Evening census for a population of Brown booby Sula leucogaster (Boddaert, 1783) (Ave: Suliformes: Sulidae) from La Tortuga Island, Venezuela
DOI:
https://doi.org/10.53157/ecotropicos.32e0012Keywords:
Waterbirds, Flocks, La Tortuga island, Population sizeAbstract
In Venezuela, the breeding of the Brown booby (Sula leucogaster) is frequently observed on tropical waters from Los Monjes, Las Aves, La Orchila and Los Hermanos islands. Nevertheless, demographical dynamic and density studies of this species are scarce. The aims of this study were count the individual numbers (adults and immatures) characterizing activity patterns for the flock sizes of S. leucogaster in La Tortuga island during three months on 2009. To perform the individual counts, we divided the observation time into four intervals, of 30 min each of them, from 04:30-06:30 h, while the flocks were classified according to the number of individuals observed into five categories: <10 (α), 10-20 (β), 21-30 (δ), 31-40 (ε) and >40 (λ). For each month, we observed the following individual total: August= 1,008 (1 immature); November = 744 (19 immatures), and December = 920 (12 immatures). We observed statistical significative differences among the number of individuals counted for intervals of observation times (χ2 = 9.21; P < 0.01). The largest amount of individual was showed during the intervals05:30-06:00 h and 06:00-06:30 h. The more frequent number of individuals for flocks were α (87%) and β (8.5%). The high number of individuals observed in August could be explained by dispersion of sexually mature individuals to other islands, for breeding purposes, or even looking for better feeding places. It recommends to identify feeding sites of Brown bobby, measure crucial to guarantee the conservation of this sea bird species in Venezuela.
Downloads
References
Beadell J, Schreiber E, Schreiber R, Schenk G & Doherty P. 2003. Survival of Brown Boobies (Sula lecogaster) at Johnston Atoll: A long-term study. The Auk 120: 811-817. https://doi.org/10.1093/auk/120.3.811
Branco JO, Fracasso HA & Moraes-Ornellas V. 2013. Reproduction and demographic trends of the Sula leucogaster at the Moleques do Sul Archipelago, Santa Catarina, Brazil. Biota Neotropical 13: 39-45. https://doi.org/10.1590/S1676-06032013000400004
Carboneras C. 1992. Family Sulidae (Gannets and Boobies). In: Del Hoyo J, Elliot A & Sargatal J (Eds). Handbook of the birds of the world, 312-325 p. Barcelona: Ediciones Lynx.
Chaves-Campos J & Torres J. 2002. Distribution of the Brown Booby (Sula leucogaster) in relation to the inclination of terrain. Ornitología Neotropical 13: 205-208.
Dorward DF. 1962. Comparative biology of the White Boobie and Brown Boobie, Sula spp., at Ascensión. Ibis 103b: 174-220. https://doi.org/10.1111/j.1474-919X.1962.tb07244.x
Fowler J & Cohen L. 1995. Statistics for ornithologists. Tring, UK: BTO Guide 22.
Hilton GM & Cuthbert RJ. 2010. The catastrophic impact of invasive mammalian predators on birds of the UK Overseas Territories: a review and synthesis. Ibis 152: 443-458. https://doi.org/10.1111/j.1474-919X.2010.01031.x
Hilty SL. 2003. Birds of Venezuela. Princeton and Oxford: Princeton University Press.
Huber O. 1997. Ambientes fisiográficos y vegetales de Venezuela. En: La Marca E (Eds.). Vertebrados actuales y fósiles de Venezuela, 280-298 p. Mérida, Venezuela: Museo de Ciencias y Tecnología de Mérida.
Kohno H, Mizutani A, Yoda K & Yamamoto T. 2019. Movements and activity characteristics of the Brown Booby Sula leucogaster during the non-breeding period. Marine Ornithology 47: 169-174. https://doi.org/10.5038/2074-1235.47.2.1312
Marín-Espinoza G, Carvajal Y & Voglar J. 2009. Anidación de aves marinas en isla La Tortuga, cayo Herradura y cayo Tortuguillo Este, Venezuela. Boletín del Instituto Oceanográfico de Venezuela 48: 35-41.
Mellink E. 2000. Breeding of Brown boobies in the Gulf of California: Seasonality and apparent effects of El Niño. Waterbirds: The International Journey of Waterbird Biology 23: 494-499. https://doi.org/10.2307/1522189
Mellink E, Domínguez J & Luévano J. 2001. Diet of Eastern Pacific Brown Boobies Sula leucogaster brewsteri on Isla San Jorge, north-eastern Gulf of California, and an April comparison with diets in the Middle Gulf of California. Marine Ornithology 29: 23-28. https://doi.org/10.5038/2074-1235.29.1.487
Miller MG, Silva FR, Machovsky-Capuska GE & Congdon BC. 2018. Sexual segregation in tropical seabirds: drivers of sex-specific foraging in the brown booby Sula leucogaster brewsteri. Journal of Ornithology 159: 425-437. https://doi.org/10.1007/s10336-017-1512-1
Muller-Karger F, Varela R, Thunell R, Scantron M, Taylor G, Capelo J, Astor Y, Tappa E, Akl J & Tung-Yuan H. 2005. Características de la fosa de Cariaco y su importancia desde el punto de vista oceanográfico. Memorias de la Fundación La Salle de Ciencias Naturales 161-162: 215-234.
Petróleos de Venezuela. 1992. Imagen de Venezuela: Una visión espacial. Las Islas. Petróleos de Venezuela S.A, Caracas, Venezuela.
Plackett RL. 1983. Karl Pearson and the chi-squared test. International Statistical Review 51: 59-72. https://doi.org/10.2307/1402731
Schreiber EA. 2000. Boobies in the West Indies: Their status and conservation. En: Schreiber EA & Lee DS (Eds.) Status and conservation of West Indians seabirds, Ruston, LA, USA, pp. 46-57.
Schreiber EA & Norton R. 2002. Brown Booby: Sula leucogaster. En: Poole, A (Ed.) The Birds of North America Online. Birds of North America. Ithaca: Cornell Lab of Ornithology. Disponible en: http://bna.birds.cornell.edu/bna/species/ 649. (Consultado el 26 de abril de 2020). https://doi.org/10.2173/bna.649
Soanes LM, Bright JA, Bolton M, Millett J, Mukhida F & Green JA. 2015. Foraging behaviour of Brown Boobies Sula leucogaster in Anguilla, Lesser Antilles: preliminary identification of at-sea distribution using a time-in-area approach. Bird Conservation International 25: 87-96. https://doi.org/10.1017/S095927091400001X
Tershey B, Breese D & D C. 2003. Insurance eggs versus additional eggs: Do Brown Boobies practice obligate siblicide? The Auk 117: 817-820. https://doi.org/10.1093/auk/117.3.817
Véliz J. 2016. Flora vascular terrestre de la isla La Tortuga. Trabajo de ascenso a la categoría de Asociado, Departamento de Biología, Escuela de Ciencias, Universidad de Oriente, Cumaná, Venezuela.
Downloads
Published
Issue
Section
License
Copyright (c) 2020 Gedio Marín-Espinoza, Yalicia Carvajal Moreno, Evelin Quilarque Quijada, José Peñuela Jiménez, Darwin López Zerpa (Author)
This work is licensed under a Creative Commons Attribution 4.0 International License.
