bluuebunny/crossref_metadata_2025 huggingface dataset:
The Polls: Polling for a Defense: The White House Public Opinion Apparatus and the Clinton Impeachment
Authors: HEITH DIANE J.
Published: February 2004

Public opinion was closely watched during President Bill Clinton's impeachment scandal and trial by the president, other political officials, and the mass media. Although polls have become an integral part of presidential politics and policy making, Clinton's use of them during this episode has raised questions with regard to their proper use. This article look at the controversy surrounding Clinton's use of polls in his effort to avoid impeachment and conviction.
Lessons from Past Presidential Transitions: Organization, Management, and Decision Making
Authors: BURKE JOHN P.
Published: February 2004

In addition to careful and early consideration of the key positions on the White House staff and other appointments, transitions are also a time when presidents‐to‐be and their advisers need to think about how the pieces fit together into a larger whole. Part of that effort involves crafting the decision‐making processes and the various channels of information and advice that, once in office, presidents will need to use in making policy choices. Another piece entails the marketing and selling of those policy proposals to the public and Congress and otherwise bringing them to successful fruition. Still another are the management task that are associated with policy making and implementation. How are the skills and talents of a diverse range of actors successfully brought together and coordinated? How is a sense of teamwork and commitment instilled and conflict and tension avoided?
The Presidency and the Political Environment
Authors: KESSEL JOHN H.
Published: February 2004

For a White House staff to be successful, it must adapt to the work style of its own president and to the needs of the external institutions with which the president has continuing relations. This dual adaptation allows the staff to stabilize the White House in a stormy political environment. Examples are given of adaptations to the work styles of Presidents Nixon, Ford, Carter, Reagan, Bush, and Clinton. Examples are also provided of adaptations to the needs of Congress, the press, and those engaged in foreign policy, economics, domestic policy, and the law. The requirements of understanding various professional vocabularies and coordinating staff units are noted.
The White House As City Hall: A Tough Place to Organize
Authors: KUMAR MARTHA JOYNT
Published: February 2004

The White House is unlike any other organization as there are few records left behind by those having the building and none of the core White House staff who remain once a President leaves. At the same time, the new team is responsible from day one for making informed and appropriate decisions. There is little preparation that can provide people with an understanding of what they are to meet once they come into office, but there are ways in which a new staff can take advantage of the knowledge of those who precede them. They can speak with their predecessors, talk with people who work at the Office of Management and Budget, and learn from the executive clerk and others at the White House who provide an institutional memory of their own.
The New World Order in Theory and Practice: The Bush Administration's Worldview in Transition
Authors: MILLER ERIC A. , YETIV STEVE A.
Published: February 2004

The twentieth century saw several major postwar efforts to create conditions conducive to the development of a new world order. This article focuses on the period of the end of the cold war, particularly the Persian Gulf crisis (1990‐1991). The authors analyze how the concept of the new world order evolved during this period and argue that the Bush administration consciously sought to create a framework for a new world order during the Gulf crisis. This framework was based on checking the offensive use of force, promoting collective security, and using great power cooperation.
Causes of Change in National Security Processes: Carter, Reagan, and Bush Decision Making on Arms Control
Authors: NEWMANN WILLIAM
Published: February 2004

This article merges the literature on national security decision making with scholarly work on presidential decision making. It examines ways in which national security decision‐making structures are changed by international and domestic political forces as well as presidential management of the bureaucratic and organizational politics within the executive branch. Three decision‐making case studies–the Carter administration's March 1977 Strategic Arms Limitations Talks II(SALT II) proposal, the Reagan administration's initial strategic arms reduction proposal of May 1982, and President Bush's speech of September 1991 that led to the Strategic Arms Reduction Talks (START) II–illustrate the dynamic and evolving nature of the national security decision‐making process. The case studies suggest that presidents make modifications in their standard interagency processes for the deliberate purpose of achieving specific political goals. Adjustments in policy are the impetus for adjustments in process.
Reform As Affirmation: Jimmy Carter's Executive Branch Reorganization Effort
Authors: SEYB RONALD P.
Published: February 2004

Modern presidents must negotiate the tension between, on one hand, public demands for systemic change and, on the other hand, contextual and institutional constraints that limit their authority and ability to achieve “reconstructive” reforms. Jimmy Carter's executive branch reorganization effort illustrates how institutional decision‐making processes can impede presidents' attempts to pursue innovative approaches to reform. This article maintains that a “garbage ca” decision‐making process led Carter and his aides to abandon their initial novel “bottom‐up” approach to reorganization in favor of the traditional “top‐down” structural approach adopted by their predecessors. The article concludes that institutional pressures compelled the recent president most intent on repudiating the past to affirm it.
The Contemporary Presidency: The Presidential “Hundred Days”: An Overview
Authors: NEUSTADT RICHARD E.
Published: February 2004

