Iguana Island Wildlife Refuge
Pedasí, Gulf of Panama, Eastern Tropical Pacific Ocean
Station 12:
earwigs
Location
As you continue down the path, be quiet. When leaving an area where the creepers are lower, one of the nesting sites of the earwigs . At this point, break up into smaller groups, maximum three (3) people, to disturb them as little as possible. Silence must be total and must be maintained until exiting the coast rocky. A person, at the beginning of the nesting site and hidden by the vegetation higher, you can signal to the rest of the group when the three that are spotting the birds retire at the other end of the trail. Meet at Station 13, in the coast rocky, out of the woods.
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In Isla Iguana we have registered more than 20 species of birds
Including:
Marine species = 8.
Forest species and open areas = 11.
Aquatic species = 1.
Migratory Species = 10.
Species that nest on the mainland and frequent the island = 6.
The Earwig or Frigatebird ( Fregata magnificens ) is the most common bird on the island
Its regional name, Earwig, derives from the particularity of its tail and movement, which closes and opens in a scissor movement when performing acrobatics.
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The Earwig is the emblematic species of Iguana Island. Throughout the day there are a large number of these flying over the island, showing their position from when one leaves the Bajadero, on the coast of Pedasí. They welcome all visitors in large flocks.
Its Spanish name, Fragata, derives from the fact that its acrobatics and agility reminded Spanish navigators of a type of light boat, more fast and agile than brigantines Large size. They fish without getting wet and are also known as pirates of the air, because they attack other fishing birds, forcing them to release their prey and catch the food before it reaches the water.
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Despite the fact that on Iguana Island they nest on creepers, where concretize in large numbers to raise their chicks, elsewhere in the Gulf of Panama they nest in trees.
The male inflates his bladder during mating, builds the nest and shows off. The females choose the male with the largest and reddest bladder.
female with a chick of about two months.
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Chick of about eight months.
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Chick about 11 months old that has just left the nest.
They reproduce at the end of the rainy season, hatching one egg per nest. The pigeon is born in January, when the parents take advantage of the abundance of fish produced by the upwelling phenomenon in the Gulf of Panama. It remains in the nest for up to 11 months, being abandoned by its parents, it takes flight to become a fisherman.
More than 5,000 earwigs nest on Iguana Island. It is the largest population in the Gulf of Panama
Between 1989 and 1992 we counted Earwig nests during the nesting season. Angher & Kurshland counted nests in 2005.
The graph expresses the results of the sampling, showing an average population of 5,293, a minimum of 3,900 and a maximum of 6,156 individuals. There is a decrease in the population between 1992 and 2005.
We use three methods:
1. Photographs from the Lighthouse with powerful lenses. We projected the slide on the wall and counted the nests.
2. Navigation around the island to count the nests in the coastal margin.
3. Visit to nesting sites to estimate nests in areas of 100 square meters, the amount was extrapolated to the areas registered with nests in the photographs from the lighthouse, superimposed on the 1981 Aerial Orthophoto. For their part, Angher and Kurshland ( 2007) carried out the counts by means of a plane overflight and analysis of the photographs.
The number of nests multiplied by 3, that is, one chick, one male and one female.
Earwigs suffer from avian encephalitis, a disease that generates epidemics that can put populations at risk. In 1994, during an El Niño event, we recorded an epidemic on Iguana Island. We did not estimate mortality but we observed many dead nestlings.
Bibliography:
Angehr, George R., and James A. Kushlan. “Seabird and Colonial Wading Bird Nesting in the Gulf of Panama.” Waterbirds: The International Journal of Waterbird Biology, vol. 30, no. 3, Waterbird Society, 2007, p. 335–57, http://www.jstor.org/stable/4501839.
Diaz Villani, Marco Lisandro. 2005. Isla Iguana Wildlife Refuge: Field Guide. Illustrations by María Gabriella Díaz de Restrepo and Juan Sucre. 2a Edison. Panama: Post Depot Press. 70 pages. 593.6 D542.
Díaz, Marco L. 1992. Nesting of the Frigatebird (Fregata magnificens) in Iguana Island, Panama Pacific. 8 pages