The interrelationship between torpor expression and nest site use of western and eastern pygmy-possums (Cercartetus spp.)

2020 ◽  
Vol 42 (1) ◽  
pp. 85 ◽  
Author(s):  
James M. Turner

Physiology and behaviour are closely linked, making knowledge of the interaction between species’ energetics and activities important when attempting to understand how animals function in the wild. I examined torpor use by western pygmy-possums (Cercartetus concinnus) and eastern pygmy-possums (C. nanus) in relation to nest site characteristics and movement patterns. In coastal mallee heath in winter, C. concinnus nested beneath leaf litter at the base of dead Banksia ornata, where they employed torpor on 69% of observed days. In warm temperate sclerophyll forest, C. nanus nested in tree hollows of Eucalyptus spp. and used torpor on 64% of days in winter and 10% in summer. Torpor was used in nest sites that were buffered from outside temperature extremes. Both species frequently reused nest sites and while C. nanus was more likely to employ torpor in a previously used site, site familiarity did not influence torpor use for C. concinnus. Additionally, C. nanus was more likely to use torpor in hollows with a higher relative thickness in both seasons. No relationship was found between range size and the number of tracking days or capture body mass, though sample sizes were small. I suggest that the thermal attributes of nest sites influence torpor use for both species and this is likely vital for maintaining a positive energy balance, stressing the importance of preserving habitat with ample potential nest sites for conservation management.

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 Auk ◽  
2004 ◽  
Vol 121 (4) ◽  
pp. 1250-1261 ◽  
Author(s):  
Jeffery W. Walk ◽  
Kevin Wentworth ◽  
Eric L. Kershner ◽  
Eric K. Bollinger ◽  
Richard E. Warner

Abstract Renesting decisions and annual fecundity are crucial for interpreting other demographic information, yet are infrequently reported. We used radiotelemetry to monitor female Dickcissels (Spiza americana) throughout the 1999 and 2000 breeding seasons in southeastern Illinois. Overall fecundity (regardless of whether females remained in the study area throughout the breeding season) was 0.61 ± 0.13 female fledglings per year. Of females that remained within the study area, 94% fledged young (1.25 ± 0.15 female fledglings per year). Most females (62%) that experienced nest failure emigrated from the study area (moved >10 km) in 2.8 ± 0.6 days; others (36%) initiated subsequent nests in 8.5 ± 0.8 days. After fledging ≥1 young, 95% of females ceased breeding for the season. Successful and failed nest sites were indistinguishable on the basis of vegetative characteristics. Moreover, replacement nests had similar vegetative characteristics and were similar distances from habitat edges, compared with initial nests, which suggests that female Dickcissels do not or cannot “improve” nest-site characteristics in response to nest failure. We observed two behaviors unusual in female Dickcissels: one bird that fledged two broods in one season, and the return of five females banded in 1999 to the study site in 2000.


2020 ◽  
Vol 13 (3) ◽  
pp. 63-69
Author(s):  
Bo Zhou ◽  
Changzhang Feng ◽  
Wei Liang

The quality of breeding habitat may directly affect the survival and development of progeny. Therefore, the selection of a suitable nest-site is an important factor affecting the reproductive success of birds. The most important reason for a bird’s reproductive failure is nest predation. Predation may cause birds to change their nest-sites and even nest morphology. Here we investigated the nest-site characteristics by long-tailed broadbills ( Psarisomus dalhousiae) in Nonggang, Guangxi, southwestern China. Our results showed that long-tailed broadbills in Nonggang mainly build their nests on power lines (88.5%) and nest-site selection was mainly affected by predation pressure and food resources. At the same time, nest-site concealment was trade-off against predator avoidance. This anti-predator strategy effectively utilizes human infrastructure.


1998 ◽  
Vol 20 (3) ◽  
pp. 377
Author(s):  
M.S. Wood ◽  
R.L. Wallis

The potential for feral Honeybees (Apis mellifera) to competitively exclude Common Brushtail Possums (Trichosurus vulpecula) from tree hollows was examined in the You Yangs Regional Park, Victoria. The characteristics and occupancy of 77 hollow-bearing trees and 250 hollows were recorded in six 2 ha sites and used to compare the extent of overlap in nest site selection between bees and posssums. Colonies of feral A. mellifera occupied 25 % of all hollow-bearing trees and 8 % of useable hollows, yielding a density of 1.66 colonies per ha, the highest recorded so far in Australia. Trichosurus vulpecula utilised 74 % of hollow-bearing trees and 48 % of useable hollows. Nest site characteristics of bees and possums overlapped in several dimensions, especially in the size of tree and height of nest. Relatively few vacant hollows were suitable for T. vulpecula, whereas many were available to Honeybees. Only 35% of bee nests were in hollows unsuitable for possums, indicating a relatively high potential for competition.


1987 ◽  
Vol 65 (6) ◽  
pp. 1411-1416 ◽  
Author(s):  
Anne E. Storey

The relationship between nest site characteristics and nest success during tidal flooding was studied in six New Jersey colonies of marsh-nesting common terns (Sterna hirundo). Most colonies were on high ground with a northeast water exposure, and almost all nests were on mats of dead vegetation. Terns nested on the thickest areas of the mats and, whether nesting on mats or on the ground, they selected nest sites with low vegetation density. The characteristics of successful nests differed with the height and date of the flood tide, and with wind direction. In the 1975 flood, nests on high ground were more successful, whereas nests in tall grass and on large mats successfully survived tidal flooding in 1976. Because grass height and ground height are negatively correlated in the marsh, it is difficult for the terns to maximize both characteristics when selecting a nest site. The large mats associated with flood survival in 1976 were also associated with higher prédation rates, indicating a further complication in selecting a safe nest site. Data from these floods were compared with floods studied by other researchers to further test whether certain nest site characteristics are associated with nest success in different types of floods.