The “Hundred Days” of 1933, when Franklin D. Roosevelt at the onset of his first term got sixteen major bills through Congress, is a poor guide to what contemporary presidents can plan or hope to do in their first three months. For one thing, under the Twentieth Amendment, Congress is already in regular session when they arrive, and three months takes one only to the Easter recess of the first session. For another thing, presidential “honeymoons” with the public, hence with Congress, rarely last until summer, while the crucial months for controversial bids usually come later. Third, brand‐new presidents and their associates in both the cabinet and White House tend to be too ignorant of Congress and of one another to take full advantage of the opportunities their first months bring.
The Law: Presidential Memoranda and Executive Orders: Of Patchwork Quilts, Trump Cards, and Shell Games
Authors: COOPER PHILLIP J.
Published: February 2004

When President Clinton took office, he moved rapidly on a batch of controversial policy initiatives using executive orders and also presidential memoranda, a device known and understood by few and virtually ignored in the literature. This article explores the use of presidential memoranda and executive orders as policy tools, focusing on the case of the Clinton administration environmental justice initiative. While the ends may be laudable, the means can be problematic. The analysis concludes that presidential memoranda are devices that have come to be increasingly important, but they can present significant political and legal problems, particularly if they confuse legal authority for presidential action and appear to hide the true nature and purpose of administration policy, in which memoranda are used in place of executive orders or even more exotic techniques are used to craft policy that is in truth in the nature of an executive order.
The Polls: Popular Views of the Vice President: Vice Presidential Approval
Authors: COHEN JEFFREY E.
Published: February 2004

Poll interest in the vice president has expanded in recent years as the office has become more important in policy making and as a stepping stone to the presidency. This article track these trends in poll interest in the vice presidency and then compares the approval ratings of Bill Clinton and Al Gore during Gore's tenure as Clinton's vice president. Clinton's approval casts a long shadow on approval of his vice president, but data also indicate some differences in the sources of approval of these two national figures.
Source Material: Presidents and Polling: Politicians, Pandering, and the Study of Democratic Responsiveness
Authors: SHAPIRO ROBERT Y. , JACOBS LAWRENCE R.
Published: February 2004

The authors review what is known about the relationship between public opinion and presidential policy making. While American presidents have paid increasing attention to public opinion with the institutionalization of polling and public opinion analysis in the White House, it should by no means be presumed that policy making has become more responsive to public opinion. Recent political developments have provided presidents and both parties in Congress increasing incentives and opportunity to attempt to lead or manipulate public opinion. Evidence from the Clinton years most strikingly demonstrates this. We are only now beginning to learn about the relationship between presidents and the polling and public opinion analysis that has gone on in presidential administrations since the 1960s. The working hypothesis is that the Reagan years are pivotal in understanding recent and future developments regarding the relationship between public opinion and presidential behavior.
Logistic regression models for predicting occurrence of terrestrial molluscs in southern Sweden – importance of environmental data quality and model complexity
Authors: Berg Åke , Gärdenfors Ulf , Von Proschwitz Ted
Published: February 2004

We compared the performance of four logistic regression models of different complexity with different environmental data quality, in predicting the occurrence of 49 terrestrial mollusc species in southern Sweden. Performance of models derived from an explanatory data set was evaluated on a confirmatory data set. The overall predictive success of our models (>80% for the three best model approaches), is as good as in other studies, despite the fact that we had to transform a text database into quantitative habitat variables. Simple models (no variable interactions), with forward selection, and detailed habitat data (from field visits) showed the best overall predictive success (mean=84.8%). From comparisons of model approaches, we conclude that data quality (map‐derived data vs habitat mapping) had a stronger impact than model complexity on model performance. However, most of these models showed relatively low values (mean=0.29) for Kappa (statistic for model evaluation), suggesting that the models need to be improved before they would be applied. Predictive success was strongly associated with species incidence but also Kappa was positively correlated with species incidence in univariate tests. Predictive success for true absences was negatively correlated with predictive success for true presences (R2=0.69) and most models failed to give a good prediction of both categories. Models for species with a high incidence in “Open dry sites” or “Mesic interior forests” had a better performance than expected, suggesting that occurrences of species with preference for “narrow” habitats are most easy to predict. Tree layer variables (openness and species abundance) were included in 48 of the 49 final predictive models, suggesting that these variables were good “indicators” of habitat conditions for ground‐living molluscs. Twenty‐four species models included distance to coast and altitude, and we interpret these associations as partly being related to differences in climate. In the final models, true presences (36.9% correctly classified) were much more difficult to predict than true absences (89.7% correct). Possible explanations might be that important habitat variables (e.g. chemical variables and site history) were not included. On the other hand, all suitable sites would not be expected to be occupied due to dynamics in local extinctions (meta‐population theory).
Growth in relation to microclimatic conditions and physiological characteristics of four Lobaria pulmonaria populations in two contrasting habitats
Authors: Gaio‐Oliveira Gisela , Dahlman Lena , Máguas Cristina , Palmqvist Kristin
Published: February 2004

