About me

I am a ecologist with broad interests in spatial and movement ecology, behavioural ecology and conservation, with a particular focus on marine predators such as seabirds and cetaceans.


I investigate how oceanic animals move and forage in their marine environment across a range of scales, as well as the effects of intrinsic factors (e.g. age, sex, morphology) on behaviour. I am also interested in the life-history and demographic consequences of particular strategies, including the extent to which animals are exposed to at-sea threats, such as fisheries bycatch, throughout their life cycles. To address these topics, I use remote monitoring tools such as biologging and passive acoustics to record animal behaviour at sea, in combination with statistical, oceanographic and atmospheric models. 

I am currently a postdoctoral researcher at the University of California, Santa Cruz and the National Oceanographic and Atmospheric Administration in the Climate and Ecosystems Group, examining cetacean predator-prey dynamics in the mesopelagic zone. 


I also serve as an Associate Editor for Marine Biology, Guest Associate Editor for Frontiers in Marine Science, Marine Megafauna and Marine Ecology Progress Series, and am a regular reviewer for several ecological and marine journals (Publons).


*** Consider submitting a paper to our theme issue in Marine Ecology Progress Series entitled "Wind and weather effects on seabird foraging, movement and energetics". Submissions due 1st July 2022. ***


  • 2022-present: Research Scientist, Environmental Defense Fund (EDF).

  • 2022-present: Research Associate, University of California, Santa Cruz (UCSC) and National Oceanic and Atmospheric Administration (NOAA) Southwest Fisheries Science Center (SWFSC).

  • 2020-2022: Postdoctoral Scholar, UCSC and NOAA SWFSC. 

  • 2017-2020: Postdoctoral Researcher, University of Liverpool.

  • 2017: Postdoctoral Researcher, British Antarctic Survey.

  • 2013-2017: PhD in Spatial Ecology, British Antarctic Survey and University of Cambridge.

  • 2011-2012: MSc Conservation and Biodiversity, University of Exeter.

  • 2008-2011: BSc Zoology, University of Bristol.


Past and present research projects

ADEON infographic V2_0.jpg

Cetacean predator-prey dynamics

I am currently part of the Atlantic Deepwater Ecosystem Observatory Network (ADEON) project which has generated long-term measurements of the soundscape of the US Mid- and South Atlantic Outer Continental Shelf.


I am combining data on whale and dolphin behaviour (from passive acoustics) with prey fields (from active acoustics) and oceanography, to determine drivers of cetacean habitat use over daily and seasonal scales. 

Photo credit: ADEON


Atmospheric drivers of seabird movements

I was part of an inter-disciplinary project funded by the Human Frontiers Research Program (HFSP) exploring the influence of atmospheric dynamics (e.g. wind, weather, infrasound) on seabird movements and navigation. I led work examining the effects of wind and morphology on the flight decisions and foraging strategies of albatrosses and petrels.


Photo credit: Michael Brooke

Movement and foraging ecology of gadfly petrels

Since my PhD, I have been working alongside Michael Brooke and others on projects relating to the at-sea behaviour and movements of little-known, endemic gadfly petrels Pterodroma sp. in the central and eastern Pacific Ocean. 

For information about our current National Geographic-funded project tracking petrels from the Juan Fernández Islands in the southeast Pacific, see our blog posted by partners Island Conservation.


Assessing overlap of seabirds with marine threats

During my postdoc at the British Antarctic Survey and in collaboration with BirdLife International and the RSPB, I combined biologging data and population models for albatrosses and petrels to map the at-sea distributions of major life-history stages (adults, immatures, juveniles) in order to assess bycatch risk from industrial longline and trawl fisheries. 


Causes and consequences of variation in seabird migration strategies

For my PhD, I analyzed archival geolocator datasets in combination with stable isotope analysis and resource selection modelling, to examine the drivers of variation in albatross and petrel migration strategies between and within populations. I determined how non-breeding distributions varied according to factors such as sex, age, ontogeny and breeding status, as well as potential carry-over effects on breeding success. 


