scholarly journals Nest density drives productivity in chestnut-collared longspurs: Implications for grassland bird conservation

PLoS ONE ◽  
2021 ◽  
Vol 16 (8) ◽  
pp. e0256346
Author(s):  
John P. Pulliam ◽  
Scott Somershoe ◽  
Marisa Sather ◽  
Lance B. McNew
Keyword(s):  
Nest Site ◽  
Nest Survival ◽  
Grassland Birds ◽  
Population Level ◽  
Survival Models ◽  
Nest Density ◽  
Bird Conservation ◽  
Grassland Bird ◽  
Nest Sites ◽  
Conservation Concern

Grassland birds are declining faster than any other avian guild in North America and are increasingly a focus of conservation concern. Adaptive, outcome-based management of rangelands could do much to mitigate declines. However, this approach relies on quantitative, generalizable habitat targets that have been difficult to extrapolate from the literature. Past work relies heavily on individual versus population response, and direct response to management (e.g. grazing) versus response to outcomes. We compared individual and population-level responses to vegetation conditions across scales to identify quantitative targets of habitat quality for an imperiled grassland songbird, the chestnut-collared longspur (Calcarius ornatus) in northern Montana, USA during 2017–2018. We estimated nest density and nest survival within 9-ha survey plots using open N-mixture and nest survival models, respectively, and evaluated relationships with plot- and nest-site vegetation conditions. Plot-scale conditions influenced nest density, whereas nest survival was unaffected by any measured condition. Nest-site and plot-scale vegetation measurements were only weakly correlated, suggesting that management targets based on nest sites only would be incomplete. While nest survival is often assumed to be the key driver of bird productivity, our results suggest that nest density and plot-scale conditions are more important for productivity of longspurs at the core of the breeding distribution. Habitat outcomes for grassland birds should incorporate nest density and average conditions at scale(s) relevant to management (e.g. paddock or pasture).

Delineating Grassland Bird Conservation Areas in the U.S. Prairie Pothole Region

2010 ◽  
Vol 1 (1) ◽  
pp. 38-42 ◽  
Author(s):  
Rex R. Johnson ◽  
Diane A. Granfors ◽  
Neal D. Niemuth ◽  
Michael E. Estey ◽  
Ronald E. Reynolds
Keyword(s):  
Spatial Data ◽  
Conceptual Models ◽  
Prairie Pothole Region ◽  
Grassland Birds ◽  
Spatial Models ◽  
Bird Conservation ◽  
Prairie Pothole ◽  
Conservation Areas ◽  
Grassland Bird ◽  
Landscape Characteristics

Abstract Conservation of birds is increasingly focused on the importance of landscape characteristics to sustain populations. Implementing conservation on a landscape scale requires reliable spatial models that provide biological context for conservation actions. Before species-specific models relating grassland birds to their habitat at landscape scales existed, we created a conceptual model and applied it to spatial data to identify priority grassland habitats for the protection and restoration of populations of area sensitive grassland birds in the Prairie Pothole Region. Since that time, these Grassland Bird Conservation Areas have been widely used to guide conservation, and variations of these models have been adopted in other regions; however, the process used to delineate them (i.e., the conceptual models) is poorly understood by many users. We describe that process here and offer perspectives on the utility and limitations of conceptual models, especially on the value of making assumptions that commonly underlie management decisions explicitly, thereby making the assumptions testable, and hopefully increasing management transparency, credibility, and efficiency.