The aim of the present study was to compare the physiological characteristics of various populations of the lichen Lobaria pulmonaria in Portugal and Sweden. For this, indirect markers of algal (photobiont) and fungal (mycobiont) activity were measured, as well as their CO2 gasexchange characteristics. Microclimatic conditions and the lichens growth performance in the two countries were compared using reciprocal transplantation. Two populations of L. pulmonaria represented each country: one collected from forest interior conditions and one from forest edge habitats. A non‐transplanted “wild” population was also studied in each country, in order to evaluate any transplantation effects per se. The main hypothesis were that; 1) growth should be faster in Portugal due to higher light availability; 2) the energy use efficiency of lichen biomass gain should be similar for the native populations in their respective native habitat; 3) if the lichens were able to adapt to the environmental conditions in the foreign habitat this should be revealed as similar growth rates among all thalli transplanted at the same site, regardless of their origin. Physiologically, the Portuguese and Swedish populations were very similar, both concerning their CO2 gas exchange characteristics and distribution of resources between photo‐ and mycobiont tissue. Environmental conditions were more advantageous for L. pulmonaria growth in Portugal, i.e. higher photon flux densities and ambient temperatures when the lichens were wet and active, and a lower fraction of the active time occurring in darkness. However, despite similar physiological characteristics of all the studied populations, the Swedish lichens were not able to grow as well in Portugal as the native, while all populations had similarly low growth rates in Sweden.
Body size trends in a Holocene island bird assemblage
Authors: Cassey Phillip , Blackburn Tim. M.
Published: February 2004

Despite the robust observation in macroecology that there are many small‐bodied species, recent comparative studies have found little evidence for elevated net rates of diversification among small‐bodied species within taxa. Here we examine the relationship between body size and species richness using the New Zealand land bird fauna, a well resolved palaeoecological Holocene assemblage. We test whether there is any evidence that net cladogenesis depended on body size in an assemblage prior to the impact of human‐induced extinction. We also test whether net cladogenesis depends on the level at which taxa are endemic to New Zealand, to see whether there is evidence for bursts of cladogenesis following taxon establishment, and examine how the body sizes of New Zealand land birds relate to those in Australia, the most likely source pool for colonising taxa. Most New Zealand land bird species are small‐bodied. We find no evidence, however, that this is due to higher net cladogenesis in small‐bodied taxa. The body mass distributions of endemic and recent colonist species do not differ statistically, but recent colonists tend to be smaller‐bodied than their closest endemic relative. This tendency is more marked for small‐bodied than large‐bodied taxa. More endemic taxa do not tend to be more species rich in New Zealand, although there is a positive relationship between level of endemism and species richness for forest taxa. The body mass distribution of New Zealand birds is very similar to that for Australia. Body mass does not dictate the likelihood that a family has colonised New Zealand from Australia, but the number of species in the family does: it is the species rich Australian families that have successfully colonised. We discuss the implications of these results for the evolution of body size distributions, and for the “island rule” of body size evolution on islands.
Population viability analysis of the butterfly Lopinga achine in a changing landscape in Sweden
Authors: Bergman Karl‐Olof , Kindvall Oskar
Published: February 2004

Metapopulation theory has generally focused only on the stochastic turn‐over rate among populations and assumed that the number and location of suitable habitat patches will remain constant through time. This study combines in a PVA both the deterministic landscape dynamics and the stochastic colonisations and extinctions of populations for the butterfly Lopinga achine in Sweden. With data on occupancy pattern and the rate of habitat change, we built a simulation model and examined five different scenarios with different assumptions of landscape changes for L. achine. If no landscape changes would be expected, around 80 populations are predicted to persist during the next 100 yr. Adding the knowledge that many of the sites are unmanaged and that the host plant will slowly deteriorate as canopies close over, and adding environmental variation and synchrony, showed that the number of populations will decrease to around of 4.3 and 2.8 respectively, with an extinction risk of 34% – quite different from the first scenario based only on the metapopulation model. This study has shown the importance of incorporating both deterministic and stochastic events when making a reliable population viability analysis. Even though one can not expect that the long‐term predictions of either occupied patches or extinction risks will be accurate quantitatively, the qualitative implications are correct. The extinction risk will be high if grazing is not applied to more patches than is the case today. The simulations indicate that an absolute minimum of 10–30 top‐ranked patches needs to be managed for the persistence of the metapopulation of L. achine in the long term. The same problem of abandoned and overgrowing habitats affects many other threatened species in the European landscape and a similar approach could also be applied to them.
Butterfly species richness in mainland Portugal: predictive models of geographic distribution patterns
Authors: Hortal Joaquín , Garcia‐Pereira Patrícia , García‐Barros Enrique
Published: February 2004