Interactions between Peruvian cetaceans and small-scale fisheries

During my masters I worked as a research assistant for the Peruvian NGO ProDelphinus. For my research project, I used passive acoustic methods to determine the habitat use of the little-known Burmeister's porpoise Phocoena spinipinnis around small-scale fishing vessels. I also examined the degree to which acoustic alarms (pingers) attached to nets influenced porpoise behaviour, to inform their use as an effective bycatch mitigation measure. 



Also see Google Scholar.


2022 and in press 

24. Halpin LR, Mott R, Clay TA, Humphries GR, Chatwin TA, Carlile N, Clarke RH (Accepted) Predicting the foraging habitats of sympatrically breeding gadfly petrels in the South Pacific Ocean. Frontiers in Marine Science.


23. Joo R, Picardi S, Boone ME, Clay TA, Patrick SC, Romero V, Basille M (Accepted). Recent trends in movement ecology of animals and human mobility. Movement Ecology.


22. Frankish, CK, Manica A, Clay TA, Wood AG, Phillips RA. (2022) Ontogeny of movement patterns and habitat selection in juvenile albatrosses. Oikos, e09057. http://doi.org/10.1111/oik.09057. [pdf]


21. Zeyl JN, Snelling EO, Connan M, Basille M, Clay TA, Joo R, Patrick SC, Phillips RA, Pistorius P, Ryan PG, Snyman A, Clusella-Trullas S (2022) Aquatic birds have middle ears adapted to amphibious lifestyles. Scientific Reports, 12: 5251. doi.org/10.1038/s41598-022-09090-3. [pdf]


20. Patrick SC*, Assink JD*, Basille M*, Clusella-Trullas S*, Clay TA*, den Ouden O*, Joo R*, Zeyl JN*, et al. (12 other authors) (2021) Infrasound as a cue for seabird navigation. Frontiers in Ecology and Evolution, 9:740027. *Equal contribution. doi.org/10.3389/fevo.2021.740027. [pdf]

19. Bonnet-Lebrun A-S, Dias MP, Phillips RA, Granadeiro JP, et al. (30 other authors including Clay TA) (2021) Seabird migration strategies: Flight budgets, diel activity patterns and lunar influence. Frontiers in Marine Science, 8:683071. doi.org/10.3389/fmars.2021.683071. [pdf]

18. Frankish CF, Cunningham C, Manica A, Clay TA, Prince S, Phillips RA (2021) Tracking juveniles confirms fisheries-bycatch hotspot for an endangered albatross. Biological Conservation, 261:109288.  

doi.org/10.1016/j.biocon.2021.109288. [pdf]


17. Borrmann RM, Phillips RA, Clay TA, Garthe S (2021) Post-fledging migration and wintering strategies of individual juvenile lesser black-backed gulls Larus fuscusIbis, 163:1017-1031doi.org/10.1111/ibi.12917. [pdf]

16. Beal M, Pearmain EJ, Phillips RA, Oppel S, et al. (78 other authors including Clay TA) (2021) Global political responsibility for the conservation of albatrosses and large petrels. Science Advances, 7(10): eabd7225. doi.org/10.1126/sciadv.abd7225. [pdf]


15. Frankish CK, Phillips RA, Clay TA, Somveille M, Manica A (2020) Environmental drivers of movement in a threatened seabird: insights from a mechanistic model and implications for conservation. Diversity and Distributions, 26:1315-3129. doi.org/10.1111/ddi.13130. [pdf]

14. Clay TA, Joo R, Weimerskirch H, Phillips RA, den Ouden O, Basille M, Clusella-Trullas S, Assink JD, Patrick SC (2020) Sex-specific effects of wind on the flight decisions of a sexually dimorphic soaring bird. Journal of Animal Ecology, 89:1811-1823. doi.org/10.1111/1365-2656.13267. [pdf]


Photo credit: Jamie Coleman. 

