scholarly journals Nesting in close quarters: Causes and benefits of high-density nesting behaviour in Painted Turtles

Author(s):  
S.J. Kell ◽  
N. Rollinson ◽  
R.J. Brooks ◽  
Jacqueline Litzgus

Many oviparous reptiles nest in aggregations and with temporal synchrony. We hypothesized that these traits reflect attraction by conspecifics rather than limiting suitable habitat. We quantified whether Painted Turtles (Chrysemys picta (Schneider, 1783)) in Algonquin Park, Ontario, were nesting communally, identified cues females used to select nest sites, and tested whether hatching success was higher in spatially-clustered nests. We found that nests were closer to one another than expected by chance (i.e., were clustered), but that individual nest site selection was only weakly influenced by micro-habitat characteristics. Survival of clustered nests (49%) was not significantly higher than that of solitary nests (39%). When turtle models were placed on the nesting embankment, females nested most often with the highest density of models. Given that reproductive lifespan is the major axis of fitness and that there was little benefit to nest survival in clustered nests, we suggest that clustering is related to females cueing to conspecific nests to expedite the nesting process and gain a good-quality nest site (chosen by the first nesting female in the cluster) while investing little energy in nest-site selection. This strategy may reduce time spent on land, thereby minimizing chances of dehydration, temperature stress, and adult depredation.

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9892
Author(s):  
Rocío Fernanda Jara ◽  
Ramiro Daniel Crego ◽  
Michael David Samuel ◽  
Ricardo Rozzi ◽  
Jaime Enrique Jiménez

Background Birds can maximize their reproductive success through careful selection of nest-sites. The ‘total-foliage’ hypothesis predicts that nests concealed in vegetation should have higher survival. We propose an additional hypothesis, the ‘predator proximity’ hypothesis, which states that nests placed farther from predators would have higher survival. We examined these hypotheses in the world’s southernmost forests of Navarino Island, in the Cape Horn Biosphere reserve, Chile (55°S). This island has been free of mammalian ground predators until recently, and forest passerines have been subject to depredation only by diurnal and nocturnal raptors. Methods During three breeding seasons (2014–2017), we monitored 104 nests for the five most abundant open-cup forest-dwelling passerines (Elaenia albiceps, Zonotrichia capensis, Phrygilus patagonicus, Turdus falcklandii, and Anairetes parulus). We identified nest predators using camera traps and assessed whether habitat characteristics affected nest-site selection and survival. Results Nest predation was the main cause of nest failure (71% of failed nests). Milvago chimango was the most common predator, depredating 13 (87%) of the 15 nests where we could identify a predator. By contrast, the recently introduced mammal Neovison vison, the only ground predator, depredated one nest (7%). Species selected nest-sites with more understory cover and taller understory, which according to the total-foliage hypothesis would provide more concealment against both avian and mammal predators. However, these variables negatively influenced nest survival. The apparent disconnect between selecting nest-sites to avoid predation and the actual risk of predation could be due to recent changes in the predator assemblage driven by an increased abundance of native M. chimango associated with urban development, and/or the introduction of exotic mammalian ground predators to this island. These predator assemblage changes could have resulted in an ecological trap. Further research will be needed to assess hypotheses that could explain this mismatch between nest-site selection and nest survival.


2012 ◽  
Vol 90 (10) ◽  
pp. 1215-1220 ◽  
Author(s):  
C.A. Peet-Paré ◽  
G. Blouin-Demers

Nest-site selection is an important behaviour in oviparous reptiles because incubation conditions affect offspring phenotype, with favourable conditions leading to higher offspring fitness. We aimed to identify the habitat characteristics involved in nest-site selection in Eastern Hog-nosed Snakes ( Heterodon platirhinos Latreille, 1801) and to determine whether females select nest sites that result in offspring with phenotypes likely to improve fitness. We compared the habitat characteristics and temperature profiles of 21 nests with 21 randomly selected sites. Eastern Hog-nosed Snakes selected open, grassy sites with less herbs and shrubs than random sites, and nests were significantly warmer than random sites during the 2 years of the study. In the second year of the study, we incubated 215 eggs from eight nests in a split-clutch design at mean nest (24 °C) and random site (22 °C) temperatures approximating those of the first year of the study. Eggs incubated at 24 °C resulted in neonates that hatched earlier, had fewer scale anomalies, were larger, and swam faster than neonates from eggs incubated at 22 °C. Our results indicate that Eastern Hog-nosed Snakes select nest sites that lead to offspring with phenotypes likely to improve fitness.