A three‐step protocol described elsewhere is used to obtain a map of butterfly species density in Portugal on a 50×50 km grid. First, all available faunistic information was compiled and analysed to explore the historic patterns of butterfly sampling in Portugal, and to determine which grid cells are sufficiently prospected to produce reliable estimates of species richness. Then, we relate the estimated species richness scores from these areas to a set of environmental and spatial variables by means of General Linear Models, obtaining a function to extrapolate of species density scores to the rest of Portugal. Finally, the model is validated, results explored and outliers identified and deleted. Any spatial autocorrelation remaining in the residuals is examined. Lastly, model parameters are recalculated in absence of deleted outliers, and the resulting function is used to predict species richness scores throughout mainland Portugal. A highly‐predictive function based on some variables previously related to butterfly composition at macro‐scale, such as number of sunny days per year, temperature or environmental heterogeneity, was obtained. However, in Portugal those variables are highly spatially structured along a steep latitudinal gradient, leading to difficulty in ascertaining if the latitudinal gradient detected by our analysis is due to macroecological or historic effects. Information on European and Iberian butterfly assemblages and causal processes are discussed in the light of the patterns observed. Then, previous information obtained on Portuguese scarabs is added to identify conservation areas, biogeographically important for both insect groups. Finally, the main drawbacks and advantages of this approach to mapping biodiversity for conservation are discussed briefly.
Interannual changes in folivory and bird insectivory along a natural productivity gradient in northern Patagonian forests
Authors: Noemi Mazía C. , Kitzberger Thomas , J. Chaneton Enrique
Published: February 2004

Trophic regulation models suggest that the magnitude of herbivory and predation (top‐down forces) should vary predictably with habitat productivity. Theory also indicates that temporal abiotic variation and within‐trophic level heterogeneity both affect trophic dynamics, but few studies addressed how these factors interact over broad‐scale environmental gradients. Here we document herbivory from leaf‐feeding insects along a natural rainfall/productivity gradient in Nothofagus pumilio forests of northern Patagonia, Argentina, and evaluate the impact of insectivorous birds on foliar damage experienced by tree saplings at each end of the gradient. The study ran over three years (1997–2000) comprising a severe drought (1998–1999), which allowed us to test how climatic events alter top‐down forces. Foliar damage tended to increase towards the xeric, least productive forests. However, we found a predictable change of insect guild prevalence across the forest gradient. Leaf miners accounted for the greater damage recorded in xeric sites, whereas leaf chewers dominated in the more humid and productive forests. Interannual folivory patterns depended strongly on the feeding guild and forest site. Whereas leaf‐miner damage decreased during the drought in xeric sites, chewer damage increased after the drought in the wettest site. Excluding birds did not affect leaf damage from miners, but generally increased chewer herbivory on hydric and xeric forest saplings. Indirect effects elicited by bird exclusion became most significant after the drought, when total folivory levels were higher. Thus, interannual abiotic heterogeneity markedly influenced the amount of folivory and strength of top‐down control observed across the forest gradient. Moreover, our results suggest that spatial turnovers between major feeding guilds may need be considered to predict the dynamics of insect herbivory along environmental gradients.
Contrasting effects of habitat quantity and quality on moth communities in fragmented landscapes
Authors: Summerville Keith S. , Crist Thomas O.
Published: February 2004

Habitat loss is commonly identified as a major threat to the loss of global biodiversity. In this study, we expand on our previous work by addressing the question of how lepidopteran species richness and composition vary among remnants of North American eastern deciduous forest located within agricultural or pastoral landscapes. Specifically, we tested the relative roles of habitat quantity (measured as stand area and percent forest in the greater landscape) and habitat quality (measured as tree species diversity) as determinants of moth species richness. We sampled >19 000 individuals comprising 493 moth species from 21 forest sites in two forested ecoregions. In the unglaciated Western Allegheny Plateau, the species richness of moths with woody host plants diminished as forest stand size and percent forest in the landscape decreased, but the total species richness and abundance of moths were unaffected by stand size, percent forest in the landscape, or tree species diversity. In contrast, the overall species richness and abundance of moths in the glaciated North Central Tillplain were affected primarily by tree species diversity and secondarily by forest size. Higher tree species diversity may reduce species loss from smaller forest stands, suggesting that small, diverse forests can support comparable numbers of species to those in less diverse, large stands. Smaller forests, however, contained a disproportionate number of moth species that possess larvae known to feed on herbaceous vegetation. Thus, although woody plant feeding moths are lost from forests with changes in stand area, new species appear capable of recolonizing smaller fragments from the surrounding habitat matrix. Our study further suggests that when species replacement occurs, local patch size and habitat quality may be more important than landscape context in determining the community structure of forest Lepidoptera.
Spore deposition of wood‐decaying fungi: importance of landscape composition
Authors: Edman Mattias , Gustafsson Mårten , Stenlid Jan , Jonsson Bengt Gunnar , Ericson Lars
Published: February 2004

