Breeding biology, reproductive success and survival of blue-breasted fairy-wrens in fragmented habitat in the Western Australian wheatbelt

2001 ◽  
Vol 28 (2) ◽  
pp. 205 ◽  
Author(s):  
Michael Brooker ◽  
Lesley Brooker
Keyword(s):  
Reproductive Success ◽  
Nest Predation ◽  
Reproductive Output ◽  
Agricultural Landscape ◽  
Predation Rate ◽  
Adult Survival ◽  
Fragmented Habitat ◽  
Fragmented Habitats ◽  
Western Australian ◽  
Vegetation Mosaic

We studied blue-breasted fairy-wrens, Malurus pulcherrimus, over a 6-year period in 17 differently sized remnants in a highly fragmented agricultural landscape at Wyalkatchem, Western Australia. The wrens lived in groups of 2–5 adults, comprising one breeding female, her consort and up to three helpers (usually adult male offspring). Groups lived in permanent year-round territories averaging 2.2 ha. Data from 536 nests indicated that breeding extends from August to December in good seasons but from August to October in years of drought. Overall, the average clutch size was 2.91 (median 3), although in the driest year of the study it was 2.31 (median 2). Individual nest success was low, with a mean of 1.02 fledglings produced per clutch. However, the wrens made 1.87 nesting attempts per year, thereby raising the annual reproductive output to 1.63 fledglings per group and 0.49 potential breeders per group. There was a positive relationship between nest predation and remnant size and no difference in the predation rate of nests in the largest remnant depending on how far they were located from the edge of the remnant. Nest parasitism by Horsfield"s bronze-cuckoo, Chrysococcyx basalis, was also positively related to remnant size. Consequently, annual reproductive success was higher in the 13 small remnants (2.16 fledglings per group per year), compared with 3 medium-sized remnants (1.94) and the largest remnant (1.32). Annual adult survival was 63.9% for breeding females and 67.2% for senior males. Survival was positively related to remnant size for adults, but not for fledglings. The annual survival of adults in small remnants was 54.5%, compared with 64.9% in medium-sized remnants and 68.6% in the largest remnant. It is suggested that, in order to conserve sedentary species living in fragmented habitats, we should try to retain the whole range of patch sizes that remain, even if some (or most) of the vegetation mosaic has been removed and even if some remnants are extremely small.

Dispersal and population dynamics of the blue-breasted fairy-wren, Malurus pulcherrimus, in fragmented habitat in the Western Australian wheatbelt

2002 ◽  
Vol 29 (3) ◽  
pp. 225 ◽  
Author(s):  
L. C. Brooker ◽  
M. G. Brooker
Keyword(s):  
Population Dynamics ◽  
Agricultural Landscape ◽  
Population Decline ◽  
Dispersal Capacity ◽  
Fragmented Habitat ◽  
Preferred Habitat ◽  
Straight Line ◽  
Socially Monogamous ◽  
Straight Line Distance ◽  
Western Australian

The blue-breasted fairy-wren, Malurus pulcherrimus, is a small, permanently sedentary, socially monogamous, co-operatively breeding, long-lived Australian passerine, whose core distribution is contained within the Western Australian wheatbelt. Little is known of their dispersal capabilities and population dynamics, knowledge of which are urgently needed as their preferred habitat becomes increasingly fragmented and degraded, due to clearing for agriculture. From 1993 to 1998, we studied a colour-banded population of blue-breasted fairy-wrens living in 13 small, 3 medium-sized and one large habitat remnant in an agricultural landscape at Wyalkatchem. Wrens in small remnants were more likely to disperse between remnants than were those in larger remnants. Females were likely to travel further and were more likely to disperse between remnants than were males. Dispersing females in the largest remnant moved a median straight-line distance of 400 m compared with 3 km for females in the smaller remnants. The furthest recorded movement was 9 km (straight-line distance) or about 14 km by the nearest corridor route. Females living in fragmented habitat may have to travel many times the distances travelled by females in unfragmented habitat. Demographic modelling shows that, over an average run of seasons, the wrens in the study population will produce sufficient yearlings to fill all breeding vacancies, provided none are lost during dispersal. However, in our study landscape, an estimated 11% of dispersers were lost to the population (i.e. either dispersed outside the study area or died during dispersal). We show that the remnants in the study landscape can be divided into neighbourhoods based on their relative connectivity. About 14% more potential dispersers were lost from the poorly-connected areas than from a core 'well connected' neighbourhood. This difference would be sufficient to cause population decline in a poorly connected neighbourhood. We conclude that, for species with poor dispersal capacity living in fragmented habitat, failure to maintain an adequate corridor network could be one of the most important factors contributing to a species' decline.