Pasture-scale vegetation predicts Dickcissel nest-site selection and success in native and exotic grass pastures

The Condor ◽  
2019 ◽  
Vol 121 (3) ◽  
Author(s):  
Adrian P Monroe ◽  
L Wes Burger ◽  
James A Martin
Keyword(s):  
Site Selection ◽  
Nest Site ◽  
Nest Survival ◽  
Nest Site Selection ◽  
Schizachyrium Scoparium ◽  
Beef Production ◽  
Exotic Grasses ◽  
Nest Sites ◽  
Exotic Grass ◽  
Tall Structure

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.

scholarly journals Nest-site selection and breeding success of passerines in the world’s southernmost forests

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9892
Author(s):  
Rocío Fernanda Jara ◽  
Ramiro Daniel Crego ◽  
Michael David Samuel ◽  
Ricardo Rozzi ◽  
Jaime Enrique Jiménez
Keyword(s):  
Site Selection ◽  
Nest Site ◽  
Nest Survival ◽  
Nest Site Selection ◽  
Camera Traps ◽  
Habitat Characteristics ◽  
Ecological Trap ◽  
Additional Hypothesis ◽  
Nest Sites ◽  
Risk Of Predation

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.

scholarly journals Relationships Between Black-Legged Kittiwake Nest-Site Characteristics and Susceptibility to Predation by Large Gulls

The Condor ◽  
2001 ◽  
Vol 103 (4) ◽  
pp. 793-801 ◽  
Author(s):  
Melanie Massaro ◽  
John W. Chardine ◽  
Ian L. Jones
Keyword(s):  
Nest Site ◽  
Nest Density ◽  
Nest Location ◽  
Rissa Tridactyla ◽  
Nest Sites ◽  
Site Characteristics ◽  
Risk Of Predation ◽  
Breeding Failure ◽  
Larus Marinus ◽  
The Relationship

Abstract We quantified the relationship between Black-legged Kittiwake (Rissa tridactyla) nest-site characteristics and risk of predation by Great Black-backed (Larus marinus) and Herring (L. argentatus) Gulls at Gull Island, Newfoundland, Canada, during 1998 and 1999. We monitored kittiwake nesting cliffs to identify nest sites attacked by large gulls and compared characteristics of attacked and successful nests among four study plots. We also examined which nest sites were attacked by Herring or Great Black-backed Gulls during calm (≤10 km hr−1) or windy conditions (>10 km hr−1). We found that kittiwake nests on plots with fewer nests were more likely to be attacked by gulls and less likely to fledge young. Nest density and nest location relative to the cliffs' upper edges significantly affected the risk of gull predation. Breeding success was correlated with nest density and ledge width and differed significantly among plots. Regardless of wind conditions both gull species were more likely to attack nests located on upper sections of cliffs than nests on lower sections. However, during calm conditions, nest sites located on narrow ledges were less likely to be attacked by Great Black-backed Gulls. Our results demonstrate that for kittiwake colonies where predation is an important source of breeding failure, the size of subcolonies and nest density affect the survival of kittiwake offspring. Relación entre las Características de los Sitios de Nidificación de Rissa tridactyla y la Susceptibilidad a la Depredación por parte de Gaviotas Resumen. Cuantificamos la relación entre las características de los sitios de nidificación de Rissa tridactyla y el riesgo de depredación por parte de Larus marinus y L. argentatus en la Isla Gull, Newfoundland, Canadá, durante 1998 y 1999. Con el objetivo de identificar los nidos atacados por gaviotas de gran tamaño, monitoreamos acantilados de nidificación de R. tridactyla en cuatro localidades de estudio y comparamos las características de los nidos atacados y exitosos. También examinamos qué nidos fueron atacados por L. marinus o por L. argentatus durante condiciones de viento calmo (≤10 km hr−1) o ventosas (>10 km hr−1). Encontramos que los nidos de R. tridactyla ubicados en localidades con menor número de nidos tuvieron mayor probabilidad de ser atacados y menor probabilidad de criar volantones. Tanto la densidad como la ubicación de los nidos en relación al vértice superior del acantilado afectaron significativamente el riesgo de depredación por gaviotas. El éxito de cría se diferenció significativamente entre localidades y se correlacionó con la densidad de nidos y con el ancho de la plataforma. Independientemente de la velocidad del viento, las dos especies de gaviotas atacaron con mayor probabilidad a los nidos ubicados en las secciones superiores del acantilado que en las secciones inferiores. Sin embargo, durante condiciones de viento calmo, los nidos localizados en plataformas angostas presentaron una menor probabilidad de ser atacados por L. marinus. Nuestros resultados demuestran que para colonias de R. tridactyla en las cuales la depredación de nidos es un factor importante en el fracaso reproductivo, el tamaño de las subcolonias y la densidad de nidos afecta la supervivencia de la progenie de R. tridactyla.