The abundance of many species of wood‐decaying fungi has decreased dramatically in Swedish boreal forests over the last century. Therefore, we have investigated the relationship between the spore dispersal of wood‐decaying fungi and two key features of landscape composition, namely the amount and age of old forest stands at different spatial scales. Spore deposition was monitored in two regions, using sampling methods based on recording the dikaryotisation of monokaryotic mycelia on nutrient agar and wood discs. The studied species, all mainly confined to Norway spruce in the boreal forest zone, were Fomitopsis pinicola,Fomitopsis rosea, Gloeoporus taxicola, Phlebia centrifuga and Trichaptum laricinum. The study of forestry intensity showed for both regions, that the spore deposition for F. pinicola, F. rosea and G. taxicola was higher in circular plots (radius 2‐km) with a high proportion of old Norway spruce forest (>80 yr) than in plots with a lower proportion of old forest. Analysis of the variation in spore deposition of F. rosea and P. centrifuga in relation to the proportion of old spruce forest within 1, 2 and 3 km of the spore sampling point showed that the proportion of old forest within a 3‐km radius explained more of the variation than the proportions within 1‐ and 2‐km radii. In addition, the proportion of forest older than 140 yr explained more of the variation than the proportion of younger forests. Thus, the results show that the spore deposition of the studied species strongly depends on the landscape composition at both regional and local scales. Further, the spore deposition at the local scale was best explained by the proportion of >140 yr old spruce forest, which exceeds the common harvest rotation period.
Characteristics of fleshy fruits in southeast Alaska: phylogenetic comparison with fruits from Illinois
Authors: Traveset Anna , F. Willson Mary , Verdú Miguel
Published: February 2004

Over 30 species of fleshy‐fruited plants are found in southeast Alaska. In this paper we examine traits such as plant growth form, phenology, fruit color, seed load, pulp dry weight, and pulp nutrient content and compare them with those of fruits from central Illinois. Two comparative methods (continuous time Markov model and phylo‐Anova) were used to compare both qualitative and quantitative traits between the two regions. Although fleshy‐fruited plants from SE Alaska appear to be predominantly shrubs or herbs in contrast to central Illinois, where trees and vines tend to be more common, no significant differences among growth forms were found when accounting for plant phylogeny. In SE Alaska, most fruits mature in August and September, whereas most fruits mature later in the autumn in Illinois. Red fruits are more common in Alaska than in Illinois, where blue‐black fruits predominate. Alaskan fruits have a significantly greater seed load than fruits in Illinois, while pulp dry weight does not differ between the two regions. Although the proportion of sugars and lipids in the pulp was not statistically different between the two regions, total reward of the pulp (estimated as the absolute amount of sugars plus twice the amount of lipids, as lipids provide about twice the energy of sugars) was greater in Alaskan than in Illinois fruits. Neither phylogenetic constraints nor selection by frugivores appear to account fully for the regional distribution of fruit characteristics.
Spatial point pattern analysis of available and exploited resources
Authors: Lancaster Jill , J. Downes Barbara
Published: February 2004

A patchy spatial distribution of resources underpins many models of population regulation and species coexistence, so ecologists require methods to analyse spatially‐explicit data of resource distribution and use. We describe a method for analysing maps of resources and testing hypotheses about species' distributions and selectivity. The method uses point pattern analysis based on the L‐function, the linearised form of Ripley's K‐function. Monte Carlo permutations are used for statistical tests. We estimate the difference between observed and expected values of L(t), an approach with several advantages: 1) The results are easy to interpret ecologically. 2) It obviates the need for edge correction, which has largely precluded the use of L‐functions where plot boundaries are “real”. Including edge corrections may lead to erroneous conclusions if the underlying assumptions are invalid. 3) The null expectation can take many forms, we illustrate two models: complete spatial randomness (to describe the spatial pattern of resources in the landscape) and the underlying pattern of resource patches in the landscape (akin to a neutral landscape approach). The second null is particularly useful to test whether spatial patterns of exploited resource points simply reflect the spatial patterns of all resource points. We tested this method using over 100 simulated point patterns encompassing a range of patterns that might occur in ecological systems, and some very extreme patterns. The approach is generally robust, but Type II decision errors might arise where spatial patterns are weak and when trying to detect a clumped pattern of exploited points against a clumped pattern of all points. An empirical example of an intertidal lichen growing on barnacle shells illustrates how this technique might be used to test hypotheses about dispersal mechanisms. This approach can increase the value of survey data, by permitting quantification of natural resource patch distribution in the landscape as well as patterns of resource use by species.
Qualitative geographical variation in interspecific interactions
Authors: Mönkkönen Mikko , Forsman Jukka T. , Thomson Robert L.
Published: February 2004

