Below is a list of publications. You can click on the click at the end of each paper to download the PDF.



Lab members are in bold.

A full list of publications can also be found at Google Scholar Citations:


King, A.J., Portugal, S.J., Strömbom, D., Mann, R.P., Carrillo, J., Kalise, D.,  Croon, G., Barnett, H., Scerri, P., Gross, R.,  Chadwick, D. & Papadopolou, M. (2022). Biologically inspired herding of animal groups by robots. Methods in Ecology and Evolution. King et al. 2023 Meth Ecol Evol

Portugal, S.J. (2023). Quick Guide: The Siamese Fighting Fish (Betta splendens). Current Biology. In Press. 


Papadopoulou, M., Hildenbrandt, H., Sankey, D.W.E., Portugal, S.J. & Hemelrijk, C.K. (2022). Self-organization of collective escape in pigeon flocks. PLOS Computational Biology. 18(1): e1009772. Papadopoulou et al. 2022 PLOS Biol.

Papadopoulou, M., Hildenbrandt, H., Sankey, D.W.E., Portugal, S.J. & Hemelrijk, C.K. (2022). Emergence of splits and collective turns in pigeon flocks under predation. Royal Society Open Science. 9: 211898. Papadopoulou et al. 2022 RS Open Science

Sankey, D.W.E., Biro, D., Ricketts, R. L., Shepard, E.LC. & Portugal, S.J. (2022). Pigeon leadership hierarchies are not dependent on environmental contexts or individual phenotypes. Behavioural Processes. 198: 104629. Sankey et al. 2022 Behavioural Processes

Jacobs, P.J., Hart, D.W., Merchant, H.N., Janse Van Vuuren, A., Faulkes, C., Portugal, S.J., van Jaarsveld, B. & Bennett, N.C. (2022). Tissue oxidative ecology along an aridity gradient in a mammalian subterranean species. Antioxidants 11: 2290. Jacobs et al. 2022 Antioxidants

Attard, M.R.G. & Portugal, S.J. (2022). Global diversity and adaptations of avian eggshell thickness indices. Ibis. In Press. Attard and Portugal 2022 Ibis      

Portugal, S.J. (2022). Quick Guide: The Secretary Bird. Current Biology. 32: 1074-1075. Portugal 2022 Current Biology

Portugal, S.J. and White, C.R. (2022). Externally attached biologgers cause compensatory body mass loss in birds. Methods in Ecology and Evolution. 13: 294-302. Portugal and White 2021 Meth Ecol Evol


Sankey, D.W.E., Storms, R.F., Musters, R.J., Russell, T.W., Hemelrijk, C.K. & Portugal, S.J. (2021). Absence of “selfish-herd” dynamics in bird flocks under threat. Current Biology. 31: 1-7. Sankey et al. 2021 Current Biology

Attard, M.R.G. & Portugal, S.J. (2021). Climate variability and parent nesting strategies influence gas exchange across avian eggshells. Proceedings of the Royal Society B. 288: 20210823. Attard and Portugal 2021 Proc Roy Soc B

McClelland, S.C., Reynolds, M., Cordall, M., Hauber, M.E., Goymann, W., McClean, L.A., Hamama, S., Lund, J., Dixit, T., Louder, M.I.M., Safari, I., Honza, M., Spottiswoode, C.N. & Portugal, S.J. (2021). Embryo movement is more frequent in avian brood parasites than birds with other reproductive strategies. Proceedings of the Royal Society B. 20211137. McClelland et al. 2021 Proc Roy Soc B 

Portugal, S.J. and White, C.R. (2021). Externally attached biologgers cause compensatory body mass loss in birds. Methods in Ecology and Evolution. In Press. Portugal and White 2021 Meth Ecol Evol

Attard, M.R.G., Bowen, J., Corado, R., Hall, L.S., Dorey, R.A.  & Portugal, S.J. (2021). Ecological drivers of eggshell wettability in birds. Journal of the Royal Society Interface.18: 20210488. Attard et al. 2021 J Roy Soc Interface

