Head of Division
Prof. Dr. Michael Taborsky

Institut für Ökologie und Evolution
Telefon: +41 31 684 91 11
Telefax: +41 31 684 91 41
E-Mail:   claudia.leiser@iee.unibe.ch

Ethologische Station Hasli
Wohlenstrasse 50a
CH-3032 Hinterkappelen

How to find us ...

Universität Bern


The smell of hunger: Norway rats provision social partners based on odour cues of need
K. Schneeberger & M. Taborsky



Sensory ecology and cognition in social decisions
Special feature edited by K. Schneeberger & M. Taborsky




SCIENCE ADVANCES Alternative male morphs solve sperm performance/longevity trade-off in opposite directions M. Taborsky, D. Schütz, O. Goffinet & G.S.van Doorn


Media release, University of Bern


Reciprocal trading of different commodities in Norway rats. M.K. Schweinfurth & M. Taborsky

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Nature research highlight
Current Biology dispatch

PNAS - Divergence of developmental trajectories is triggered interactively by early social and ecological experience in a cooperative breeder. Fischer, Bohn, Oberhummer, Nyman & B. Taborsky
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commentary on Fischer et al

PNAS - Predation risk drives social complexity in cooperative breeders. Groenewoud, Frommen, Josi, Tanaka, Jungwirth & Taborsky
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The evolution of cooperation based on direct fitness benefits. Phil Trans theme issue compiled and edited by Taborsky M., Frommen JG & Riehl C. (2016)
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NATURE COMMUNICATIONS Kinship reduces alloparental care in cooperative cichlids where helpers pay-to-stay
Zoettl M., Heg D., Chervet N. & Taborsky M. (2013)

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Social competence: an evolutionary approach
Taborsky, B. & Oliveira, R.F.
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Larval helpers and age polyethism in ambrosia beetles
Biedermann P.H.W. & Taborsky M.
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Animal personality due to social niche specialisation
Bergmueller R. & Taborsky M.
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Environmental Change Enhances Cognitive Abilities in Fish
Kotrschal, A. & Taborsky, B.
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Extended phenotypes as signals
Franziska C. Schaedelin and Michael Taborsky
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On the Origin of Species by Natural and Sexual Selection
G. Sander van Doorn, Pim Edelaar, Franz J. Weissing
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Cambridge University Press
Alternative Reproductive Tactics: An Integrative

Oliveira R., Taborsky M. & Brockmann H.J.
more information


Dik Heg "The bird, the beetle and the cichlid"

Research interests

I am a PostDoctoral researcher at the Department of Behavioural Ecology, University of Bern. My main research interest is the evolutionary ecology of cooperative breeding in cichlids, and I have done some additional work on life-history decisions and mating systems (oystercatchers, beetles). My current interests are designing experiments to understand: (1) variation in helping behaviour (together with Roger Sch├╝rch, Susan Rothenberger); (2) reproductive skew mediated by group composition and strategic or status-dependent growth adjustments (together with Eva Jutzeler, Jeremy Mitchell, Danielle Bonfils); (3) within-group genetic relatedness of various cooperatively breeding Lake Tanganyika cichlids and mating system, helping behaviour (together with Danielle Bonfils, Masanori Kohda, Satoshi Awata, Tomohiro Takeyama); (4) development of the kin-reconstruction software KINGROUP (see www.kingroup.org together with Dmitry Konovalov).

DikPortrait Hummingbird Frog

Master Thesis Projects

The following MSc students were involved in my projects on cooperative breeding in Lake Tanganyika cichlids: Lyanne Brouwer, Renske Hekman, Eva Jutzeler (see her wonderful fantasy drawings at Science Fiction and Fantasy Art, Susan Rothenberger and Fardo Witsenburg (the latter two were co-supervised with my PhD student Roger Sch├╝rch). My current interest is understanding variation in cooperative behaviour and reproductive participation using the behavioural syndrome paradigm (or animal personalities, temperament; see Roger Sch├╝rch et al. upcoming papers). Within this project we are interested in attracting new students from Switzerland or abroad, please contact Michael Taborsky for further information. Please note that your local supervisor(s) should support your decision to do so and that living in Switzerland can be expensive (although the difference with other countries has been reduced since the introduction of the euro). Rent of a single-room with shared kitchen in Bern will cost you approximately CHF 500-700 per month. We have also a guestroom available at the Ethologische Station Hasli, which can be intermittently / short-term used for CHF 9 per day.

