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Time use and foraging behaviour in pre-breeding dabbling ducks Anas spp. in sub-arctic Norway

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Abstract

We studied time budgets and foraging methods in pre-breeding Mallard Anas platyrhynchos, (Eurasian) Teal Anas crecca, Wigeon Anas penelope, Pintail Anas acuta, Shoveler Anas clypeata and Gadwall Anas strepera in subarctic Norway in May. Among all six species studied, foraging accounted for the most common use of time, ranging from 19 % in male Pintail to 40–60 % in female Mallard, Teal, Pintail and Gadwall. Comfort behaviours amounted to 20–34 % of the time budget, and interaction and disturbance were marginal. Vigilance time ranged from 8 % in female Mallard to 20 % in male Pintail. Movement amounted to some 20 % of the time in most species and sexes. In Wigeon, sexes did not differ in time use, whereas in Mallard, Pintail and, in particular, Teal, females foraged more and engaged less in vigilance and interactions than did males. In addition, Teal and Mallard males engaged in the riskier foraging methods less than females, but more in those permitting vigilance. Although overlap in feeding methods was large among these species, Mallard and Teal were generalists, feeding at all depths, Wigeon foraged mainly in shallow water and Pintail foraged essentially in deep water. Our results support the income/capital breeder hypothesis with respect to males only; compared to lighter species, heavier species allocated less time to foraging but more to vigilance. We found no support for the hypothesis that long-distance migrants forage more to compensate for energy loss due to migratory flight. Foraging time in females was related to breeding phenology; early nesters spent more time feeding than later nesters.

Zusammenfassung

Aktivitätsbudgets und Verhaltensweisen der Nahrungssuche bei Gründelenten der Gattung Anas vor der Brutzeit im subarktischen Norwegen

Wir untersuchten Zeitbudgets und Methoden des Nahrungserwerbs bei Stockente Anas platyrhynchos, Krickente Anas crecca, Pfeifente Anas penelope, Spießente Anas acuta, Löffelente Anas clypeata und Schnatterente Anas strepera im Mai vor Beginn der Brutzeit im subarktischen Norwegen. Die meiste Zeit wurde für die Nahrungssuche verwendet; anteilig zwischen 19 % bei männlichen Spießenten bis hin zu 40–60 % bei den Weibchen von Stock-, Krick-, Spieß- und Schnatterente. Der Anteil des Komfortverhaltens betrug 20–34 %, Interaktionen und Störungen traten nur in geringem Maße auf. Wachsamkeitsverhalten nahm zwischen 8 % der Zeit bei Stockentenweibchen und 20 % der Zeit bei Spießerpeln ein. Fortbewegung beanspruchte etwa 20 % der Zeit bei beiden Geschlechtern der meisten Arten. Bei Pfeifenten gab es keine Geschlechtsunterschiede in den Aktivitätsbudgets, wohingegen die Weibchen von Stockente, Spießente und insbesondere Krickente mehr nach Nahrung suchten und weniger an Wachsamkeit und Interaktionen teilhatten als die Männchen. Außerdem nutzen Krick- und Stockentenmännchen bei der Futtersuche im Vergleich zu den Weibchen seltener riskantere Methoden und dafür eher solche, die eine gleichzeitige Wachsamkeit erlaubten. Obgleich die Methoden des Nahrungserwerbs sich zwischen den Arten stark überschnitten, traten Stock- und Krickenten als Generalisten auf, die alle Wassertiefen nutzten, Pfeifenten fanden hauptsächlich in seichtem Wasser ihr Futter, und Spießenten suchten primär in tiefem Wasser nach Nahrung. Unsere Ergebnisse betätigten die „Income-Capital-Breeder“-Hypothese nur in Bezug auf die Männchen; schwerere Arten verbrachten im Vergleich zu leichteren weniger Zeit mit dem Nahrungserwerb als mit Wachsamkeit. Wir fanden dagegen keine Bestätigung der Hypothese, dass Langstreckenzieher mehr nach Futter suchen, um durch den Zug bedingte Energieverluste auszugleichen. Bei den Weibchen hing die mit Nahrungserwerb verbrachte Zeitspanne mit der Brutphänologie zusammen; früh nistende Weibchen verwandten mehr Zeit auf die Futtersuche als später brütende.

