Nest-site Choice Research Articles

Deep Communal Nesting by Yellow-Spotted Monitors in a Desert Ecosystem: Indirect Evidence for a Response to Extreme Dry Conditions

Abstract In oviparous reptiles with no parental care, the choice of nest site is a mother's final investment in her offspring. Although linkages between nest site choice, egg temperatures, and embryonic success have been well studied, much less is known about analogous linkages with soil moisture encompassing developing embryos. Most ground-nesting reptiles nest at depths <25 cm, with the deepest nests <1.0 m deep. Recently, however, the nests of two species of monitor lizards (Varanus panoptes and V. gouldii) have been discovered at depths of 2.3–3.0 m, suggesting that nesting at extreme depths in these species is an adaptive response to the lack of sufficient soil moisture at shallower depths. Herein, we examine this idea with V. panoptes, specifically predicting that deeper nests in a desert ecosystem compared with those in a savannah ecosystem are attributable to differences in the magnitude of rainfall. We excavated a communal nesting warren to a depth of 4 m and identified 11 fresh nests and 99 hatc...

Interspecific information on predation risk affects nest site choice in a passerine bird

BackgroundBreeding site choice constitutes an important part of the species niche. Nest predation affects breeding site choice, and has been suggested to drive niche segregation and local coexistence of species. Interspecific social information use may, in turn, result in copying or rejection of heterospecific niche characteristics and thus affect realized niche overlap between species. We tested experimentally whether a migratory bird, the pied flycatcher Ficedula hypoleuca, collects information about nest predation risk from indirect cues of predators visiting nests of heterospecific birds. Furthermore, we investigated whether the migratory birds can associate such information with a specific nest site characteristic and generalize the information to their own nest site choice.ResultsOur results demonstrate that flycatchers can use the fate of heterospecific nesting attempts in their own nest site choice, but do so selectively. Young flycatcher females, when making the decision quickly, associated the fate of an artificial nest with nest-site characteristics and avoided the characteristic associated with higher nest predation risk.ConclusionsCopying nest site choices of successful heterospecifics, and avoiding choices which led to failed attempts, may amplify or counter effects of nest predation on niche overlap, with important consequences for between-species niche divergence-convergence dynamics, species coexistence and predator-prey interactions.

Offspring dispersal ability covaries with nest-site choice

Nesting strategy shifts with offspring dispersal ability. In snapping turtles, larger offspring have higher survival than smaller offspring when dispersing long distances. Mothers that produce better dispersing offspring nest farther from water where nest predation risk is lower. Mothers that produce poorer dispersing offspring are constrained to nest closer to water so offspring can successfully disperse if they aren’t eaten first. Thus, accounting for offspring dispersal ability increases offspring survival and maternal fitness.

Maternal nest building and choice of nest site are temperature dependent in mink: Parent-offspring temperature conflict?

We investigated whether nest building and nest site preference are temperature dependent in female mink. We designed two experiments: in Experiment 1, female mink had access to unheated (7 °C, Room7C group) or heated (25 °C, Heated25C group) nest boxes; in Experiment 2, female mink had free choice of nest boxes at three temperatures (7 °C, 16 °C, and 25 °C). We hypothesised that the progress in nest building would be temperature dependent (Experiment 1), with female mink having a temperature preference, and that this preference would shift toward a higher temperature when giving birth (Experiment 2). Nest building decreased with increasing nest box temperature from Day −3 to Day 7 relative to the day of birth (Experiment 1: P < 0.001; Experiment 2: 7 °C > 16 °C > 25 °C, P < 0.05). In Experiment 1, females in the Heated25C group stayed for significantly shorter times inside the nest boxes than did females in the Room7C group (P = 0.007). In Experiment 2, dams spent the most time in the 7 °C nest boxes and the least time in the 25 °C boxes (P < 0.05). Similarly, dams given a choice preferred not to place their litters in the 25°C nest boxes through Day 7 (Experiment 2, P < 0.05). Offspring placed in 25°C nest boxes weighed 17.5% more than those placed in 7°C boxes on Day 7 (Experiment 1, P = 0.028). When dams were away from the nest, 1) offspring in unheated nest boxes vocalised longer than did those in heated boxes (Experiment 1: P = 0.010), and 2) offspring in 7 °C boxes huddled more than did those in 25 °C boxes (Experiment 1, P = 0.021). These results show that maternal nest building and choice of nest site are temperature dependent, with a potential temperature preference conflict between dams and offspring.