I am also supporting a new MSc project by Liana Lasut on anemonefish from Bunaken Marine National Park, starting 2009. This project is financed by the University of Bern F├Ârderungsstiftung, and students interested to join should be prepared to find extra financing (i.e. travel and lodging costs financed by student funding agencies in your country). Please check out Liana's website for the latest developments.

Contact adress

Dik Heg
Department of Behavioural Ecology
Institute of Ecology and Evolution
University of Bern
Wohlenstrasse 50a
CH-3032 Hinterkappelen

E-Mail: dik.heg [at] iee.unibe.ch
Phone: +41 31 631 91 51
Fax: +41 31 631 91 41

The bird: Oystercatcher (Haematopus ostralegus)

I did my MSc and PhD Thesis projects on European oystercatchers living on the Waddensea Island Schiermonnikoog. My project was part of a long-term project initiated by Jan Hulscher, and run by many undergraduate and graduate students. In chronological order five PhD students were involved in the project: Bruno Ens, Marcel Kersten, Dik Heg, Leo Bruinzeel, Martijn van de Pol. Important work has been done by Allix Brenninkmeijer, Kees van Oers, Kees Oosterbeek and Simon Verhulst. The project was supervised by Prof. Rudi Drent, Jaap Kruijt and Joost Tinbergen. See for more information about the project: http://www.myscience.eu/martijn/

Martijn's site also contains all the information how to report sightings of colour-banded oystercatchers.


Colour-banded oystercatcher from the Schiermonnikoog population. Note the combination of a large ring with bands, EURING steel-ring (left leg) and two small rings (white and yellow, right leg). See the very useful website: bird ringing website by Dirk Raes for details on all European colour-banding shemes of birds (assuming you have correctly identified the species and made exact notes of the colours, sizes and positions of all the rings: you should be able to locate the person to send your sighting to).

The oystercatcher project has been well covered in the scientific and popular media, you will find some popular papers under e.g.:

New York Times


Scientific American

Swiss Info

Some of the best coverage has appeared in the NRC Handelsblad (in Dutch), e.g. 21 Feb 1998. Koos van Zomeren has written several articles about the oystercatchers in the 1990's. The famous prize winning movie "The Careerplanning of the Oystercatcher" (on DVD) about the project might be obtained from:

Musch & Tinbergen
Tijs Tinbergen
Vondellaan 45
1401 RX Bussum
Ph. +31 35 6923670
F. +31 35 6923515
M. +31 6 55155816
mustin [at] planet.nl

My PhD study in oystercatcher has focused on life-history decisions, mating systems and sibling competition.


The beetle: Parastizopus armaticeps

I did my first PostDoc project with an Alexander von Humboldt Stiftung Fellowship at the University of Bonn, supervisor Prof. O. Anne E. Rasa. I worked on determinants of reproduction, offspring sex ratio and mating systems in a subsocial beetle from the Kalahari Desert, using laboratory experiments. I also worked on the interaction with a cleptoparasite Eremostibes opacus, a project currently run at the University of Freiburg (Prof. K. Peschke and co-workers). These beetles are highly interesting in many respects, including biparental care and the ecological challenges set by living in a semi-arid or arid environment. I have also visited the Kalahari Desert and Namaqua Land on several occasions: this is definitely a place you should go and visit. Anne Rasa is running a lodge at Twee Rivieren (near Kalahari Gemsbok National Park, Sout Africa) and offers excursions: www.kalahari-trails.co.za



Pictures show Parastizopus armaticeps caring for a brood in an artificial breeding chamber, hyena, long-tailed shrike, impala.

The cichlid: Neolamprologus pulcher

In the last couple of years I have been working at the Department of Behavioural Ecology (Prof. Michael Taborsky) on various cichlids from Lake Tanganyika. About 19 to 21 Lamprologine cichlids from this Lake are highly unusual in showing extended family groups (e.g. Heg et al. 2005; Heg & Bachar 2006) and complex within-group genetic relatedness structures (e.g. Dierkes et al. 2005). These cooperative breeding groups can be easily studied under both laboratory and field conditions, and in contrast to many other vertebrates we are also able to do extensive experimental studies.


Pictures show Neolamprologus pulcher subordinate helper digging away sand from a flower-pot half used for breeding (photo by Ralph Bergm├╝ller), Roger Sch├╝rch observing, and Ralph Bergm├╝ller and Dik Heg observing 'inside' the ring-tank using the software the Observer (photo by Ralph Bergm├╝ller).