The Auk ◽  
1988 ◽  
Vol 105 (3) ◽  
pp. 433-438 ◽  
Author(s):  
Joanna Burger ◽  
Michael Gochfeld

Abstract Roseate Terns (Sterna dougallii) nest in a wide variety of habitats. We examined nest-site selection in a mixed-species colony of Roseate and Common (S. hirundo) terns on the interdune area of a barrier beach to determine species differences, to identify which characteristics at nest sites differed from the available habitat, and to compare nest-site preferences of early- and late-nesting Roseate Terns. Both species nested in the same area, but Roseate Terns nested under dense vegetation and Common Terns nested in more open sites. For Roseate Terns, cover within 0.5 m of the nest was greater than that within 1 m; the opposite was true for Common Terns. Cover within 5 m was similar for both species. Roseate and Common terns select different habitat features. Site characteristics of early- and late-nesting Roseate Tern nests differed. Late-nesting terns used sites with greater cover within 0.5 m, less cover within 5 m, taller vegetation, and with less visibility compared with early-nesting terns. Late-nesting Roseate Terns were still able to find sites in dense cover. At this colony, competition between the two species may not be limiting, and abundant sites remain available.


The Condor ◽  
2001 ◽  
Vol 103 (4) ◽  
pp. 793-801 ◽  
Author(s):  
Melanie Massaro ◽  
John W. Chardine ◽  
Ian L. Jones

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.


1980 ◽  
Vol 58 (6) ◽  
pp. 1075-1089 ◽  
Author(s):  
J. K. Schmutz ◽  
S. M. Schmutz ◽  
D. A. Boag

We investigated the extent of ecological segregation in the use of the food, space, and habitat resources of three sympatric species of the genus Buteo (red-tailed, ferruginous, and Swainson's hawks) coexisting in the prairie–parkland ecotone of southeastern Alberta. We concluded that food was not a resource for which the hawks were competing because the overlap in diets exceeded 80%, and because ferruginous hawks successfully fledged supernumerary broods and Swainson's hawks, broods of at least average size. Furthermore, there was no evidence that each species hunted prey at different times of the day or concentrated on different-sized prey. Each of the three species exhibited a dispersed distribution of nest sites which suggests competition for space; this pattern was not as evident when the distribution of nests among species was considered. Nevertheless, when pairs of different species nested in close proximity their reproductive success declined significantly, suggesting interspecific competion for space. The three species exhibited differences in nest site characteristics, suggesting that, although sympatric, they tended to segregate on the basis of habitat. Ferruginous hawks appear to inhabit arid and open landscapes, red-tailed hawks woodland habitat, and Swainson's hawks the interface.


2020 ◽  
Vol 98 (9) ◽  
pp. 573-580 ◽  
Author(s):  
G.I. Holmes ◽  
L. Koloski ◽  
E. Nol

Vegetation communities in the subarctic are at risk of change due to climate-driven tree and shrub encroachment. Vegetation change may lead to unsuitable habitat for arctic-breeding birds, many of whom are declining. Although many possible factors are contributing to their decline, loss of breeding habitat could be a major contributor. We examined nest-site selection in Dunlin (Calidris alpina hudsonia (Todd, 1953)), a shorebird that nests in open fen habitats in the Churchill, Manitoba, Canada, region. Our objective was to determine whether this species avoids treed habitats and the possible fitness consequences for this. We examined the role of vegetative horizontal and vertical concealments on nest-site selection and nest fate. Dunlin selected nest sites with lower densities of trees than present at unused sites (40 m radius). Both horizontal and vertical concealments were significantly greater at nests than at unused sites, and horizontal concealment was greatest in the north. No measure of tree density or height, or concealment, significantly predicted nest fate. Although Dunlin appear to select nest sites that may minimize exposure to northerly winds and that may provide cover against potential predators, the current nest-site characteristics are not reinforced by contemporary selection.


2016 ◽  
Vol 24 (1) ◽  
pp. 81-95 ◽  
Author(s):  
Gábor Ónodi ◽  
Dániel Winkler

Abstract This study was carried out in Hungary, in an old unmanaged riparian poplar-willow forest during the breeding seasons of 2014 and 2015. The occurrence of two invasive tree species, the green ash and boxelder, is significant in the study area, which influences negatively the populations of native riparian tree species in Central Europe. We studied Great-spotted Woodpecker nest sites in the presence of these invasive species. Throughout the study period, eight and twelve nesting cavity trees were mapped. Trees were recorded in 20-20 circular plots of 0.05 ha both for each mapped nest trees and random plots as well. Species, diameter at breast height and condition were recorded for each tree. Composition and diversity of nest site and random plots were compared. Distributions and preferences were calculated for nest tree use. Most of the recorded trees were invasive. Nest site plots had more native trees compared to random plots. Nest site showed higher diversity in terms of all three variables. Decayed and dead willow and white poplar hybrid trees were preferred for nesting. Diameter at breast height of nest trees was between 30-90 cm. Studies about cavity excavators in transformed habitats have high importance for nature conservation of riparian forests.


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