scholarly journals Declining reproductive output in capercaillie and black grouse – 16 countries and 80 years

2016 ◽  
Vol 66 (3-4) ◽  
pp. 363-400 ◽  
Author(s):  
Torfinn Jahren ◽  
Torstein Storaas ◽  
Tomas Willebrand ◽  
Pål Fossland Moa ◽  
Bjørn-Roar Hagen
Keyword(s):  
Land Use ◽  
Reproductive Success ◽  
Boreal Forests ◽  
Reproductive Output ◽  
Temporal Trends ◽  
Adult Survival ◽  
Generalist Predator ◽  
Black Grouse ◽  
Proximate Cause ◽  
Underlying Mechanisms

Declines in populations of capercaillie (Tetrao urogallus) and black grouse (Lyrurus tetrix) have been reported from both Central Europe and the continuous boreal forests of Fennoscandia. While intensified land-use is assumed to be the underlying cause of these declines, the mechanisms are not yet understood. Predation is the proximate cause of mortality of eggs, chicks and adults throughout capercaillie and black grouse ranges, but the link between predation and habitat and/or climate change remains unclear. To investigate temporal trends in reproductive output of woodland grouse, we collated previously published and unpublished data of reproduction in capercaillie and black grouse throughout their ranges from 1930 to 2012. We show that, overall, reproductive success has decreased and stabilized at low levels in most regions whilst capercaillie reproductive output in Scotland is still declining. With today’s net reproduction, capercaillie and black grouse adult survival is too low to compensate for reproduction declines. Consequently, populations are expected to further decline unless reproductive performances improve. We put our findings in the context of changes in land use, climate and generalist predator numbers. By critically reviewing how these factors limit reproductive success in capercaillie and black grouse, we hope to shed light on the underlying mechanisms causing the decline. Our results imply that measures should be undertaken to reduce mortality of capercaillie and black grouse chicks and eggs. We suggest that future studies should aim to better understand which predators limit capercaillie and black grouse populations and how predation rates are mediated by continuously changing habitat and climate.

scholarly journals The influence of subcolony-scale nesting habitat on the reproductive success of Adélie penguins

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Annie E. Schmidt ◽  
Grant Ballard ◽  
Amélie Lescroël ◽  
Katie M. Dugger ◽  
Dennis Jongsomjit ◽  
...  
Keyword(s):  
Reproductive Success ◽  
Colony Size ◽  
Nest Predation ◽  
Size Variation ◽  
Area Ratio ◽  
Slope Aspect ◽  
Nesting Habitat ◽  
Terrain Attributes ◽  
Small Colony ◽  
Adélie Penguins

AbstractGroup-size variation is common in colonially breeding species, including seabirds, whose breeding colonies can vary in size by several orders of magnitude. Seabirds are some of the most threatened marine taxa and understanding the drivers of colony size variation is more important than ever. Reproductive success is an important demographic parameter that can impact colony size, and it varies in association with a number of factors, including nesting habitat quality. Within colonies, seabirds often aggregate into distinct groups or subcolonies that may vary in quality. We used data from two colonies of Adélie penguins 73 km apart on Ross Island, Antarctica, one large and one small to investigate (1) How subcolony habitat characteristics influence reproductive success and (2) How these relationships differ at a small (Cape Royds) and large (Cape Crozier) colony with different terrain characteristics. Subcolonies were characterized using terrain attributes (elevation, slope aspect, slope steepness, wind shelter, flow accumulation), as well group characteristics (area/size, perimeter-to-area ratio, and proximity to nest predators). Reproductive success was higher and less variable at the larger colony while subcolony characteristics explained more of the variance in reproductive success at the small colony. The most important variable influencing subcolony quality at both colonies was perimeter-to-area ratio, likely reflecting the importance of nest predation by south polar skuas along subcolony edges. The small colony contained a higher proportion of edge nests thus higher potential impact from skua nest predation. Stochastic environmental events may facilitate smaller colonies becoming “trapped” by nest predation: a rapid decline in the number of breeding individuals may increase the proportion of edge nests, leading to higher relative nest predation and hindering population recovery. Several terrain covariates were retained in the final models but which variables, the shapes of the relationships, and importance varied between colonies.