Wild zebra finches do not use social information from conspecific reproductive success for nest site choice and clutch size decisions

Information about the quality of local habitat can greatly help to improve an individual’s decision-making and, ultimately, its fitness. Nevertheless, little is known about the mechanisms and significance of information use in reproductive decisions, especially in unpredictable environments. We tested the hypothesis that perceived breeding success of conspecifics serves as a cue for habitat quality and hence influences breeding decisions (nest site choice and clutch size), using the zebra finch (Taeniopygia guttata) as a model species. Zebra finches breed opportunistically in the unpredictable, arid zone of Australia. They often inspect the nests of conspecifics, potentially to prospect on conspecific reproductive success, i.e., to collect social information. We conducted a clutch and brood size manipulation to experimentally create the perception of high and low quality areas. In six areas, clutch sizes of almost 300 zebra finch nests were either all increased (N = 3 areas) or reduced (N = 3 areas) throughout one breeding season. The number of breeding pairs and sizes of newly laid clutches were not significantly affected by the manipulated reproductive success of the areas. Thus, zebra finches did not use social cues for their reproductive decisions, which contrasts with findings of species in temperate zones, and could be an adaptation to the high unpredictability of their habitat. Even the personal experience of rebreeding birds did not directly affect their clutch size. Our study suggests that zebra finches employ a high level of opportunism as a key strategy for reproduction. Further, this is the first study to our knowledge using an experimental approach in the wild to demonstrate that decision-making in unpredictable natural environments might differ from decision-making in temperate environments with seasonal breeding. Social information can help to optimize the behavior of animals. Birds in temperate climates with seasonality use breeding success of others to predict where they should breed. However, very little is known about information use in less predictable environments. In a field experiment, we created a patchy environment by increasing and decreasing brood sizes of wild zebra finches to test if social information is also used in unpredictable conditions. We found no evidence that zebra finches in the Australian outback use social information from their conspecifics when deciding on nest site and clutch size. They probably gather personal information on environmental parameters and the current availability of resources, which might be more reliable than social information.

Consistent nest-site selection across habitats increases fitness in Asian Houbara

ABSTRACT Nest-site choice profoundly influences reproductive success and the survival of incubating adult birds. Asian Houbara (Chlamydotis macqueenii) nest in subtly contrasting habitats where the main cause of nest failure is predation. We examined nest-site selection across 3 semiarid shrub habitats that differed in vegetation structure and hypothesized that increased concealment would reduce nest predation. We quantified vegetation structure at 210 nests and 194 random control sites at 2 scales, the “nest area” (50 m radius, considering mean “shrub height” and mean “shrub frequency”) and “nest scrape” (2 m radius, considering a “concealment index”). Variance ratio tests showed that variance in both shrub height and concealment index was lower at nests than at random sites, indicating nonrandom selection. Analysis of the probability of nest occurrence for nest area indicated consistent selection of intermediate shrub heights (shrub height + shrub height2) in the Astragalus, Salsola arbuscula, and S. ri...

Evaluating the importance of managed forests as habitat for the Semi-collared Flycatcher (Ficedula semitorquata)

Intensive forest management has caused a decline in the numbers of birds specialized on old growth. Understanding how forest stand attributes influence the distribution of these specialists has hence become a prerequisite for sustainable forest management. In this study, we evaluated the conservation value of managed forests for old-growth forest specialists using the poorly studied Semi-collared Flycatcher as an example. We applied a boosted generalized additive model to identify forest characteristics that determine the occurrence of the bird in Bulgaria. We found that on a national scale, forest stand age and percent cover of broad-leaved forests best explain the breeding distribution of the flycatcher. Although, forest stands became suitable habitat at an age of around 70 years for this species, stands in the interior forest featuring trees older than 160 years and composed of more than 80% broad-leaved trees were preferred by the species. At a local scale, the amount of dead wood positively influenced nest site choice of the flycatcher. In total, 22.3% of all studied broad-leaved forests in Bulgaria showed a predicted habitat suitability higher than 50%. High-stem forests that are old enough to develop old-growth characteristics had the highest potential to serve as habitat for the Semi-collared Flycatcher in Bulgaria. Therefore, we conclude that a decrease in logging of forests stands older than 160 years decreases the risk of decline of the Semi-collared Flycatcher.

Immune configuration in hatchling snakes is affected by incubation moisture, and is linked to subsequent growth and survival in the field.