scholarly journals Nesting Success of Forest Birds in Southeast Alaska and Adjacent Canada

The Condor ◽  
2000 ◽  
Vol 102 (2) ◽  
pp. 314-324 ◽  
Author(s):  
Mary F. Willson ◽  
Scott M. Gende
Keyword(s):  
Nest Site ◽  
Nest Success ◽  
Nest Survival ◽  
Nesting Success ◽  
Nest Site Selection ◽  
Nest Density ◽  
Coastal Forests ◽  
Southeast Alaska ◽  
Daily Survival ◽  
Site Diversity

Abstract Predation caused 78% of nest failures in coastal forests of southeast Alaska and interior forests of adjacent Canada. Nest success tended to be better in coastal than interior forests. Mayfield daily nest survival from predation on open-cup nests was higher in egg than nestling phase for most species. Species building large (thrush-sized) nests had lower Mayfield daily survival from predation than species building smaller (warbler-sized) nests, but there was no difference in daily survival (total and from predation only) among species nesting in different vegetation strata. Nesting success differed little with nest cover or nest site diversity for most species. Total nest success within species was only sometimes higher in commonly used nest sites than in less frequently used sites. Nest survival from predation did not generally decrease with increasing nest density within guilds of species with similar nests or with nest-site similarity. We emphasize the likelihood of varied outcomes of natural selection on nest-site selection in differing circumstances.

scholarly journals Edge Avoidance by Nesting Grassland Birds: A Futile Strategy in a Fragmented Landscape

The Auk ◽  
2005 ◽  
Vol 122 (2) ◽  
pp. 618-636 ◽  
Author(s):  
Rosalind B. Renfrew ◽  
Christine A. Ribic ◽  
Jamie L. Nack
Keyword(s):  
Nest Predation ◽  
Bos Taurus ◽  
Grassland Birds ◽  
Nest Density ◽  
Fragmented Landscape ◽  
Spermophilus Tridecemlineatus ◽  
Grassland Bird ◽  
Passerculus Sandwichensis ◽  
Dolichonyx Oryzivorus ◽  
Vegetation Height

Abstract Some grassland passerine species are considered area-sensitive, but the mechanisms underlying that phenomenon are not understood, particularly on grazed grasslands. Area sensitivity may result from edge avoidance or higher nest predation near edges, both of which may be influenced by predator activity or cattle-induced vegetational differences between pasture edge and interior. We assessed the effect of distance to edge on nest density and predation Savannah Sparrows (Passerculus sandwichensis), Grasshopper Sparrows (Ammodramus savannarum), Bobolinks (Dolichonyx oryzivorus), and meadowlarks (Sturnella spp.) along wooded and nonwooded edges of Wisconsin pastures in 1998-2000 and the activity of potential mammalian nest predators along those edges in 2000-2001. We found a positive relationship between nest density and distance from edge for all edge types combined, but that was not the result of effects of wooded edges: we found no difference in density between nests located <50 or <100 m from wooded versus nonwooded (crop or grassland) edges. Models that included combinations of vegetation structure (e.g. concealment), initiation date, year, or edge variables (or all four) were poor predictors of the probability of nest predation. Placing nests away from edges, therefore, did not reduce the risk of nest predation. Eight species known to prey on grassland bird nests were documented along pasture edges, raccoon (Procyon lotor) being the most common. Frequency of raccoon and thirteen-lined ground squirrel (Spermophilus tridecemlineatus) visitation was higher along wooded edges and nonwooded edges, respectively. Cattle (Bos taurus) activity did not differentially affect vegetation height-density along edges compared with that in the pasture interior. Possible reasons for predation risk being similar in both pasture interiors and edges in a fragmented landscape include the ease with which predators can move within pastures, high percentage of resident grassland predators, and small size (median = 47.2 ha) of pastures.