1997 ◽  
Vol 75 (11) ◽  
pp. 1835-1844 ◽  
Author(s):  
Stanislav Pribil ◽  
Jaroslav Picman

Nest-site preferences of birds have traditionally been inferred from correlations between reproductive success and various habitat attributes. Because there are several problems associated with this method, we examined preferences by comparing characteristics of actual nest sites with those of sites available to females at the time of their settlement. We examined these preferences on two spatial scales using the marsh-nesting Red-winged Blackbird (Agelaius phoeniceus). On the broad spatial scale, univariate analyses established that female settlement was nonrandom with respect to four of five habitat characteristics. However, a multivariate analysis revealed that females settled nonrandomly only with respect to water depth (they preferred areas located in deep water). The other characteristics, including cattail density, were not important. On the narrow spatial scale, females preferred sites located in dense cattail clumps that were surrounded by unusually sparse cattail vegetation. The preference of female redwings for deep-water areas was not detected in an earlier study conducted in the same marsh using the traditional method. In addition, if we were to have examined female preferences on the broad scale only, we would have failed to recognize the importance of cattail density in nest-site selection. The results of this study demonstrate the importance of examining nest-site selection using an appropriate method and multiple spatial scales.


2006 ◽  
Vol 84 (11) ◽  
pp. 1545-1554 ◽  
Author(s):  
E.J. Hughes ◽  
R.J. Brooks

We tested the hypothesis that female midland painted turtles ( Chrysemys picta marginata Agassiz, 1857) provide significant parental care to their offspring through their choice of nest site. Painted turtle nest sites can be described in relation to specific microhabitat characteristics that, because of their effects on soil microclimate, may influence survival to hatch. We created models of the relationships between nest-site microhabitat and nest-site selection and between nest-site microhabitat and survival to hatch, and judged the fit of the models using Akaike’s information criterion corrected for small sample sizes. Female painted turtles selected nest sites with little canopy cover, little understory vegetation, and a southwestern slope aspect. Increased survival to hatch was associated with decreased organic content, which may serve as a surrogate for little or no vegetation or canopy cover. Nests in sites selected by turtles had slightly higher survival to hatch rates than nests in randomly chosen sites, suggesting that turtles may choose nest sites which increase offspring survival. Selection of nest sites may constitute significant parental investment and should be considered in studies of turtle life history.


2019 ◽  
Vol 129 (2) ◽  
pp. 388-397
Author(s):  
Benjamin J Muller ◽  
Robin M Andrews ◽  
Lin Schwarzkopf ◽  
David A Pike

Abstract Microhabitat orientation and structure and the presence of conspecifics may strongly influence the choice of habitat. We studied how these variables influence retreat- and nest-site selection in gravid females of a globally successful invasive species, the Asian house gecko (Hemidactylus frenatus). When provided with various substrates (vertical and horizontal ceramic tiles, vertical and horizontal plywood tiles, horizontal bark over leaf litter, vertical bark over a log, and sand) gravid female geckos preferred to retreat to, and nest in, materials with crevices commonly found in urban habitats. When housed alone, gravid females most frequently retreated to vertical ceramic tile or wooden crevices, and 66.7% nested in vertical ceramic tiles. When housed with two other conspecifics, gravid females most frequently retreated to vertical ceramic tiles, but selected a wider range of nest sites. Overall, gravid geckos housed alone typically nested in the same substrates that they used as diurnal retreats; when housed in groups, however, females oviposited in locations different from those they selected as retreats. Thus, H. frenatus females use a wider range of substrates when conspecifics are present. Invasion success in this species might be driven, in part, by preferences for retreat and nest substrates that are common in human-dominated habitats.


The Condor ◽  
2005 ◽  
Vol 107 (4) ◽  
pp. 849-862 ◽  
Author(s):  
Carina Gjerdrum ◽  
Chris S. Elphick ◽  
Margaret Rubega

