Nest-site Choice Research Articles

The use and relative importance of intraspecific and interspecific social information in a bird community

Lay Summary Information from conspecifics outweighs other information sources for collared flycatchers making their nest site choices late in the spring. Collared flycatchers copy the nest site characteristics apparently chosen by earlier settled flycatchers and competing tits. When the apparent decisions of the fellow flycatchers and competing tits are in conflict, flycatchers copy conspecifics when conspecifics outnumber the competitors, which is the case late in the spring.

Variation in clutch size in relation to nest size in birds.

Nests are structures built to support and protect eggs and/or offspring from predators, parasites, and adverse weather conditions. Nests are mainly constructed prior to egg laying, meaning that parent birds must make decisions about nest site choice and nest building behavior before the start of egg-laying. Parent birds should be selected to choose nest sites and to build optimally sized nests, yet our current understanding of clutch size-nest size relationships is limited to small-scale studies performed over short time periods. Here, we quantified the relationship between clutch size and nest size, using an exhaustive database of 116 slope estimates based on 17,472 nests of 21 species of hole and non-hole-nesting birds. There was a significant, positive relationship between clutch size and the base area of the nest box or the nest, and this relationship did not differ significantly between open nesting and hole-nesting species. The slope of the relationship showed significant intraspecific and interspecific heterogeneity among four species of secondary hole-nesting species, but also among all 116 slope estimates. The estimated relationship between clutch size and nest box base area in study sites with more than a single size of nest box was not significantly different from the relationship using studies with only a single size of nest box. The slope of the relationship between clutch size and nest base area in different species of birds was significantly negatively related to minimum base area, and less so to maximum base area in a given study. These findings are consistent with the hypothesis that bird species have a general reaction norm reflecting the relationship between nest size and clutch size. Further, they suggest that scientists may influence the clutch size decisions of hole-nesting birds through the provisioning of nest boxes of varying sizes.

Nesting and neonates of the yellow-spotted river turtle (Podocnemis unifilis, Podocnemididae) in the Araguari River basin, eastern Amazon, Brazil

Predation and alteration of microhabitats may represent high risk for nesting of Amazonian turtles. This study aimed at investigating the nesting and body parameters of neonates of Podocnemis unifilis in the Araguari River basin, State of Amapá, Brazil. The spawning sites of this turtle were monitored along the Falsino River (a region with two reserves) and in the urban area of the Porto Grande city along the Araguari River, from August to December 2011. A total of 180 nests were found and the nesting occurred from September to November, with prevalence in October. Eggs hatching occurred in December. The mean incubation period was 63.5 ± 5.2 days and the eggs hatching success was 25%. However, approximately 80% of the nests had suffered predation mainly by humans, which occurred in both the protected areas of the reserves and the urban area. The pattern of nesting site choice was discussed. Egg size was larger than that previously described for the same turtle species in the other regions. The body condition index of neonates indicated a good use of vitelline reserves. The results indicate the urgent need for strategic actions to conserve and maintain the natural stocks of this relatively vulnerable turtle in the region.

Cryptic and Complex Nesting in the Yellow-Spotted Monitor,Varanus panoptes

Abstract Despite the general importance of nest site choice in reproductive success in taxa with little or no parental care, little is known for reptiles other than turtles. Here we report on the nesting ecology of the Yellow-Spotted Monitor, Varanus panoptes, a large tropical lizard that utilizes warrens (concentrated groups of burrows) in northern Australia. We used radio-telemetry, remote photography, and the complete excavation of a warren to test the hypotheses that 1) warrens are used by multiple individual V. panoptes; and if so, 2) they are used for communal nesting; or alternatively 3) they are used for communal estivation during the dry season. At least six individual V. panoptes utilized the warren system including four females and two males, and burrows were excavated by both sexes. Excavation of the warren revealed no estivating lizards at a time when four radio-telemetered V. panoptes had begun estivation. However, we found two nests in the warren, indicative of either communal nesting or mu...

