Royal Netherlands Institute for Sea Research
Royal Netherlands
Institute for Sea Research
Phone number
+31 (0)222 369 452
Location
Texel
Function
Postdoc
Expertise
  • Development of individual differences
  • Ontogeny of Migratory routines
  • Tracking local and migratory movements
  • Wadden Sea, Red Knots

Eva Kok

Postdoc
Interest

Research Interests

 

I am a behavioural ecologist with a passion for birds and marine ecosystems. I’m fascinated with understanding why individuals behave the way they do. Known causes of intraspecific variation in behaviour include previous exposure to varying environmental factors and differences in internal state (both the physiologically and psychological state). Understanding an individual’s motivation to act may play a key role in predicting a species response to change.

 

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My research primarily focusses on unraveling causes and consequences of consistent among-individual variation in migratory behaviour in Red Knots (Calidris canutus). Red knots are shorebirds that annually migrate between their arctic breeding grounds and their southern intertidal wintering areas. A major axis of my research is focused on understanding intraspecific variation of their migratory routines. I am especially interested in the role of experience (= a developmental cognitive process) in shaping individual variation in behaviour. Because, understanding the influence of experience in the shaping individual migratory routines may play a key role in predicting the species response to Global Change. To unravel underlying mechanisms leading to individual variation in behaviour I combine experimental work, field observation and satellite tracking of individuals.

 

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Postdoc: ‘Phenological and behavioural responses to climate change in migratory shorebirds

 

In my current postdoc project, I joined Jan van Gils and his team to investigate how global warming affects red knots from their Arctic breeding grounds to their tropical wintering areas and back.

All too briefly: Due to global warming, which is especially strong at higher latitudes, the Arctic summer has advanced by almost a month in the past decades. As a result, the emergence of insects (the main prey for red knot chicks) has also advanced and this seems to induce a so-called ‘tropic mismatch’, with red knot chicks growing up after the peak food supply. Read more about this VICI-funded project. 

 

Within this project I focus on unraveling potential ways red knots can mitigate the effects of an Arctic-warming-induced trophic mismatch, with special attention to migration. The most straightforward way to deal with the advanced Arctic phenology for red knots is to advance northward migration. To investigate this possibility, we will focus on the timing of key events during migration (i.e., onset of fueling, departure from wintering and staging sites and arrival at the breeding grounds) and how these are influenced by current changes in climate.

(1)   More specifically, we will set up a field experiment in which we manipulate timing of spring migration to investigate the potential constraints which limit advancements in migration. We will manipulate the fuel deposition rates of two groups of individuals (slow, fast) to assess whether timing and duration of stops is flexible, and indeed limited by fueling rate. By means of satellite tracking of the manipulated individuals, and in comparison, with an unmanipulated control group equipped with transmitters, we will be able to pinpoint exactly at what point during migration individuals are most constrained.

(2)   Plastic responses to climate may be constrained by inherited circannual rhythms. Consequently, potential mechanism for keeping pace with shifting phenology may require evolutionary adjustments. I will use a large dataset that contains weekly measurements of body mass and plumage to assess changes in onset of fueling and moult over the past 30 years.

(3)   Coming back to the role of experience in the shaping individual routines I will investigate potential downstream effects of the tropic mismatch on intraspecific variation in behaviour. To this extend I will relate food conditions experienced during early development to variation in foraging behaviour at a later age.

 

 

​​​​​[image cover thesis]

I recently received my PhD from the University of Groningen. The aim of my thesis ('Why Knot? Exploration of Variation in Long-Distance Migration) was to increase understanding of the development of individual migratory routines. To that extend I first explored individual variation in migratory behaviour present in wild red knots (Calidris canutus) using a novel solar-powered satellite transmitter. Second, I investigated how differences in experience effect the development of physiological and behavioural traits in birds temporarily held in captivity. By combining these results I show that environmental conditions play a key role in shaping individual migratory routines.

This work was done at NIOZ under supervision of Theunis Piersma and Kimberley Mathot. A pdf of my thesis can be downloaded here.

Functions

Functions

2020-current: Postdoctoral researcher at NIOZ 

2014-2020: PhD student at NIOZ and University of Groningen (click here for more information).

Publications

Key-publications

Please find my complete list of NIOZ-publications at the bottom of this webpage. You can also find all my publications on Research Gate.

 

 

Education

Professional education

 

Awards

Awards and Prizes

2016: Poster Price at the International Wader Study Group conference in Cork, Ireland

Other

Other

Media

2020: Bioscoop film Silence of the Tides

2018: De Eilanden Het Wad, met Midas Dekkers 

Blog

2018: Tracking Red Knots in the East Asian - Australasian Flyway in NW Australia

 

Linked news

Friday 28 August 2020
Red knots base migration strategy on both environment and experience
In her dissertation Why Knot? Eva Kok (NIOZ and the University of Groningen) investigates how individual red knots develop their migration strategy. Although environmental conditions play a key role in shaping individual routines, she urges not to…
Monday 08 June 2020
Flying home. Examining the role of memorized locations as motivation for migration in red knots
NIOZ biologist Eva Kok and red knot Paula met in 2016 when the bird was caught in mist nets in the Dutch Wadden Sea. Once ringed and tagged with a very small transmitter, the first of its kind, Kok followed Paula on two of her migratory journeys from…
Tuesday 11 June 2019
Trekvogel kanoet verandert wel zijn maag, niet zijn gedrag
Het gezegde dat een vos wel zijn haren maar niet zijn streken verliest, lijkt enigszins van toepassing op kanoeten, trekvogels die in voor- en najaar de Waddenzee bezoeken om zich er vol te eten. Onderling verschillen de individuele vogels vooral in…
Tuesday 20 September 2016
Eva Kok wins poster prize at Wader Study Group Symposium
Paula the Pioneer: One tagged knot commutes from the Wadden Sea to its Canadian Arctic breeding ground and finally shows us the details of its migration route.
Wednesday 20 July 2016
From Canadian breeding grounds to Wadden Sea
On Friday morning, 'Paula', a red knot mounted with a very small satellite transmitter, landed on de Boschplaat on the island of Terschelling, The Netherlands. She did so after leaving the most northerly breeding grounds on Earth in a non-stop flight…

Linked blogs

Monday 21 August 2017
Waddentrekkers | Wadden Flyways 8 | Paula is weer thuis
Er gaat niets boven een visuele waarneming. De afgelopen weken heeft de zender van kanoet Paula signalen verstuurd vanuit Canada, Groenland, het noorden van Schotland en de Duitse Waddeneilanden Sylt en Borkum. Uiteindelijk kwamen de signalen deze…
Thursday 03 August 2017
Waddentrekkers | Wadden Flyways 7
De gezenderde kanoet 'Paula' is weer 'gezien', dat wil zeggen de zender heeft weer signalen uitgezonden. Wat is er allemaal gebeurd sinds het laatste contact? | Knot 'Paula' has been 'seen' again, that is her transmitter has transmitted signals .…
Wednesday 07 June 2017
Waddentrekkers | Waddenflyways 5
Knot Paula: Ellesmere Island, touch down!

NIOZ publications

Linked projects

Arctic warming and migrant shorebirds
Supervisor
Jan van Gils
Funder
Netherlands Organization for Scientific Research - Veni/Vidi/Vici
Project duration
1 Oct 2019 - 1 Oct 2024