We explore geographical variation in the density relationship between potential competitor forest bird groups, resident Parus spp. and migrant Fringilla spp., across Europe using published bird census results. In addition, we summarized results from three experimental studies from northern Europe on their density associations. Based on anticipated changes in the relative intensity of positive and competitive interactions we predicted a unimodal density association between Parus and Fringilla: at low and intermediate densities the two groups are positively associated (positive interaction), whereas high densities promote interspecific competition. In central Europe where densities are high, densities were unimodally related to each other. In northern and southern Europe linear and positive associations appeared. Experimental studies provided consistent support for positive interspecific interactions in the north. The results suggest that species interactions may indeed vary in relation to the density of potential competitor and switch from positive to negative along environmental gradients.
Sexual dichromatism in the yellow‐breasted chat Icteria virens: spectrophotometric analysis and biochemical basis
Authors: Mays Jr. Herman L. , McGraw Kevin J. , Ritchison Gary , Cooper Steve , Rush Victor , Parker Robert S.
Published: February 2004

Sexual dimorphism or dichromatism has long been considered the result of sexual selection. However, for many organisms the degree to which sexual dichromatism occurs has been determined within the confines of human perception. For birds, objective measures of plumage color have revealed previously unappreciated sexual dichromatism for several species. Here we present an unbiased assessment of plumage dichromatism in the yellow‐breasted chat Icteria virens. Chats exhibit yellow to orange throat and breast plumage that to the unaided human observer differs only subtly in color. Spectrophotometric analyses revealed that chat throat and breast feathers exhibited reflective curves with two peaks, one in the ultraviolet and one in the yellow end of the spectrum. We found differences in both the shape and magnitude of reflectance curves between males and females. Moreover, for feathers collected from the lower edge and middle of the breast patch, male plumage reflected more light in the ultraviolet and yellow wavelengths compared to females, whereas male throat feathers appeared brighter than those of females only in the ultraviolet. Biochemical analyses indicated that the plumage pigmentation consisted solely of the carotenoid all‐trans lutein and we found that males have higher concentrations of plumage carotenoids than females. Feathers that were naturally unpigmented reflected more UV light than yellow feathers, suggesting a potential role of feather microstructure in UV reflectance.
Are long‐distance migrant passerines faithful to their stopover sites?
Authors: Catry Paulo , Encarnação Vitor , Araújo António , Fearon Peter , Fearon Anne , Armelin Michael , Delaloye Peter
Published: February 2004

Long‐distance migrant passerines are well known to often display high levels of philopatry to breeding and wintering grounds. One could expect that similar selective pressures and similar navigation skills would result in their being faithful to stopover sites, a pattern that has been described for several populations of migratory waders and waterfowl. In this paper, we develop the argument that passerines should suffer from higher costs and receive lower benefits from stopover site faithfulness than waterfowl and waders. Based on Alerstam's (1979)“optimal drift strategy” theory and other considerations, we predict that passerines should have lower stopover site fidelity than geese and waders, and that site faithfulness should decrease with increasing distance from either end of the migratory journey. We present results from a long‐term study on the stopover ecology of migrant passerines in southern Portugal that support these predictions and show that, for species and populations that neither nest nor winter in this country, few individuals are faithful to the stopover site. On the other hand, populations that included individuals at (or near to) the start or the end of the migratory journey, had much higher return rates. We could not find any evidence that species linked to scarce habitats, such as wetlands, were more site faithful. Our results are in agreement with several other reports, but in apparent contrast to previous conclusions resulting from some studies involving Old World warblers. These differences are discussed and it is argued that there is no solid evidence to suggest that site fidelity should be important for passerines at stopovers far away from breeding or wintering grounds, meaning that there is a large within‐individual variability in the precise migratory routes and stopover sequence used each year.
Energetics of the moult fast in female macaroni penguins Eudyptes chrysolophus
Authors: Green Jonathan A. , Butler Patrick J. , Woakes Anthony J. , Boyd Ian L.
Published: February 2004

