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Threats and conservation status of Common and Roseate terns Sterna hirundo/S. dougallii in the Azores: A case study for Terceira Island



1Azorean Biodiversity Group, University of the Azores, Rua Capitão João d'Ávila, 9700-042 Angra do Heroísmo, Terceira, Azores, Portugal (lucaslamelaslopez@gmail.com)
2Terceira Natural Park, Regional Directorate for the Environment, Rua do Galo 118, Azores, 9700-091 Angra do Heroísmo, Terceira, Azores, Portugal
3Marine & Environmental Sciences Centre, Institute of Marine Research & Okeanos, Department of Science and Technology, Azores University, 9901-862 Horta, Faial, Azores, Portugal

Received 02 March 2021, accepted 28 June 2021

Date Published: 2021/10/15
Date Online: 2021/10/14

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LAMELAS-LÓPEZ, L., PIETRZAK, M., FERREIRA, M. & NEVES, V.C. 2021. Threats and conservation status of Common and Roseate terns Sterna hirundo/S. dougallii in the Azores: A case study for Terceira Island. Marine Ornithology 49: 301-309.

Key words: seabirds, North Atlantic, Macaronesia, camera traps, depredation, introduced mammals, control actions


The Azores Archipelago holds the second most important population of Roseate Terns in the North Atlantic. However, the size of the population has been decreasing. In this study, we used remote-sensing cameras and visits to the main colonies of Common Terns Sterna hirundo and Roseate Terns S. dougallii on Terceira Island to identify the causes of breeding failure. Nest depredation by introduced mammals, particularly rats and cats, was the main cause of breeding failure, leading, in some cases, to the complete destruction of the colony. Additional threats included nest disturbance by humans and dogs, which caused the destruction of some nests. Measures aimed at mitigating depredation were tested but in the case of rodents, control plans proved difficult to achieve. This is probably because rodents are widespread in the Azores, they are not limited by food resources, and/or trapping methods are ineffective.


AMARAL, J.J.S., ALMEIDA, S., SEQUEIRA, M. & NEVES, V.C. 2010. Black rat Rattus rattus eradication by trapping allows recovery of breeding Roseate Tern Sterna dougallii and Common Tern S. hirundo populations on Feno Islet, the Azores, Portugal. Conservation Evidence 7: 16-20.

BELL, E., BELL, P. & LOMAX, K. 1997. Habitat restoration: Ilhéu da Praia (Graciosa, Azores, Portugal) eradication of Rabbits. Report prepared for the Direção Regional do Ambiente and Secretaria Regional da Agricultura, Pescas e Ambiente. Azores, Portugal.

BIRDLIFE INTERNATIONAL (2018). Sterna dougallii. The IUCN Red List of Threatened Species 2018: e.T22694601A132260491. [Accessed online at https://dx.doi.org/10.2305/IUCN.UK.2018-2.RLTS.T22694601A132260491.en on 30 September 2020.]

BOLTON, M., STANBURY, A., BAYLIS, A.M.M. & CUTHBERT, R. 2014. Impact of introduced house mice (Mus musculus) on burrowing seabirds on Steeple Jason and Grand Jason Islands, Falklands, South Atlantic. Polar Biology 37: 1659-1668. doi:10.1007/s00300-014-1554-2

BONNAUD, E., BERGER, G., BOURGEOIS, K., LEGRAND, J. & VIDAL, E. 2012. Predation by cats could lead to the extinction of the Mediterranean endemic Yelkouan Shearwater Puffinus yelkouan at a major breeding site. Ibis 154: 566-577. doi:10.1111/j.1474-919X.2012.01228.x

BORGES, P.A.V., COSTA, A.C., CUNHA, R. ET AL. 2010. A List of the Terrestrial and Marine Biota from the Azores. Cascais, Portugal: Princípia Editora, Lda.

BRIED, J., MAGALHÃES, M.C., BOLTON, M. ET AL. 2009. Seabird habitat restoration on Praia Islet, Azores Archipelago. Ecological Restoration 27: 27-36. doi:10.3368/er.27.1.27

BRIED, J. & NEVES, V.C. 2015. Habitat restoration on Praia islet, Azores Archipelago, proved successful for seabirds, but new threats have emerged. Airo 23: 25-35.

BRODIER, S., PISANU, B., VILLERS, A. ET AL. 2011. Responses of seabirds to the rabbit eradication on Ile Verte, sub‐Antarctic Kerguelen Archipelago. Animal Conservation 14: 459-465. doi:10.1111/j.1469-1795.2011.00455.x

BROOKE, M. DE L., HILTON, G.M. & MARTINS, T.L.F. 2007. The complexities of costing eradications: A reply to Donlan & Wilcox. Animal Conservation 10: 157-158. doi:10.1111/j.1469-1795.2007.00107.x

BURGER, J. & GOCHFELD, M. 1994. Predation and effects of humans on island-nesting seabirds. In: NETTLESHIP, D.N., BURGER, J. & GOCHFELD, M. (Eds.) Seabirds on Islands: Threats, Cases Studies and Actions Plans. Cambridge, UK: BirdLife International.