Particularly the N. pulcher cichlid has been established as a model system by our group, other groups working with these cichlids are: Sigal Balshine (see homepage Sigal Balshine) and Kathryn Arnold (see homepage Kathryn Arnold). I am currently also working on related species, notably Julidochromis and other Neolamprologus species, together with Satoshi Awata, Tomohiro Takeyama and Prof. Masanori Kohda (see Japanese homepage Masanori Kohda).


Pictures shows me entering data in a laptop at the Tanganyika Lodge (photo by Ralph Bergm├╝ller) and Julidochromis ornatus at Wonzye Point, Lake Tanganyika (Zambia).

We organise diving expeditions to Lake Tanganyika, Zambia, where we stay at the beautiful pristine lodge "Tanganyika Lodge" on the shore of the Lake (near the villages Kasakalawe and Mpulungu, see website Zambia Tourism). Our cooperation patterns are people from the Fisheries Department in Mpulungu (Zambia Ministry of Agriculture & Co-operatives), who conduct biological and hydrological research inside the lake and monitor fishing activities.



Pictures show Dik boat driving, Dik and Masanori Kohda, Dik catching Julidochromis ornatus (photo by Ralph Bergm├╝ller), Fisheries Department, Mpulungu, construction of underwater cages.

The people from Zambia are extremely friendly and I hope you will feel encouraged to visit this country in the near future. Many safari companies offer special trips to the unspoiled and pristine nature of Zambia (Victoria Falls, South-Luangwe NP, etc) but it is also possible to visit the country organising everything yourself (just remember that you will need a vehicle to enter the larger National Parks).


Pictures show sunset at the Tanganyika Lodge, Zina Heg-Bachar, Jeremy Mitchell and Tomohiro Takeyama in SCUBA gear.

Personal info

I am leading a very happy family life with my wife Zina and sons Nuri and Miro in M´┐Żhleberg. The rest of my family lives in the Netherlands, but are absolute lovers of the Alps and eagerly come over to go hiking or snowboarding. My favourite snowboarding areas are Grindelwald, Saanenm´┐Żser, Adelboden and Schilthorn, but I regularly visit other areas as well.



  • 2001 - 2010
    PostDoc project Zoology at the University of Berne, Switzerland. Laboratory and field work on the evolutionary ecology of cooperative breeding in Lake Tanganyika cichlids (Prof. M. Taborsky). See Heg et al. 2004-2010.
  • 1999-2000
    PostDoc project Zoology at the University of Bonn, Germany. Laboratory work on various themes in the Kalahari Desert beetle Parastizopus armaticeps at the Department of Ethology (Prof. A. Rasa). See Heg et al. 2004, 2004, 2006.
  • 1992-1999
    PhD project Zoology at the University of Groningen, Netherlands. PhD Thesis on life-history decisions in oystercatchers (see Heg 1999) at the Departments of Animal Ecology (Prof. R. Drent) and Ethology (Prof. J. Kruijt). See Heg et al. 1989-2008.
  • 1986-1992
    Biology at the University of Groningen, Netherlands. MSc Thesis on extra-pair copulation behaviour in oystercatchers (see Heg et al. 1993) at the Departments of Animal Ecology (Prof. R. Drent) and Ethology (Prof. J. Kruijt).



  • S. Raveh, D. Heg, V. Viblanc, D.W. Coltman, J.C. Gorrell, F.S. Dobson, A. Balmer & P. Neuhaus (2010) Male reproductive tactics to increase paternity in the polygynandrous Columbian ground squirrel (Urocitellus columbianus). Behavioral Ecology & Sociobiology, in press.
  • K. Ota, D. Heg, M. Hori & M. Kohda (2010) Sperm phenotypic plasticity in a shell-brooding cichlid: a territorial male's counterstrategy to spawning takeover. Behavioral Ecology, in press.
  • D. Heg, S. Rothenberger, R. Sch├╝rch (2010) Habitat saturation, benefits of philopatry, relatedness and the extent of cooperative breeding in a cichlid. Behavioral Ecology, in press.

