Predation on common tern eggs by the yellow-legged gull at the Ebro Delta
The Ebro Delta holds a large seabird community, including a common tern (Sterna hirundo) local population of 3,085 pairs in 2000 which breeds scattered in several colonies. At El Canalot colony, 1,178 (1999) and 1,156 pairs (2000) of this species bred distributed in 32 and 38 sub-colonies respective...
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ftubarcepubl:oai:diposit.ub.edu:2445/32308 2024-02-11T10:02:57+01:00 Predation on common tern eggs by the yellow-legged gull at the Ebro Delta Hernández Matías, Antonio, 1974- Ruiz, Xavier 2003 7 p. application/pdf http://hdl.handle.net/2445/32308 eng eng Consejo Superior de Investigaciones Científicas (CSIC) Reproducció del document publicat a: http://dx.doi.org/10.3989/scimar.2003.67s295 Scientia Marina, 2003, vol. 67, num. Suppl. 2, p. 95-101 Articles publicats en revistes (Biologia Evolutiva, Ecologia i Ciències Ambientals) http://dx.doi.org/10.3989/scimar.2003.67s295 0214-8358 http://hdl.handle.net/2445/32308 502378 cc-by-nc (c) Consejo Superior de Investigaciones Científicas (CSIC), 2003 http://creativecommons.org/licenses/by-nc/3.0/es info:eu-repo/semantics/openAccess Predació (Biologia) Gavines Ebre Delta de l' (Catalunya) Predation (Biology) Gulls Ebro River Delta (Catalonia) info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion 2003 ftubarcepubl https://doi.org/10.3989/scimar.2003.67s295 2024-01-24T00:53:23Z The Ebro Delta holds a large seabird community, including a common tern (Sterna hirundo) local population of 3,085 pairs in 2000 which breeds scattered in several colonies. At El Canalot colony, 1,178 (1999) and 1,156 pairs (2000) of this species bred distributed in 32 and 38 sub-colonies respectively. These sub-colonies varied in size from 1 to 223 pairs and were placed near the main breeding colonies of yellow-legged gulls (Larus cachinnans) and Audouin´s gulls (L. audouinii), which are potential egg-predators of terns. We studied egg predation during 1999 (6 sub-colonies) and 2000 (27 sub-colonies). Overall, we found that 10.6% of the nests in 1999 and 16.7% in 2000 suffered partial or total egg predation, being total in 81.1% of the predatory events. Predation was significantly higher in small sub-colonies (< 11 pairs): 49.4% in 1999 and 75.5% in 2000. Only attacks from yellow-legged gulls were observed, and defence behaviour of terns was significantly more frequent against this gull species (40.5 hours of observation), suggesting that in most cases the egg predation recorded was due to this species. Probability of egg predation was significantly and negatively correlated with distance to the nearest yellow-legged gull sub-colony, although this relationship was no more significant after adjustment for sub-colony size. On the other hand, distance to the nearest Audouin´s gull sub-colony did not show any effect. Our results suggest that the impact of large gulls (at least yellow-legged gulls) upon smaller seabirds breeding in the area might be important, especially when they are breeding in small sub-colonies. Further studies are needed to analyse the general impact of large gulls upon the breeding populations of other colonial bird species in the area. Article in Journal/Newspaper Common tern Sterna hirundo Dipòsit Digital de la Universitat de Barcelona Scientia Marina 67 S2 95 101 |
institution |
Open Polar |
collection |
Dipòsit Digital de la Universitat de Barcelona |
op_collection_id |
ftubarcepubl |
language |
English |
topic |
Predació (Biologia) Gavines Ebre Delta de l' (Catalunya) Predation (Biology) Gulls Ebro River Delta (Catalonia) |
spellingShingle |
Predació (Biologia) Gavines Ebre Delta de l' (Catalunya) Predation (Biology) Gulls Ebro River Delta (Catalonia) Hernández Matías, Antonio, 1974- Ruiz, Xavier Predation on common tern eggs by the yellow-legged gull at the Ebro Delta |
topic_facet |
Predació (Biologia) Gavines Ebre Delta de l' (Catalunya) Predation (Biology) Gulls Ebro River Delta (Catalonia) |
description |
The Ebro Delta holds a large seabird community, including a common tern (Sterna hirundo) local population of 3,085 pairs in 2000 which breeds scattered in several colonies. At El Canalot colony, 1,178 (1999) and 1,156 pairs (2000) of this species bred distributed in 32 and 38 sub-colonies respectively. These sub-colonies varied in size from 1 to 223 pairs and were placed near the main breeding colonies of yellow-legged gulls (Larus cachinnans) and Audouin´s gulls (L. audouinii), which are potential egg-predators of terns. We studied egg predation during 1999 (6 sub-colonies) and 2000 (27 sub-colonies). Overall, we found that 10.6% of the nests in 1999 and 16.7% in 2000 suffered partial or total egg predation, being total in 81.1% of the predatory events. Predation was significantly higher in small sub-colonies (< 11 pairs): 49.4% in 1999 and 75.5% in 2000. Only attacks from yellow-legged gulls were observed, and defence behaviour of terns was significantly more frequent against this gull species (40.5 hours of observation), suggesting that in most cases the egg predation recorded was due to this species. Probability of egg predation was significantly and negatively correlated with distance to the nearest yellow-legged gull sub-colony, although this relationship was no more significant after adjustment for sub-colony size. On the other hand, distance to the nearest Audouin´s gull sub-colony did not show any effect. Our results suggest that the impact of large gulls (at least yellow-legged gulls) upon smaller seabirds breeding in the area might be important, especially when they are breeding in small sub-colonies. Further studies are needed to analyse the general impact of large gulls upon the breeding populations of other colonial bird species in the area. |
format |
Article in Journal/Newspaper |
author |
Hernández Matías, Antonio, 1974- Ruiz, Xavier |
author_facet |
Hernández Matías, Antonio, 1974- Ruiz, Xavier |
author_sort |
Hernández Matías, Antonio, 1974- |
title |
Predation on common tern eggs by the yellow-legged gull at the Ebro Delta |
title_short |
Predation on common tern eggs by the yellow-legged gull at the Ebro Delta |
title_full |
Predation on common tern eggs by the yellow-legged gull at the Ebro Delta |
title_fullStr |
Predation on common tern eggs by the yellow-legged gull at the Ebro Delta |
title_full_unstemmed |
Predation on common tern eggs by the yellow-legged gull at the Ebro Delta |
title_sort |
predation on common tern eggs by the yellow-legged gull at the ebro delta |
publisher |
Consejo Superior de Investigaciones Científicas (CSIC) |
publishDate |
2003 |
url |
http://hdl.handle.net/2445/32308 |
genre |
Common tern Sterna hirundo |
genre_facet |
Common tern Sterna hirundo |
op_relation |
Reproducció del document publicat a: http://dx.doi.org/10.3989/scimar.2003.67s295 Scientia Marina, 2003, vol. 67, num. Suppl. 2, p. 95-101 Articles publicats en revistes (Biologia Evolutiva, Ecologia i Ciències Ambientals) http://dx.doi.org/10.3989/scimar.2003.67s295 0214-8358 http://hdl.handle.net/2445/32308 502378 |
op_rights |
cc-by-nc (c) Consejo Superior de Investigaciones Científicas (CSIC), 2003 http://creativecommons.org/licenses/by-nc/3.0/es info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.3989/scimar.2003.67s295 |
container_title |
Scientia Marina |
container_volume |
67 |
container_issue |
S2 |
container_start_page |
95 |
op_container_end_page |
101 |
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1790599057164468224 |