CAPIZZI, D., BACCETTI, N. & SPOSIMO, P. 2010. Prioritizing rat eradication on islands by cost and effectiveness to protect nesting seabirds. Biological Conservation 143: 1716-1727. doi:10.1016/j.biocon.2010.04.020

CEC (COUNCIL OF THE EUROPEAN COMMUNITIES) 1992. Council Directive 92/43/EEC of 21 May 1992 on the conservation of natural habitats and of wild fauna and flora. Official Journal of the European Communities L206: 7-50. [Accessed online at https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:31992L0043 ]

CHAPUIS, J.-L., PISANU, B., BRODIER, S. ET AL. 2011. Eradication of invasive herbivores: Usefulness and limits for biological conservation in a changing world. Animal Conservation 14: 471-473. doi:10.1111/j.1469-1795.2011.00499.x

CLARKE, T. 2006. Birds of the Atlantic Islands - Canary Islands, Madeira, Azores & Cape Verde. Helm Field Guides. London, UK: Bloomsbury Publishing

COURCHAMP, F., CHAPUIS, J.-L. & PASCAL, M. 2003. Mammal invaders on islands: Impact, control and control impact. Biological Reviews 78: 347−383. doi:10.1017/S1464793102006061

COURCHAMP, F., LANGLAIS, M. & SUGIHARA, G. 1999. Cats protecting birds: Modelling the mesopredator release effect. Journal of Animal Ecology 68: 282-292. doi:10.1046/j.1365-2656.1999.00285.x

COURCHAMP, F., LANGLAIS, M. & SUGIHARA, G. 2000. Rabbits killing birds: Modelling the hyperpredation process. Journal of Animal Ecology 69: 154-164. doi:10.1046/j.1365-2656.2000.00383.x

CUTHBERT, R. & DAVIS, L.S. 2002. Adult survival and productivity of Hutton's Shearwaters. Ibis 144: 423-432. doi:10.1046/j.1474-919X.2002.00071.x

DEL NEVO, A.J., DUNN, E.K., MEDEIROS, F.M. ET AL. 1993. The status of Roseate Terns Sterna dougallii and Common Terns Sterna hirundo in the Azores. Seabird 15: 30-37.

DOHERTY, T.S., GLEN, A.S., NIMMO, D.G., RITCHIE, E.G. & DICKMAN, C.R. 2016. Invasive predators and global biodiversity loss. Proceedings of the National Academy of Sciences 113: 11261-11265. doi:10.1073/pnas.1602480113

DUMONT, Y., RUSSELL, J.C., LECOMTE, V. & LE CORRE, M. 2010. Conservation of endangered endemic seabirds within a multi‐predator context: The Barau's Petrel in Réunion Island. Natural Resource Modeling 23: 381-436. doi:10.1111/j.1939-7445.2010.00068.x

FRUTUOSO, G. 1561. Saudades da Terra. Ponta Delgada, Portugal: Instituto Cultural de Ponta Delgada.

EPCEU (EUROPEAN PARLIAMENT AND THE COUNCIL OF THE EUROPEAN UNION) 2010. Directive 2009/147/EC of the European Parliament and of the Council of 30 November 2009 on the Conservation of Wild Birds. Official Journal of the European Union 53: L020/7. doi:10.3000/17252555.L_2010.020.eng

HERVÍAS, S., HENRIQUES, A., OLIVEIRA, N. ET AL. 2013. Studying the effects of multiple invasive mammals on Cory's Shearwater nest survival. Biological Invasions 15: 143-155. doi:10.1007/s10530-012-0274-1

JESCHKE, J.M. & GENOVESI, P. 2011. Do biodiversity and human impact influence the introduction or establishment of alien mammals? Oikos 120: 57-64. doi:10.1111/j.1600-0706.2010.18621.x

JONES, H.P., TERSHY, B.R., ZAVALETA, E.S. ET AL. 2008. Severity of the effects of invasive rats on seabirds: A global review. Conservation Biology 22: 16-26. doi:10.1111/j.1523-1739.2007.00859.x

LAMELAS-LÓPEZ, L., BORGES, P.A.V., CASANOVAS, J. ET AL. 2016. Feral cat in the Azores islands: habitat preferences and biological interactions. Poster presented at the 2nd International Conference of Island Biology, Azores. Arquipelago - Life and Marine Sciences S9: 485-486.

LAMELAS-LÓPEZ, L. & FERRANTE, M. 2021. Using camera-trapping to assess grape consumption by vertebrate pests in a World Heritage vineyard region. Journal of Pest Science 94: 585-590. doi:10.1007/s10340-020-01267-x

LAMELAS-LÓPEZ, L., PARDAVILA, X., BORGES, P.A.V., SANTOS-REIS, M., AMORIM, I.R. & SANTOS M.J. 2019. Predicting the spatial distribution of an introduced carnivore, Mustela putorius furo, in the Azores. Poster presented at the Encontro Nacional de Ciência e Tecnologia em Portugal. Lisbon, Portugal.

