Indices of Structural Size and Condition of Canada Geese

Moser, Timothy J.; Rusch, Donald H.

doi:10.2307/3801223

Cited by 24 publications

(13 citation statements)

References 25 publications

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“…Typically, mass is correlated with structural size. Structural size usually refers to an integrated measurement of linear skeletal dimensions (Ankney and Afton 1988;Moser and Rusch 1988;Rising and Somers 1989;Piersma and Davidson 1991). For example, an investigator might measure body length, wing chord, tarsus length, bill length, and head length, and then perform a principal components analysis.…”

Section: Body Massmentioning

confidence: 99%

Morphometric indices of body condition in birds: a review

2011

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Morphometric estimates of body condition are widely used by ornithologists, but which estimates work best is a matter of debate. We review morphometric approaches (body mass, ratio and residual condition indices, predictive regression models, fat scoring, and abdominal profiles) for estimating body condition (defined as fat mass) in birds. We describe the strengths and weaknesses of each approach. Across diverse indices and species (*200 estimates total), the mean r 2 relating condition indices to mass of body fat was 0.55, and 64% of the r 2 values were greater than 0.50. But despite their generally good performance, condition indices sometimes perform poorly (i.e., r 2 is low). The data indicate that: (1) no single index was clearly best, (2) on average body mass alone, fat scores, and predictive multiple regression equations explained slightly more than 50% of the variation in fat content, (3) on average, ratio and residual indices explained slightly less than 50% of the variation in fat content, and (4) body mass alone, a variable that can be easily and reliably measured, is as good or nearly as good an indicator of fat content as any other condition index. We recommend that: (1) morphometric indicators of condition be empirically validated, (2) researchers publish their body composition data in sufficient detail that they can be used in future analyses exploring the relative merits of different condition indices, and (3) multiple regression directly on measured traits be used instead of condition indices whenever the condition index is not empirically validated.

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Section: Body Massmentioning

confidence: 99%

Morphometric indices of body condition in birds: a review

2011

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“…We included body mass to calculate one set of gosling and adult PC1 scores despite the fact that adult mass varies by as much as 40% annually in Arctic geese (Ankney 1982, Alisauskas andAnkney 1990). Even so, of variables that we measured, body mass should be most closely correlated with overall body size and capacity to store nutrient reserves (Moser and Rusch 1988). Furthermore, adult female geese are at annual low body mass at hatching (Raveling I 979a, Ankney 1984), and average female mass increased relatively little between hatching and banding (see Results).…”

Section: Body Sizementioning

confidence: 99%

Environmental Influence on Life‐History Traits: Growth, Survival, and Fecundity in Black Brant (Branta Bernicla)

Sedinger

Flint

Lindberg

1995

Ecology

234

182

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We studied relationships between body size of female Black Brant goslings (Branta bernicla nigricans) late in their growth period and first year survival, eventual adult body size, breeding propensity, and size and volume of clutches they eventually produced to examine the relationship between growth and fitness in this population. We indexed body size by calculating PC1 scores based on either culmen and tarsus, or culmen, tarsus, and mass. Gosling (PC scores based on culmen and tarsus) size was positively correlated with resighting rate (P = 0.005), indicating that larger goslings survived at a higher rate than did smaller goslings. Gosling size was correlated with adult size of the same individuals (P = 0.0004). Larger goslings were more likely to breed as 2— or 3—yr—olds than were medium or small goslings (P = 0.008). Larger adult brant laid more eggs (P = 0.03) and produced clutches with greater total volume (P = 0.03) than did smaller brant. Given the important role of foraging environment in growth of goslings, these data suggest an important role of early environment in determining life—history traits.

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“…We calculated relative hatching date of web‐tagged goslings as the number of days between hatching date and the median hatching date of its cohort. We used body mass adjusted by a structural body‐size index to estimate individual condition (Johnson et al , Moser and Rusch ). We used the first principal component of the correlation between tarsus, culmen, and skull lengths as the structural body‐size index (PCA, JMP IN 5, SAS Institute, Inc., Cary, NC).…”

Section: Methodsmentioning

confidence: 99%

Factors influencing survival of Canada geese breeding in Southern Quebec

et al. 2014

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Temperate nesting Canada geese are considered a nuisance in many regions of eastern North America. In southern Quebec, a breeding population became established 20 years ago and has grown steadily since that time. Because of the long‐lived nature of geese, understanding the factors that influence annual survival is critical to the management of these populations. Our objectives were to describe the spatiotemporal distribution of the harvest of Canada geese that breed in southern Quebec, determine how year, sex, and age affect survival rates, and to evaluate the effects of hatch date and body condition near fledging on juvenile survival. We conducted mixed live recapture and dead recovery capture‐mark‐recapture analyses using data from birds banded as pre‐fledged juveniles between 2003 and 2009 (n = 3,972). Recoveries were distributed near the breeding area and along the east coast of the United States. Juveniles were mainly recovered in Quebec and yearlings in the United States. Harvest during the special early hunting season in Quebec represented only 9% of the total harvest. Annual survival rates were similar for both males and females, but varied among years for each age class. Survival averaged 0.82 (95% CI 0.76–0.87) for juveniles, 0.76 (0.69–0.82) for yearlings, and 0.82 (0.75–0.87) for adults. We observed a negative relationship between hatch date and juvenile survival but did not find significant effects of body condition and age at banding on survival. In addition to a short migration, a possible explanation for the high survival of juveniles includes the use by family groups predominantly of areas that are not open to hunting. The use of rural habitats where susceptibility to hunting is high, combined with the behavior of molt migration could explain the lower survival rates of yearlings than juveniles. We argue that high survival rates for all age classes contribute significantly to the growth of this population. © 2014 The Wildlife Society.

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Indices of Structural Size and Condition of Canada Geese

Cited by 24 publications

References 25 publications

Morphometric indices of body condition in birds: a review

Morphometric indices of body condition in birds: a review

Environmental Influence on Life‐History Traits: Growth, Survival, and Fecundity in Black Brant (Branta Bernicla)

Factors influencing survival of Canada geese breeding in Southern Quebec

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