We incubated the eggs of field-caught keelback snakes (Tropidonophis mairii) on wet versus dry substrates to explore impacts of incubation conditions on white blood cell (WBC) concentrations and differential WBC counts of hatchlings. In a second, independent study young snakes were released into the field, allowing us to explore fitness correlates of WBC profiles. Dry incubation reduced embryonic survival and hatchling body size, thus decoupling egg size from hatchling size. Incubation conditions also altered WBC profiles. Lymphocyte and azurophil counts were related to hatchling body size but not to initial egg mass, whereas heterophil counts were related to both of these traits. The egg-size effect on heterophil counts may reflect a maternal effect on offspring immune configuration. The ratio of heterophils to lymphocytes (an index of stress) was higher in hatchlings from eggs incubated on dry substrates. Snakes with higher counts of lymphocytes at hatching were more likely to be recaptured as adults (H:L; an index of survival), whereas snakes with higher basophil counts exhibited more rapid growth. In summary, our experiments show that incubation moisture levels influence the immune configuration of hatchling snakes, and that variation among individuals in WBC counts at hatching is a significant predictor of an individual's fitness after it is released into the wild. The demonstrated link between incubation conditions and offspring fitness is likely to impose strong selection on maternal nest-site choice.

Home, dirty home: effect of old nest material on nest-site selection and breeding performance in a cavity-nesting raptor.

The quality of a breeding site may have major fitness consequences. A fundamental step to understanding the process of nest-site selection is the identification of the information individuals use to choose high-quality nest sites. For secondary cavity-nesting bird species that do not add nest lining material, organic remains (faeces, pellets) accumulated inside nest cavities during previous breeding events may be a cue for high-quality nest-sites, as they contain information about past successful breeding and may improve thermal insulation of eggs during incubation. However, cavities in which breeding was successful might also contain more nest-dwelling ectoparasites than unoccupied cavities, offering an incentive for prospective parents to avoid them. We exposed breeding cavity-nesting lesser kestrels (Falco naumanni) to nestbox dyads consisting of a dirty (with a thick layer of organic substrate) and a clean nestbox (without organic material). Dirty nestboxes were strongly preferred, being occupied earlier and more frequently than clean ones. Hatching success in dirty nestboxes was significantly higher than in clean ones, suggesting a positive effect of organic nest material on incubation efficiency, while nestbox dirtiness did not significantly affect clutch and brood size. Nestlings from dirty nestboxes had significantly higher ectoparasite load than those from clean nestboxes soon after egg hatching, but this difference was not evident a few days later. Nest substrate did not significantly affect nestling growth. We concluded that nest substrate is a key driver of nest-site choice in lesser kestrels, although the adaptive value of such a strong preference appears elusive and may be context-dependent.

Host nest site choice depends on risk of cuckoo parasitism in magpie hosts

Host nest site choice depends on risk of cuckoo parasitism in magpie hosts

The importance of illumination in nest site choice and nest characteristics of cavity nesting birds

Light has a significant impact on many aspects of avian biology, physiology and behaviour. An increasing number of studies show that illumination may positively influences birds’ offspring fitness by e.g. acceleration of embryo development, stimulation of skeleton growth or regulation of circadian rhythm. Because nest cavities have especially low illumination, suitable light levels may be especially important for species which nest there. We may therefore expect that birds breeding in relatively dim conditions should prefer brighter nest sites and/or evolve behavioral mechanisms to secure sufficient light levels in the nest. Using nest boxes with modified internal illumination, we experimentally tested whether light regime is a cue for nest site selection of secondary cavity-nesting species. Additionally, we investigated whether nest building strategies are tuned to internal illumination. Our results demonstrate that, nest boxes with elevated illumination were chosen twice as often as dark nest boxes. Moreover, birds built higher nests in dark nest boxes than birds in boxes with elevated illumination, which suggests a mechanism of compensating for low light conditions. Our results provide the first experimental support for the idea that nest site choice and nest building behaviour in cavity-nesting birds are influenced by ambient illumination.

Density and Dispersion of Cavity Dwelling Ant Species in Nuts of Eastern US Forest Floors

ABSTRACT Here we report on nut-nesting ant communities in the southeastern United States. We compared species diversity, ant abundance, and nut occupancy rates among sites in five states, and report the spatial dispersion of ant colonies in nuts in relation to colony-housing opportunities created by nuts and nest-site choice. Our results indicated that species diversity and nut occupancy rates do not differ among sites or states and that ant-occupied nuts are spatially aggregated across ant species, a pattern inconsistent with spatial segregation of species that might arise in a competition-assembled community. We tested the ability of artificial nest cavities (“Mobile Artificial Ant Pods”, MAAPs) to attract ant colonies, a method for sampling the ant fauna in litter. MAAP occupancy rates were similar to occupancy rates for nearby nuts.

