Ewch i’r prif gynnwys
Rob Thomas

Dr Rob Thomas

(Translated he/him)


Ysgol y Biowyddorau

+44 29208 76653
Adeilad Syr Martin Evans, Ystafell C5.11, Rhodfa'r Amgueddfa, Caerdydd, CF10 3AX
Ar gael fel goruchwyliwr ôl-raddedig


My research group studies animal behaviour in changing environments. The environmental changes that we study range from long-term climate changes, through seasonal and daily changes, to the sudden appearance of a potential predator or an unfamiliar type of food. This work falls under four main headings, though there is plenty of overlap between these topics.

Climate change biology

Focusing on major study systems that use migratory birds as sensitive bio-indicators of climate-driven changes in trophic relationships.

  • The Storm Petrels –the smallest of the seabirds, spending most of their lives on the open ocean
  • The Northern Wheatear –an upland species with the most extreme trans-oceanic migration of any songbird
  • Reed-bed warblers (Reed Warblers and Sedge Warblers) –a pair of congeneric migrants with contrasting migration strategies
  • The Pied Flycatcher -a rapidly-declining songbird of the Welsh oak woodlands
  • The Barn Swallow -familiar herald of summer in a rapidly changing climate
  • The European Nightjar -specialist predator of nocturnal moths

An online talk about some of my current climate change research is available here: https://www.youtube.com/watch?v=yizBE01S9hc

Sensory constraints on behaviour

  • Eye design in birds and visual constraints on behaviour
  • Impacts of light and noise pollution on wildlife
  • Automated acoustic monitoring and identification of bat echolocation calls as a monitoring tool

Dietary wariness and foraging ecology

  • Novel-food wariness in birds and fish, and its evolutionary consequences
  • Strategic regulation of energy reserves in wild birds
  • Diet choice and foraging ecology
  • Co-author/curator of the Wikipedia page for Dietray Conservatism: https://en.wikipedia.org/wiki/Dietary_conservatism

Impacts of human activities on wild animals

  • Impacts of capture and handling on birds and other animals
  • Practical conservation of populations, habitats and biodiversity hotspots in a changing world -an online talk about this work is available here: https://www.cardiff.ac.uk/sustainable-places/events/webinar-series
  • Ecological impacts of eco-tourism and game-bird shooting
  • Birds of prey in human-modified landscapes -here is a recent podcast discussion about the challenges of preventing illegal persecution of birds of prey in the UK: https://www.theyorkshiregent.com/podcast/068/ (main discussion begins at 58 mins).
  • Human-elephant conflicts in Sabah and Sri-Lanka























Book sections



Climate change biology

What are the biological impacts of climate change? My research group is investigating the effects of climate on individuals, populations and ecological processes - particularly how such effects may be mediated by the behaviour of individual animals. Our current work in this field focuses on major study systems that use migratory birds as sensitive bio-indicators of climate-driven changes in trophic relationships.

Effects of climate changes on trophic relationships in marine ecosystems

The body mass regulation behaviour of the smallest Atlantic seabird (the European storm petrel) changes between years in response to climate-driven changes in sea temperatures. Together with Renata Medeiros and collaborators, we coordinate a long-term monitoring project investigating how these changes are mediated by changes in the marine food webs on which storm petrels rely.

The speciation of the band-rumped storm petrel "super-species" is the first documented example of sympatric speciation in a bird (and indeed in any tetrapod). Renata Medeiros, Hannah Hereward, Annalea Beard and collaborators are investigating how diet and foraging ecology varies between sibling-species breeding in different seasons and locations and years, with the aim of understanding how foraging traits are linked to speciation events.

Effects of climate changes on migrant birds

Migration is one of the major challenges to survival faced by many animals, and the availability of food and other resources along the migration route is of critical importance to successfully completing the journey. Furthermore, climate may impact individuals in different ways in different parts of the annual cycle (breeding grounds, migration stopover sites and wintering areas). Together with Adam Seward, James Vafidis, Rich Facey, Jez Smith, Mike Shewring, Sarah Davies and collaborators, we combine observational studies in the field, lab and field mesocosm experiments, experimental manipulations of food availability and analyses of long-term climate and bird ringing databases, to examine the effects of climate changes on breeding behaviour, reproductive success, migration decisions, wintering ecology and annual survival of migrant songbirds. The species studied to date are primarily northern wheatears and various species of reedbed warblers, with a new project on barn swallows now underway. This work is carried out at breeding locations (Wales for warblers, flycatcher, swallows and nightjars, Shetland and Greenland for wheatears), migration stopovers (Portugal and Shetland) and wintering areas (Senegal).