LAMELAS-LÓPEZ, L., PARDAVILA, X., BORGES, P.A.V., SANTOS-REIS, M., AMORIM, I.R. & SANTOS M.J. 2020. Modelling the distribution of Mustela nivalis and M. putorius in the Azores archipelago based on native and introduced ranges. PLoS One 15: e0237216. doi:10.1371/journal.pone.0237216

LAMELAS-LÓPEZ, L. & SALGADO, I. 2021. Applying camera traps to detect and monitor introduced mammals on oceanic islands. Oryx 55: 181-188. doi:10.1017/S0030605319001364

MATHIAS, M.L., RAMALHINHO, M.G., SANTOS-REIS, M. ET AL. 1998. Mammals from the Azores islands (Portugal): an updated overview. Mammalia 62: 397-408. doi:10.1515/mamm.1998.62.3.397

MONTEIRO, L.R. 2000. The Azores. In: HEATH, M.F., EVANS, M.I., HOCCOM, D.G., PAYNE, A.J. & PEET, N.B. (Eds.) Important Bird Areas in Europe: Priority Sites for Conservation. Volume 2, Southern Europe. Cambridge, UK: BirdLife International.

MONTEIRO, L.R., RAMOS, J.A. & FURNESS, R.W. 1996. Past and present status and conservation of the seabirds breeding in the Azores Archipelago. Biological Conservation 78: 319-328. doi:10.1016/S0006-3207(96)00037-7

NEVES, V.C., MURDOCH, N. & FURNESS, R.W. 2006a. Population status and diet of the Yellow-legged Gull in the Azores. Arquipelago - Life and Marine Sciences 23A: 59-73.

NEVES, V.C., NAVA, C.P., CORMONS, M. ET AL. 2015. Migration routes and non-breeding areas of Common Terns (Sterna hirundo) from the Azores. Emu - Austral Ornithology 115: 158-167. doi:10.1071/MU13112

NEVES, V.C., NAVA, C., MONTEIRO, E.V., MONTEIRO, P.R. & BRIED, J. 2017. Depredation of Monteiro's Storm-petrel (Hydrobates monteiroi) chicks by Madeiran wall lizards (Lacerta dugesii). Waterbirds 40: 82-86. doi:10.1675/063.040.0113

NEVES, V.C., PANAGIOTAKOPOULOS, S. & FURNESS, R.W. 2006b. A control taste aversion experiment on predators of Roseate Tern (Sterna dougallii) eggs. European Journal of Wildlife Research 52: 259-264. doi:10.1007/s10344-006-0044-4

NEVES, V.C., PANAGIOTAKOPOULOS, S. & RATCLIFFE, N. 2011. Predation on Roseate Tern eggs by European starlings in the Azores. Arquipelago - Life and Marine Sciences 28: 15-23.

PIEC, D. & DUNN, E.K. 2021. International (East Atlantic) Species Action Plan for the Conservation of the Roseate Tern Sterna dougallii (2021-2030). Developed under framework of Roseate Tern LIFE Project (LIFE14 NAT/UK/000394). Brussels, Belgium: European Commission 2021.

PITTA GROZ, M., PEREIRA, J.C. & SILVA, A.G. 2002. Invasive Alien Species as the main threat to Azores seabird populations. In: Directorate of Culture and of Cultural and Natural Heritage (Ed.) Proceedings of the Workshop on Invasive Alien Species on European Islands and Evolutionary Isolated Ecosystems. Horta, Azores, Portugal, 10 Oct 2002. Strasbourg, France: Council of Europe.

RAMOS, J.A. & DEL NEVO, A.J. 1995. Nest-Site Selection by Roseate Terns and Common Terns in the Azores. The Auk 112: 580-589. doi:10.1093/auk/112.3.580

RINGLER, D., RUSSELL, J.C. & LE CORRE, M. 2015. Trophic roles of black rats and seabird impacts on tropical islands: Mesopredator release or hyperpredation? Biological Conservation 185: 75-84. doi:10.1016/j.biocon.2014.12.014

SCOPEL, L.C. & DIAMOND, A.W. 2017. The case for lethal control of gulls on seabird colonies. Journal of Wildlife Management 81: 572-580. doi:10.1002/jwmg.21233

SILVEIRA, L., JÁCOMO, A.T.A. & DINIZ-FILHO, J.A.F. 2003. Camera trap, line transect census and track surveys: A comparative evaluation. Biological Conservation 114: 351-355. doi:10.1016/S0006-3207(03)00063-6

STOKES, V.L. 2013. Trappability of introduced and native rodents in different trap types in coastal forests of south-eastern Australia. Australian Mammalogy 35: 49-53. doi:10.1071/AM12002

TOMKINS, R.J. 1985. Breeding success and mortality of dark-rumped petrels in the Galapagos, and control of their predators. ICBP Technical Publication 3: 159-175.

TOWNS, D.R., BYRD, G.V., JONES, H.P., RAUZON, M.J., RUSSELL, J.C. & WILCOX, C. 2011. Impacts of introduced predators on seabirds. In: MULDER, C.P.H., ANDERSON, W.B., TOWNS, D.R. & BELLINGHAM, P.J. (Eds.) Seabird Islands: Ecology, Invasion, and Restoration. New York, USA: Oxford University Press.

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