Nest site characteristics and breeding success of the red-backed shrike (Lanius collurio) in agricultural landscape in eastern Poland: Advantage of nesting close to buildings

One of the most important factors influencing breeding success in many bird species is predation. Nest site choice is one way of lowering the probability of such losses. In an agricultural landscape of eastern Poland, we examined the relationship between red-backed shrike (Lanius collurio) nest site characteristics, i.e., height above ground, concealment, and occurrence of thorns, and the risk of nest predation. We also considered the relationship with distance to potential predators, i.e., corvid nests, and the distance to buildings. Our results showed that only 1 environmental factor significantly influenced breeding success. Birds nesting closer to buildings achieved higher breeding success than those more distant from buildings. A positive correlation between date of first egg laying and distance from the nest to the buildings was also found. These results indicate that areas with human activities and buildings can created habitats that improve breeding success for some species. On the other hand, the growth of such habitats also contributes to decreasing availability of semi-natural areas for breeding and foraging for these species.

Breeding biology and reproductive success of the Spectacled Tetraka Xanthomixis zosterops (Bernieridae) in a rainforest of Madagascar

The Spectacled Tetraka Xanthomixis zosterops is a sexually monomorphic species in a family (Bernieridae) endemic to Madagascar and is found in various humid forest types. It is categorised as Least Concern by the IUCN. Despite its commonness, the biology of this species is little known. This study focused on its breeding biology and took place from September to December 2010 at Talatakely, Ranomafana National Park, Madagascar. Thirty nests were monitored and incubating birds were marked. Direct observations were made associated with nest building, incubating and nestling periods. Habitat structure was assessed to detect nesting site choice. The breeding episode, from the nest-building stage to fledging of the last chick, lasted on average 45 d. Only one individual, probably the female, in each presumed pair incubated eggs and brooded hatchlings, whereas both parents fed and cared for the nestlings. The mean clutch size was 2.4 ± 0.2 egg per nest (range 1–3, n = 24), the incubation period averaged 17.7 ± 0.3 d (range 16–19, n = 10), and the nestling period averaged 14.7 ± 0.3 d (range 14–15, n = 3). We estimated the reproductive success to be 13.6% (n = 59 eggs). Nest predation was believed to be the primary cause of nesting failure with 24 eggs (40.7%) and 18 (64.3%) nestlings being predated.

Population sex ratios under differing local climates in a reptile with environmental sex determination

Populations that experience different local climates, such as those along a latitudinal gradient, must match life history traits to local environmental conditions. In species with temperature-dependent sex determination, such as many reptiles, population sex ratio is strongly influenced by local climate, yet local climate differs substantially among populations in geographically-widespread species. We studied the painted turtle at three sites across the species' geographic range to gain a mechanistic understanding of how sex ratios are produced under different local climates. We combined data on maternal nest- site choice, nest incubation temperature, and the resultant offspring sex ratio of populations across a climatic gradient, to demonstrate how geographic variation in behavior and physiology translates into sex ratios among populations of a widely-distributed species. We found that populations across the species' geographic range match incubation conditions with local climatic conditions through population-specific adjustment of maternal nest-site choice. Incubation temperatures during the thermosensitive period were cooler and clut- ches were more male-biased in the south, with populations farther north having warmer

Equal reproductive success of phenotypes in the Larus glaucescens–occidentalis complex

Glaucous‐winged gulls Larus glaucescens and western gulls L. occidentalis hybridize extensively where their ranges overlap along the coasts of Washington and Oregon, producing a continuum of phenotypic intergrades between the two parental species. This zone often is considered an example of geographically bounded hybrid superiority, but studies of relative success among parental types and hybrids have not provided consistent support for this model. We tested the predictions of the dynamic‐equilibrium and geographically bounded hybrid superiority hypotheses by studying mate choice and reproductive success among gulls on Protection Island, Washington, the largest breeding colony of glaucous‐winged/western gulls within the hybrid zone. The dynamic‐equilibrium hypothesis posits that hybridization due to dispersal balances selection against less fit hybrids and assortative mating is adaptive. Geographically bounded hybrid superiority posits that hybrids are better fit than parental types within an ecotone between the environments to which the parental species are adapted, and a preference for hybrid mates is adaptive. Additionally, we investigated whether hatching success and nest site choice are correlated for Protection Island gulls. We assigned a hybrid index to each sample bird by examining plumage melanism and bare part coloration in the field. Sheltered nests contained larger clutches and exhibited increased hatching success, but choice of nest habitat was not associated with hybrid index. Western gull‐like pairs produced smaller third eggs; however, hybrid index was not correlated with clutch size or hatching success. Protection Island gulls did exhibit assortative mating. In short, we did not find strong support for either geographically bounded hybrid superiority or the dynamic‐equilibrium hypothesis.

