Aggression, superterritories, and reproductive success in tree swallows

1979 ◽  
Vol 57 (10) ◽  
pp. 2072-2078 ◽  
Author(s):  
Reid N. Harris
Keyword(s):  
Reproductive Success ◽  
Reproductive Output ◽  
Future Generations ◽  
Tree Swallows ◽  
Nestling Growth ◽  
Territorial Aggression ◽  
Nest Boxes ◽  
Nestling Period ◽  
The Relationship ◽  
Insular Population

The relationship between territorial aggression and reproductive success was studied on a well-established, insular population of tree swallows. Four treatments of nest boxes that differed in interbox distances were created. Short interbox distances significantly reduced the occupancy of nest boxes both between and within years. Swallows in short interbox distance treatments defended more than one nest box, which was an additional resource not necessary for their successful reproduction. Excluded potential breeders attempted to colonize vacant boxes within another swallow's territory throughout the nestling period, but were usually prevented by the aggression of the resident pair. Aggressive activity had no direct effect on three measures of a swallow's reproductive output: percent young fledged, nestling growth, and fledgling weights. The concept of intraspecific aggressive neglect is questioned. However, by excluding potential breeders from nesting, for whatever reason, breeding tree swallows increased their relative genetic contribution to future generations.

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.

Comparative effects of mites and lice on the reproductive success of rock doves (Columba livia)

Parasitology ◽  
1995 ◽  
Vol 110 (2) ◽  
pp. 195-206 ◽  
Author(s):  
D. H. Clayton ◽  
D. M. Tompkins
Keyword(s):  
Reproductive Success ◽  
Body Mass ◽  
Growth Rates ◽  
Columba Livia ◽  
Nestling Growth ◽  
Adult Body Mass ◽  
Evolution Of Virulence ◽  
Relationship Of ◽  
The Impact ◽  
The Relationship

SUMMARYWe report experimental data comparing the effects of Mesostigmatid mites and Ischnoceran lice on the reproductive performance of a single group of captive rock doves (Columba livia). Several components of host reproductive success were compared for the two groups, including number of eggs laid, hatching success, nestling growth rates, fledging success, post-fledging body mass and survival. Adult body mass and survival were also compared. There was a dramatic difference in the effects of the mites and lice. The former drove host reproductive success to zero, mainly by agitating adults and causing them to incubate eggs less faithfully. Nestling growth rates and post-fledging survival were also significantly reduced by mites. Lice showed no effect on reproductive success whatsoever, even though the feather damage they cause is known to have energetic consequences (Booth, Clayton & Block, 1993). Neither parasite had a significant effect on adult birds. Although Ischnocera are found on most species of birds, our results for lice constitute the first experimental test of the impact of Ischnocera on avian reproductive success (preliminary report by Clayton & Tompkins, 1994). We discuss reasons for the different effects of mites and lice, including the relationship of horizontal (mites) and vertical (lice) transmission to the evolution of virulence.

scholarly journals Sharing the burden: on the division of parental care and vocalizations during incubation

2019 ◽  
Vol 30 (4) ◽  
pp. 1062-1068 ◽  
Author(s):  
Marwa M Kavelaars ◽  
Luc Lens ◽  
Wendt Müller
Keyword(s):  
Reproductive Success ◽  
Parental Care ◽  
Reproductive Output ◽  
Biparental Care ◽  
Parental Effort ◽  
Levels Of Care ◽  
Incubation Behavior ◽  
Evolutionary Conflict ◽  
Larus Fuscus ◽  
Nestling Period

Abstract In species with biparental care, individuals only have to pay the costs for their own parental investment, whereas the contribution of their partner comes for free. Each parent hence benefits if its partner works harder, creating an evolutionary conflict of interest. How parents resolve this conflict and how they achieve the optimal division of parental tasks often remains elusive. In this study, we investigated whether lesser black-backed gulls (Larus fuscus) divide parental care during incubation equally and whether this correlates with the extent of vocalizations between pair-members during incubation. We then investigated whether pairs showing more evenly distributed incubation behavior had a higher reproductive success. To this end, we recorded incubation behavior and vocalizations for 24-h time periods. Subsequently, we experimentally increased or decreased brood sizes in order to manipulate parental effort, and followed offspring development from hatching till fledging. Although incubation bouts were, on average, slightly longer in females, patterns varied strongly between pairs, ranging from primarily female incubation over equal sex contributions to male-biased incubation. Pairs contributing more equally to incubation vocalized more during nest relief and had a higher reproductive output when brood sizes were experimentally increased. Thus, vocalizations and a more equal division of parental care during incubation may facilitate higher levels of care during the nestling period, as suggested by a greater reproductive success when facing high brood demand, or they indicate pair quality.