scholarly journals The effect of pollen source on seed traits and dispersability in the heterocarpic annual Crepis sancta

2020 ◽  
Author(s):  
Efrat Dener ◽  
Hagai Shemesh ◽  
Itamar Giladi
Keyword(s):  
Reproductive Success ◽  
Reproductive Output ◽  
Seed Traits ◽  
Dispersal Strategy ◽  
Physiological Constraints ◽  
Dispersal Traits ◽  
Distant Neighbor ◽  
The Common ◽  
Nonsignificant Effect ◽  
Crepis Sancta

Abstract Aims The evolution and expression of dispersal-related traits are intertwined with those of other life-history functions and are manifested within various physiological constraints. Such a relationship is predicted between inbreeding levels and dispersability, which may be anatomically and ontogenetically linked so that the selection pressures on one may affect the other. While both the effect of inbreeding on reproductive success and on dispersal strategies received much attention, only a few studies considered both simultaneously. Furthermore, such studies often rely on two dichotomic representations of breeding and dispersal: using selfing vs. outcrossing as a representation of breeding level, and dispersal ratio as the sole representation of dispersal strategy. Methods Here we used pollination experiments in the heterocarpic Crepis sancta (Asteraceae) to expand in two different manners on the common practice of using dichotomic representations of breeding and dispersal. First, we used pollination treatments that represent a continuum from selfing through pollination by kin to pollination by a distant neighbor. Second, we measured a whole set of continuous morphological and dispersal-related traits, in addition to measurements of reproductive success and dispersal ratio. Important findings The proportion of developed capitula and the number of both dispersed and non-dispersed achenes were significantly lower in the self-pollination treatment in comparison to the out-crossed treatments. The effect of pollen sources on dispersal ratio was not statistically significant, though self-pollinated plants rarely produced non-dispersing seeds. Achene’s biomass increased with distance between parent plants, but pappus width did not, leading to a nonsignificant effect of pollination on falling velocity. Overall, pollen source affected mainly traits that were associated with reproductive output, but it had no clear effect on predominately dispersal-related traits. Such differences in the response of reproduction and dispersal traits to variation in pollen source suggest that dispersal-related selection is probably weak and/or masked by other forces.

scholarly journals Fitness of breeders in social Damaraland mole-rats is independent of group size

2021 ◽  
Author(s):  
Jack Thorley ◽  
Hanna Bensch ◽  
Kyle Finn ◽  
Tim Clutton-Brock ◽  
Markus Zöttl
Keyword(s):  
Reproductive Success ◽  
Group Size ◽  
Survival Rates ◽  
Group Living ◽  
Adult Survival ◽  
High Survival ◽  
Successful Reproduction ◽  
Related Group ◽  
Group Members ◽  
Using Data

Damaraland mole-rats (Fukomys damarensis) are usually viewed as an obligatorily group living eusocial species in which successful reproduction is dependent on reproductive altruism of closely related group members. However, the reproductive ecology of social mole-rats in their natural environment remains poorly understood and it is unclear to what extent successful reproduction is dependent on assistance from other group members. Using data from a 7-year field study of marked individuals, we show that, after dispersal from their natal group, individuals typically settled alone in new burrow systems where they enjoyed high survival rates, and often remained in good body condition for several years before finding a mate. Unlike most other eusocial or singular cooperative breeders, we found that Damaraland mole-rats reproduced successfully in pairs without helpers and experimentally formed pairs had the same reproductive success as larger established groups. Overall there was only a weak increase in reproductive success with increasing group size and no effect of group size on adult survival rates across the population. Juveniles in large groups grew faster early in life but their growth rates declined subsequently so that they eventually plateaued at a lower maximum body mass than juveniles from small groups. Taken together, our data suggest that the fitness benefits of group living to breeders are small and we suggest that extended philopatry in Damaraland mole-rats has evolved because of the high costs and constraints of dispersal rather than because of strong indirect benefits accrued through cooperative behaviour.