Retirement investment theory explains patterns in songbird nest-site choice

When opposing evolutionary selection pressures act on a behavioural trait, the result is often stabilizing selection for an intermediate optimal phenotype, with deviations from the predicted optimum attributed to tracking a moving target, development of behavioural syndromes or shifts in riskiness over an individual's lifetime. We investigated nest-site choice by female golden-winged warblers, and the selection pressures acting on that choice by two fitness components, nest success and fledgling survival. We observed strong and consistent opposing selection pressures on nest-site choice for maximizing these two fitness components, and an abrupt, within-season switch in the fitness component birds prioritize via nest-site choice, dependent on the time remaining for additional nesting attempts. We found that females consistently deviated from the predicted optimal behaviour when choosing nest sites because they can make multiple attempts at one fitness component, nest success, but only one attempt at the subsequent component, fledgling survival. Our results demonstrate a unique natural strategy for balancing opposing selection pressures to maximize total fitness. This time-dependent switch from high to low risk tolerance in nest-site choice maximizes songbird fitness in the same way a well-timed switch in human investor risk tolerance can maximize one's nest egg at retirement. Our results also provide strong evidence for the adaptive nature of songbird nest-site choice, which we suggest has been elusive primarily due to a lack of consideration for fledgling survival.

Breeding ecology and behaviour of the Great Reed Warbler, Acrocephalus arundinaceus, in Poyrazlar Lake, Turkey

In this study, the breeding ecology and behaviour of the Great Reed Warbler, Acrocephalus arundinaceus, was studied at Poyrazlar Lake, Turkey. The breeding period started in the first week of May. The incubation period lasted 14 days. As clutch size increased, the diameter of the nests became larger (r = 0.65). Diameters of nests containing different clutch sizes varied significantly from one another (P < 0.01). However, their height did not change (r = 0.24). There was no significant height difference between nests containing different clutch sizes (P > 0.05). As the nests became farther from the shore, the clutch size and the egg weight increased, because mature adults built their nests on the reeds in deeper areas (r = 0.59, r = 0.73). On the other hand, young breeders showed no location preference in their choice of nest site. The number of the nests showed a positive correlation with the height of reeds (r = 0.80). In all nests, 4 different behaviours (Nest Empty, Sitting, Edge of Nest Waiting, Feeding Nestlings) were observed from the appearance of the first egg until the female left the nest. On average, a given female spent 38.11% of her time away from the nest, 51.84% of her time in incubation, 0.91% of her time around the nest, and 9.24% feeding her nestlings per day.

Does sex-ratio selection influence nest-site choice in a reptile with temperature-dependent sex determination?

Evolutionary theory predicts that dioecious species should produce a balanced primary sex ratio maintained by frequency-dependent selection. Organisms with environmental sex determination, however, are vulnerable to maladaptive sex ratios, because environmental conditions vary spatio-temporally. For reptiles with temperature-dependent sex determination, nest-site choice is a behavioural maternal effect that could respond to sex-ratio selection, as mothers could adjust offspring sex ratios by choosing nest sites that will have particular thermal properties. This theoretical prediction has generated decades of empirical research, yet convincing evidence that sex-ratio selection is influencing nesting behaviours remains absent. Here, we provide the first experimental evidence from nature that sex-ratio selection, rather than only viability selection, is probably an important component of nest-site choice in a reptile with temperature-dependent sex determination. We compare painted turtle (Chrysemys picta) neonates from maternally selected nest sites with those from randomly selected nest sites, observing no substantive difference in hatching success or survival, but finding a profound difference in offspring sex ratio in the direction expected based on historical records. Additionally, we leverage long-term data to reconstruct our sex ratio results had the experiment been repeated in multiple years. As predicted by theory, our results suggest that sex-ratio selection has shaped nesting behaviour in ways likely to enhance maternal fitness.