  • R. Sch├╝rch, S. Rothenberger, D. Heg (2010) The building-up of social relationships: behavioural types, social networks and cooperative breeding in a cichlid. Philosophical Transactions of the Royal Society B, in press.
  •  F. Witsenburg, R. Sch├╝rch, O. Otti & D. Heg (2010) Behavioural types and ecological effects in a natural population of the cooperatively breeding cichlid Neolamprologus pulcher. Animal Behaviour, in press.
  • M. van de Pol, B.J. Ens, D. Heg, L. Brouwer, J. Krol, M. Maier, K.-M. Exo, K. Oosterbeek, T. Lok, C.M. Eising & K. Koffijberg (2010) Do changes in the frequency, magnitude and timing of extreme climatic events threaten the population viability of coastal birds? Journal of Applied Ecology, in press.
  • D. Heg & M. Taborsky (2010) Helper response to experimentally manipulated predation risk in the cooperatively breeding cichlid Neolamprologus pulcher. PLoS ONE e10784. [pdf]
  •  S. Awata, M. Kohda, J. Shibata, M. Hori & D. Heg (2010) Group structure, nest size and reproductive success in the cooperatively breeding cichlid Julidochromis ornatus: a correlation study. Ethology, 116: 316-328. [request pdf, E-Mail]
  • S. Raveh, D. Heg, F.S. Dobson, D.W. Coltman, J.C. Gorrell, A. Balmer & P. Neuhaus (2010) Mating order and reproductive success in male Columbian ground squirrels (Urocitellus columbianus). Behavioral Ecology, 21: 537-547. [request pdf, E-Mail]
  • D. Heg (2010) Status-dependent and strategic growth adjustments in female cooperative cichlids. Behavioral Ecology & Sociobiology, 64: 1309-1316. [request pdf, E-Mail]
  • Sch├╝rch & D. Heg (2010) Variation in helper type affects group stability and reproductive decisions in a cooperative breeder. Ethology, 115: 1-13. [request pdf, E-Mail]
  • Sch├╝rch & D. Heg (2010) Life history and behavioral type in the highly social cichlid Neolamprologus pulcher. Behavioral Ecology, 21: 588-598. [request pdf, E-Mail]
  • J. S. Mitchell, E. Jutzeler, D. Heg & M. Taborsky (2009) Gender differences in the costs that subordinate group members impose on dominant males in a cooperative breeder. Ethology, 115: 1-13. [request pdf, E-Mail]
  • J. S. Mitchell, E. Jutzeler, D. Heg & M. Taborsky (2009) Dominant members of cooperatively-breeding groups adjust their behaviour in response to the sexes of their subordinates. Behaviour, 146: 1665-1686. [request pdf, E-Mail]
  • M. Kohda, D. Heg, Y. Makino, T. Takeyama, J. Shibata, K. Watanabe, H. Munehara, M. Hori & S. Awata (2009) Living on the wedge: female control of paternity in a cooperatively polyandrous cichlid. Proceedings of the Royal Society of London B, 276: 4207-4214. [request pdf, E-Mail]

  • D. Heg, Jutzeler E., Mitchell J.S. & Hamilton I.M.. (2009) Helpful female subordinate cichlids are more likely to reproduce. PLoS ONE 4: e5458. [pdf]  
  • D. Heg, Heg-Bachar Z., Brouwer L. & Taborsky M. (2008) Experimentally induced helper dispersal in colonially breeding cooperative cichlids. Environmental Biology of Fishes 83: 191-206. [request pdf, E-Mail]
  • Kohda M., Shibata Y., Awata S., Gomagano D., Takeyama T., Hori M. & Heg D. (2008) Niche differentiation depends on body size in a cichlid fish: a model system of a community structured according to size regularities. Journal of Animal Ecology 77: 859-868. [request pdf, E-Mail]
  • D. Heg & Hamilton I. M. (2008) Tug-of-war over reproduction in a cooperatively breeding cichlid. Behavioral Ecology & Sociobiology 62: 1249-1257.  [request pdf, E-Mail]

  • Hamilton I. M. & Heg D. (2008) Sex differences in the effect of social status on the growth of subordinates in a cooperatively breeding cichlid. Journal of Fish Biology 72: 1079-1088. [request pdf, E-Mail]

  • D. Heg (2008) Reproductive suppression in female cooperatively breeding cichlids. Biology Letters 4: 606-609. [request pdf, E-Mail]