McClelland, S.C., Cassey, P., Maurer, G., Hauber, M.E. & Portugal, S.J. (2021). How much calcium to shell out? Eggshell calcium carbonate content is greater in birds with thinner shells, larger clutches, and longer lifespans. Journal of the Royal Society Interface. 18: 20210502. McClelland et al J Roy Soc Interface 2021

Ricketts, R.L., Sankey, D.W.E., Tidswell, B.P., Brown, J., Deegan, J.F. & Portugal, S.J. (2021). Overall dynamic body acceleration as an indicator of dominance in Homing Pigeons Columba livia. Ibis. 164: 581-586. Ricketts et al. 2021 Ibis

White, C.R., Marshall, D.J., Chown, S.L., Clusella-Trullas, S., Portugal, S.J., Franklin, C.E. & Seebacher, F. (2021). Geographical bias in physiological data limits predictions of global change impacts. Functional Ecology. 00: 1-7.  White et al. 2021 Functional Ecology

Garde, B., Wilson, R.P, Lempidakis, E., Borger, L., Portugal, S.J., Hedenström, A., Dell’Omo, G., Quetting, M., Wikelski, M. & Shepard, E.L. (2021). Fine-scale changes in speed and altitude suggest protean movements in homing pigeon flights. Royal Society Open Science. 8: 210130. Garde et al RS Open Science 2021


Portugal, S.J. (2020) Flocking in Birds. Current Biology. 30: R206-R210. Portugal Current Biology 2020

Portugal, S.J., Usherwood, J.A., White, C.R., Sankey, D.W.E. & Wilson, A.M. (2020). Artificial mass loading disrupts stable social order in pigeon dominance hierarchies. Biology Letters. 16: 20200468. Portugal et al. 2020 Biology Letters

Cantlay, J.C., Bond, A.L, Wells-Berlin,  A.M., Crawford, R., Martin, G.R., Rouxel, Y., Peregoy, S., McGrew, K.A. & Portugal, S.J. (2020) Ineffectiveness of light emitting diodes as underwater deterrents for Long-tailed Ducks Clangula hyemalis. Global Ecology and Conservation. 23: e01102. Cantlay et al 2020

Jones, S.E.I., Tobias, J., Freeman, R. & Portugal, S.J. (2020) Weak asymmetric interspecific aggression and divergent habitat preferences at an elevational contact zone between tropical songbirds. Ibis. 62: 814-826. Jones et al 2020

Jones, S.E.I., Suanjak, M., Tobias, J., Freeman, R. & Portugal, S.J. (2020) Comparative physiology of five tropical montane songbirds reveals differential seasonal acclimatisation and cold adaption. BiorXiv PrePrint. Also under review.

Portugal, S.J., Nudds, R.L., Green, J.A., Alexander, R.M., Butler, P.J. & Ker, R.F. (2020) Mechanics Of Flight Feathers: Effects Of Captivity? BioRxiv. PrePrint. Also under review.

McGoran, R.E., Papworth, S.K. & Portugal, S.J. (2020) The determinants of aggression in male Siamese fighting fish, Betta splendens. BioRxiv. PrePrint.

Portugal, S.J., McGill. R.N., Green, J.A. & Butler, P.J. (2020) Pre-winter fattening and fat loss during wing moult: the annual cycle of fat deposition in captive barnacle geese (Branta leucopsis). BioRxiv. PrePrint.


Taylor, L.A., Taylor. G.K., Biro, D., Lambert, B., Walker, J.A. & Portugal, S.J. (2019) Birds invest wingbeats to keep a steady head and reap the ultimate benefits of flying together. PLOS Biology17: e3000299. Taylor et al 2019 PLOS Biology

McClelland, S.M., Jamie, G., Waters, K.S., Caldas, L., Spottiswoode, C.N. & Portugal, S.J. (2019) Convergent evolution of reduced eggshell conductance in avian brood parasites. Philosophical Transactions of the Royal Society B. 374: 20180194. McClelland et al. 2019 Phil Trans Roy Soc B.