Do small swarms have an advantage when house hunting? The effect of swarm size on nest-site selection by Apis mellifera

Reproductive swarms of honeybees are faced with the problem of finding a good site to establish a new colony. We examined the potential effects of swarm size on the quality of nest-site choice through a combination of modelling and field experiments. We used an individual-based model to examine the effects of swarm size on decision accuracy under the assumption that the number of bees actively involved in the decision-making process (scouts) is an increasing function of swarm size. We found that the ability of a swarm to choose the best of two nest sites decreases as swarm size increases when there is some time-lag between discovering the sites, consistent with Janson & Beekman (Janson & Beekman 2007 Proceedings of European Conference on Complex Systems, pp. 204-211.). However, when simulated swarms were faced with a realistic problem of choosing between many nest sites discoverable at all times, larger swarms were more accurate in their decisions than smaller swarms owing to their ability to discover nest sites more rapidly. Our experimental fieldwork showed that large swarms invest a larger number of scouts into the decision-making process than smaller swarms. Preliminary analysis of waggle dances from experimental swarms also suggested that large swarms could indeed discover and advertise nest sites at a faster rate than small swarms.

Patterns of Nesting Migrations in the Tuatara (Sphenodon punctatus), A Colonially Nesting Island Reptile

The costs of nesting to female animals can be substantial, and may dictate patterns of nest-site choice. In particular, females that travel longer distances to nest likely incur greater energetic costs and may be at greater risk of losing territories to conspecific competitors. We examined patterns of nesting migrations for a population of Tuatara on Stephens Island, New Zealand, over 5 yr. We found that only about 7% of female Tuatara observed nesting in a rookery also lived in that rookery. Of 140 females for which we had both residence and nesting locations, 42% traveled to a nesting rookery from their residential area. The average distance traveled by these females was 84 m, and travel was directed toward the rookery closest to a female's residence area. Our results demonstrate that female Tuatara on Stephens Island minimize the distance traveled on nesting migrations. We suggest that the patterns in nesting travel we observed in this population may be due to natal philopatry of nesting females, or to females minimizing the costs of nesting-related travel.

Nest site preference and intrasexual competition in female sockeye salmon, Oncorhynchus nerka

Many ecological circumstances present individuals with a conflict between the inherent benefits of a particular habitat and the costs incurred in acquiring or retaining use of the habitat in the face of competition. For example, the reproductive biology of female Pacific salmon (Oncorhynchus spp.) led us to hypothesize that female nest site choice should reflect a compromise between the benefits of obtaining a high quality nest site and the cost of competing for and defending it. To test this hypothesis we studied female sockeye salmon (O. nerka) spawning on beaches in Iliamna Lake, Alaska using a combination of snorkel surveys, tagging, behavior observations, and models. Females showed spatial preferences in nest site selection (for shallower water, where water circulation was higher), aggressive competition in preferred areas was higher, and there was evidence for costs associated with this increased competition. Over the course of the season, spawning activity shifted from shallower to deeper water, consistent with a tradeoff between benefits for embryo survival associated with shallow sites and the costs of competing for them. However, it was also consistent with date-specific optimal sites related to the probability of embryo mortality for eggs spawned in shallow water late in the season, due to annual cycles in lake level and temperature.

Nest-seeking rock ants (Temnothorax albipennis) trade off sediment packing density and structural integrity for ease of cavity excavation

We investigated excavation and nest site choice across sediment-filled cavities in the ant Temnothorax albipennis. Colonies were presented with sediment-filled cavities, covering a spectrum from ones that should be quick to excavate but will form a weak enclosing wall to those that should be slow to excavate but form a strong wall. Overall, colonies only showed a significant preference for cavities that were fastest to excavate over those that were slowest. The speed of decision making and moving appears paramount over the suitability of the sediment for forming an enclosing wall. The mechanism behind the choice is the differential between the rates at which alternatives are excavated and accumulate ants. The rates for a particular type of cavity were unaffected by the type with which it was paired. This suggests that there is no significant competition between sites during the decision-making process. Certain colonies were able consistently to discriminate across more closely matched alternatives. These colonies required a greater number of ants to be present and took longer before beginning to move. A race is run between alternatives to become habitable but the process may be tuned across colonies such that it may run for longer and an incorrect or split decision is less likely.

Nest site characteristics and nesting success of the Western Burrowing Owl in the eastern Mojave Desert

We evaluated nest site selection at two spatial scales (microsite, territory) and reproductive success of Western Burrowing Owls (Athene cunicularia hypugaea) at three spatial scales (microsite, territory, landscape) in the eastern Mojave Desert. We used binary logistic regression within an information-theoretic approach to assess factors influencing nest site choice and nesting success. Microsite-scale variables favored by owls included burrows excavated by desert tortoise (Gopherus agassizii), burrows with a large mound of excavated soil at the entrance, and a greater number of satellite burrows within 5 m of the nest burrow. At the territory scale, owls preferred patches with greater cover of creosote bush (Larrea tridentata) within 50 m of the nest burrow. An interaction between the presence or absence of a calcic soil horizon layer over the top of the burrow (microsite) and the number of burrows within 50 m (territory) influenced nest site choice. Nesting success was influenced by a greater number of burrows within 5 m of the nest burrow. Total cool season precipitation was a predictor of nesting success at the landscape scale. Conservation strategies can rely on management of habitat for favored and productive nesting sites for this declining species.

