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Preserving the continued existence of a dwindling population of any species of plant or animal is a daunting task, to say the least. Why this is so difficult is because the reason many endangered species are threatened in the first place is because they compete with, or are desired by, our growing population. We either want their land, their flesh, their fur or they are simply in the way. Two particularly disturbing reasons for animals becoming endangered is because we’ve nearly wiped them out for our own amusement or because they compete with our recreational needs. The piping plover can be filed under this latter category.

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The piping plover (Charadrius melodus) is a very small species of shore bird. One of those cute little birds that spend most of their time in the intertidal zone following the ebbing waves to pick up small crustaceans that are exposed and then running back up the beach as the next wave rolls in.

This is a migratory bird that winters in the southern United States and the Bahamas. It returns north in the spring to breed on the beaches of the northeastern U.S. and Canada, including the Great Lakes area. Although once very common, they were nearly hunted to extinction around the turn of the century. I couldn’t imagine why the demand was so high for them back then, thinking they couldn’t possibly be large enough to provide any kind of food source. Digging around I quickly discovered that it was the mad hatters that needed so many of them. Milliners used the soft feathers to decorate women’s hats. The only thing that saved them was the 1918 passage of the Migratory Bird Treaty Act. Although they made a spectacular recovery during the first half of the 20th century, their numbers again declined as coastal development accelerated after the second world war. During the 1940’s the population returned to it’s former peak levels of the 1800’s but today there are fewer than 1700 breeding pairs left.

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Let’s take a look at the life history of this animal so we can see why they are so vulnerable to the pressures of habitat encroachment. Like many species of animal that becomes threatened due to human activity, these birds have very specific requirements when it comes to feeding and raising their young. They are found exclusively on sandy beaches. The food is made up mainly of small worms and crustaceans that live along the waterline. These are plucked from the sand with each receding wave. Being migratory, plovers usually return to the same tropical beach each fall and back to the same nesting beach each spring.

The eggs are sand-colored and blend in perfectly with the surroundings. The nest is simply a depression in the sand, set among the dunes found on the upper beach, and sometimes encircled by small stones or shell fragments. The nest is made and defended by the male. The clutches are pretty consistent, nearly always made up of four eggs. When the eggs hatch the young remain in the nest for a week or so and are fed by both parents. Eventually they are allowed to follow the adults down the beach to learn how to catch food on their own. Although they become independent within a month after hatching, the young tend to stay with the parents until migration time arrives in September.

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A plover’s nest contains four
camouflaged eggs. Photo by
U.S. Fish & Wildlife Service.

Although it’s true that coastal development and recreational beach use is primarily responsible for their decline, another factor that goes hand in hand with human intrusion also plays a large role. This is the killing of both eggs and chicks by domesticated animals. Being ground-nesters, plovers have enough to worry about from natural predators, such as sea gulls, raccoons and skunks. Adding dogs and cats to the mix is devastating to the population. And dogs and cats won’t always fall for the broken wing ruse the parents use to lure predators away from the nest. This behavior is a brilliant adaptation used by many types of ground-nesting birds. The eggs are perfectly camouflaged in the sand. As are the chicks, which also have a built-in instinct to instantly freeze at any sign of danger. The parent, meanwhile, uses a predator’s instinct to go for the easy meal (ie: an already sick or injured prey) by luring the predator away from the nest by feigning a broken wing. Limping and chirping to get and keep the enemy’s attention, the adult will allow itself to be chased by the predator, always keeping just enough distance to keep from being caught itself.

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An adult showing the "broken-wing" pose
used to lure predators away from the nest.

The main way the nesting sites are protected today is by the identification of breeding colonies and fencing off the habitat to prevent foot traffic, vehicles and predators from killing the young. In some cases entire beach sections are declared off-limits.

However, protecting the plover doesn’t require fully eliminating recreational beach use. The pairs return to their nesting grounds in March and the chicks hatch 25 days later and are fledged a month after that. Which means there is only a two-month window where disturbing the nesting sites will affect the birds ability to successfully raise the young. By the time the kids are out of school in June the plover chicks are able to survive on their own, hardly interfering with the summer tourist season. However (and there’s always an "however") during those two months it is absolutely vital that the eggs and chicks are not disturbed. If they are, and even if they are not outright killed, the parents will abandon the nest and start a new family on a different part of the beach. This of course lengthens the breeding season and these late-breeding adults won’t fledge their young until July or August. In other words, during peak sun-worshipping season. Catch-22 is that by abandoning the original disturbed nest, the birds have pretty much guaranteed that the subsequent broods will be disturbed as well.

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It’s the bird’s bad luck to have such specific nesting ground requirements that also happen to coincide with what is one of the most intensively used and valuable real estate for humans.  And as if the politics of coastal recreation and tourism doesn’t impact the ability of conservationists to have this nesting habitat set aside enough, here in Rhode Island one of the two primary plover breeding beaches also happens to have been shared by our only public naturist beach. Naturists, which sounds like they would be all in favor of helping out a little bird, right?, is actually the term now used for what we once called "nudist colonies". Along with all of the economic reasons not to protect these birds was the charge that the state and town governments were using plover conservation as an excuse to rid themselves of a controversial group of people. Whether that’s true or not doesn’t change the fact that with the beach open during breeding season the plovers cannot raise their chicks.

Fun Fact: The name for this bird comes from it’s call, which is a soft whistling sound. Listen to a piping plover’s song.

Not-So-Fun Fact: The piping plover was designated as a threatened species under the Endangered Species Act in 1986. Being listed as "threatened" means it is considered to be vulnerable to extinction if steps are not taken to protect it.

Other diaries in this series can be found here.

Originally posted to Mark H on Fri May 04, 2007 at 03:46 PM PDT.


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