Portugal, S.J., White, C.R., Frappell, P.B. & Butler, P.J. (2019) Impacts of “supermoon” events on the physiology of a wild bird. Ecology and Evolution. 9: 7974-7984. Portugal et al 2019 Ecol and Evol

Portugal, S.J., White, C.R., Green, J.A. & Butler, P.J. (2019) Flight feather moult drives minimum daily heart rate in wild geese. Biology Letters. 14: 20180650. Portugal et al. 2019 Biol Lett

Sankey, D.W.E., Shepard, E.L.C., Biro, D. & Portugal S.J. (2019) Speed consensus and the “Goldilocks principle” in flocking birds (Columba livia). Animal Behaviour. 157: 105-119. Sankey et al 2019

Sankey, D.W.E. & Portugal, S.J. (2019) When flocking is costly: reduced cluster-flock density over long-duration flight in pigeons. The Science of Nature. 106: 47. Sankey and Portugal 2019 Sci of Nature

White, C.R., Marshall, D., Alton, L., Arnold, P., Beaman, J.E., Bywater, C., Condon, C., Crispin, T., Janetzki, A., Pirtle, E., Winwood-Smith, H., Angilletta, M., Chenoweth, S., Franklin, C., Halsey, L., Kearney, M., Portugal, S.J. & Ortiz-Barrientos, D. (2019) The origin and maintenance of metabolic allometry: genetic constraint, random evolution, and multivariate selection. Nature Ecology and Evolution3: 598-603. White et al. 2019 Nature Ecology and Evolution

Cantlay, J.C., Portugal, S.J. & Martin, G.R. (2019) Visual fields and foraging ecology of Blacksmith Lapwings Vanellus armatusIbis. 161: 895-900. Cantlay, Portugal and Martin 2019 Ibis

Thorogood, R., Spottiswoode, C.N., Portugal, S.J. & Gloag, R. (2019) The co-evolutionary biology of brood parasitism. Philosophical Transactions of the Royal Society B. 374: 20180190. Thorogood et al. 2019 Phil Trans Roy Soc B


Portugal, S. J. and White, C. R. (2018) Miniaturisation of biologgers is not alleviating the 5% rule. Methods in Ecology and Evolution. 9: 1662-1666.  Portugal and White 2018 Methods Ecol Evol.

Portugal, S. J., Bowen, J. and Riehl, C. (2018) A rare mineral, vaterite, acts as a shock absorber in the eggshell of a communally nesting bird. Ibis. 160: 173-178. Portugal et al. 2018 Ibis


Portugal, S.J., Ricketts, R., Chappell, J., White, C.R., Shepard, E.L. and Biro, D. (2017) Boldness traits, not dominance, predicts exploratory flight range and homing behaviour in homing pigeons. Philosophical Transactions of the Royal Society B. 372: 20160234. Portugal et al. 2017 Phil Trans B

Taylor, L. A., Portugal, S. J. and Biro, D. (2017) Homing pigeons modulate wingbeat characteristics as a function of route familiarity. Journal of Experimental Biology. 220: 2908-2915. Taylor et al 2017 JEB

Guillemette, M., Polymeropoulos, E.T., Portugal, S.J. and Pelletier, D. (2017) It takes time to be cool: on the relationship between hyperthermia and body cooling in a migrating seaduck. Frontiers in Physiology. doi: 10.3389/fphys.2017.00532. Guillemette et al 2017 Frontiers

Tate, M., McGoran, R.E., White, C.R. and Portugal, S.J. (2017) Life in a bubble: the role of the labyrinth organ in determining territory, mating and aggressive behaviours in Anabantoid fish. Journal of Fish Biology. 91: 723-749. Tate et al. 2017 JFB

Portugal, S.J., Murn, C.P. and Martin, G.R. (2017) White-headed vultures show visual field characteristics of hunting raptors. Ibis. 159: 463-466. Portugal et al. 2017b Ibis

Portugal, S.J., Sivess, L., Butler, P.J., Martin, G.R. and White, C.R. (2017) Perch height predicts dominance rank in birds. Ibis. 159: 456-462. Portugal et al. 2017 Ibis


Guillemette, M., Woakes A.J., Larochelle, J, Polymeropoulos, E, Granbois, J-M, Butler, P.J., Pelletier, D., Frappell, P.D and Portugal, S.J. (2016) Does hyperthermia constrain flight duration in a short–distance migrant? Philosophical Transactions of the Royal Society B. 371: 20150386. Guillemette et al. 2016 Phil. Trans. Roy. Soc. B.