Abstract We examined nest-site selection and nesting success in Saltmarsh Sharp-tailed (Ammodramus caudacutus) and Seaside Sparrows (A. maritimus), at seven sites in Connecticut. We found 160 Saltmarsh Sharp-tailed Sparrow nests and 23 Seaside Sparrow nests, and compared characteristics of their locations to each other and to random locations. We tracked success of all nests, quantified nest productivity and causes of nest losses, and tested for habitat differences between successful and unsuccessful nests. Saltmarsh Sharp-tailed Sparrows nested in higher than average locations, where the vegetation was taller and more dense than at random locations, where there was a deep layer of thatch, and where saltmeadow cordgrass (Spartina patens) dominated the vegetation. There was little evidence that habitat characteristics influenced the success of nesting birds, but the timing of nest initiation relative to spring tides was important. Seaside Sparrow nests occurred in even taller vegetation, that was more sparse than average and dominated by the tall form of smooth cordgrass (S. alterniflora). Habitat influenced the success of Seaside Sparrow nests, but timing did not; on average, successful nests occurred in taller vegetation. Model comparisons suggest that vegetation structure influences site selection more than species composition or inherent differences among marshes. Overall, our results indicate that nest flooding is a major threat to successful reproduction in both species, but they have different strategies to avoid flooding. Saltmarsh Sharp-tailed Sparrows time their reproduction to avoid especially high tides, while Seaside Sparrows avoid flooding spatially by nesting in tall vegetation.


2006 ◽  
Vol 84 (11) ◽  
pp. 1533-1539 ◽  
Author(s):  
Rebecca Jo Safran

Despite hundreds of studies, we know very little about the causes and fitness-related consequences of nest-site selection. For example, it is not typically known whether the rarely reported fitness consequences of site selection are the result of nest, individual, or nest-site variables or combinations of these factors. Reuse of previously constructed nest sites is a prevalent behavior in many animals and offers the opportunity to experimentally tease apart whether seasonal reproductive success is a function of nest, individual, or nest-site characteristics. I used observational and experimental data to test three hypotheses related to these factors in association with barn swallow ( Hirundo rustica L., 1758) nest reuse. While both nest and individual characteristics explain variation in seasonal reproductive success, nest location per se is not an important factor defining the outcome of nest-site selection. Whereas traits related to habitat and individual characteristics are likely confounded in correlational studies, my experiments demonstrate a causal relationship between seasonal reproductive success and aspects of the nest and individual, the latter explaining more variation in the model than nest characteristics. Knowledge of the relative roles of individual, nest, and nest-site attributes are important for understanding the causes and consequences of habitat selection behavior.


The Condor ◽  
2002 ◽  
Vol 104 (3) ◽  
pp. 507-517 ◽  
Author(s):  
Joseph R. Liebezeit ◽  
T. Luke George

AbstractAmong hypotheses explaining nest-site selection, the potential-prey-site hypothesis predicts that birds place nests in areas with many potential nest sites, while the nest-concealment hypothesis predicts nest placement in sites with greater surrounding vegetation. We examined these hypotheses by comparing habitat attributes between Dusky Flycatcher (Empidonax oberholseri) nest sites and random sites, successful and unsuccessful nests, and nests depredated by birds versus mammals. Nesting success was 28% (n = 167), and predation was the most important cause of nest failure (96%) during the study (1998–2000) at our site in northeastern California. We identified 28 nest predators using surveillance cameras. Sciurid mammals were the most common predators (17 of 28, 61%), with Cooper's Hawks (Accipiter cooperii; 25%), small owls (11%), and Steller's Jays (Cyanocitta stelleri; 3%) accounting for the rest. Raptors preyed on nestlings more frequently than on eggs, while small mammals depredated nestlings and eggs in proportion to their availability. Dusky Flycatchers nested in larger shrub patches with greater shrub cover than at random sites, supporting the potential-prey-site hypothesis. Successful nests were in larger shrub patches surrounded by fewer seedlings and saplings compared to depredated nests, providing equivocal support for the potential-prey-site hypothesis. Nests depredated by birds were less concealed, located in smaller shrub patches, surrounded by fewer seedlings and saplings, and were closer to the shrub edge than nests depredated by mammals. Our results, strengthened by identification of nest predators, suggest that differences in search strategies among predators may constrain the ability of Dusky Flycatchers to optimize nest-site selection.Depredadores de Nidos, Selección de Sitios de Anidación y Éxito de Anidación de Empidonax oberholseri en un Bosque Manejado de Pino PonderosaResumen. Entre las hipótesis que explican la selección de sitios de anidación, la de “presa potencial” predice que las aves ubican sus nidos en lugares con muchos sitios de anidación, mientras que la de “ocultación del nido” predice la ubicación de nidos en sitios con mayor vegetación circundante. Nosotros examinamos estas hipótesis comparando características del hábitat entre sitios de anidación del mosquerito Empidonax oberholseri y sitios aleatorios, entre nidos exitosos y no exitosos, y entre nidos depredados por aves y por mamíferos. Entre 1998 y 2000 en un área del noreste de California, el éxito de anidación fue del 28% (n = 167) y la depredación fue la causa más importante del fracaso de los nidos (96%). Identificamos 28 depredadores de nidos utilizando cámaras. Los mamíferos sciúridos fueron los depredadores más comunes (17 de 28, 61%), mientras que los demás nidos fueron depredados por Accipter cooperii (25%), búhos pequeños (11%) y Cyanocitta stelleri (3%). Las aves rapaces se alimentaron con mayor frecuencia de pichones que de huevos, mientras que los mamíferos pequeños depredaron pichones y huevos en proporción a su disponibilidad. Los mosqueritos anidaron en parches con mayor cobertura de arbustos que sitios aleatorios, lo cual apoya la hipótesis de presa potencial. Los nidos exitosos se ubicaron en parches de arbustos más grandes rodeados por menos plántulas y renovales en comparación con los nidos depredados, lo que apoya equívocamente la hipótesis de presa potencial. Los nidos depredados por aves estuvieron menos ocultos, ubicados en parches de arbustos más pequeños, rodeados por menos plántulas y renovales, y estuvieron más cerca del borde del matorral que los nidos depredados por mamíferos. Nuestros resultados, fortalecidos por la identificación de los depredadores, sugieren que las diferencias en las estrategias de búsqueda entre depredadores pueden limitar la habilidad de los mosqueritos para optimizar la selección de sitios de anidación.