Colony characteristics influence nest survival of Caribbean Roseate Terns

The Condor ◽  
2021 ◽  
Vol 123 (1) ◽  
Author(s):  
Paige A Byerly ◽  
Susan Zaluski ◽  
Daniel Nellis ◽  
Paul L Leberg
Keyword(s):  
Reproductive Success ◽  
Colony Size ◽  
Nest Site ◽  
Resource Competition ◽  
Nest Survival ◽  
The United States ◽  
Nest Density ◽  
Nest Failure ◽  
Nest Location ◽  
Site Characteristics

Abstract Determining how site characteristics influence reproductive success can help guide conservation planning for declining wildlife populations. For colonially breeding seabirds, nest survival and predation risk can be influenced by both colony and nest site characteristics such as colony size, nest density, and nest location. We evaluated the reproductive success of a declining population of Roseate Terns (Sterna dougallii) in the United States and British Virgin Islands to identify primary causes of nest failure and investigate the influence of colony and nest site covariates on nest survival. In addition, we measured the influence of colony characteristics on chick provisioning to determine if resource competition in larger colonies affected foraging rates. Monitoring was conducted in 2017–2018 via motion-triggered cameras, which enable 24-hr monitoring with minimal nest disturbance. Nest survival was defined by both hatch success and early chick success, defined as a chick surviving from hatching through the fourth post-hatch day. We monitored 118 nests in 6 colonies over the 2 breeding seasons. We found that predation was the primary cause of nest failure. Both hatch and nest success increased with colony size, and neither nest survival nor predation probability was influenced by individual nest site characteristics. Provisioning rates were comparable among colony sites and did not vary with colony size. Our results suggest that directing management efforts toward enhancing colony size, rather than focusing on nest site characteristics, can be beneficial for tropical seabird conservation.

scholarly journals Nest-site selection, reproductive ecology and shifts within core-use areas of Black-necked Cranes at the northern limit of the Tibetan Plateau

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e2939 ◽  
Author(s):  
Lixun Zhang ◽  
Bei An ◽  
Meilin Shu ◽  
Xiaojun Yang
Keyword(s):  
Water Depth ◽  
Site Selection ◽  
Nest Site ◽  
Nest Survival ◽  
Habitat Type ◽  
Nest Site Selection ◽  
Breeding Habitat ◽  
Nest Density ◽  
Food Density ◽  
The Tibetan Plateau

We investigated population dynamics, breeding pairs, breeding habitat selection, nest density, distance between neighboring nests, nest survival, reproductive success, and recruitment rate for Black-necked Cranes (BNC, Grus nigricollis) during 2013–2015 in Yanchiwan National Nature Reserve (YCW), Gansu, China. Numbers of BNC and breeding pairs remained relatively stable at around 140 individuals and 40 pairs. Recruitment rates ranged from 15.7% to 25.8%. The average nest distance was 718.66 ± 430.50 m (2013), 1064.51 ± 323.99 m (2014) and 534.99 ± 195.45 m (2015). Average nest survival rate, hatching success, and breeding success of all 29 nests were 65.56 ± 5.09%, 57.04 ± 6.12% and 32.78% ± 2.55. Water depth, water body area, and distance to land were positively related to nest survival, while disturbance level showed a negative relationship. However, nest site selection of BNC was determined by habitat type, disturbance and water depth. BNC often foraged in mudflats and freshwater marsh but seldom foraged in saline-alkali wet meadows due to food density and quantity in April, the month when BNC choose nest sites. Conservation strategies based on habitats should consider ecological factors that may not be well predicted by nest site selection. Shifts within core-use areas from satellite tracking of BNC demonstrated that maintaining populations demands that conservation areas are large enough to permit breeding BNC changes in space use. Our results are important for conservation management and provide quantitative reproductive data for this species.

