By Beverly Clyde
The brown pelican (Pelecanus occidentalis) has many claims to fame. It is the national bird of Turks and Caicos Islands, the state bird of Louisiana, an expert diver, and an ecological success story.
It battled back from near extinction in the United States. During the early 1900's brown pelicans could be found from along the Atlantic, Pacific and Gulf of Mexico coasts - from California to Chile and from Maryland to Venezuela. However, by the 1960's this bird had disappeared from Louisiana, the pelican state and from most of the coastal areas of the USA.
The main cause of this decline was the pesticide DDT. The DDT was carried into the coastal waters from farm lands and then entered the food chain. As these pelicans ate tainted fish, they laid eggs with thin shells. Since brown pelicans incubate their eggs by holding the them under their webbed feet rather than against their breasts, the eggs would break from the weigh of the parents. After DDT and similar pesticides were banned in the 1970's, the brown pelican population began to recover. From 1970 until 2009 the brown pelican was on the endangered species list.
Just months after being removed from the endangered species list the brown pelican is again fighting for its existence in the waters of the Gulf of Mexico. On April 20, 2010, the Horizon Deepwater drilling rig exploded and caused an oil leak which is threatening much of the wildlife in the Gulf of Mexico including the brown pelican. Because this bird depends on the waters of the Gulf for food and the barrier islands for nesting areas, this ecological disaster could reverse their wonderful recovery over the last 40 years.
The brown pelican is truly an incredible bird. It is the smallest of the pelicans but definitely not a small bird. It is 4 to 5 feet tall and has a wingspan of 6 to 8 feet wide. The beak is about a foot long and has a very large pouch of skin used to scoop up fish and water. The pouch can also be pulsated to allow for cooling during the heat of the day. A pelican on land can look very awkward and clumsy but they are magnificent in the air. They can soar and glide low over the water searching for fish.
The brown pelican is a great angler. The pelican flies across the water looking for menhaden, herring, mullet, sheepshead, silversides and other fish. When fish are spotted, they dive head first to catch their food and net both fish and water in their pouch. When they come to the surface, they drain the water from their pouch and swallow the fish. Gulls sometimes try to steal fish from the pelican's pouch; in fact gulls will sit on a pelican's head waiting for just the right moment to strike. The brown pelican is the only pelican to be a diving angler.
Brown pelicans live only in marine waters. They are very rarely found inland. Most of the time, they are found within 20 miles of the shore. They prefer bays and other shallow marine waters. These birds are very gregarious nesting in flocks of male and female year round. They build nests on islands. They nest on the ground or in the lower lying branches of trees or bushes if predators are nearby. They mate for life.
Brown pelicans had been suffering from a lost of nesting sites due to coastal erosion. There have been some efforts to rehabilitate prime nesting areas. The elimination of DDT and the restoration of their nesting sites made the brown pelican a true ecological success story.
The brown pelican is now threatened again by the Gulf of Mexico oil spill. The brown pelicans' way of life makes it very vulnerable to this oil spill. The oil spill can affect these birds in the following ways.
1. As they dive into the water to eat, they dive into and through the oil which coats their feathers. Depending on how much oil is on the feathers they may be subject to hypothermia or even drowning.
2. Ingesting oil or oil contaminated fish may cause sickness or death for these birds.
3. Even if the oil doesn't cause harm to these pelicans, it could cause a reduction in the fish available for food. Since adult pelicans can eat up to 4 pounds of fish a day, any lessening of the food supply could cause great harm to the flocks.
4. Because it is Spring, pelicans and many other birds and marine life are producing offspring. Some pelican eggs have been found with oil smudges. Scientists don't know what the effect of the smudges may be. The egg shells are porous in order to allow the embryos to exchange carbon dioxide for oxygen. If there is enough oil on the shells the embryos could suffocate or suffer significant damage from the oil.
5. Volatile organic compounds (VOC), oil's toxic components, could pass through the egg shell and cause almost certain death to the embryo.
6. Once the embryos are born they will face the same threats from oil and oil contaminated fish that their parents face - only they will be much weaker and smaller.
To learn more about the efforts to rescue brown pelicans and other birds endangered by the oil spill go to International Bird Rescue Research Center (http://www.ibrrc.org). It's not known how much damage will be done to the brown pelican by the Gulf of Mexico oil spill; only time will tell. Forty years of work may be undone but this incredible bird has recovered from ecological disasters before. It has proven to be quite a fighter and if needed, it can fight back again. Not all brown pelicans live around the Gulf of Mexico and so they can be relocated again just as they were after the DDT ecological problems and the flocks can again recover.
The Gulf of Mexico will not be the same until brown pelicans can safely build nests on the barrier islands, dive into the water for fish, and perch around piers and marinas waiting for that unattended fish. Brown pelicans are an integral part of what makes the Gulf of Mexico special.
Beverly Clyde, Avid birdwatcher and President BirdWatchersDepot.com
For all your birdwatching needs go to http://www.birdwatchersdepot.com
Article Source: http://EzineArticles.com/?expert=Beverly_Clyde
http://EzineArticles.com/?Brown-Pelican---Ecological-Success-Story&id=4430672
No comments:
Post a Comment