21 abril, 2013 a las 3:02 #6308cessamoModerador
Saludos a tod@s
Les adjunto un artículo escrito por el biólogo y fotógrafo Nick Hawkins, quien tuvo la ocasión de estudiar la nidificación de un Amazilia boucardi. Agradecemos a Nick por su colaboración.
Nest of a Mangrove Hummingbird – Nick Hawkins – Wildlife Photojournalist
As a wildlife and conservation photojournalist, I am always looking for opportunities to create compelling stories and images of species on the brink. It is no mystery that human activity is causing the widespread and rapid loss of habitats the world over, and with it comes the increasing potential for species extinction. While working in Costa Rica, I became fascinated by the story of the mangrove hummingbird, Amazilia boucardi, an endemic and endangered species that can only be found in the mangrove forests along Costa Rica’s pacific coast. It is one of three true Costa Rican endemic birds, being found only within the borders of the country. Habitat destruction driven by coastal development, selective logging and the construction of shrimp and desalination ponds has led to a steady decline in suitable habitat. The situation is complicated by the species dependence on the nectar from the tea mangrove, Pelliciera rhizophorae, which can now only be found on a few select coastlines in Central and South America and is considered the rarest mangrove species in the world. Although the birds do feed on nectar from other species, they rely heavily on P. rhizophorae and populations of mangrove hummingbirds occur only where significant stands still grow. Interestingly, the birds are absent from many areas of seemingly suitable habitat. This could possibly be caused by interspecific competition with other hummingbird species that also covet the nectar from P. rhizophorae, although this is speculation based upon my own observations.
I first observed the species while working in the small town of Tambor, located at the tip of the Nicoya Peninsula in Costa Rica. I observed a single female visiting feeders at a hotel and after becoming interested in the species biology I set off to look for more in the area, as well as the tea mangrove they depended on. To my amazement, I could locate only three tea mangroves in the area, guarded by the same female that I had observed earlier. Further searches produced no additional birds, or tea mangroves. I had discovered a microcosm of the species natural condition; a tiny isolated island of habitat within a larger area of developed coastline. Over the next month I spent many days at the trees, photographing the female feeding on the ornamental white flowers of the tea mangrove and becoming ever more concerned for the future of this beautiful bird.
The flowers of the tea mangrove form a perch from which the hummingbird clings to feed on the nectar. It is a beautiful example of ornithophily, where a plant structure is modified to facilitate pollination by a bird, and it also hints at the enduring relationship of these two species throughout evolutionary time.
I observed that with the beginning of the dry season came a change in the females behavior; she spent less time at the tea mangroves, coming only occasionally to feed before disappearing once again. I suspected that she had begun building a nest; the dry season is when many trees flower and the hummingbird species in the area choose this time of abundant blooms to raise their young. I set off to find the impossibly tiny structure, and after a bit of research, careful searching, and a bit of luck, I found a delicately woven nest, decorated with lichen and placed at the drooping tips of a black mangrove tree.
The female was already incubating two eggs, and within a few days of finding the nest, two tiny chicks had hatched. It was a relieving moment to know that other mangrove hummingbirds were nearby. Although I had never seen a male in the area, there was another mangrove system within 10 kilometers that was likely home to the male that had fathered these chicks. Over the next two weeks I observed the female as she worked effortlessly to raise her brood. She would visit the nest on average once to twice an hour, during which she would evenly regurgitate a mixture of nectar and insects directly into the crop of each chick.
The young birds grew extremely fast and 20 days after hatching, both chicks had successfully fledged. The mother continued to feed the birds for many days after they had left the nest and both birds often visit the feeders at Hotel Tambor Tropical, where I first saw their mother a year prior.
It was a unique chance to create perhaps the first and only images of the nesting habits of this endangered bird. It is my hopes that the images can be used to raise awareness for the conservation of this species in Costa Rica. The mangrove hummingbird could be used as a flagship species to gain public and political support for the protection of mangrove ecosystems within the country and also draw attention to the plight of these ecosystems around the world. Currently the area in which this bird nested and the trees it depends on remain unprotected and at risk from development and pollution. This small area could be set aside as a refuge and tea mangrove trees could be planted to enhance the current stand, insuring the continuation of the species in this area. Similar projects could be undertaken in other areas of Costa Rica. I am seeking the help of conservation groups, biologists and concerned citizens to help bring this story to the public and gain support for these conservation projects. Please contact me if you can help in anyway.
The population of mangrove hummingbird was last estimated in 2008 at between 1,500 to 7,000 adult birds (reference IUCN). Its extreme locality and specification to a narrow and declining habitat make it one of the most endangered bird species in Central America. To see all the images and read more about this project and others, you can visit my website at http://www.njhawkins.com
Nick Hawkins is a biologist and wildlife photojournalist from Canada who firmly believes that photography and story telling is a key component to conservation. He can be reached through e-mail at firstname.lastname@example.org
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