The factor of adapatability of two kinds of crows to urban environment thtough nest site choices

The factor of adapatability of two kinds of crows to urban environment thtough nest site choices

Does shade cover availability limit nest-site choice in two populations of a turtle with temperature-dependent sex determination?

Shifts in resource use may be an important mechanism by which organisms can adjust to novel environmental conditions, such as those imposed by climate change. However, for such shifts to be possible, environmental space must exist into which organisms can move. Habitat that ensures successful survival and reproduction is one such critical resource. We studied resource selection of shade cover over nest sites by painted turtles in populations in Illinois (center of range) and New Mexico (southern edge of range). We targeted this habitat feature because shade can influence hatching success and offspring phenotype (including sex in the study species) by affecting nest microenvironments. We found that while turtles in both populations selected nest sites that were shadier than average available sites, overall resource selection differed between the populations. This disparity may have been due to differences in structure of vegetation that provides shade at each site, because areas with high shade cover in New Mexico (low dense thickets) were much more difficult for turtles to access than those in Illinois (dense tree canopy cover). Further, shade cover predicted different parameters of incubation regime at each site, suggesting that turtles must assess dissimilar components of shade cover in order to choose nest sites and predict their future incubation regimes. Our results suggest that shade cover within nesting areas is a key component of painted turtle habitat, and that accessible, highly-shaded nest sites may be limited at the New Mexico site. Maintaining a range of shade cover from which turtles can select nest sites would permit plasticity in nest-site choice to be expressed, which may be important in preventing sex ratio skews due to climate change.

Phenotypic and fitness consequences of maternal nest‐site choice across multiple early life stages

Identifying the relative contributions of genetic, maternal, and environmental factors to phenotypic variation is critical for evaluating the evolutionary potential of fitness-related traits. We employed a novel two-step cross-fostering experiment to quantify the relative contributions of clutch (i.e., maternal identity) and maternally chosen nest sites to phenotypic variation during three early life stages (incubation, hibernation, dispersal) of the painted turtle (Chrysemys picta). By translocating eggs between nests in the field, we demonstrated that both clutch and nest site contribute to phenotypic variation at hatching. Because hatchling C. picta hibernate inside nests, we performed a second cross-foster to decouple the effects of the incubation nest with that of the hibernation nest. Incubation nest explained little variation in phenotypes at spring emergence, but winter nest site was important. We found no evidence that mothers select nest sites specific to reaction norms of their own offspring, suggesting that females may select nest sites with microhabitats that broadly meet similar requirements across the population. After hibernation, we released hatchlings to assess performance and phenotypic selection during dispersal. Hibernation nest site influenced physiological performance during dispersal, and we detected nonlinear selection on hatchling carapace length. Our experiment demonstrates that nest-site choice has substantial effects on phenotypic variation and fitness across multiple early life stages.

Vertical and horizontal transmission of nest site preferences in titmice

Social learning is widely used among vertebrates to acquire information about a variable environment. We conducted a study of social learning in the wild which involved cross-fostering eggs of blue tits, Cyanistes caeruleus, to nests of great tits, Parus major, and vice versa. This allowed us to quantify the consequences of being reared in a different social context but in an environment otherwise natural to the birds. We studied choice of nest site by offering to the local recruits either a small or a large nestbox. Most blue tits bred in small nestboxes, whereas most great tits used the large boxes. Size of the natal nestbox affected subsequent box choice. In addition, in blue tits, more cross-fostered birds than controls nested in large nestboxes, with an opposite result for cross-fostered great tits. Apparently, as a consequence of sexual misimprinting on their foster parents, the cross-fostered young used members of the foster species as models for subsequent nest site choice. Such social copying may apply broadly to other types of behaviours and not only to the choice of nest site. This study demonstrates both vertical and horizontal transmission of nest site preference of two vertebrates in the wild. Future studies should try to find out how animals balance the use of personal experience with the information socially acquired.