The metabolic rate of moulting macaroni penguins Eudyptes chrysolophus was investigated using three techniques in order to test two hypotheses concerning the energetic cost of the moult fast in penguins. First, that energy expenditure during the moult is greater than that while penguins are onshore during the breeding season. Second, techniques that do not measure energy expenditure throughout the moult fast do not accurately determine the true cost of the moult. Mass loss calculations, measurement of the rate of oxygen consumption and estimation of the rate of oxygen consumption from heart rate in the field were used with captive and free‐ranging penguins. Comparison of the results from these techniques suggest that metabolic rate is higher in the field than in a respirometer due to an increase in thermoregulatory costs. Furthermore the average metabolic rate of female penguins during the moult at 5.04±0.85 W kg−1 was not significantly different from that of female penguins on‐shore during the breeding season at 6.27±0.38 W kg−1. Metabolic rate in the field changed during the moult fast as feather loss and increased vascularisation of the skin caused increased heat production, illustrating the importance of determining energy expenditure from animals in the field throughout the whole of the moult fast.
Egg characteristics are unreliable in determining maternity in communal clutches of guira cuckoos Guira guira
Authors: O. Cariello Mariana , R. Lima Marcos , G. Schwabl Hubert , H. Macedo Regina
Published: February 2004

Egg characteristics have been used to determine egg maternity for birds in situations where two or more females lay eggs in a single nest (as in communal breeders and intraspecific parasites). We assessed the applicability of egg morphometry and eggshell appearance in ascribing egg ownership in communal clutches of guira cuckoos Guira guira, a species where up to seven females may lay eggs in a joint nest. We used both combined variables (including egg mass, length, width, shape and two eggshell variables), and a shape index to test whether eggs laid by each female were similar but different from eggs laid by other females. Also, we conducted discriminant function analyses to verify if eggs could be correctly classified to their mothers based on their characteristics. The correct maternity was determined by yolk protein electrophoresis of freshly‐laid eggs. Individual female chutches were separated through egg characteristics or shape alone in 29% and 41% of the groups tested, respectively. Differences were mostly due to a single female that differed from her nest‐mates in a unique egg variable. On average, 55% of the eggs analyzed were not assigned to the correct mother using egg dimensions and eggshell speckling pattern. In conclusion, the egg characteristics used do not reliably indicate maternity in guira cuckoo communal clutches. We therefore recommend a protein‐based verification of egg appearance characteristics for assigning maternity in other species in which multiple female laying occurs.
Effects of microhabitat preferences on kelp gull Larus dominicanus breeding performance
Authors: García‐Borboroglu Pablo , Yorio Pablo
Published: February 2004

We examined microhabitat preferences and their adaptiveness for the kelp gull Larus dominicanus in one of its largest colonies in Patagonia. We quantified 13 habitat variables at 104 and 92 nest‐sites and at 70 and 60 random points in 1998 and 1999, respectively. We recorded egg laying dates, hatching success, number of chicks fledged and breeding success at 92 of these nests in each of the study seasons. Compared to random points, nest sites had more vegetation cover and were closer to the nearest available bush, but they were located further from the nearest clearing for flight take‐off, all variables included in the “vegetation” principal component. Nests were built on substrates with lower slopes and higher percentages of silt‐clay, but with lower percentages of rock. In both years, hatching success, number of chicks fledged and breeding success were related positively to the vegetation principal component. Substrate slope and composition contributed to explain the variation in hatching and breeding success in 1998 and 1999, respectively. Our study shows that some kelp gull breeding parameters are affected by nest‐site habitat characteristics. These associations were in most cases influenced by the timing of breeding, with earlier breeders being more successful. Vegetation effects and substrate characteristics were important variables in distinguishing random sites from nest sites, and in explaining variation in breeding performance, showing that their habitat preferences are adaptive and allowing us to detect both the pattern and process in kelp gull habitat selection.
Feeding patch selection by herbivorous Anatidae: the influence of body size, and of plant quantity and quality
Authors: Durant Daphné , Fritz Hervé , Duncan Patrick
Published: February 2004