scholarly journals Preliminary survival and movement data for a declining population of Flesh-footed Shearwater Ardenna carneipes in Western Australia provides insights into marine threats

2018 ◽  
Vol 29 (2) ◽  
pp. 327-337 ◽  
Author(s):  
JENNIFER L. LAVERS ◽  
SIMEON LISOVSKI ◽  
ALEXANDER L. BOND
Keyword(s):  
Western Australia ◽  
Survival Rates ◽  
Adult Survival ◽  
Seabird Species ◽  
Movement Data ◽  
Central Indian Ocean ◽  
Breeding Grounds ◽  
Wintering Areas ◽  
Fisheries Bycatch ◽  
Western Australian

SummarySeabirds face diverse threats on their breeding islands and while at sea. Human activities have been linked to the decline of seabird populations, yet over-wintering areas typically receive little or no protection. Adult survival rates, a crucial parameter for population persistence in long-lived species, tend to be spatially or temporally restricted for many seabird species, limiting our understanding of factors driving population trends at some sites. We used bio-loggers to study the migration of Western Australian Flesh-footed Shearwaters Ardenna carneipes carneipes and estimated adult survival over five years. Western Australia is home to around 35% of the world’s breeding Flesh-footed Shearwaters, a population which was up-listed to Vulnerable in 2015. During the austral winter, shearwaters migrated across the central Indian Ocean to their non-breeding grounds off western Sri Lanka. Low site fidelity on breeding islands, mortality of adult birds at sea (e.g. fisheries bycatch), and low annual breeding frequency likely contributed to the low estimated annual adult survival (2011–2015: ϕ = 0.634-0.835).

Annual Reproductive Yield in the Cooperative Pygmy Nuthatch (Sitta pygmaea)

The Auk ◽  
1988 ◽  
Vol 105 (1) ◽  
pp. 70-77 ◽  
Author(s):  
William J. Sydeman ◽  
Marcel Güntert ◽  
Russell P. Balda
Keyword(s):  
Reproductive Success ◽  
Cooperative Breeding ◽  
Reproductive Output ◽  
Breeding Birds ◽  
Overwinter Survival ◽  
Northern Arizona ◽  
Floral Diversity ◽  
Indirect Fitness ◽  
The Difference ◽  
The Relationship

Abstract We studied cooperative-breeding Pygmy Nuthatches (Sitta pygmaea) for 4 yr in northern Arizona. Breeding units contained 2-5 birds. Helpers were found at about 30% of all nests. All helpers that later bred on the study area were male. Helpers were mostly yearlings, and offspring or siblings of the birds that they aided, but often aided at least one unrelated breeder. Breeding units with helpers produced significantly more young than those without helpers. Breeding units in habitats with the greatest floral diversity and structural maturity fledged significantly more young than those in other habitats. Habitat did not influence the effect of helpers. Year effects increased the strength of the relationship between helpers and annual reproductive output. Previous breeding experience and pair-bond duration were not related to reproductive success. Total brood loss, although rare, was responsible for the difference in reproductive output among pairs with and without helpers and between habitats. Breeding birds with helpers benefit by an increase in direct fitness. The advantage to the helpers is not clear but may be an increase in indirect fitness associated with aiding relatives. Helpers may benefit directly, however, by sharing roosting cavities on a group territory thereby enhancing overwinter survival.

scholarly journals Factors Influencing Predation on Ovenbird (Seiurus Aurocapilla) Nests in Northern Hardwoods: Interactions Across Spatial Scales

