest site selection included two scales and two choices, namely the choice of nest site habitat type within the macro-habitat scale and nest site micro-habitat selection within the micro-habitat scale. Nest sites were recorded only in reed marshes. The choice of nest site micro-habitat included three basic elements and six factors, namely incubation element (nest parameters factor, incubation temperature factor and incubation humidity factor), safety element (protection factor and concealment factor), and food element (water factor). Water, remnant reed clusters, and fire were major resource management challenges during the breeding period for the white-naped crane in this Reserve.

Experimental analysis of nest-site choice and its relationship to nest success in an open-cup–nesting passerine

ABSTRACT Nest placement presumably reflects selection for secure sites to minimize failure. Most tests of this hypothesis, however, have failed to support it. We used artificial nests (ARTs) to experimentally evaluate nest-site-choice behavior by an open-cup–nesting bird, the Eastern Kingbird (Tyrannus tyrannus). In 2010 and 2011, we placed ARTs in trees in the riparian zone at Malheur National Wildlife Refuge, Oregon, USA, to test whether (1) characteristics describing the physical location in trees of used and unused ARTs differed, (2) used ART sites more closely resembled naturally chosen sites, (3) successful natural nests (NATs) and successful ARTs were similarly located along the major axis describing nest placement, and (4) unused ARTs resembled failed NATs. Used and unused ART sites differed, but unused ART sites were more similar to NAT sites. The latter unexpected result occurred because (1) unused ARTs were located at sites between more heavily used higher and lower locations and (2) most kingb...