Sensory constraints on behaviour

How do animals decide when to be active? My research collaboration with Alex Pollard, Rhian Newman and others focuses on the role of eye design and visual constraints in an animal's behavioural decisions, particularly under varying light levels at twilight and at night. Specific projects have examined eye size and the timing of singing (in songbirds) and foraging (in shorebirds), as well as aviary and field studies of the impacts of light pollution, using night-singing in European robins and activity of aquatic organisms as case-studies.

Dietary wariness and foraging ecology

When a forager encounters an unfamiliar object, it must decide whether to eat it and risk being poisoned (if it is toxic) or avoid it and risk missing out on a valuable food source (if it is palatable). Foragers generally show brief aversions to novel objects (neophobia) but some individuals also show a much more persistent aversion to eating novel foods (dietary conservatism), which can last for weeks or even years. In collaboration with Nicola Marples, Jo Cable and others, we investigate the function, control and evolutionary consequences of these aspects of dietary wariness, in a range of taxonomic groups –primarily birds and fish. Related to this, I am also interested in the foraging decisions underlying the strategic regulation of energy reserves in foraging birds, over minutes, days, seasons and years.

Impacts of human activities on wild animals

Large numbers of wild animals are captured, handled, often marked for individual identification, and released in the course of scientific research and conservation monitoring programmes. Surprisingly, little is known about the effects of capture and handling on the animals themselves. Together with Leila Duarte and others, I am investigating the impact of capture and handling on the body mass regulation and foraging behaviour of animals throughout the annual cycle, and on breeding behaviour and fitness parameters. This work has implications for the design and implementation of ethical field studies on wild animals. Other studies of human impacts include evaluating and minimising the impacts of eco-tourism, and monitoring habitat use and foraging ecology of birds and other animals, in areas earmarked for –or currently undergoing- development.



  • PhD student supervision (see "supervision" tab)
  • PhD assessor / examiner
  • Data analysis training (see below)


  • Data Science (module leader)
  • Survey methods: Ornithology
  • Personal tutor
  • MSc project supervisor

MBiol / MRes

  • Project supervisor
  • Research methods: Ornithology

Final year

  • Conservation Biology
  • Global Change Biology
  • Final-year project supervision

Professional Training Year (PTY)

I provide a substantial contribution to Cardiff School of Biosciences work-placement programme for undergraduates, normally supervising 2-3 PTY students per year as Cardiff University academic supervisor, plus 1-3 placements per year as Eco-explore co-director.

Second year

  • Animal Diversity & Adaptation
  • Brain & Behaviour (assessment leader)

Field courses

  • Ecological Survey Methods (Kenfig and Parc Slip Nature Reserves, South Wales)
  • Behaviour and ecology (Cardiff)

First year

  • Animal Behaviour
  • Sexual selection
  • Ecological survey methods

Data analysis and statistics

I run regular courses in Data Analysis through the year. for staff and students, including courses for PhD students (NERC GW4+ DTP), the Royal Society for the Protection of Birds (RSPB), and the Student Conference for Conservation Science (SCCS) at Cambridge University.

General teaching / learning activities

  • Various activities relevant to the Zoology degree scheme, including supporting the Cardiff University Ornithological Scociety ("Bird Club"), and the Wildlife and Conservation Society ("Wildsoc")
  • Personal tutor


Cefais fy ngeni a'm magu yn y Bannau Brycheiniog, lle mae llawer o'm hymchwil prifysgol bellach wedi'i leoli. Gwnes fy ngradd gyntaf (MA, BA) mewn Sŵoleg ac Ecoleg ym Mhrifysgol Caergrawnt (graddio yn 1993), a fy D.Phil. ym Mhrifysgol Sussex (graddio yn 1997). Ar ôl cyfnod byr fel warden cynorthwyol yn Arsyllfa Adar Rocha yn Ne Portiwgal, symudais i'r Ganolfan Bioleg Ymddygiadol ym Mhrifysgol Bryste ym 1998 i ymgymryd â swydd ôl-ddoethurol a ariennir gan NERC. Yn 2002 cefais Gymrodoriaeth Ymchwil Ôl-ddoethurol NERC, a gyflwynais i Ysgol y Biowyddorau Caerdydd. Cefais fy mhenodi i ddarlithyddiaeth yma yn 2006 ac rwyf bellach yn Uwch-Ddarlithydd.