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Acknowledgments

The authors extend their sincerest thanks to Per Lundberg for his indispensable maps and for making JE curious about Andøya´s ducks. Anette Jensen of Andenes provided valuable information on the weather, wintering birds and breeding sites. Nigel Turrell at the Andøy Friluftscenter and Ole Petter Bergland at Naturpartner are acknowledged for their logistic help. For data and comments regarding the annual nest initiation order of dabbling ducks in northern Europe we are deeply grateful to Linus Andersson, Preben Clausen, Lars Edenius, Gustaf Egnell, Arni Einarsson, Gunnar Gunnarsson, Adjan de Jong, Ian Newton, Leif Nilsson, Ulf Ottosson, Jukka Rintala, Ulf Sperens, Ole Therkildsen and Marcus Wikman. We thank Tony Fox and an anonymous reviewer for comments on an earlier version of this manuscript. This work was supported by grant V-162-05 from the Swedish Environmental Protection Agency and a grant from Kone foundation (accorded to C. Arzel).

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Authors and Affiliations

  1. Section of Ecology, Department of Biology, Turku University, 20014, Turku, Finland

    Céline Arzel

  2. Johan Elmberg, Division of Natural Sciences, Kristianstad University, 291 88, Kristianstad, Sweden

    Johan Elmberg

Authors
  1. Céline Arzel
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  2. Johan Elmberg
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Corresponding author

Correspondence to Céline Arzel.

Additional information

Communicated by F. Bairlein.

Appendices

Appendix 1

Pairwise post-hoc Tukey tests of interspecific differences in the number of observations allocated to six categories of behaviour in males of Mallard, Teal, Wigeon, and Pintail

Behaviour

Species 1

Species 2

z

p

Interaction

Teal

Pintail

0.022

1

Wigeon

Pintail

−0.059

1

Mallard

Pintail

−1.169

0.636

Wigeon

Teal

−0.088

1

Mallard

Teal

−1.512

0.418

Mallard

Wigeon

−0.907

0.794

Disturbance

Teal

Pintail

0.761

0.868

Wigeon

Pintail

0.425

0.973

Mallard

Pintail

0.961

0.766

Wigeon

Teal

−0.381

0.981

Mallard

Teal

0.364

0.983

Mallard

Wigeon

0.715

0.888

Foraging

Teal

Pintail

0.519

0.953

Wigeon

Pintail

−0.869

0.816

Mallard

Pintail

−1.083

0.692

Wigeon

Teal

−1.659

0.337

Mallard

Teal

−2.213

0.115

Mallard

Wigeon

−0.071

1

Comfort

Teal

Pintail

1.518

0.417

Wigeon

Pintail

0.749

0.873

Mallard

Pintail

2.399

0.074

Wigeon

Teal

−0.473

0.964

Mallard

Teal

1.081

0.693

Mallard

Wigeon

1.231

0.598

Movement

Teal

Pintail

−0.270

0.993

Wigeon

Pintail

1.810

0.260

Mallard

Pintail

0.218

0.996

Wigeon

Teal

2.596

0.045

Mallard

Teal

0.709

0.890

Mallard

Wigeon

−2.127

0.138

Vigilance

Teal

Pintail

−3.927

<0.001

Wigeon

Pintail

−0.842

0.829

Mallard

Pintail

−2.068

0.158

Wigeon

Teal

2.240

0.108

Mallard

Teal

2.139

0.135

Mallard

Wigeon

−0.888

0.805

  1. Significant relationships are shown in boldface. Results are based on 1,961 observations

Appendix 2

Pairwise post-hoc Tukey tests of interspecific differences in the number of observations allocated to six categories of behaviour in females of Mallard, Teal, Wigeon, and Pintail