The Auk ◽  
2006 ◽  
Vol 123 (1) ◽  
pp. 82-96
Author(s):  
Brady J. Mattsson ◽  
Gerald J. Niemi
Keyword(s):  
Nest Predation ◽  
Spatial Scales ◽  
Agricultural Practices ◽  
Predation Rate ◽  
Mean Values ◽  
Core Habitat ◽  
Litter Depth ◽  
Seiurus Aurocapilla ◽  
Forest Songbirds ◽  
Main Effects

Abstract Microsite, patch, and landscape conditions may interact to influence nest predation. In northern Minnesota, silvicultural and agricultural practices may be involved in recent increases in nest predators and regional declines in several ground-nesting songbirds. To examine this problem, we evaluated 17 hierarchical models of predation on Ovenbird (Seiurus aurocapilla) nests that included microsite variables, distances to edges, and amount of core forest within a 2-km radius surrounding six study plots. During 2000 and 2001, 157 Ovenbird nests were monitored to estimate nest predation rates. A model that included the main effects of litter depth and core forest area and an interaction term between the two best described variation in predation on Ovenbird nests (AICc weight = 0.83). The nest predation rate from this model was 0.51 ± 0.01 (mean ± SE), assuming mean values of litter depth and amount of core forest. Shallow litter was associated with higher nest predation in three plots surrounded by less core habitat (40–60 ha), whereas there was no relationship in three plots surrounded by more core area (100–150 ha). Management that promotes deep leaf litter and the maintenance of large, intact forest tracts will likely benefit Ovenbirds and other forest songbirds. Factores que Influencian la Depredación de Nidos de Seiurus aurocapilla en los Bosques del Norte: Interacciones a través de las Escalas Espaciales

scholarly journals Nesting With The Wasp Ropalidia Cincta Increases Nest Success of Red-Cheeked Cordonbleu (Uraeginthus Bengalus) in Ghana

The Auk ◽  
2006 ◽  
Vol 123 (4) ◽  
pp. 1022-1037 ◽  
Author(s):  
Paul Beier ◽  
Agba Issahaku Tungbani
Keyword(s):  
Reproductive Success ◽  
Nest Predation ◽  
Northern Ghana ◽  
Social Hymenoptera ◽  
Tropical Regions ◽  
Nest Sites ◽  
Wasp Nests ◽  
Habitat Feature ◽  
Working Hypotheses ◽  
Rule Out

AbstractAssociations between birds and social Hymenoptera (ants, wasps, bees) are common in tropical regions and are usually assumed to be commensal relationships that benefit birds but neither help nor harm the arthropods. However, benefits to birds have been documented in only four such associations, and no previous research has rigorously investigated costs or benefits to associated hymenopterans. We followed the nesting cycles of an estrildid finch, the Red-cheeked Cordonbleu (Uraeginthus bengalus), and a common nesting associate, the wasp Ropalidia cincta, during 2002 and 2003 in northern Ghana to compare reproductive success of birds and wasps nesting in association with that of birds and wasps nesting separately. Red-cheeked Cordonbleus and wasps nested together in the same tree 3.7 × as often as expected if nesting decisions were made independently, with 74% of bird nests and 74% of wasp colonies occurring in associations. Bird nesting was initiated ≈33 days after founding of an associated wasp colony; bird nests and wasp colonies were, on average, 42 cm apart. In both years, Red-cheeked Cordonbleus in nesting associations with wasps were twice as likely to fledge young as birds nesting in trees without wasps. Reduced predation was apparently a major reason for increased fledging success: we documented four cases of nest predation on 122 Red-cheeked Cordonbleu nests associated with wasps, and 11 cases on 90 nests not associated with wasps. Association with birds did not affect the success of wasp colonies. Although our observational study cannot rule out the possibility that both species coincidentally shared a preference for a habitat feature in limited supply, suitable nest sites did not appear to be limiting (74% of potential nest trees had neither bird nor wasp nests). Reproductive success of Red-cheeked Cordonbleu populations in this region may be limited by the number of available wasp colonies. By designing our study to address four working hypotheses (commensalism, mutualism, parasitism, coincidence of habitat preference), we have provided strong evidence that this relationship is commensal.Augmentation du Succès de Nidification de Uraeginthus bengalus Nichant avec des Guêpes Ropalidia cincta au Ghana

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