Portugal, S.J., Murn, C.P., Sparkes, E.S. and Daley, M.A. (2016) The fast and forceful kicking strikes of snake-hunting Secretary Birds (Sagittarius serpentarius). Current Biology. 26: 58-59. Portugal et al. 2016 Curr. Biol.

Biro, D. , Sasaki, T. and Portugal, S.J. (2016) Bringing a time-depth perspective to collective animal behaviour. Trends in Ecology and Evolution. 31: 550-562. Biro et al. 2016 TREE

Pollard, A., Pitsillides, A. & Portugal, S.J. (2016) Validating a non-invasive technique for monitoring embryo movement in ovo. Physiological and Biochemical Zoology. 89: 331-339. Pollard et al. 2016 PBZ

Brulez, K., Miksik, I., Cooney, C.R., Hauber, M.E., Lovell, P.G., Maurer, G., Portugal, S.J., Russell, D., S.J. Reynolds & Cassey, P.  (2016) Eggshell pigment composition co-varies with phylogeny but not with life history nor with nesting ecology traits of British passerines. Ecology and Evolution. 6: 1637-1645. Brulez et al. 2016 Ecol Eco

Portugal, S.J., Green, J.A., Halsey, L.G., Arnold, W., Careau, V., Dann, P., Frappell, P.B., Grémillet, D., Handrich, Y., Martin, G.R., Ruf, T., Guillemette, M. and Butler, P.J. (2016) Associations Between Resting, Activity and Daily metabolic rate in Free-living Endotherms: No Universal Rule for Birds and Mammals. Physiological and Biochemical Zoology. 89: 251-261. Portugal et al. 2016 PBZ

Shepard, E.L.C., Ross, A.N. and Portugal, S.J. (2016) Moving in a moving medium: New perspectives on flight. Philosophical Transactions of the Royal Society B. 371: 20150382. Shepard et al. 2016 Phil. Trans. Roy. Soc. B.

Portugal, S.J. (2016) Lissaman, Shollenberger and formation flight in birds. Journal of Experimental Biology. 219: 2778-2780. portugal-2016-jeb


Voelkl, B., Portugal, S.J., Unsold, M., Usherwood, J.R., Wilson, A.M., & Fritz, J. (2015) Matching times of leading and following suggest cooperation through direct reciprocity during V-formation flight of Northern bald ibis. PNAS (Proceedings of the National Academy of Sciences of the United States). 112: 2115-2120. Voelkl et al. 2015 PNAS (

Maurer, G., Portugal, S.J., Hauber, M.E., Miksik, I., Russell, D.G. & Cassey, P. (2015) First light for avian embryos: eggshell thickness and pigmentation mediate variation in development and UV exposure in wild bird eggs. Functional Ecology. 29: 209-218.( Maurer et al. 2015

Portugal, S.J., Maurer, G., Thomas, G.H., Hauber, M.E., Grim, T. & Cassey, P. (2015) Nesting behaviour influences species-specific gas exchange across avian eggshells. Journal of Experimental Biology. 217: 3326-3332. ( et al. 2015 JEB


Portugal, S. J., Hubel, T. Y., Hailes, S., Heese, S., Trobe, D., Voelkl, B., Fritz, J., Wilson, A. & Usherwood, J. (2014) Position and flap phasing between ibises in formation flight: evidence for upwash exploitation and downwash avoidance? Nature. 505: 399-402. Watch documentary here. ( et al. 2014 Nature