Behaviour

Species 1

Species 2

z

p

Interaction

Teal

Pintail

−0.550

0.944

Wigeon

Pintail

0.498

0.958

Mallard

Pintail

1.166

0.639

Wigeon

Teal

0.942

0.775

Mallard

Teal

1.908

0.217

Mallard

Wigeon

0.501

0.957

Disturbance

Teal

Pintail

0

1

Wigeon

Pintail

0

1

Mallard

Pintail

0

1

Wigeon

Teal

−0.034

1

Mallard

Teal

1.376

0.459

Mallard

Wigeon

1.361

0.469

Foraging

Teal

Pintail

−0.956

0.760

Wigeon

Pintail

−3.098

0.010

Mallard

Pintail

−0.246

0.994

Wigeon

Teal

−3.676

0.001

Mallard

Teal

0.724

0.879

Mallard

Wigeon

3.373

0.004

Comfort

Teal

Pintail

−1.005

0.735

Wigeon

Pintail

0.639

0.915

Mallard

Pintail

−1.134

0.656

Wigeon

Teal

1.834

0.246

Mallard

Teal

−0.342

0.985

Mallard

Wigeon

−1.725

0.298

Movement

Teal

Pintail

1.835

0.247

Wigeon

Pintail

3.039

0.012

Mallard

Pintail

0.270

0.993

Wigeon

Teal

2.370

0.079

Mallard

Teal

−1.443

0.460

Mallard

Wigeon

−2.979

0.015

Vigilance

Teal

Pintail

0.078

1

Wigeon

Pintail

1.327

0.536

Mallard

Pintail

−0.020

1

Wigeon

Teal

1.835

0.249

Mallard

Teal

−0.092

1

Mallard

Wigeon

−1.284

0.563

  1. Significant relationships are shown in boldface. Results are based on 1,011 observations

Appendix 3

Post-hoc Tukey tests of interspecific differences in the number of observations allocated to different foraging methods (column ‘behaviour’) in Teal, Wigeon, Mallard and Pintail males

Behaviour

Species 1

Species 2

z

p

On land

Teal

Pintail

−1.168

0.601

Wigeon

Pintail

1.826

0.221

Mallard

Pintail

1.690

0.284

Wigeon

Teal

2.448

0.054

Mallard

Teal

2.222

0.095

Mallard

Wigeon

−0.474

0.957

Water surface

Teal

Pintail

2.328

0.084

Wigeon

Pintail

4.548

<0.001

Mallard

Pintail

1.441

0.453

Wigeon

Teal

4.166

<0.001

Mallard

Teal

−1.098

0.673

Mallard

Wigeon

−4.630

<0.001

Head under water

Teal

Pintail

2.323

0.083

Wigeon

Pintail

1.551

0.382

Mallard

Pintail

2.382

0.072

Wigeon

Teal

−0.926

0.775

Mallard

Teal

0.479

0.960

Mallard

Wigeon

1.228

0.585

Neck under water

Teal

Pintail

−2.415

0.069

Wigeon

Pintail

−6.833

<0.001

Mallard

Pintail

−3.623

0.002

Wigeon

Teal

−6.385

<0.001

Mallard

Teal

−2.306

0.091

Mallard

Wigeon

4.763

<0.001

Up-ending

Teal

Pintail

−0.311

0.987

Wigeon

Pintail

0.000

1.000

Mallard

Pintail

−0.431

0.967

Wigeon

Teal

0.000

1.000

Mallard

Teal

−0.243

0.994

Mallard

Wigeon

0.000

1.000

  1. Behavioural categories are defined in the "Analyses" section. Significant relationships are shown in boldface. Results are based on 671 observations

Appendix 4

Post-hoc Tukey tests of interspecific differences in the number of observations allocated to different foraging methods (column ‘behaviour’) in Teal, Wigeon, Mallard and Pintail females

Behaviour

Species 1

Species 2

z

p

On land

Teal

Pintail

−2.299

0.073

Wigeon

Pintail

2.910

0.013

Mallard

Pintail

N/A

 

Wigeon

Teal

3.924

<0.001

Mallard

Teal

N/A

 

Mallard

Wigeon

N/A

 

Water surface

Teal

Pintail

0.513

0.953

Wigeon

Pintail

2.135

0.132

Mallard

Pintail

0.215

0.996

Wigeon

Teal

3.145

0.008

Mallard

Teal

−0.197

0.997

Mallard

Wigeon

−1.750

0.280

Head under water

Teal

Pintail

1.090

0.680

Wigeon

Pintail

−1.201

0.609

Mallard

Pintail

1.208

0.604

Wigeon

Teal

−2.386

0.074

Mallard

Teal

−0.179

0.998

Mallard

Wigeon

2.085

0.147

Neck under water

Teal

Pintail

−0.132

0.999

Wigeon

Pintail

−4.018

<0.001

Mallard

Pintail

−0.266

0.993

Wigeon

Teal

−4.926

<0.001

Mallard

Teal

−0.154

0.999

Mallard

Wigeon

3.541

0.002

Up-ending

Teal

Pintail

0.065

1

Wigeon

Pintail

0.003

1

Mallard

Pintail

1.280

0.663

Wigeon

Teal

−0.066

1

Mallard

Teal

1.046

0.703

Mallard

Wigeon

1.103

0.668

  1. Behavioural categories are defined in the "Analyses" section. Significant relationships are shown in boldface. Results are based on 471 observations
  2. N/A, Test not applicable due to small sample size

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Arzel, C., Elmberg, J. Time use and foraging behaviour in pre-breeding dabbling ducks Anas spp. in sub-arctic Norway. J Ornithol 156, 499–513 (2015). https://doi.org/10.1007/s10336-014-1151-8

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