Breeding sex ratios in two declining diving duck species: between-year variation and changes over six decades

Pöysä, Hannu; Linkola, Pentti; Paasivaara, Antti

doi:10.1007/s10336-019-01682-7

Cited by 10 publications

(10 citation statements)

References 34 publications

(52 reference statements)

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“…Nests further away from water bodies in forests survived better than nests around the permanent lakes in both Finland and Denmark. In Finland, lake shorelines of eutrophic lakes in particular, have been occupied by three novel nest predator species: American mink, raccoon dog and western marsh harrier in the past 50 years (Pöysä, Linkola, & Paasivaara 2019, including our Finnish eutrophic study lakes, Väänänen, V.-M. unpubl.).…”

Section: Discussionmentioning

confidence: 99%

“…unpubl.). As a result, duck species nesting on eutrophic lakes and especially those preferring shorelines as nesting places have, in all likelihood, experienced a major increase in predator diversity and abundance, which may have contributed to their declining population trends (Lehikoinen et al 2016;Pöysä, Linkola, & Paasivaara 2019). Several currently threatened duck species in Finland typically nest close to shorelines (e.g.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Landscape and habitat affect frequency of artificial duck nest predation by native species, but not by an alien predator

Holopainen

Väänänen

Fox

2020

Basic and Applied Ecology

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Landscape and habitat affect frequency of artificial duck nest predation by native species, but not by an alien predator

Holopainen

Väänänen

Fox

2020

Basic and Applied Ecology

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“…Surveys of populations of adult and fledged juvenile small-bodied waterfowl (Anseriformes), including many duck species, have found male-biased sex ratios (e.g. Bellrose et al 1961;Dean and Skead 1977;Owen and Dix 1986;Mitchell et al 2008;Brides et al 2017;Frew et al 2018;Pöysä et al 2019). In contrast, these species typically show balanced sex ratios among embryos and hatchlings (e.g.…”

mentioning

confidence: 99%

Adults have more male-biased sex ratios than first-winter juveniles in wintering duck populations

et al. 2021

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Background The long-term monitoring of demographic changes in waterbird populations remains limited, but such information can be valuable for conservationists and waterbird managers. Biased sex ratios can indicate differences in survival rates between sexes. In particular, differences in the sex ratios of fledged juveniles and adults can provide insight into the development of male bias among populations. Methods In this study, we used data from individual birds captured over a 57-year period to assess the extent, and temporal variability in male bias in nine populations of ducks wintering in the United Kingdom: Gadwall (Mareca strepera), Northern Mallard (Anas platyrhynchos), Northern Pintail (Anas acuta), Common Pochard (Aythya ferina), Common Shelduck (Tadorna tadorna), Northern Shoveler (Spatula clypeata), Eurasian Teal (Anas crecca), Tufted Duck (Aythya fuligula), and Eurasian Wigeon (Mareca penelope). Results Overall, eight of these populations were significantly male-biased and adults were more male-biased than first-winter juveniles for all nine populations. The increased male bias among adults is consistent with the hypothesis that factors such as higher mortality of reproductive-age females during the breeding season is a major cause of male bias in duck populations. However, such predation cannot explain the male bias detected in first-winter juveniles in four of the populations. The temporal trends in male bias differed between adults and first-winter juveniles in Northern Mallard, Northern Pintail, Common Pochard, Common Shelduck, Eurasian Teal, Tufted Duck, and Eurasian Wigeon. Over the study period we found increased male bias among adult Northern Mallard, Northern Pintail, Common Pochard, Common Shelduck, and Tufted Duck as well as both adult and first-winter juvenile Northern Shoveler. Conclusions We provide evidence that among wintering duck populations, sex ratios are typically male-biased, with adults exhibiting stronger male-biased sex ratios than first-winter juveniles. Improved monitoring of sex ratios of wintering waterbirds would help to increase our understanding of changes in waterbird demography, population structure, and observed population trends; our study shows that birds caught during ringing projects can be a valuable source of such data.

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“…2018, Pöysä et al . 2019) – has been observed in many duck species. A lower proportion of females is critical for population change and can lead to rapid decline of reproductive success when fewer females reproduce.…”

Section: Discussionmentioning

confidence: 95%

Long‐term increase in female body condition and its effect on reproduction in two European red‐listed species, Common Pochard (Aythya ferina) and Tufted Duck (Aythya fuligula)

Gajdošová

Musil

Zouhar

et al. 2023

Ibis

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Body condition of breeding females is an important driver of an individual's fitness and the consequent dynamics of populations. Long‐term changes in female body condition are likely to be affected by recent shifts in climatic and environmental conditions that can result in changes to population demography. To help explain the drivers shaping body condition during the incubation period and its consequences for reproductive success, we examined the long‐term pattern in the body condition of breeding females of two declining sympatric diving duck species: Common Pochard Aythya ferina and Tufted Duck Aythya fuligula. We analysed the data obtained from 139 females of Common Pochard and 251 females of Tufted Duck breeding on fishponds in South Bohemia, Czechia, between 2004 and 2020. We calculated the body condition index of females during late incubation based on the residuals from the relationship between body mass and tarsus length and used the incubation stage as an additional predictor of body mass. Body condition of both species did not decline over the 17 years of the study. The effect of winter weather conditions (winter temperature), water transparency (a proxy for food availability) and reproductive investment on body condition was not confirmed. Female body condition positively affected mean egg mass and hatchability in both studied species, i.e. females in better body condition laid larger eggs and hatched eggs with a higher hatching probability. We conclude that the population declines of the studied species are probably not connected to decreasing body condition of breeding females, but other reasons such as change in breeding propensity or offspring survival and recruitment should be considered in future studies.

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Breeding sex ratios in two declining diving duck species: between-year variation and changes over six decades

Cited by 10 publications

References 34 publications

Landscape and habitat affect frequency of artificial duck nest predation by native species, but not by an alien predator

Landscape and habitat affect frequency of artificial duck nest predation by native species, but not by an alien predator

Adults have more male-biased sex ratios than first-winter juveniles in wintering duck populations

Long‐term increase in female body condition and its effect on reproduction in two European red‐listed species, Common Pochard (Aythya ferina) and Tufted Duck (Aythya fuligula)

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