The Condor ◽  
2000 ◽  
Vol 102 (2) ◽  
pp. 401-408 ◽  
Author(s):  
Cheryl R. Dykstra ◽  
Jeffrey L. Hays ◽  
F. Bernard Daniel ◽  
Melinda M. Simon

Abstract We measured nest site selection and productivity of suburban-nesting Red-shouldered Hawks (Buteo lineatus) in southwestern Ohio and rural-nesting Red-shouldered Hawks in south-central Ohio. At both the suburban and the rural locations, nest sites had greater canopy height and overall tree basal area than paired random plots, and were located closer to water than were paired random plots. Nest trees also had greater diameter and height than random plot-center trees. Reproductive rates at suburban and rural sites were similar, averaging 2.6–3.1 nestlings per successful nest. Results indicated that suburban-nesting Red-shouldered Hawks were very similar to rural-nesting hawks in both nest site selection and productivity, suggesting that Red-shouldered Hawks were habituated to their suburban environs.


The Condor ◽  
2019 ◽  
Vol 121 (3) ◽  
Author(s):  
Adrian P Monroe ◽  
L Wes Burger ◽  
James A Martin

Abstract Exotic grasses such as bermudagrass (Cynodon dactylon) and tall fescue (Schedonorus arundinaceus) are widely established across the southeastern United States as livestock forage, but their structure and management can limit avian reproductive success. Native warm-season grasses (NWSG) are promoted as sustainable forage alternatives. To examine nesting suitability for tall structure specialists such as Dickcissels (Spiza americana) we established an operational-scale study in northeastern Mississippi, USA, with 4 treatments along a gradient of beef production intensity. Treatments included grazed exotic forages, 2 grazed NWSG treatments including Indiangrass (Sorghastrum nutans) monoculture and NWSG polyculture of Indiangrass, little bluestem (Schizachyrium scoparium), and big bluestem (Andropogon gerardii), and an ungrazed NWSG polyculture treatment. We monitored 208 Dickcissel nests in 2011 and 2012 to evaluate effects of treatment, vegetation structure, fire ants (Solenopsis spp.), and arthropod prey biomass on nest-site selection and nest survival. Survival rates varied among treatments and increased with pasture-scale visual obstruction reading (VOR), being lowest among grazed exotic grass, intermediate in grazed NWSG, and highest in ungrazed NWSG. Although Dickcissels selected nest sites with greater VOR, we found little support for effects of nest-site vegetation on survival. However, nest survival was lower for nests in shrubs that also occurred in pastures with greater shrub cover, and selection for shrubs declined as pasture-scale VOR increased, suggesting a functional response in selection. We found little support for food availability influencing nest survival. These results suggest NWSG pastures increase Dickcissel nest success through greater pasture-scale VOR by reducing Dickcissel selection of shrubs for nest sites, and possibly by reducing predator efficiency. Incorporating NWSG into beef production systems while maintaining availability of tall vegetation could benefit Dickcissels and other tall structure specialists.


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