Hatch-year Piping Plover (Charadrius melodus) prospecting and habitat quality influence second-year nest site selection

ABSTRACT Juvenile prospecting, or exploratory behavior for gleaning information about areas or events, can have profound effects on the selection of future breeding habitat, particularly for birds with high site fidelity whose initial choice of breeding habitat could represent a lifetime investment in fitness. We present data from a 10-yr study of Piping Plovers (Charadrius melodus) on the Missouri River, USA, to determine whether postfledging, hatch-year (HY) prospecting movements inform second-year (SY) nest site choices. First, we compared the home ranges of HY and adult (after-hatch-year; AHY) plovers to investigate whether differences in habitat use existed between HY and AHY plovers. Second, we evaluated the effects of prospecting, nest density, reproductive success, and nesting and foraging habitat availability on SY plover nest site selection. Lastly, we evaluated the potential reproductive benefits of nesting in prospected areas by comparing the nest success and fledging success of SY plovers tha...

Nest-site selection and the factors influencing hatching success and offspring phenotype in a nocturnal skink

Nest-site selection in ectothermic animals influences hatching success and offspring phenotype, and it is predicted that females should choose nesting sites that maximise their reproductive fitness, ultimately through the reproductive success of their offspring. We completed nest-site choice experiments on a nocturnal lizard, the egg-laying skink (Oligosoma suteri), to determine whether eggs (and subsequent hatchlings) from cooler nests do better at cooler incubation temperatures, and conversely if those laid in warmer nests perform better at warmer incubation temperatures. We provided a simple nest-choice experiment, with oviposition-retreat sites available in either a hot or a cool sector of the enclosure; in the wild females nest under objects. Female O. suteri laid eggs both during the day and night, and nested more in the hot than cool sector. Eggs from each clutch were split across three egg incubation temperatures (18°C, 22°C, 26°C) to decouple the impact of initial nest-site choice from the subsequent incubation temperature regime. Whether eggs were initially laid in the hot or cool sector was not related to hatching success, offspring phenotype or offspring locomotor performance. We conclude that offspring phenotype and performance is primarily influenced by the temperature during incubation, rather than the initial thermal environment of the nest location. Thus, female O. suteri may select warmer nesting sites to ensure higher incubation temperature and enhanced offspring fitness.

Potential consequences of angling on nest-site fidelity in largemouth bass

Breeding site fidelity has evolved in many vertebrate taxa, suggesting both that site selection has an important influence on fitness potential and that the decision to reuse a nesting site is related to the individual’s prior nesting success at that location. For a species that provides parental care, such as the Largemouth Bass Micropterus salmoides, catch-and-release angling impacts individual nesting success and fitness through physiological disturbance and by removing the nest-guarding male from its brood, thereby allowing temporary access to eggs and hatchlings by brood predators. To assess the impact of catch-and-release angling on nest site fidelity, we compared the consequences of angling on individually marked (i.e., with passive integrated transponders) nest-guarding male Largemouth Bass in Ontario. An extremely high degree of nest site fidelity in year two was observed for males that were angled only once during year one (87% within 10 m of the previous year’s nest), 96.7% of which remained on the nest and completed parental care activities. There was significantly lower fidelity in year two, however, for males that were angled multiple times during year one (27% within 10m of the previous year’s nest), only 5.6% of which remained on the nest and completed parental care activities. This observed difference suggests that angling nesting bass may cause them to avoid previously used nest sites and instead search for alternative sites during future reproductive seasons. This human-induced impact on nest site choice may impact the future reproductive success of those Largemouth Bass.

Olfaction as a Cue for Nest-Site Choice in Turtles

Nest-site choice in turtles has a demonstrated impact on their fitness. Previous studies of nest-site choice have focused on environmental factors potentially affecting that choice (e.g., temperature, insolation, soil type, or moisture). Observations of nesting of painted turtles (Chrysemys picta) at the Crescent Lake National Wildlife Refuge in the Nebraska Sandhills suggest that females might use olfactory cues (specifically odors of other nesting females) to choose nest sites. We tested this hypothesis indirectly by using the nearest neighbor (nest) distance algorithm in ArcMap 10.1. Our results for nests in 2012–2014 were mixed, with nesting at some sites, in some years, and by some turtles occurring nonrandomly, in very close proximity to previous nests. Preliminary experimental data from 2015 using urine-treated sites in primary nesting areas also suggested that females showed more interest in those sites than sites moistened with equal amounts of water. These data provide some support for the use of nest odor as an important cue for nest-site choice in turtles, but they are insufficient to reject the possibility of the simultaneous use of other fine-scale environmental cues.

