Markus Öst

Ph.D., Adjunct Professor of Zoology, Senior Researcher

ARONIA, Coastal Zone Research Team
Raseborgsvägen 9
FI-10600 Ekenäs
+358 (0)19 224 8414


Research interests

I am a behavioural ecologist also interested in evolutionary and population ecology. My long-time interest is to understand the cooperation and conflicts involved in social brood care in waterfowl, ranging from the good-natured eider females forming multi-female brood-rearing coalitions (‘kindergartens') to the ill-tempered Barrow's goldeneye females, in which the winner takes it all - in this case, the pooled lot of ducklings.

The main themes of my current and future research are:

  • Personality, cooperativeness and fitness. Personalities are quantified by measuring individual quality, dominance, boldness, activity, and physiological stress responses (corticosterone concentrations in blood and faeces). This exciting project started up in 2009.
  • Population consequences of individual reproductive decisions in Baltic eiders facing a changing climate, food conditions, and predation risk. Designing novel monitoring methods for assessing population health status.
  • The division of parental effort and reproduction in socially breeding groups as a function of individual quality, social status and relatedness.
  • Partner choice in relation to individual characteristics and its fitness consequences. What role does the brood size of partners play for cooperation, as different-sized broods contribute unequally to diluting the risk of combined brood?
  • Social, maternal and environmental influences on offspring survival.
  • Fitness consequences of alternative parental care strategies.


You can also have a look at the BEU (Bird Ecology Unit) website at the University of Helsinki to see what I was up to until 2007.


Seltmann, M. W., Jaatinen, K., Steele, B. B. & Öst, M. 2014: Boldness and stress responsiveness as drivers of nest-site selection in a ground-nesting bird. Ethology 120: 77-89. Abstract

Öst, M. & Jaatinen, K. 2013: Relative importance of social status and physiological need in determining leadership in female eiders. PLoS ONE 8(5): e64778. Abstract PDF

Jaatinen, K., Seltmann, M. W., Hollmén, T., Atkinson, S., Mashburn, K. & Öst, M. 2013: Context dependency of baseline glucocorticoids as indicators of individual quality in a capital breeder. General and Comparative Endocrinology 191: 231-238. Abstract

Jaatinen, K. & Öst, M. 2013: Brood size matching: a novel perspective on predator dilution. American Naturalist 181: 171–181 Abstract Press Release

Jaatinen, K., Öst, M., Gienapp, P. & Merilä, J. 2013: Facultative sex allocation and sex-specific offspring survival in Barrow's goldeneyes. Ethology 119: 146–155. Abstract

Ekroos, J., Öst, M., Karell, P., Jaatinen, K. & Kilpi, M. 2012: Philopatric predisposition to predation-induced ecological traps: habitat-dependent mortality of breeding eiders. Oecologia 170: 979-986. Abstract

Jaatinen, K., Noreikienė, K., Merilä, J. & Öst, M. 2012: Kin association during brood care in a facultatively social bird: active discrimination or by-product of partner choice and demography? Molecular Ecology 21: 3341-3351 Abstract PDF

Ekroos, J., Fox, A. D., Christensen, T. K., Petersen, I. K., Kilpi, M., Jónsson, J. E., Green, M., Laursen, K., Cervencl, A., Boer, P., Nilsson, L., Meissner, W., Garthe, S. & Öst, M. 2012: Declines amongst breeding eider Somateria mollissima numbers in the Baltic/Wadden Sea flyway. Ornis Fennica 89: 81-90. PDF

Seltmann, M. W., Öst, M., Jaatinen, K., Atkinson, S., Mashburn, K. & Hollmén, T. 2012: Stress responsiveness, age and body condition interactively affect flight initiation distance in breeding female eiders. Animal Behaviour 84: 889–896. Abstract

Jaatinen, K., Öst, M., Gienapp, P. & Merilä, J. 2011: Differential responses to related hosts by nesting and non-nesting parasites in a brood-parasitic duck. Molecular Ecology 20: 5328-5336. Abstract

Jaatinen, K. & Öst, M. 2011: Experience attracts: the role of age in the formation of cooperative brood-rearing coalitions in eiders. Animal Behaviour 81: 1289-1294. Abstract

Öst, M. & Tierala, T. 2011: Synchronized vigilance while feeding in common eider brood-rearing coalitions. Behavioral Ecology 22: 378-384. Abstract PDF

Öst, M., Lehikonen, A., Jaatinen, K. & Kilpi, M. 2011: Causes and consequences of fine-scale breeding dispersal in a female-philopatric species. Oecologia 166: 327-336. Abstract

Jaatinen, K., Öst, M. & Lehikoinen, A. 2011: Adult predation risk drives shifts in parental care strategies: a long-term study. Journal of Animal Ecology 80: 49-56. Abstract PDF

Öst, M. & Steele, B. B. 2010: Age-specific nest-site preference and success in eiders. Oecologia 162: 59-69. Abstract

Lehikoinen, A., Jaatinen, K. & Öst, M. 2010: Do female ornaments indicate quality in eider ducks? Biology Letters 6: 225-228 Abstract

Jaatinen, K., Jaari, S., O'Hara, R. B., Öst,M. & Merilä, J. 2009: Relatedness and spatial proximity as determinants of host-parasite interactions in the brood parasitic Barrow's goldeneye (Bucephala islandica). Molecular Ecology 18: 2713-2721.  Abstract    PDF

Jaatinen, K., Öst, M., Waldeck, P. & Andersson, M. 2009: Clutch desertion in Barrow's goldeneyes (Bucephala islandica) - effects of non-natal eggs, the environment and host female characteristics. Annales Zooogici Fennici 46: 350-360. Abstract

