Patterns of growth in birds
TL;DR: In this article, the authors analyzed 105 species of birds of many taxonomic groups from a wide range of geographical localities and found that the shape of the growth curve is not related to the mode of development (i.e. whether precocial or altricial).
Abstract: Summary Parameters used to characterize the course of growth are described, and calculated growth parameters are presented for 105 species of birds of many taxonomic groups from a wide range of geographical localities. Growth parameters are found to exhibit as much as 20% variation within a species with respect to geographic locality and time of the nesting season. There is also considerable local variation, irrespective of season and locality, which is related to nutrition and perhaps to an inherited variability. The application of curve-fitting as a method of analysing intraspecific variation is discussed briefly, and the importance of comparative growth studies is emphasized. Growth patterns are correlated with other parameters of the life-history to evaluate the extent of diversity in the course of growth. Low rates of growth and prolonged growth periods occur primarily in species large for their families and in oceanic species. In most others, high rates of growth are maintained for longer periods of time. The shape of the growth curve is not related to the mode of development (i.e. whether precocial or altricial). Overall relative, or weight-specific growth rates, as measured by the constants of fitted growth equations, are most highly correlated with the adult body size of the species, changing as the -0–278 power of adult body weight. Smaller variations in the rate of growth appear to be correlated with differences in nesting success; open-nesting passerines grow faster than hole-nesting species of a similar size. Growth rate is further correlated with brood size. Oceanic species with single egg clutches and tropical land-birds with small clutches have low growth rates. The asymptote of the growth curve of the young (in relation to the adult weight) is related to the foraging behaviour of the adults. Aerial feeders generally have high asymptotes while those of ground feeding species are usually below adult weight. These differences are related to the need in the former for well-developed flight at the time of fledging. The diversity of growth patterns is related to evolutionary trends which are the result of (1) selective forces acting at stages of the life-history cycle other than development, (2) factors which affect the survival of offspring during the growth period, and (3) adjustments made to balance the energy budget of the family group. The last trend is discussed in detail in relation to the correlations found in the analysis. Two hypotheses are presented. Firstly, in species which cannot gather enough food to support even one young at a normal growth rate, the pace of development is reduced to decrease the energetic requirements of the young. Secondly, in species with small clutches, where adjustments to feeding capacities are not readily made by changing brood size, growth rate may be adjusted to accomplish this. The lack of critical energetic data to test these hypotheses is emphasized as a major deficiency in our understanding of the breeding biology of birds.
TL;DR: Evidence for food limitation in the context of life history theory is reviewed because it provides a fundamental framework from which to interpret.
Abstract: Food limitation is an important issue in ecology because it can influence life history traits, population sizes, and community structure (through effects of competition). Work at the level of populations and communities has led to arguments that food limitation and competition are more important in winter than during the breeding season (e.g. 1, 2, 7, 8, 83, 85, 211, 234). In fact, it is commonly argued that food is superabundant during the breeding season (7, 8, 161, 213, 246, 250, 251, 308-311). However, such arguments are based on indirect rather than direct evidence of the effects of food on reproduction and survival (fitness) (149). Direct evidence for food limitation and competition in winter exists when survival is affected, and some experimental evidence suggests such effects (e.g. 75, 113, 122, 132). However, if current or future reproductive success is limited by food, then food limitation will also exist during the breeding season. Reproductive ecologists historically have argued that food limits reproductive success (e.g. 13, 297). Yet, even this school has included recent arguments against food limitation. For instance, Ettinger & King (77) think that perching time of birds commonly reflects loafing time because birds set their clutch and brood sizes based on years and periods of stringent (low food) conditions. However, perching time may not reflect loafing but rather an important time commitment to reproductive success (T. Martin, unpublished ms.) Thus, the status of food limitation in breeding birds is not clear. Here, I review evidence for food limitation in the context of life history theory because it provides a fundamental framework from which to interpret
TL;DR: Examination of variation and covariation of life history traits of 123 North American Passeriformes and Piciformes in relation to nest sites, nest predation, and foraging sites found that number of broods was much more strongly correlated with annual fecundity and adult survival among species than was clutch size, suggesting that clutch size may not be the primary fecundation trait on which selection is acting.