Availability of nest sites does not limit population size of southern flying squirrels

2000 ◽  
Vol 78 (7) ◽  
pp. 1144-1149 ◽  
Author(s):  
Matthew J Brady ◽  
Thomas S Risch ◽  
F Stephen Dobson
Keyword(s):  
South Carolina ◽  
Population Size ◽  
Nest Site ◽  
Nest Density ◽  
Glaucomys Volans ◽  
Flying Squirrels ◽  
Nest Sites ◽  
Nest Boxes ◽  
Before And After ◽  
Population Sizes

Among factors that may limit population size, nest site is generally considered important for cavity-nesting species. We tested the hypothesis that nest-site availability limits population size in the southern flying squirrel (Glaucomys volans) by examining the effect of experimentally increasing the number of nest sites. We compared population sizes before and after adding 100 nest boxes (high-quality nests, increasing overall nest density by at least about 65%) on each of three experimental sites on the Savannah River Site in South Carolina. We also compared the experimental populations with three reference (unmanipulated) sites in a paired-block experimental design. All six populations were similarly monitored with livetrapping grids, and flying squirrels readily nested in the supplemental boxes. We predicted that population size would increase where nest sites were added. No increases in population size were observed after nest boxes were added to the three experimental sites, however, nor were populations higher on the experimental sites than on the reference sites. The lack of increase in population size after nest boxes were added demonstrates that the availability of nest sites was not limiting the size of these populations.

scholarly journals Optimizing Nest Survival and Female Survival: Consequences of Nest Site Selection for Canada Geese

The Condor ◽  
2007 ◽  
Vol 109 (4) ◽  
pp. 769-780 ◽  
Author(s):  
David A. Miller ◽  
James B. Grand ◽  
Thomas F. Fondell ◽  
R. MICHAEL Anthony
Keyword(s):  
Nest Site ◽  
Nest Survival ◽  
Negative Relationship ◽  
Nest Site Selection ◽  
Site Quality ◽  
Adult Survival ◽  
Canada Geese ◽  
Bald Eagles ◽  
Nest Sites ◽  
Female Survival

Abstract We examined the relationship between attributes of nest sites used by Canada Geese (Branta canadensis) in the Copper River Delta, Alaska, and patterns in nest and female survival. We aimed to determine whether nest site attributes related to nest and female survival differed and whether nest site attributes related to nest survival changed within and among years. Nest site attributes that we examined included vegetation at and surrounding the nest, as well as associations with other nesting birds. Optimal nest site characteristics were different depending on whether nest survival or female survival was examined. Prior to 25 May, the odds of daily survival for nests in tall shrubs and on islands were 2.92 and 2.26 times greater, respectively, than for nests in short shrub sites. Bald Eagles (Halieaeetus leucocephalus) are the major predator during the early breeding season and their behavior was likely important in determining this pattern. After 25 May, when eagle predation is limited due to the availability of alternative prey, no differences in nest survival among the nest site types were found. In addition, nest survival was positively related to the density of other Canada Goose nests near the nest site. Although the number of detected mortalities for females was relatively low, a clear pattern was found, with mortality three times more likely at nest sites dominated by high shrub density within 50 m than at open sites dominated by low shrub density. The negative relationship of nest concealment and adult survival is consistent with that found in other studies of ground-nesting birds. Physical barriers that limited access to nest sites by predators and sites that allowed for early detection of predators were important characteristics of nest site quality for Canada Geese and nest site quality shifted within seasons, likely as a result of shifting predator-prey interactions.

Sign in / Sign up

Export Citation Format

Share Document