Summary 1.The biases and shortcomings of stepwise multiple regression are well established within the statistical literature. However, an examination of papers published in 2004 by three leading ecological and behavioural journals suggested that the use of this technique remains widespread: of 65 papers in which a multiple regression approach was used, 57% of studies used a stepwise procedure. 2. The principal drawbacks of stepwise multiple regression include bias in parameter estimation, inconsistencies among model selection algorithms, an inherent (but often overlooked) problem of multiple hypothesis testing, and an inappropriate focus or reliance on a single best model. We discuss each of these issues with examples. 3. We use a worked example of data on yellowhammer distribution collected over 4 years to highlight the pitfalls of stepwise regression. We show that stepwise regression allows models containing significant predictors to be obtained from each year's data. In spite of the significance of the selected models, they vary substantially between years and suggest patterns that are at odds with those determined by analysing the full, 4-year data set. 4. An information theoretic (IT) analysis of the yellowhammer data set illustrates why the varying outcomes of stepwise analyses arise. In particular, the IT approach identifies large numbers of competing models that could describe the data equally well, showing that no one model should be relied upon for inference.

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The life histories of organisms can show pronounced variation in the way that the costs of reproduction are financed. To facilitate discussions of this variation, two terms are increasing in use: "capital breeding" describes the situation in which reproduction is financed using stored capital; "income breeding" refers to the use of concurrent intake to pay for a reproductive attempt. We consider the value of the capital and income typology with reference to three functions that it might serve: description, explanation, and prediction. We find that interpretations of the terms have diversified and lack rigidity, leading to subjectivity in their definition. We recognize that time frames of interest will vary among taxa, but we urge consistency of use within those taxa. We also urge consistency in the use of a single metric designed to measure the reliance of an organism on capital. The concepts of capital and income breeding have served well as proximate explanations for behavioral or physiological diversity, but efforts to explain their adaptive value have been disproportionately focused on individual taxa. Mapping cause to effect is difficult in ecology. Nevertheless, further analyses, based on consistently applied measures of reliance on stored capital, may reveal which of the putative ecological, morphological, and physiological drivers have the most consistent and widespread effects. The capital-income typology has yet to be applied to the question of prediction, and thus, it remains to be seen whether these concepts will be of use in identifying the likely responses of different populations to changes in their environment.