Abstract: Food limitation is generally thought to underlie much of the variation in life history traits of birds. I examined variation and covariation of life history traits of 123 North American Passeriformes and Piciformes in relation to nest sites, nest predation, and foraging sites to examine the possible roles of these ecological factors in life history evolution of birds. Annual fecundity was strongly inversely related to adult survivaI, even when phylogenetic effects were controlled. Only a little of the variation in fecundity and survival was related to foraging sites, whereas these traits varied strongly among nest sites. Interspecific differences in nest predation were correlated with much of the variation in life history traits among nest sites, although energy trade-offs with covarying traits also may account for some variation. For example, increased nest predation is associated with a shortened nestling period and both are associated with more broods per year, but number of broods is inversely correlated with clutch size, possibly due to an energy trade-off. Number of broods was much more strongly correlated with annual fecundity and adult survival among species than was clutch size, suggesting that clutch size may not be the primary fecundity trait on which selection is acting. Ultimately, food limitation may cause trade-offs between annual fecundity and adult survival, but differences among species in tecundity and adult survival may not be explained by differences in food abundance and instead represent differing tactics for partitioning similar levels of food limitation. Variation in fecundity and adult survival is more clearly organized by nest sites and more closely correlated with nest predation; species that use nest sites with greater nest predation have shorter nestling periods and more broods, yielding higher fecundity, which in turn is associated with reduced adult survival. Fecundity also varied with migratory tendencies; short-distance migrants had more broods and greater fecundity than did neotropical migrants and residents using similar nest sites. HowevEr, migratory tendencies and habitat use were confounded, making separation of these two effects difficult. Nonetheless, the conventional view that neotropical migrants have fewer broods than residents was not supported when nest site effects were controlled
TL;DR: Empirical evidence is reviewed for costs of rapid growth, including increased fluctuating asymmetry, reduced immune capacity, and reduced ability to respond to environmental stress.
Abstract: The evolution of intrinsic growth rate has received less attention than other life history traits, and has been studied differently in plants, homoiotherms, and poikilotherms. The benefits of rapid growth are obvious, so the problems is to explain the costs and tradeoffs that cause organisms to grow below their physiological maximum. Four prevailing themes emerge from the literature: (1) slow growth is adaptive for dealing with nutrient stress, (2) the tradeoff between growth rate and development limits growth in species that require mature function early in life, (3) rapid growth evolves when a minimum size must be reached quickly, such as for sexual maturation or overwintering, and (4) rapid growth may evolve to compensate for slowed growth owing to environmental conditions. Evidence for each of these themes is detailed for plants, homoiotherms, and poikilotherms. In addition, empirical evidence is reviewed for costs of rapid growth, including increased fluctuating asymmetry, reduced immune capacity, and reduced ability to respond to environmental stress.
01 Jan 2004
TL;DR: This book presents a meta-anatomy of sexual selection in birds and mammals, focusing on the role of courtship and courtship strategies in the courtship of birds and mammal species.
Abstract: Introduction Walter D Koenig and Janis L Dickinson 1 Evolutionary origins J David Ligon and D Brent Burt 2 Delayed dispersal Jan Ekman, Janis L Dickinson, Ben J Hatchwell and Michael Griesser 3 Fitness consequences of helping Janis L Dickinson and Ben J Hatchwell 4 Parental care, load-lightening and costs Robert G Heinsohn 5 Matings systems and sexual conflict Andrew Cockburn 6 Sex-ratio manipulation Jan Komdeur 7 Physiological ecology Morne Du Plessis 8 Endocrinology Steven J Schoech, S James Reynolds and Raoul K Boughton 9 Incest and incest avoidance Walter D Koenig and Joseph Haydock 10 Reproductive skew Robert D Magrath, Rufus A Johnstone and Robert G Heinsohn 11 Joint-laying systems Sandra L Vehrencamp and James S Quinn 12 Conservation biology Jeffrey R Walters, Caren B Cooper, Susan J Daniels, Gilberto Pasinelli and Karen Schiegg 13 Mammalian contrasts and comparisons Andrew F Russell Summary Steven J Pruett-Jones Names of bird and mammal species mentioned in the text References Index
TL;DR: A new hypothesis is presented for the adaptive significance of song learning in songbirds, suggesting that this specialized form of vocal development provides an indicator mechanism by which females can accurately assess the quality of potential mates.