Portugal, S.J., Maurer, G., Thomas, G.H., Hauber, M.E., Grim, T. & Cassey, P. (2014) Nesting behaviour influences species-specific gas exchange across avian eggshells. Journal of Experimental Biology. 217: 3326-3332. ( et al. 2014 JEB

Portugal, S.J., Hauber M. E., Maurer, G., Stokke, B. G., Grim, T. & Cassey, P. (2014) Early hatching of an avian brood parasites embryo cannot be explained by enhanced gaseous exchange across the eggshell.  Journal of Zoology. 293: 219-226. ( et al. 2014 JoZ

Brulez, K., Choudhary, P. K., Maurer, G., Portugal, S. J., Boulton, R. L., Webber, S. L. & Cassey, P. (2014) A note on the repeatability of visually scoring eggshell patterns. Journal of Ornithology. 155: 701-706. ( et al. JoO 2014


Alton, L. A., Portugal, S. J. & White, C. R. (2013) Balancing the competing requirements and display-behaviour during male-male interactions in Siamese fighting fish, Betta splendens. Comparative and Biochemical Physiology. 164: 363-367.( Alton et al. CBP 2013

White, C. R., Cassey, P., Schimpf, N., Green, J. A., Halsey, L. G. & Portugal, S. J. (2013) Implantation reduces the negative effects of bio-logging devices on birds. Journal of Experimental Biology.  216: 537-542. ( et al. 2013 JEB

Portugal, S. J., Green, J. A., White, C. R., Guillemette, M. & Butler, P. J. (2013) Wild geese do not increase flight behaviour prior to migration. Biology Letters. 8: 469-472. ( et al. Bio Lett 2013


Guillemette, M. G., Richman, S. E., Portugal, S. J., & Butler, P. J. (2012) Behavioural compensation reduces energy expenditure during migration hyperphagia in a large bird. Functional Ecology. 26: 876-883. ( et al. FeC 2012

Martin, G. R., Portugal, S. J. & Murn, C. P. (2012) Visual fields, foraging and collision vulnerability in Gyps vultures. Ibis. 154: 626-631. ( et al. Ibis 2012

Cassey, P., Thomas, G., Portugal, S. J., Maurer, G., Hauber, M., Grim, T., Lovell, G. & Mikšík, I. (2012) Why birds paint their eggs: eggshell pigments covary with life history and nesting ecology among British birds. Biological Journal of the Linnean Society. 106: 657-672. ( et al. BJLS 2012

Cassey, P., Mikšík, I., Portugal, S. J., Maurer, G., Ewen, J. G., Zarate, E., Sewell, M. A., Grim, T.& Hauber, M. (2012) How costly is producing a colourful egg? A trade-off hypothesis between eggshell pigments and maternal egg constituents in Turdus thrushes. Journal of Avian Biology. 43: 503-512. ( et al. JAB 2012

Portugal, S. J., Green, J. A., White, C. R., Guillemette, M. & Butler, P. J. (2013) Wild geese do not increase flight behaviour prior to migration. Biology Letters. 8: 469-472. ( et al. Bio Lett 2013

Maurer, G., Portugal, S. J. & Cassey, P. (2012) An assessment of measurements and indices of eggshell thickness and its variation with egg region and shape in European birds. Ibis. 154: 714-724. ( et al. Ibis 2012


Portugal, S. J. & Guillemette, M. G. (2011) The use of body mass loss to estimate metabolic rate in birds. Comparative and Biochemical Physiology A. 158: 329-336. ( & Guillemette CBP 2010

Portugal, S. J., Butler, P. J., Green, J. A. & Cassey, P. (2011) Indications of phenotypic plasticity in moulting birds: captive geese reveal adaptive changes in mineralisation of their long bones during wing moult. Journal of Ornithology. 152: 1055-1061. ( et al. JoO 2011

Portugal, S. J. & Guillemain, M. (2011) Vigilance patterns of wintering Eurasian wigeon: female benefits from male low-cost behaviour. Journal of Ornithology. 152: 661-668. ( & Guillemain JoO 2011