Engström-Öst, J., Öst, M. & Yli-Renko, M. 2009: Balancing algal toxicity and turbidity with predation risk in the three-spined stickleback. Journal of Experimental Marine Biology and Ecology 377: 54-59. Abstract

Öst, M., Wickman, M., Matulionis, E. & Steele, B. 2008: Habitat-specific clutch size and cost of incubation in eiders reconsidered. Oecologia 158: 205-216. Abstract

Lehikoinen, A., Christensen, T. K., Öst, M., Kilpi, M., Saurola, P. & Vattulainen, A. 2008: Large-scale change in the sex ratio of a declining eider population.Wildlife Biology 14: 288-301.  Abstract   PDF

Lehikoinen, A., Öst , M., Hollmén, T. & Kilpi, M. 2008: Does sex-specific duckling mortality contribute to male bias in adult common eiders? Condor 110: 574-578. Abstract

Öst, M., Smith, B. D & Kilpi, M. 2008: Social and maternal factors affecting duckling survival in eiders Somateria mollissima. Journal of Animal Ecology 77: 315-325.   Abstract     PDF

Waldeck, P., Andersson, M., Kilpi, M. & Öst, M. 2008: Spatial relatedness and brood parasitism in a female-philopatric bird population. Behavioral Ecology 19: 67-73. Abstract     PDF

Öst, M., Clark, C. W., Kilpi, M. & Ydenberg, R. C. 2007: Parental effort and reproductive skew in coalitions of brood-rearing female common eiders. American Naturalist 169: 73-86.   Abstract    Press Release    PDF

Öst, M., Jaatinen, K. & Steele, B. 2007: Aggressive females seize central positions and show increased vigilance in brood-rearing coalitions of eiders. Animal Behaviour 73: 239-247. Abstract

Steele, B., Lehikoinen, A., Öst, M. & Kilpi, M. 2007: The cost of mate guarding in the common eider. Ornis Fennica 84: 49-56. PDF

Lehikoinen, A., Kilpi, M. & Öst, M. 2006: Winter climate affects subsequent breeding success of common eiders.Global Change Biology 12: 1355-1365.   Abstract    PDF

Öst, M., Vitikainen, E., Waldeck, P., Sundström, L., Lindström, K., Hollmén, T., Franson, J. C. & Kilpi, M. 2005: Eider females form non-kin brood-rearing coalitions. Molecular Ecology 14: 3903-3908. Abstract   PDF

Waldeck, P., Kilpi, M., Öst, M. & Andersson, M. 2004: Brood parasitism in a population of common eider (Somateria mollissima). Behaviour 141: 725-739. Abstract

Kilpi, M. & Öst, M. 2004: Haahkan lastentarhat: kuka hoitaa ja miksi. Jahtimailla: Riistalinnut (eds. P. Nummi & V.-M. Väänänen), p. 25. Weilin+Göös, Helsinki.

Öst, M. & Bäck, A. 2003: Spatial structure and parental aggression in eider broods. Animal Behaviour 66: 1069-1075. Abstract

Öst, M., Ydenberg, R., Kilpi, M. & Lindström, K. 2003: Condition and coalition formation by brood rearing common eider females. Behavioral Ecology 14: 311-317.    Abstract     PDF

Öst, M., Ydenberg, R., Lindström, K. & Kilpi, M. 2003: Body condition and the grouping behavior of brood-caring female common eiders (Somateria mollissima). Behavioral Ecology and Sociobiology 54: 451-457. Abstract

Kilpi, M., Öst, M., Lehikoinen, A. & Vattulainen, A. 2003: Male sex bias in eiders Somateria mollissima during spring migration into the Gulf of Finland. Ornis Fennica 80: 137-142. PDF

Öst, M., Mantila, L. & Kilpi, M. 2002: Shared care provides time-budgeting advantages for female eiders. Animal Behaviour 64: 223-231. Abstract

Hario, M. & Öst, M. 2002: Does heavy investment in foraging implicate low food acquisition for female common eiders Somateria mollissima? Ornis Fennica 79: 111-120. Abstract

Kilpi, M. & Öst, M. 2002: Merikotkan vaikutus Tvärminnen haahkakantaan. - Suomen Riista 48: 27-33.

Kilpi, M., Öst, M., Lindström, K. & Rita, H. 2001: Female characteristics and parental care mode in the crèching system of eiders, Somateria mollissima. Animal Behaviour 62: 527-534. Abstract

Öst, M. & Kilpi, M. 2000: Eider females and broods from neighboring colonies use segregated local feeding areas. Waterbirds 23: 24-32. Abstract

Öst, M. 2000: Feeding constraints and parental care in female eiders. Ph.D. thesis, University of HelsinkiE-thesis.

Öst, M. 1999: Within-season and between-year variation in the structure of common eider broods. Condor 101: 598-606. Abstract

Öst, M. & Kilpi, M. 1999: Parental care influences the feeding behaviour of female eiders Somateria mollissima. Annales Zoologici Fennici 36: 195-204. Abstract

Hario, M., Hollmén, T., Kilpi, M., Lehtonen, J. T., Mustonen, O., Westerbom, M. & Öst, M. 1999: Riittääkö haahkalle ravintoa Suomenlahdella? Suomen Riista 45: 34-43.

Öst, M. & Kilpi, M. 1998: Blue mussels in the Baltic: good news for foraging eiders, Somateria mollissima. Wildlife Biology 4: 81-89.    Abstract    PDF

Kilpi, M. & Öst, M. 1998: Reduced availability of refuse and breeding output in a herring gull (Larus argentatus) colony. Annales Zoologici Fennici 35: 37-42. Abstract

Öst, M. & Kilpi, M. 1997: A recent change in size distribution of blue mussels (Mytilus edulis) in the western part of the Gulf of Finland. Annales Zoologici Fennici 34: 31-36. Abstract