Abstract: SYNOPSIS. The developmental processes through which songbirds acquire their species—typical songs have been well—studied from a proximate perspective, but less attention has been given to the ultimate question of why birds learn to sing. We present a new hypothesis for the adaptive significance of song learning in songbirds, suggesting that this specialized form of vocal development provides an indicator mechanism by which females can accurately assess the quality of potential mates. This hypothesis expands on the established idea that song can provide an indicator of male quality, but it explicitly links the variation in song expression that females use to choose mates to the developmental processes through which song is acquired. How well a male sings—reflected in repertoire size or in other learned features of a male's singing behavior—provides an honest indicator of quality because the timing of song learning and, more importantly, the timing of the development of brain structures mediating learning corresponds to a period in development during which young songbirds are most likely to undergo nutritional stress. This correspondence means that song learning can provide a sensitive indicator of early developmental history in general, which in turn reflects various aspects of the phenotypic and genotypic quality of a potential mate.
TL;DR: King and Farner (1961) discuss the possibility that the avian relationship may be curvilinear in the lower ranges of body weight, since small birds have higher metabolic rates than predicted by their equation, and re-analyzed the relationship using more rigorous criteria for including data in their computations.
Abstract: An exponential relation exists between standard energy metabolism and body weight in organisms that is described by the generalized equation: Metabolic Rate = a (Body Weight) b (a) where a and b are empirically derived constants. This equation can be rewritten in the more convenient logarithmic form: log Metabolic Rate = log a + b log Body Weight (b) recognizable as a mathematical expression of a straight line. Hemmingsen (1950, 1960) has reviewed the relation of energy metabolism to body size in all organisms, and argues that a b-value of 0.75 best describes the existing data for unicellular organisms, plants, poikilothermal and homeothermal animals. However, the observed limits of b are 0.63-1.0 among individual groups (Zeuthen, 1953, and others). Despite recent increased interest in avian bioenergetics, a definitive statement concerning the relationship between metabolic rate and body weight in birds has been lacking. Several formulas for this relationship have been presented. Brody and Proctor (1932) fitted the following equation to data on avian body weight and metabolism: log M = log 89 + 0.64 log W (c) where M is in kcal/day and W is in kilograms. This expression, in which the regression coefficient (b) of 0.64 differs markedly from those obtained from mammals (0.73-0.76) by Brody and Proctor (1932), Kleiber (1932, 1947), Benedict (1938), and Brody (1945), has been generally accepted for birds until recently. King and Farner (1961) have commented that “on theoretical grounds there seems to be no reason to believe a priori that the relationship of metabolic rate and body weight should be very different in the homoiotherm classes.” With many more metabolic values than were available previously, King and Farner re-analyzed the relationship, using more rigorous criteria for including data in their computations. They obtained the following equation: log M = log 74.3 + 0.744 log W * 0.074. (d) King and Farner believe that this equation is superior to that of Brody and Proctor (1932) in predicting the metabolic rates of birds weighing more than 0.1 kg. However, they concluded that it does not adequately portray the metabolism-weight relationship for smaller birds. Equation (d) is statistically indistinguishable from Kleiber’s (1947) equation for mammals, and it is therefore doubtful that the metabolism-weight relationship for birds weighing more than 0.1 kg really differs from that in mammals. King and Farner (1961) discuss the possibility that the avian relationship may be curvilinear in the lower ranges of body weight, since small birds have higher metabolic rates than predicted by their equation. Virtually all of the small birds (< 0.1 kg) are passerines, whereas all but two of the species weighing more than 0.1 kg belong to other orders. Dawson and Lasiewski have suggested (see Lasiewski, 1963 ; Lasiewski et al., 1964) that passerines as a group show the same weight-regression coefficient as nonpasserines, but have a higher metabolism per unit weight than nonpasserines of comparable size. Documentation of this suggestion required additional data on large passerines and small nonpasserines. Now that these are available, it is
01 Sep 1965
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