Rolau a chyfrifoldebau

  • Cyd-gyfarwyddwr Eco-explore Community Interest Company.
  • Aelod o'r Gymdeithas Astudio Ymddygiad Anifeiliaid (ASAB, 2009-2016).
  • Ysgrifennydd Addysg y Gymdeithas Astudio Ymddygiad Anifeiliaid (2011-2016).
  • Aelod o Bwyllgor Moeseg y Gymdeithas Astudio Ymddygiad Anifeiliaid (2006-2013, Ysgrifennydd dros dro 2007, 2009).
  • Aelod o Bwyllgor Moeseg Prifysgol Caerdydd sy'n ymdrin ag ymchwil nad yw'n ASPA (2019-presennol).
  • Ymddiriedolwr y Fenter ar gyfer Cadwraeth Natur Cymru (INCC; 2023-presennol)

Meysydd goruchwyliaeth

Myfyrwyr PhD cyfredol

Ymchwilwyr Cysylltiedig

Stephen Davison

Addysg:BSc (Anrh.) Prifysgol Leeds. MSc Prifysgol Salford. MBA Open University. BA (Anrh.) Prifysgol Cymru Llanbedr Pont Steffan.

Diddordebau Ymchwil: ystlumod, yn enwedig agweddau ecolegol ystlumod coetir De-ddwyrain Cymru.


Stephen P. Davison & Robert J. Thomas.   Ymddygiad heidio ymddangosiadol y gwanwyn o ystlumod pedol lleiaf (Rhinolophus hipposideros). Journal of Bat Research and Conservation 10 (1).

Stephen Davison 2021 Ffobia Lunar yn Ystlumod Cynhesu Prydain. Ystlumod Ynys Prydain vol 2 P174 – 185.  

Ashoka Ranjeewa

Gwefan ymchwil: https://www.wilsonperformancelab.com/ashoka-ranjeewa


Ranjeewa A. D. G., Pastorini J., Isler K., Weerakoon D. K., Kottage H. D., Fernando P; Mae lleihau lefelau dŵr cronfa ddŵr yn gwella ansawdd cynefinoedd eliffantod Asiaidd. (Paratoi'r llawysgrif)

Ranjeewa A. D. G., Tharanga Y. J. S., Sandanayake G. H. N. A., Perera B. V., & Fernando P. (2015) trapiau camera dadorchuddio'r cyrchwyr cnwd enigmatig yn Udawalawe, Sri Lanka. Gajah 42, 7-14.

Ranaweera E., Ranjeewa A. D. G.,  Koun Sugimoto (2015). Ysgogodd twristiaeth aflonyddwch ar fywyd gwyllt mewn ardaloedd gwarchodedig; Astudiaeth achos o eliffantod rhydd yn Sri Lanka. Ecoleg a Chadwraeth Fyd-eang, 4, 625–631.

de Silva S., Ranjeewa A. D. G., Weerakon D. K. (2011) Demograffeg eliffantod Asiaidd (Elephasmaximus) ym mharc cenedlaethol Udawalawe, Sri Lanka, yn seiliedig ar unigolion a nodwyd. Cadwraeth fiolegol 144, 1742-1752. 

de Silva S., Ranjeewa A. D. G., & Kryazhimskiy S. (2011) Dynameg rhwydweithiau cymdeithasol ymhlith eliffantod Asiaidd benywaidd. Ecoleg BMC, 11 17. 

Nils Bouillard

Mae Nils yn cynnig ystod o wasanaethau mewn ymchwil, hyfforddiant ac ymgynghoriaeth ystlumod: https://www.batacoustics.com/


Goruchwyliaeth gyfredol

Sarah Morgan

Sarah Morgan

Myfyriwr ymchwil

Lucy Rowley

Lucy Rowley

Myfyriwr ymchwil

Elisa Panjang

Elisa Panjang

Myfyriwr ymchwil

Paul Robinson

Paul Robinson

Myfyriwr ymchwil

Annalea Beard

Annalea Beard

Myfyriwr ymchwil

Amanda Wilson

Amanda Wilson

Myfyriwr ymchwil