Tree Swallow (Tachycineta bicolor) nest success and nestling growth near oil sands mining operations in northeastern Alberta, Canada

2019 ◽  
Vol 97 (6) ◽  
pp. 547-557 ◽  
Author(s):  
Christine M. Godwin ◽  
Robert M.R. Barclay ◽  
Judit E.G. Smits
Keyword(s):  
Reproductive Success ◽  
Oil Sands ◽  
Industrial Development ◽  
Nest Success ◽  
Tachycineta Bicolor ◽  
Tree Swallows ◽  
Reference Sites ◽  
Mining Operations ◽  
Contaminant Exposure ◽  
Nestling Growth

Industrial development and contaminant exposure may affect reproductive success and food quality for birds. Tree Swallows (Tachycineta bicolor (Vieillot, 1808)) nesting near oil sands development in northern Alberta (Canada) potentially experience elevated environmental stressors that could influence reproduction. We measured reproductive and growth endpoints in Tree Swallows, predicting reduced reproductive success and nestling growth near oil sands operations compared with reference sites. We also identified the invertebrate prey in the stomach contents of nestlings to understand variability in the diet and its potential effect on growth and survival of nestlings. From 2012 to 2015, clutch initiation varied among years but was not influenced by proximity to oil sands operations. Hatching and fledging success decreased in response to increased precipitation, regardless of location. Measurements of nestling growth reflected the variation associated with nestling sex and possibly asynchronous hatching. The composition of the nestling diet was significantly different; birds near oil sands development consumed Odonata, whereas birds at reference sites consumed Ephemeroptera. Nestlings from all sites consumed relatively high quantities of terrestrial insects. Our results demonstrate that factors such as weather conditions, diet, hatching order, and nestling sex are important when interpreting the potential effects of oil sands development on nest success and nestling growth.

Ectoparasites, nestling growth, parental feeding rates, and begging intensity of tree swallows

2001 ◽  
Vol 79 (2) ◽  
pp. 346-353 ◽  
Author(s):  
Krista Thomas ◽  
Dave Shutler
Keyword(s):  
Linear Models ◽  
Tree Swallow ◽  
Tree Swallows ◽  
Feeding Rates ◽  
Blow Fly ◽  
Nestling Growth ◽  
Nest Boxes ◽  
Significant Relationships ◽  
Parental Feeding ◽  
Nestling Begging

Many studies fail to show relationships between ectoparasite loads and nestling growth rates. One explanation is that parent birds increase feeding rates to compensate for nestling energetic losses to ectoparasites. Nestling begging behaviours could signal need to parents. Accordingly, we tested whether higher flea and blow fly loads in tree swallow (Tachycineta bicolor) nests were associated with smaller nestlings, higher parental feeding rates, and increased nestling begging intensity. The study area was the Gaspereau Valley of Nova Scotia, Canada. When nestlings were 10 days old, parental feeding rates and nestling begging intensity were measured with tape recorders. At 13 days of age, nestlings were weighed and measured. Within 2 days of fledging, nest material was removed from nest boxes and enumerated for adult fleas and blow fly pupae. After including brood size and date of first egg as covariates in general linear models, no significant relationships were found between ectoparasite loads and nestling size, parental feeding rate, or nestling begging intensity. Our results suggest that nestling tree swallows were able to buffer the effects of naturally occurring ectoparasite loads without significant help from their parents. Low levels of virulence may have resulted from relatively benign weather during the study, low numbers of ectoparasites, selection on ectoparasites to avoid killing their hosts, and host defences.

scholarly journals Nest boxes increase reproductive output for Tree Swallows in a forest grassland matrix in central British Columbia

PLoS ONE ◽  
2018 ◽  
Vol 13 (10) ◽  
pp. e0204226 ◽  
Author(s):  
Andrea R. Norris ◽  
Kathryn E. H. Aitken ◽  
Kathy Martin ◽  
Stanley Pokorny
Keyword(s):  
British Columbia ◽  
Reproductive Output ◽  
Tree Swallows ◽  
Nest Boxes

Gender and belief factors on attitude towards Social and Environmental Accounting (SEA)

2009 ◽  
Vol 6 (2) ◽  
pp. 51
Author(s):  
Salina Abdullah ◽  
Ern Chen Loo
Keyword(s):  
Natural Resources ◽  
Undergraduate Students ◽  
Environmental Issues ◽  
Environmental Accounting ◽  
Future Generations ◽  
Business And Society ◽  
Four Dimensions ◽  
Sustain Ability ◽  
The Relationship

