Islands are living ecosystems that can become unhealthy if they are not taken care of. Learn how the population size of American Oystercatchers helps scientists determine if the islands of Cape Lookout are healthy or not.
- Credit / Author:
- Cape Lookout National Seashore
- Date created:
- 2010-10-29
Nurse: Ranger Cheryl the doctor can see you now.
Doctor: Ranger Cheryl nice to see you. Let’s have a quick check of your vital statistics
Doctor: Pulse 68 excellent, Blood Pressure 120/80 very good, 98.6 temperature perfect
Doctor: Ranger Cheryl, your numbers are great, but how is your island?
Ranger: Excuse me?
Doctor: Your Island… Is it healthy?
Ranger: I don’t know let’s find out. Why don’t you come with me?
Barrier islands are long thin strips of land that run parallel to the mainland. These islands provide much needed protection not only to people living on the coast but also to numerous species of seashore wildlife.
Healthy undeveloped barrier islands act as a storm break to approaching storms including hurricanes and nor’easters. The high stable dunes cause the winds to divert or slow down, which in turn reduces its’ strength. So by the time the storm hits the mainland, the force is reduced and there is less damage.
A healthy undeveloped barrier island also provides a wonderful place for shorebirds and marine life to thrive, grow, and reproduce.
Birds, like humans, prefer a little privacy to raise their families. They prefer not having an audience or a hectic environment.
American Oystercatchers are one of those shorebirds that truly enjoy solitude and living in a rural environment.
Oystercatchers are large black and white birds about the size of a crow. They have large orange bills and pink colored legs. The most striking feature of oystercatchers is the red ring around a yellow eye. Some people think that this feature gives the bird an eerie look of wearing a mask.
Now using your deductive reasoning any ideas as to what an American Oystercatcher eats?
Why Yes oysters, mussels, and other marine invertebrates. Their big bright orange bills are designed to sever the oysters’ abductor mussel causing them to remain open giving the oystercatcher easy lunch. Oystercatchers need to live in areas with a high concentration of bi-valves which is usually undisturbed barrier islands and coastal marshes.
Similar, to most mankind, Oystercatchers mate for life which span approximately 17 years. One oystercatcher has been recorded to have lived 30 years. That is a long time for a bird.
Once they have chosen mates and the time is right, they search out a nice isolated sandy beach to scrape out a small divot to lay their small clutch of 2-4 eggs. They tend to make their nests above high tide line to keep them safe from rising waters.
After 24 - 29 days the chicks have grown enough to hatch and start wandering the beach. With the protection of the parent they grow and learn to survive on their own. Then after 35-45 days the little balls of puff have grown enough feathers to begin flight. Once flight has been achieved independence is theirs for the taking. This process takes approximately 2 months. The like a young adult human, they leave the family and begin a life of their own.
This seems like a wonderful story with a fairy tale ending, but unfortunately, American oystercatchers are struggling to have these happy endings.
Like most people, American Oystercatchers enjoy privacy and being left alone. They don’t enjoy living next to a public beach with people and kids swimming, and running up and down the beach. They prefer being in a quiet neighborhood and not along a busy highway of beach driving vehicles.
They also like being in a safe neighborhood, free from harm. Occasionally, people will unintentionally damage a nest by walking or driving over a nest and crushing the eggs, but more often the damage is done by dogs. Oystercatchers are easily scared off their nest by dogs. Not only is this a life and death situation to the adults but leaving the nest causes the eggs to become unprotected and the eggs can become over heated which can result in death. This is why Cape Lookout National Seashore requires all pets to be on a leash.
There are also some others predators that can cause harm. One of the most common predators is the raccoon. Yes, raccoons are cute and furry but they can become very aggressive and over populate an area rapidly. Whenever people become sloppy with their trash removal and food storage, raccoons populate quickly and become quite fearless of humans. When there are an above average number of raccoons, they begin to search out more and more food. This means they will be searching out anything they can eat which includes bird eggs. Sometimes they get to the nest and eat everything and sometimes they just scare the parents so badly that they abandon the nest. Either way, the chicks don’t hatch.
The effect of the over population of raccoons was realized when North Carolina State University removed over 149 raccoon from South Core banks in late 2008 as an experimental study. The nesting success for the island improved considerably the following year to the highest rate since 1995.
Like a lot of shorebirds, the adults will attempt to distract an approaching stranger by giving a territorial call and running away from nest with heads down and tails up. If the intruder continues they will give an aerial chase. If this does not work the pair may decide leave the nest and not return to hatch the eggs. American Oystercatchers are easily scared off their nest. Even a kite, having the appearance of a predatory bird can cause the parents to leave the nest. Every little disturbance can cause disastrous consequences. The oystercatchers may choose not to come back to the nest or the temperature of the eggs may be altered so much that they may not hatch.
Unfortunately finding a secluded undeveloped beach is really tough in this high tech and highly developed world. With the human urge to live on the coast, undeveloped beach is hard to come by. There is only about 118 miles of undeveloped beach left in North Carolina, 56 of that being at Cape Lookout National Seashore.
Due to the small amount of undisturbed area left for the American Oystercatcher, nest survival rate is less than 25% which means only 1 out of every 4 nests hatch. So needless to say, oystercatchers are not reproducing very well. The populations of the American Oystercatcher are very small. There are only about 700 in North Carolina.
Since oystercatchers are easy birds to recognize they tend to be a little easier to observe and study. They also let us know when an island is getting over developed because they will leave an area that is getting too busy for them. If it is too developed for oystercatchers then it’s too developed for other birds and wildlife to live. We are here to share the earth and to get along with all species of life. If one species starts to suffer and die off, then that is an indication that humanity is in danger. So we need to keep a close eye on our beaches.
Cape Lookout had 61 recorded nesting pairs in 2009. This number has remained relatively close in the last several years because there is little to no disturbance on these islands. Places of high visitor use and development disturb the nesting pairs and chase them off their nests.
So how can we help make better nesting places for these wonderful birds?
First of all having an area set aside where there cannot be any construction is a good start. There are many different agencies and environmental groups that are designating areas for this purpose. Cape Lookout National Seashore is 56 miles shoreline giving protection to all coastal life including Oystercatchers.
Another way to help the oystercatcher population is to be very careful when driving on the beach. Young chicks tend to hide in shallow places, such as washed out areas and vehicle ruts. Though it is easier for us to drive down the beach following someone else’s vehicle tracks, it can be dangerous for birds.
Sadly, 3 oz baby chicks or fragile eggs fail to win against a 2000 pound vehicle.
That is why portions of the beach get closed off to vehicle travel. Most agencies that put up bird closures make every attempt to provide alternative routes for vehicles, if possible. But sometimes it is impossible. Just remember that the closures are only temporary, once the chicks leave the nest the closure comes down. So when you see a sign such as this (photo of closure sign) realize that there are birds trying to raise their young and that they only need a little space free of disruptions.
Doctor: It sounds like barrier islands of Cape Lookout National Seashore are very healthy. Their vital statistics sound pretty good 56 miles of undeveloped beaches, 61 nesting pairs in 2009 which fledged 21 hatchlings, 37% success rate. Wow those numbers are good. I sure hope we can keep them at this level and maybe even increase them some.
Those numbers are very good. Cape Lookout National Seashore has been able to improve the health of the islands through various management practices. Not only do these practices help with the American Oystercatchers but they help with all coastal wildlife. So with your help and the appropriate management by the National Seashore, these islands will continue to provide undisturbed nesting area for all shorebirds.