Nest and Colony Site Selection in Common Terns (Sterna hirundo) in Mongolia

Abstract. The biology of the Common Tern (Sterna hirundo) has been studied on several continents, but information from central Asia is limited. Colony characteristics and nest site selection of Common Terns were studied in the desert and steppe of Mongolia to determine factors that influence their choices. Common Terns nested in marshy areas around small ponds, on sand bars adjacent to a lake in the Gobi, and on small islands in a water treatment plant in the steppe of Ulaanbaatar. In the Gobi, they nested with Pied Avocets (Recurvirostra avosetta) that defended the colony site, while the terns left. Common Terns selected colony sites surrounded by water and muck/ mud, and nest sites with good visibility. Their choice of colony and nest sites seemed to be a compromise between avoiding flooding, avoiding nest trampling by livestock, and finding any safe nesting place to avoid terrestrial predators.

Nest site choice: a potential pathway linking personality and reproductive success

Animal personality has been linked to individual fitness across many taxa. However, the exact path by which personality translates into fitness is rarely identified. We tested whether nest site choice may serve as a potential pathway linking personality and reproductive success in a natural population of chestnut thrush, Turdus rubrocanus. Using path analysis, we found that human disturbance and choice of nest site with respect to nest density may both mediate the link between personality and reproductive success. Bolder females may choose nest sites with lower nest density, and the low nest density in turn may be responsible for a positive effect on nestling number, and have a negative effect on nestling mass. Bolder females may also prefer nest sites further from human settlements, resulting in a negative effect on nestling mass. Our findings provide rare exact mechanistic pathways by which boldness might be translated into reproductive success.

Considering Spatial Scale and Reproductive Consequences of Habitat Selection when Managing Grasslands for a Threatened Species.

Habitat selection that has fitness consequences has important implications for conservation activities. For example, habitat characteristics that influence nest success in birds can be manipulated to improve habitat quality with the goal of ultimately improving reproductive success. We examined habitat selection by the threatened streaked horned lark (Eremophila alpestris strigata) at both the breeding-site (territory) and nest-site scales. Larks were selective at both spatial scales but with contrasting selection. At the territory scale, male larks selected sparsely vegetated grasslands with relatively short vegetation. At the nest-site scale, female larks selected sites within territories with higher vegetation density and more perennial forbs. These nest-site scale choices had reproductive consequences, with greater nest success in areas with higher densities of perennial forbs. We experimentally manipulated lark habitat structure in an attempt to mimic the habitat conditions selected by larks by using late summer prescribed fires. After the burn, changes in vegetation structure were in the direction preferred by larks but habitat effects attenuated by the following year. Our results highlight the importance of evaluating habitat selection at spatial scales appropriate to the species of interest, especially when attempting to improve habitat quality for rare and declining species. They also highlight the importance of conducting restoration activities in a research context. For example, because the sparsely vegetated conditions created by fire attenuate, there may be value in examining more frequent burns or hotter fires as the next management and research action. We hope the design outlined in this study will serve as an integrated research and management example for conserving grassland birds generally.

Nest-site Choice and Nest Construction in Non-avian Reptiles: Evolutionary Significance and Ecological Implications

In oviparous animals, nest-site choice is both a critical determinant of an individual's lifetime fitness, and an important demographic parameter of populations. At the individual level, the location and characteristics of a nest site impact survival of both the nesting female and the nestling or hatchling stage, and can also influence offspring phenotype and the survival of emerging juveniles. At the population level, survival rates of females and offspring, and phenotypes affected by incubation conditions, affect population trends. Reptiles differ from birds in several key life-history traits associated with nesting behaviour in that they have long incubation periods, bury eggs within a substrate, and have minimal parental care. However, studies in reptile systems have also demonstrated several evolutionary drivers of nest-site choice that are also likely to be important in avian systems. These include the role of incubation conditions in affecting offspring phenotype, and the contribution of nest-site choice to survival of the juvenile life stage. Overall, studies on the evolution and ecology of nest-site choice in reptiles and birds have much to offer each other in terms of both theoretical basis and applications to conservation and management. Incorporating knowledge gained from a range of taxa into our research, and testing hypotheses in one system that have demonstrated importance in other systems, will provide a richer understanding of the ecology and evolution of nest-site choice.