  • D. Heg , Jutzeler E., Bonfils D. & Mitchell J. S. (2008) Group composition affects male reproductive partitioning in a cooperatively breeding cichlid. Molecular Ecology 17: 4359-4370. [request pdf, E-Mail]
  • Konovalov D. A. & Heg D. (2008) Estimation of population allele frequencies from small samples containing multiple generations. Series on Advances in Bioinformatics and Computational Biology. Proceedings of the 6th Asia-Pacific Bioinformatics Conference, Kyoto. [request pdf, E-Mail]
  • Konovalov D.A. & Heg D. (2008): A maximum-likelihood relatedness estimator allowing for negative relatedness values Molecular Ecology Notes 8, 256-263 [pdf, 305 KB]

  • De Pol M.V., Heg I.P.D., Weissing F.J. (2007): Variation in habitat choice and delayed reproduction: Adaptive queuing strategies or individual quality differences? Amercian Naturalist 170 530-541.[pdf, 372 KB]

  • Hamilton I.M., Heg D. (2007): Clutch-size adjustments and skew models: effects on reproductive partitioning and group stability Behavioral Ecology 18, 467-476. [pdf, 281KB]

  • Dalbeck L. & Heg D. (2006): Reproductive success in relation to habitat characteristics of a reintroduced population of eagle owls Bubo bubo in the Eifel, Germany. Ardea 94, 3-21. [pdf, 663 KB]

  • Heg D. & Bachar Z. (2006): Cooperative breeding in the Lake Tanganyika cichlid Julidochromis ornatus. Environmental Biology of Fishes 76, 265-281. [request pdf, E-Mail]

  • Heg D., Bergmueller R., Bonfils D., Otti O., Bachar Z., Burri R., Heckel G. & Taborsky M. (2006): Cichlids do not adjust reproductive skew to the availability of independent breeding options. Behavioral Ecology 17, 419-429. [pdf, 159 KB]

  • Van de Pol M., Bruinzeel L.W., Heg D., van der Jeugd H.P. & Verhulst S. (2006): A silver spoon for a golden future: long-term effects of natal origin on fitness prospects of oystercatchers (Haematopus ostralegus). Journal of Animal Ecology 75, 616-626. [pdf, 182 KB]

  • Bender N., Heg D., Hamilton I.M., Bachar Z., Taborsky M. & Oliveira R.F. (2006): The relationship between social status, behaviour, growth and steroids in male helpers and breeders of a cooperatively breeding cichlid. Hormones and Behavior 50, 173-182. [pdf, 261 KB]

  • Awata S., Heg D., Munehara H. & Kohda M. (2006): Testis size depends on social status and the presence of male helpers in the cooperatively breeding cichlid Julidochromis ornatus. Behavioral Ecology 17, 372-379. [pdf, 186 KB]

  • Heg D., Heyl S., Rasa O.A.E. & Peschke K. (2006): Reproductive skew and communal breeding in the subsocial beetle Parastizopus armaticeps. Animal Behaviour 71, 427-437 [pdf, 473 KB]

  • Heg, D. (2006): Monogamy pays. Experimental liaisons and threesomes. In: R. Drent (ed.): Seeking Nature?s Limits. Ecologists in the Field. KNNV Publishing, Utrecht. [pdf, 481 KB / pdf, 114 KB]

  • Hamilton I.M., Heg, D. & Bender, N. (2005): Size differences within a dominance hierarchy influence conflict and help in a cooperatively breeding cichlid. Behaviour 142, 1591-1613. [pdf, 195 KB]

  • Komdeur J. & Heg D. (2005): Cooperation and conflict over invest strategies in animals. Behaviour 142, 1433-1447. [pdf, 128 KB]

  • Dierkes P., Heg D., Taborsky M., Skubic E., & Achmann R. (2005): Genetic relatedness in groups is sex-specific and declines with age of helpers in a cooperatively breeding cichlid. Ecology Letters 8, 968-975. [pdf, 234 KB]

  • Heg D., Bachar Z. & Taborsky M. (2005): Cooperative breeding and group structure in the Lake Tanganyika cichlid Neolamprologus savoryi. Ethology 111, 1017-1043. [pdf, 330 KB]

  • Brouwer L., Heg D. & Taborsky M. (2005): Experimental evidence for helper effects in a cooperatively breeding cichlid. Behavioral Ecology 16, 667-673. [pdf, 118 KB]

  • Heg D., Brouwer L., Bachar Z. & Taborsky M. (2005): Large group size yields group stability in the cooperatively breeding cichlid Neolamprologus pulcher. Behaviour 142, 1615-1641. [pdf, 282 KB]

