scholarly journals How much does habitat isolation drive forest bird morphology?

2021 ◽  
Author(s):  
André Desrochers ◽  
Flavie Noreau
Keyword(s):  
Body Mass ◽  
Boreal Forests ◽  
Large Body ◽  
Bird Species ◽  
Passerine Bird ◽  
Landscape Scale ◽  
Habitat Isolation ◽  
Selective Pressures ◽  
North American Bird ◽  
Rapid Environmental Change

Rapid environmental change caused by humans has become a major concern for wildlife conservationists. But phenotypic and evolutionary responses of species to such change may often be swift enough to prevent their collapse. Several North American bird species living in boreal forests now have more pointed wings (a proxy for sustained ight efficiency), than they had a century ago. This remarkable pattern has been hypothesized as resulting from selective pressures favoring colonization of isolated habitat. Additionally, aerodynamics predict that heavier birds can achieve faster ight, a further advantage for exploring isolated habitats. We tested whether birds establishing territories in isolated areas have more pointed wings and are heavier than con-specifics found in more densely populated areas. Wing shapes of wild-caught adults from 21 passerine bird species did not generally support this prediction. However individuals with large body mass relative to their species were found more frequently in isolated habitats. Our results offer partial support for the isolation hypothesis at the landscape scale. We encourage further work at coarser, regional, scales to further examine whether wing shape and body mass evolutionarily respond to habitat isolation.

Hematological and Body-Mass Changes of Small Passerines Overwintering in South-Eastern Australia

1995 ◽  
Vol 43 (1) ◽  
pp. 31 ◽  
Author(s):  
K Breuer ◽  
A Lill ◽  
J Baldwin
Keyword(s):  
Body Mass ◽  
Bird Species ◽  
Volume Ratio ◽  
Passerine Bird ◽  
Minor Role ◽  
South Eastern ◽  
The North ◽  
Eastern Australia ◽  
Haemoglobin Content ◽  
South Eastern Australia

Haematological parameters and body mass of four passerine bird species resident in south-eastern Australia were compared in winter and summer to determine whether there were changes indicative of metabolic adjustments associated with seasonal acclimatisation. Haematocrit and whole-blood haemoglobin content did not change seasonally, but erythrocyte numbers increased (by 45-72%) and erythrocyte volume decreased (by 40-73%) significantly in winter in all species. The greater surface area to volume ratio and shorter diffusion pathway of smaller erythrocytes in winter should enhance blood oxygen transport efficiency and thus potentially facilitate metabolic acclimatisation to cold stress. Only one species showed a significant, but small (3%), increase in body mass in winter, suggesting only a minor role for winter fattening in any such seasonal metabolic adjustments in the species studied. The findings contrast with those for some passerines overwintering in the north temperate zone, but the generality of these possible north-south differences needs further investigation.

scholarly journals Biologic features and prognosis of ductal carcinoma in situ are not adversely impacted by initial large body mass

2012 ◽  
Vol 133 (3) ◽  
pp. 1131-1141 ◽  
Author(s):  
Henry M. Kuerer ◽  
Sara A. Lari ◽  
Banu K. Arun ◽  
Chung-Yuan Hu ◽  
Abenaa Brewster ◽  
...  
Keyword(s):  
Body Mass ◽  
Ductal Carcinoma In Situ ◽  
Carcinoma In Situ ◽  
Ductal Carcinoma ◽  
Large Body

scholarly journals Demography, heritability and genetic correlation of feline hip dysplasia and response to selection in a health screening programme

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Matthew Low ◽  
Per Eksell ◽  
Kjell Högström ◽  
Ulrika Olsson ◽  
Lars Audell ◽  
...  
Keyword(s):  
Genetic Correlation ◽  
Body Mass ◽  
Hip Dysplasia ◽  
Selective Breeding ◽  
Screening Programme ◽  
Large Body ◽  
Health Screening ◽  
Response To Selection ◽  
Body Type ◽  
Breeding Programmes

AbstractFeline hip dysplasia (FHD) is a debilitating condition affecting the hip joints of millions of domestic cats worldwide. Despite this, little is known about FHD except that it is relatively common in the large breed Maine Coon. We used 20 years of data from 5038 pedigree-registered Maine Coon cats in a radiographic health screening programme for FHD to determine, for the first time, its heritability, genetic correlation to body mass and response to selection. FHD prevalence was 37.4%, with no sex predilection; however, FHD severity increased with age and body mass. Heritability of the radiographic categories used to classify FHD severity was 0.36 (95%CI: 0.30–0.43). The severity of FHD symptoms was also genetically correlated with body mass (0.285), suggesting that selection for a large body type in this breed concurrently selects for FHD. Support for this was found by following generational responses to selective breeding against FHD. Not only did selective breeding successfully reduce the severity of FHD symptoms in descendants, but these cats were also smaller than their ancestors (−33g per generation). This study highlights the value of breeding programmes against FHD and cautions against breed standards that actively encourage large bodied cats.

scholarly journals Limited reproductive impairment in a passerine bird species exposed along a perfluoroalkyl acid (PFAA) pollution gradient

2019 ◽  
Vol 652 ◽  
pp. 718-728 ◽  
Author(s):  
Thimo Groffen ◽  
Robin Lasters ◽  
Ana Lopez-Antia ◽  
Els Prinsen ◽  
Lieven Bervoets ◽  
...  
Keyword(s):  
Bird Species ◽  
Passerine Bird ◽  
Pollution Gradient ◽  
Reproductive Impairment ◽  
Perfluoroalkyl Acid

scholarly journals Habitat-of-origin predicts degree of adaptation in urban tolerant birds