Recent findings suggest that herbivores select feeding sites of intermediate biomass in order to maximise their digestible nutrient intake as the result of the trade‐off between forage quality and quantity (‘forage maturation hypothesis’). We propose a reformulation of this hypothesis which recognises this trade‐off, but also underlines that constraints due to body mass (i.e. metabolism and digestive constraints, size of the feeding apparatus) can lead to variations in grazing patterns. We tested this latter hypothesis experimentally in three species of herbivorous Anatidae of different body mass: the wigeon Anas penelope (in our study c. 620 g), the barnacle goose Branta leucopsis (c. 2000 g), and the greylag goose Anser anser (c. 3500 g). Each species was tested separately from 0600 to 0930 hours, in an enclosure with a mosaic of patches of grass of three different heights: short, medium and tall. The behaviour, and the location (i.e. patch) of each individual were recorded every 5 minutes. Our results show important interspecific differences in intake rates resulting in different feeding site selection: wigeon and barnacle goose fed fastest on the shortest swards, and selected short grass which was also of higher quality. Tall grass provided the highest dry matter intake rate and digestible protein intake for greylag geese, and they preferred these swards. These choices allowed the birds to maximise their digestible nitrogen intake rate rather than dry matter intake rate and our results thus underline the importance of nitrogen as a major currency for foraging decisions in herbivorous Anatidae. Since the birds selected the two extreme sward heights (instead of the medium one), the results give support to our hypothesis and underline the role of body size as an important cause of variations in patch selection in herbivorous Anatidae.
Mitochondrial phylogeny of Locustella and related genera
Authors: V. Drovetski Sergei , M. Zink Robert , V. Fadeev Igor , V. Nesterov Evgeniy , A. Koblik Evgeniy , A. Red'kin Yaroslav , Rohwer Sievert
Published: February 2004

We used maximum likelihood analysis of complete mitochondrial ND2 sequences (1041 bp) to clarify the taxonomy and relationships of various species and genera of grass and bush warblers. The tree revealed two clades of grass and bush warblers. One clade was comprised of all four western Palearctic Locustella and two species of Asian Bradypterus. The other clade included five eastern Palearctic Locustella (including the distinctive Sakhalin warbler Locustella amnicola) and the marsh grassbird Megalurus pryeri. African Bradypterus and Australian little grassbird Megalurus gramineus were distantly related to their Asian congeners. Therefore, current taxonomy of these genera does not reflect their evolutionary history and needs revision. It is proposed that a phylogenetic analysis of morphology and ecological preferences would show that the current taxonomy of grass and bush warblers reflects species’ habitat preferences and morphology related to locomotion and foraging in their habitats, rather than their shared ancestry. Distinct clades were found in grasshopper warbler Locustella naevia and Pallas's grasshopper warbler L. certhiola. Detailed phylogeographic studies are needed to elucidate the species status of the clades within these two species.
Movement and direction of movement of a simulated prey affect the success rate in barn owl Tyto alba attack
Authors: Shifferman Eran , Eilam David
Published: February 2004

The present study was aimed at testing a novel idea, that rather than maximizing their distance from a predator during close‐distance encounters, prey species are better off moving directly or diagonally toward the predator in order to increase the relative speed and confine the attack to a single available clashing point. We used two tamed barn owls Tyto alba to measure the rate of attack success in relation to the direction of prey movement. A dead mouse or chick was used to simulate the prey, pulled to various directions by means of a transparent string during the owl's attack. Both owls showed a high success rate in catching stationary compared with moving food items (90% and 21%, respectively). Success was higher when the prey moved directly away, rather than towards the owls (50% and 18%, respectively). Strikingly, these owls had 0% success in catching food items that were pulled sideways. This failure to catch prey that move sideways may reflect constraints in postural head movements in aerial raptors that cannot move the eyes but rather move the entire head in tracking prey. So far there is no evidence that defensive behavior in terrestrial prey species takes advantage of the above escape directions to lower rates of predator success. However, birds seem to adjust their defensive tactics in the vertical domain by taking‐off at a steep angle, thus moving diagonally toward the direction of an approaching aerial predator. These preliminary findings warrant further studies in barn owls and other predators, in both field and laboratory settings, to uncover fine predator head movements during hunting, the corresponding defensive behavior of the prey, and the adaptive significance of these behaviors.
Gizzard and other lean mass components increase, yet Basal Metabolic Rates decrease, when red knots Calidris canutus are shifted from soft to hard‐shelled food
Authors: Piersma Theunis , Gessaman James A. , Dekinga Anne , Visser G. Henk
Published: February 2004

We measured basal metabolic rate (BMR), body mass, lean mass, and gizzard mass of captive red knots Calidriscanutusislandica maintained on a trout chow diet (soft‐texture, low ash and water content) for several years and then shifted to small mussels Mytilus edulis (hard‐texture, high ash and water content). During a 3‐week period of feeding on mussels, body mass, lean mass, and gizzard mass increased 7.3 g (+7%), 10.5 g (+12%), and 4.9 g (+213%), respectively, yet BMR decreased from 0.96 to 0.89 W (−8%). Under the new mussel regime, red knots must have reduced the metabolic intensity of some of the tissues. This suggests that the experimental red knots experienced the transition to a mussel diet as stressful and energy limiting, resulting in an energy‐saving strategy by reducing BMR in spite of hypertrophy of the gizzard and other organs.