Caracterización poblacional de piqueros de nazca en Punta Cevallos, Galápagos – Ecuador.
Fecha
2018
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Facultad de Ciencias Naturales, Universidad de Guayaquil
Resumen
El presente trabajo tiene como objetivo caracterizar la población de Piqueros de Nazca
(Sula granti) en la colonia de anidación ubicada en Punta Cevallos, Galápagos, durante
los períodos reproductivos correspondientes a los años 2001-2003 y 2014-2017, se
realizaron censos nocturnos de reavistamiento de aves marcadas en un área
delimitada (MAEx), estableciéndose que la media poblacional fue de 420 ± 30.6
individuos, registrándose el máximo y mínimo de aves en 2001 y 2016,
respectivamente. Al analizar la relación se establecieron tasas de residencia entre 68.6
y 79.9 % para residentes y de 20,2 a 31,4 % para no residentes; mientras que la
permanencia de los individuos durante los períodos reproductivos analizados
corresponde a un 55.5 % de la población total, con una mayor presencia de machos
en relación a las hembras. La fluctuación del número de individuos en los períodos
reproductivos analizados no permite establecer una tendencia de la población,
mientras que la tasa de fidelidad establecida caracterizada por dominancia de
individuos residentes, valida la baja dispersión reproductiva en estas aves, sin dejar
de considerar otras condiciones referentes a su adaptación a sitios específicos.
The present work aims to characterize the Nazca Booby nesting colony population at Punta Cevallos and determine its variations, during the breeding seasons 2001-2003 and 2014-2017. Bird re-sighting night censuses were performed on marked birds in a previously delimited area (MAEx). Mean population size was 420 ± 30.6 individuals, and maximum and minimum abundances were recorded in 2001 and 2016, respectively. When looking at the relationship change ratios were of 68.6 and 79.9% for residents and 20,2 and 31,4%for non-residents; whereas permanence of individuals during the studied breeding periods was 55% of the total population, with a higher number of males over females. Fluctuations in the numbers of individuals during the breeding periods of these study do not allow to establish a population trend. However, the fidelity rate is characterized by a dominance of resident individuals, it validates the low breeding dispersal in these birds, without to take into consideration other conditions that may affect their adaptations to other specific sites.
The present work aims to characterize the Nazca Booby nesting colony population at Punta Cevallos and determine its variations, during the breeding seasons 2001-2003 and 2014-2017. Bird re-sighting night censuses were performed on marked birds in a previously delimited area (MAEx). Mean population size was 420 ± 30.6 individuals, and maximum and minimum abundances were recorded in 2001 and 2016, respectively. When looking at the relationship change ratios were of 68.6 and 79.9% for residents and 20,2 and 31,4%for non-residents; whereas permanence of individuals during the studied breeding periods was 55% of the total population, with a higher number of males over females. Fluctuations in the numbers of individuals during the breeding periods of these study do not allow to establish a population trend. However, the fidelity rate is characterized by a dominance of resident individuals, it validates the low breeding dispersal in these birds, without to take into consideration other conditions that may affect their adaptations to other specific sites.
Descripción
Palabras clave
GALAPAGOS, POBLACION, RESIDENCIA, SULA GRANTI