13. Handley JM, Pearmain EJ, Oppel S, Carneiro APB, Hazin C, Phillips RA, Ratcliffe N, Staniland IJ, Clay TA, Hall J, Scheffer A, Fedak M, Boehme L, Pütz K, Belchier M, Boyd IL, Trathan PN, Dias MP (2020). Evaluating the effectiveness of a large multi-use MPA in protecting key biodiversity areas for marine predators. Diversity and Distributions, 26:715-729. doi.org/10.1111/ddi.13041. [pdf]

12. Carneiro APB, Pearmain EJ, Oppel S, Clay TA, Phillips RA, et al. (42 other authors) (2020) A framework for mapping the distribution of seabirds by integrating tracking, demography and phenology. Journal of Applied Ecology, 57:514-525. doi.org/10.1111/1365-2664.13568. [pdf]

11. Joo R, Boone ME, Clay TA, Patrick SC, Clusella-Trullas S, Basille M (2020). Navigating through the R packages for movement. Journal of Animal Ecology, 89:248-267. doi.org/10.1111/1365-2656.13116. [pdf]

10. Williams HJ, Taylor LA, Benhamou S, Bijleveld AI, Clay TA, de Grissac S, Demsar U, English HE, Franconi N, Gomez-Laich A, Griffiths RC, Kay WP, Morales JM, Potts JR, Rogerson KF, Rutz C, Spelt A, Trevail AM, Wilson RP, Borger L (2020). Optimising the use of bio-loggers for movement ecology research. Journal of Animal Ecology, 89:186-206. doi.org/10.1111/1365-2656.13094. [pdf]


9. Borrmann RM, Phillips RA, Clay TA, Garthe S. High foraging site fidelity and spatial segregation among individual great black-backed gulls (2019). Journal of Avian Biology, e02156:1-10. doi.org/10.1111/jav.02156. [pdf]


8. Clay TA, Alfaro-Shigueto J, Godley BJ, Tregenza N, Mangel JC (2019) Pingers reduce the activity of Burmeister’s porpoises around small-scale gillnet vessels. Marine Ecology Progress Series, 626:198-208. doi.org/10.3354/meps13063. [pdf

7. Clay TA, Small C, Tuck GN, Pardo D, Carneiro APB, Wood AG, Croxall JP, Crossin GT, Phillips RA (2019) A comprehensive large-scale assessment of fisheries bycatch risk to threatened seabird populations. Journal of Applied Ecology, 56:1882-1893. doi.org/10.1111/1365-2664.13407. [pdf]

6. Clay TA, Oppel, S, Lavers, JL., Phillips RA, Brooke MdeL (2019) Divergent foraging strategies during incubation of an unusually wide-ranging seabird, the Murphy’s petrel. Marine Biology, 166:8. doi.org/10.1007/s00227-018-3451-7. [pdf]


5. Clay TA, Mangel JC, Alfaro-Shigueto J, Hodgson DJ, Godley BJ (2018) Distribution and habitat use of a cryptic small cetacean, the Burmeister’s porpoise, monitored from a small-scale fishery platform. Frontiers in Marine Science, 5:220.  doi.org/10.3389/fmars.2018.00220. [pdf]

4. Clay TA, Pearmain EJ, McGill RAR, Manica A, Phillips RA (2018) Age-related variation in non-breeding foraging behaviour and carry-over effects on fitness in an extremely long-lived bird. Functional Ecology, 32:1832-1846. doi.org/10.1111/1365-2435.13120. [pdf]


3. Clay TA, Phillips RA, Manica A, Jackson HA, Brooke MdeL (2017) Escaping the oligotrophic gyre? Year-round movements, foraging behaviour and habitat preferences of Murphy’s petrels. Marine Ecology Progress Series, 579:139-155. doi.org/10.3354/meps12244. [pdf]


2. Clay TA, Manica A, Ryan PG, Silk JRD, Croxall JP, Ireland L, Phillips RA (2016) Proximate drivers of spatial segregation in non-breeding albatrosses. Scientific Reports, 6:29932. doi.org/10.1038/srep29932. [pdf

1. Carneiro APB, Manica A, Clay TA, Silk JRD, King M, Phillips RA (2016) Consistency in migration strategies and habitat preferences of brown skuas over two winters, a decade apart. Marine Ecology Progress Series, 553:267–281.  doi.org/10.3354/meps11781. [pdf]


Frankish CK, Clay TA, Small C, Phillips RA (2019) At-sea distribution and fisheries bycatch risk of juvenile grey-headed albatrosses from South Georgia. Paper submitted to the International Commission for the Conservation of Atlantic Tunas (ICCAT) Ecosystems Sub-committee, Madrid, 9-12 April, 2019, and the 5th Meeting of the ACAP Population and Conservation Status Working Group, Florianópolis, Brazil, 9-10 May 2019. 