Portugal, S. J., Green, J. A., Piersma, T., Eichhorn, G. & Butler, P. J. (2011) Energy stores enable flightless moulting geese to maintain cryptic behaviour. Ibis. 153: 868-874. ( Portugal et al. Ibis 2011

Maurer, G., Portugal, S. J. & Cassey, P. (2011) Review: an embryos eye view of eggshell pigmentation in birds. Journal of Avian Biology. 42: 494-504. (, Portugal & Cassey JAB 2011

Maurer, G., Portugal, S. J., Boomer, I & Cassey, P. (2011) Avian embryonic development does not change the stable isotope composition of the calcite eggshell. Reproduction, Fertility and Development. 23: 339-345. ( et al. 2011 RFD

Maurer, G., Portugal, S. J. & Cassey, P. (2011) Cryptic patterning reveals separate mechanical and gas conductance functions of bird egg speckles. Journal of Zoology. 285: 194-204. ( et al. JoZ 2011

Martin, G. R. & Portugal, S. J. (2011) Feeding ecology dictates visual field topography in Ibis and Spoonbills. Ibis. 153: 662-671. ( & Portugal Ibis 2011


Portugal, S. J., Quinton, K., Isaac, R. & Reynolds, S. J. (2010) Do captive waterfowl respond to the flightless period of wing moult in the same manner as their wild counterparts? Journal of Ornithology. 151: 443-448.( et al. 2010 JoO

Portugal, S. J., Cooper, H. J., Zamprione, C. D., Wallace, L. L. & Cassey, P. (2010) Can museum egg specimens be used for proteomic analyses? Proteome Science. 8: 40. ( et al. P 2010

Portugal, S. J., Maurer, G. & Cassey, P. (2010) Eggshell permeability: A standard technique for determining inter-specific rates of water vapour conductance. Physiological and Biochemical Zoology. 83: 1023-1031.( et al. PBZ 2010

Cassey, P., Portugal, S. J., Maurer, G., Boulton, R., Hauber, M., Ewen, J. & Blackburn, T. M. (2010) A comparative study of the evolutionary variability in eggshell colour of birds.  PLoS One. 5: e1205 ( et al. PLoS 2010


Portugal, S. J., Green, J. A., Cassey, P., Frappell, P. B. & Butler, P. J. (2009) Predicting the rate of oxygen consumption from heart rate in barnacle geese: effects of captivity and annual changes in body condition. Journal of Experimental Biology. 212: 2941-2948. ( et al. JEB 2009a

Portugal, S. J., Thorpe, S. K. S., Green, J. A., Myatt, J. P. & Butler, P. J. (2009) Testing the use/disuse hypothesis: pectoral and leg muscle changes in captive barnacle geese during wing moult. Journal of Experimental Biology. 212: 2403-2410.( et al. JEB 2009

Halsey, L. G., Portugal, S. J., Smith, J. A., Murn, C. A. & Wilson, R. P. (2009) Recording raptor behaviour on the wing via accelerometry. Journal of Field Ornithology. 80: 171-177. ( et al. JFO 2009


Portugal, S. J., Green, J. A. & Butler, P. J. (2007) Annual changes in body mass and resting metabolism in captive barnacle geese: the importance of wing moult. Journal of Experimental Biology. 210: 1391-1397.( et al. JEB 2007


White, C. R., Portugal, S. J., Martin, G. R. & Butler, P. J. (2006) Respirometry: Anhydrous Drierite equilibrates with carbon dioxide and increases washout times. Physiological and Biochemical Zoology. 79: 977-980.( et al. PBZ 2006

Thesis: ECOPHYSIOLOGICAL ASPECTS OF THE ANNUAL CYCLE OF BARNACLE GEESE, BRANTA LEUCOPSIS. (2008) University of Birmingham. Supervisors: Prof. Patrick Butler and Dr Jon Green. Examiners: Prof. Theunis Piersma and Prof. Graham Martin. s portugal full thesis

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