2013 ◽  
Author(s):  
Lawrence E Conole
Keyword(s):  
Bird Species ◽  
Landscape Scale ◽  
Predictor Variables ◽  
Indirect Inference ◽  
Behavioural Ecology ◽  
Urban Rural ◽  
Direct Data ◽  
Urban Bird ◽  
Similar Kind ◽  
Urban Exploiter

Urban exploiters and adapters are often coalesced under a term of convenience as ‘urban tolerant’. This useful but simplistic characterisation masks a more nuanced interplay between and within assemblages of birds that are more or less well adapted to a range of urban habitats. Furthermore, cues are generally sought in behavioural ecology and physiology for the degree to which particular bird species are predisposed to urban living. The data in this paper are focused on two assemblages characterised as urban exploiters and suburban adapters from Melbourne, Australia. This study departs from the approach taken in many others of similar kind in that urban bird assemblages that form the basis of the work were identified at the landscape scale and from direct data analyses rather than indirect inference. Further, this paper employs a paired, partitioned analysis of exploiter and adapter preferences for points along the urban-rural gradient that seeks to decompose the overall trend into diagnosable parts for each assemblage. In the present paper I test the hypotheses that the distinct urban exploiter and suburban adapter assemblages within the broad urban tolerant grouping in Melbourne vary in their responses within the larger group to predictor variables, and that the most explanatory predictor variables vary between the two assemblages. In the end, habitat-of-origin better predicts degree of adaptation amongst urban tolerant birds.

A New Approach to Animal Flight Mechanics

1979 ◽  
Vol 80 (1) ◽  
pp. 17-54 ◽  
Author(s):  
J. M. V. RAYNER
Keyword(s):  
Body Mass ◽  
Large Body ◽  
Simple Expression ◽  
The Body ◽  
Flight Mechanics ◽  
Total Power ◽  
Forward Flight ◽  
Vortex Theory ◽  
Rate Of Increase ◽  
Total Power Consumption

The mechanics of lift and thrust generation by flying animals are studied by considering the distribution of vorticity in the wake. As wake generation is not continuous, the momentum jet theory, which has previously been used, is not satisfactory, and the vortex theory is a more realistic model. The vorticity shed by the wings in the course of each powered stroke deforms into a small-cored vortex ring; the wake is a chain of such rings. The momentum of each ring sustains and propels the animal; induced power is calculated as the rate of increase of wake kinetic energy. A further advantage of the vortex theory is that lift and induced drag coefficients are not required; estimated instantaneous values of these coefficients are generally too large for steady state aerodynamic theory to be appropriate to natural flapping flight. The vortex theory is applied to hovering of insects and to avian forward flight. A simple expression for induced power in hovering is found. Induced power is always greater than simple momentum jet estimates, and the discrepancy becomes substantial as body mass increases. In hovering the wake is composed of a stack of horizontal, coaxial, circular vortex rings. In forward flight of birds the rings are elliptic; they are neither horizontal nor coaxial because the momentum of each ring balances the vector sum of parasite and profile drag and the bird's weight. Total power consumption as a function of flight velocity is calculated and compared for several species. Power reduction is one of the major factors influencing the choice of flight style. A large body of data is used to obtain an approximate scaling between stroke period and the body mass for birds. Together with relations between other morphological parameters, this is used to estimate the variation of flight speed and power with body mass for birds, and on this basis deviations from allometric scaling can be related to flight proficiency and to the use of such strategies as the bounding flight of small passerines. Note: Present address: Department of Zoology, University of Bristol, Woodland Road, Bristol BS8 IUG, U.K.

Acyl composition of muscle membranes varies with body size in birds

2002 ◽  
Vol 205 (22) ◽  
pp. 3561-3569 ◽  
Author(s):  
A. J. Hulbert ◽  
S. Faulks ◽  
W. A. Buttemer ◽  
P. L. Else
Keyword(s):  
Body Size ◽  
Body Mass ◽  
Acyl Chain ◽  
Bird Species ◽  
Unsaturation Index ◽  
Pectoral Muscle ◽  
Muscle Membrane ◽  
Index Number ◽  
Acyl Composition ◽  
Metabolic Intensity

SUMMARYThe acyl composition of phospholipids from pectoral muscle of eight species of birds, ranging in size from the 13 g zebra finch to the 34 kg emu, were measured and combined with recent published results for a 3 g hummingbird. This represents an approximately 11000-fold range in body mass. Muscle phospholipids, and thus muscle membrane bilayers, from birds had a relatively constant unsaturated acyl chain content of 62% but exhibited a significant allometric decline in unsaturation index (number of double bonds per 100 acyl chains) with increasing body mass. There was a significant allometric increase in the percentage of mono-unsaturates and a significant allometric decline in the percentage of n-3 polyunsaturates with increasing body mass,whilst there were no significant allometric trends in either percentage of n-6 or percentage of total polyunsaturates in bird muscle. The relative content of the highly polyunsaturated docosahexaenoic acid (22:6 n-3) showed the greatest scaling with body mass, having an allometric exponent of -0.28. The contribution of this n-3 polyunsaturate to the unsaturation index varied with body size, ranging from less than a 6%contribution in the emu to approximately 70% in the hummingbird. Such allometric variation in the acyl composition of bird muscle phospholipids is similar to that observed in mammals, although birds have fewer n-3 polyunsaturates and more n-6 polyunsaturates than do mammalian phospholipids. This allometric variation in phospholipid acyl composition is discussed with respect to both the metabolic intensity and lifespan of different sized bird species.

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