Carneiro APB, Pearmain EJ, Oppel S, Clay TA et al. (2019) Mapping the global distribution of seabird populations: a framework for integrating biologging, demographic and phenological datasets. Paper submitted to the 5th Meeting of the ACAP Population and Conservation Status Working Group, Florianópolis, Brazil, 9-10 May 2019. 

Clay TA, Small C, Carneiro APB, Mulligan B, Pardo D, Wood AG, Phillips RA (2017) Identifying areas, seasons and fleets of potential highest bycatch risk to South Georgia albatrosses and petrels. Paper submitted to the International Commission for the Conservation of Atlantic Tunas (ICCAT) Ecosystems Sub-committee, Madrid, 10-14 July, 2017; the Western and Central Pacific Fisheries Commission (WCPFC) 13th Regular Session of the Scientific Committee, Rarotonga, 9-17th August, 2017; the 4th Meeting of the ACAP Population and Conservation Status Working Group, Wellington, 7-8 September 2017; and the Indian Ocean Tuna Commission (IOTC) 13th Working Party on Ecosystems and Bycatch, San Sebastian, 4-8 September 2017. 


Datasets and code

Published datasets and R code


Clay TA, Joo R, Weimerskirch H, Phillips RA, den Ouden O, Basille M, Clusella-Trullas S, Assink J, Patrick SC (2020). Data from: Sex‐specific effects of wind on the flight decisions of a sexually dimorphic soaring bird: Data and R code (Version v.1.0). Zenododoi.org/10.5281/zenodo.3824064.


Joo R, Boone M E, Clay TA, Patrick SC, Clusella-Trullas S, Basille M (2019). rociojoo/RmovementPaperRep: Navigating through the R packages for movement: Supporting information (Version v1.1). Zenododoi.org/10.5281/zenodo.3483853.


Clay TA, Small C, Tuck GN, Pardo D, Carneiro APB, Wood AG, Croxall JP, Crossin GT, Phillips RA (2019). Data from: A comprehensive large‐scale assessment of fisheries bycatch risk to threatened seabird populations. Dryad Digital Repositorydoi.org/10.5061/dryad.k540b54.


Clay TA, Pearmain EJ, McGill RAR, Manica A, Phillips, RA (2018) Data from: Age‐related variation in non‐breeding foraging behaviour and carry‐over effects on fitness in an extremely long‐lived bird. Dryad Digital Repositorydoi.org/10.5061/dryad.cr266nb.

Also, see my GitHub account.


Biologging data in online repositories


Brooke MB, Clay TA. Juan Fernández petrel incubation GPS data, Alejandro Selkirk Island, 2019-2020.  Requestable through BirdLife International Seabird Tracking Database.


Oppel S, Brooke MB, Clay TA. Murphy’s petrel incubation GPS data, Henderson Island, 2015. Requestable through BirdLife International Seabird Tracking Database.


Brooke MB, Clay TA. Murphy’s petrel year-round GLS data, Henderson Island, 2011-2013. Requestable through BirdLife International Seabird Tracking Database.


Blog posts and media

University of California, Santa Cruz News. November 2021. Scholar Spotlight - Tommy Clay.

University of Liverpool News. June 2020. Wind beneath their wings: Albatrosses fine-tuned to wind conditions.

SeabirdSound blog. January 2020. Perspectives on an interdisciplinary perspective.

Island Conservation. December 2019. Unraveling The Mysterious Lives of Oceanic Seabirds in the Remote Pacific.

University of Exeter. October 2019. MSc Graduate in Focus: Tommy Clay

The Applied Ecologist. August 2019. Identifying fishery risk zones for seabird populations.

BirdLife International. August 2019. Tracking down threats.

British Antarctic Survey News stories. June 2018. In old age, efficiency is key to successful parenting.

British Antarctic Survey News stories. July 2016. Albatrosses use different regions when on migration.

University of Cambridge Animal Alphabet Series. June 2015. A is for Albatross.