  • Bergmueller R., Heg D. & Taborsky M. (2005): Extended safe havens and between group dispersal of helpers in a cooperatively breeding cichlid. Behaviour 142, 1643-1667 [pdf, 272 KB]

  • Bergmueller R., Heg D. & Taborsky M. (2005): Helpers in a cooperatively breeding cichlid stay and pay or disperse and breed, depending on ecological constraints. Proceedings of the Royal Society of London B 272, 325-331. [pdf, 141 KB]

  • Heg D. & Rasa O.A.E. (2004): Effects of parental body condition and size on reproductive success in a tenebrionid beetle with biparental care. Ecological Entomology 29, 410-419. [pdf, 161 KB]

  • Heg D., Bender N. & Hamilton I. (2004): Strategic growth decisions in helper cichlids. Proceedings of the Royal Society of London B (Supplement: Biology Letters) 271, 5505-5508. [pdf, 106 KB, pdf, 290 KB - supplement]

  • Rasa O.A.E. & Heg D.(2004): Individual variation and prior experience affect the discrimination of a brood-parasite by its subsocial beetle host. Behavioral Ecology and Sociobiology 57, 155 - 163. [pdf, 206 KB]

  • Saether B.-E., Engen S., Mueller A. P., Weimerskirch H., Visser M. E., Fiedler W., Matthysen E., Lambrechts M. M., Freckleton R., Badyaev A., Becker P. H., Brommer J. E., Bukacinski D., Bukacinska M., Christensen H., Dickinson J., du Feu C., Gehlbach, F. R., Heg D., Hoetker H., Merilae J., Nielsen J. T., Rendell W., Thomson D., Toeroek J., Van Hecke P. (2004). Life history variation predicts stochastic effects on avian population dynamics. American Naturalist 164, 793-802. [pdf, 169 KB]

  • Heg, D., Bruinzeel, L.W. & Ens, B.J. (2003): Fitness consequences of divorce in the oystercatcher (Haematopus ostralegus). Animal Behaviour 66, 175-184. [pdf, 153 KB]

  • Oers K.V., Heg D., Le Drean Quenec`Hdu S. (2002): Anthelminthic treatment negatively affects chick survival in the Eurasian oystercatcher Haematopus ostralegus, Ibis 144: 509-517 [pdf, 130 KB]

  • Heg D. & van der Velde M. (2001): Effects of territory quality, food availability and sibling competition on the fledging success of oystercatchers. - Behavioral Ecology and Sociobiology 49, 157-169. [pdf, 379 KB]

  • Heg D., Dingemanse N. J., Lessells C.M. & Mateman A.C. (2000): Parental correlates of offspring sex ratio in the eurasian oystercatcher. Auk 117, 984-990. [pdf, 152 KB]

  • Heg D., Ens B. J., van der Jeugd H.P. & Bruinzeel L.W. (2000): Local dominance and territorial settlement of nonbreeding oystercatchers. Behaviour 137, 473-530. [pdf, 606 KB]

  • van Treuren R., Bijlsma R., Tinbergen J. M., Heg D. & van de Zande L. (1999): Analysis of population structure and estimates of gene flow in the oystercatcher (Haematopus ostralegus) using microsatellites. Molecular Ecology 8, 181-187. [pdf, 181 KB]

  • Camphuysen C.J., Ens B.J., Heg D., Hulscher J.B., van der Meer J. & Smit C.J. (1996): Oystercatcher Haematopus ostralegus winter mortality in the Netherlands: the effect of severe weather and food supply. - Ardea 84A, 469-492. [pdf, 1055 KB]

  • Hulscher J. B., Alting D., Bunskoeke E.J., Ens B.J. & Heg D. (1996): Subtle differences between male and female oystercatcher Haematopus ostralegus in feeding on the bivalve Macoma balthica. Ardea 84A, 117-130. [pdf, 973 KB]

  • Verboven M., Weissing F. J., Heg D. & Huisman J. (1996): Competition between segregation distorters: coexistence of 'superior' and 'inferior' haplotypes at the t complex. Evolution 50, 2488-2498. [pdf, 1690 KB]

  • Heg D., Ens B. J., Burke T., Jenkins L. & Kruijt J. P. (1993): Why does the typically monogamous oystercatcher (Haematopus ostralegus) engage in extrapair copulations? - Behaviour 126, 247-289. [pdf, 2800 KB]