Research on social and environmental accounting (SEA) has mainly concentrated on disclosure of SEA by corporate bodies, where investigations on ones attitude towards SEA are rarely discussed. SEA is a medium that develops relationships between business and society, community and nature. In addition, SEA involves a concept of sustain ability; where natural resources need to be sustained for the needs of future generations (Alhabshi et al., 2003). SEA also tries to recognise the role of accounting in sustainable development and the use of environmental resources. There are arguments that the young generations today are not fully aware of preserving these natural resources as well as handling social and environmental issues wisely. This perhaps link closely to their belief and cultural background. Hence, this paper examines the influence of gender and belief factors on the undergraduate students’ attitude towards SEA. Four dimensions of belief (fixed ability, quick learning, simple knowledge and certain knowledge) proposed by Schommer (2005) were adapted to analyse how belief factors have influence on their attitude towards SEA. An independent sample t-test was used to examine the relationship between gender and students’ attitude towards SEA. Spearmen’s correlation was employed to show the relationship between belief and attitude towards SEA. The results revealed that gender differences did not show influences on their attitude towards SEA. It was found that there is a significant relationship between belief and students’ attitude towards SEA. Students who believe on the importance of SEA tend to report positive attitude towards SEA. Perhaps findings of this study may provide some information on the SEA education and further be incorporated in the syllabus.

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.

An ecological explanation for hyperallometric scaling of reproduction

2021 ◽  
Author(s):  
Tomos Potter ◽  
Anja Felmy
Keyword(s):  
Body Size ◽  
Reproductive Output ◽  
Resource Competition ◽  
Natural Populations ◽  
Scaling Exponent ◽  
Wild Populations ◽  
Wet Season ◽  
Size Dependent ◽  
In The Wild ◽  
The Relationship

AbstractIn wild populations, large individuals have disproportionately higher reproductive output than smaller individuals. We suggest an ecological explanation for this observation: asymmetry within populations in rates of resource assimilation, where greater assimilation causes both increased reproduction and body size. We assessed how the relationship between size and reproduction differs between wild and lab-reared Trinidadian guppies. We show that (i) reproduction increased disproportionately with body size in the wild but not in the lab, where effects of resource competition were eliminated; (ii) in the wild, the scaling exponent was greatest during the wet season, when resource competition is strongest; and (iii) detection of hyperallometric scaling of reproduction is inevitable if individual differences in assimilation are ignored. We propose that variation among individuals in assimilation – caused by size-dependent resource competition, niche expansion, and chance – can explain patterns of hyperallometric scaling of reproduction in natural populations.

Individual Variation in the Strength of Territory Defense in Male Song Sparrows: Correlates of Age, Territory Tenure, and Neighbor Aggressiveness

Behaviour ◽  
2004 ◽  
Vol 141 (1) ◽  
pp. 15-27 ◽  
Author(s):  
Jeremy Hyman ◽  
Melissa Hughes ◽  
Stephen Nowicki ◽  
William Searcy
Keyword(s):  
Individual Differences ◽  
Reproductive Success ◽  
Extrinsic Factors ◽  
Territory Defense ◽  
Intrinsic Factors ◽  
Territorial Aggression ◽  
Male Song ◽  
Song Sparrows ◽  
Territory Owner ◽  
Older Males

AbstractIn many species, the ability to defend a territory is essential for a male to obtain any reproductive success at all, and even among territorial individuals, variation in the strength of territory defense could have a significant impact on how much reproductive success is obtained. Previous studies have documented consistent individual differences in the vigor with which male song sparrows (Melospiza melodia) defend their territories, as measured by the strength of their reactions to territorial intrusions simulated through song playback. Variation in the strength of defense could reflect intrinsic differences among individuals in their resource holding potential (RHP), or variation in extrinsic factors. In this study, we examined whether variation in the strength of territory defense corresponds to differences in intrinsic factors such as the age or experience of the territory owner, the extrinsic factor of the level of aggression shown by neighbours, or both. Results indicate that males that previously held territories on the study site, regardless of whether they were holding the same territory as the previous year, show higher levels of territory defense than males that are new to the study site, and, assuming that returning males are older males, suggest that age is more important than experience on a specific territory in determining strength of territory defense. In addition, we found evidence that males with high levels of territorial aggression tend to be spatially clustered. The pattern observed suggests that a combination of intrinsic and extrinsic factors contribute to the expression of individual differences in territorial aggression.

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