Cheniere Habitats

Cheniere Ridges: Mother Nature's Premier Birding Opportunities

 

What is a cheniere?

Grand Isle's cheniere forestThe chenieres of coastal Louisiana, with their venerable moss-cloaked oaks, wind-sculpted hackberries, and tangled grapevines, are little known to the Americas at large.  Even in Louisiana few people know of the existence of these unusual wooded groves that rise abruptly from the vast sea of marshland and stand forth as the most dominant feature of the landscape.  Cheniere (pronounced "shin-EAR" or "shane-YEAR") is an expression roughly translated as "oak grove" which ooriginated from the early French inhabitants of southeast Louisiana.  Chenieres are acient, stranded woodlands that are supported by landforms that rise above the flat marshes.  Also known as maritime forest – these “oak groves” represented some of the highest ground found in coastal Louisiana. For this reason, people built small villages on some of these ridges, which afforded them quick access to the gulf’s natural resources and provided them refuge from some flood events.

Many historical chenieres have disappeared – lost to a continual process of barrier island retreat largely caused by the forces of nature and sometimes man. Of the live oak ridges that still exist, many will likely suffer the same fate – a slow death – a result of battering waves, subsidence of the land, saltwater intrusion, hurricanes, conversion by man, etc. Today, many of these places are nothing more than names of historical settlements such as Chenier au Tigre, Chenier Caminada, and others. This has prompted the Louisiana Natural Heritage Program to list these habitats as imperiled to critically imperiled.

 

Why are chenieres important to migrating birds?

 

American Redstart perched in a treeCoastal cheniere ridges are considered to be the most important habitat for many neotropical migratory birds during fall and spring seasons. Millions of migrating birds use maritime forests as vital resting and foraging habitat during their migration. In the spring, many trans‑gulf migrants flying from the Yucatan peninsula to North America use cheniere habitats as their first landfall. When they fly south during fall migration, many use chenieres as their "jumping off" point. Although trans‑gulf migrants each spring reach the gulf coast from west of Houston, Texas, to Florida, a large proportion of the migrant population uses the upper Texas coast and coastal Louisiana around to Mississippi.

In spring, 70-plus species of Nearctic-Neotropical migrants regularly use cheniere woods, and nearly that many - about 65 - use them year in and year out during autumn.  Only a handful of migrants, like the Orchard Oriole, White-eyed Vireo, Ruby-throated Hummingbird, Painted Bunting, and Yellow-billed Cuckoo, stay to breed.  About half as many species of Nearctic migrants can be found on chenieres in winter.  There are still fewer species that have a cheniere as their permanent address.  Of the 160 species of Nearctic-Neotropical birds in the Western Hemisphere, more than half are found on chenieres at some time during the year.

 

Why are the Barataria-Terrebonne basins important for migrants?

 

For over one hundred years, but especially since the work of Dr. George Lowery in the 1940s and 1950s on Grand Isle (1946, for example), the area of Barataria-Terrebonne has been recognized as a very heavily used stopover by Nearctic-Neotropical trans‑gulf migrant birds. It is especially critical when foul weather in spring causes migrating birds to reach land exhausted, or in fall when bad weather forces the birds to abort their southward migration at the last moment, before leaving land.

Scarlet Tanager perched on a branchIn addition to chenieres, these coastal stopover habitats include barrier beaches, tidal mudflats, marsh ponds, swamps, and natural levees of the upper estuary. Because many of North America's breeding birds winter in the Neotropics, they fly south each fall funneling along the Mississippi River and staging in Barataria-Terrebonne, building up fat reserves to sustain them on their arduous journey to Central and South America. For birds returning across the gulf in spring, Barataria-Terrebonne can be a critical refueling stop, especially if adverse weather is encountered during the trans‑gulf flight.

Several years ago, New Orleans native and well-known ornithologist, Dr. Sidney Gauthreaux, used weather radar data to estimate that, in spring, some 80,000 birds per mile of migration front arrive on the Louisiana coast each day during peak migration. On these days, between 20 and 100% of the birds alight in cheniere woods, depending on the weather over the gulf. Either way, that’s a lot of hungry birds to feed. In North America during autumn months, educated guesses suggest that between two and five billion birds leave for the tropical environs of Middle and South America each year. Because the vast majority of Nearctic-Neotropical migrants breed in the eastern deciduous forests or the boreal forests of eastern North America, tens of millions of them filter through Louisiana twice each year. These migrants thus depend on Louisiana’s cheniere woods to provide safe resting areas and enough food at just the right time to ensure a successful migration. We're thinking: Louisiana's coast truly is Americas’ Avian Port of Call.

 “Possibly the greatest single factor, however, favoring Louisiana as a place to find many kinds of birds is its geographical position. It lies athwart the great Mississippi River Valley migratory flyway, a route over which millions of birds wing their way twice a year in their annual migrations….Its southern location affords a mild climate, which encourages many northern birds to spend the winter here, along with the many southern birds that are resident throughout the year. But the state’s important advantage over other southern states results from its strategic east-west location. It receives, at least in seasons of migration, nearly all of the species of the eastern United States and, at the same time, a strong representation of western forms. The latter are notably evident in fall when the southward migrations of western species, those of the Great Plains particularly and even those of the Rocky Mountains, are probably being swung southeastward by the general southeastward trajectory of much of the continental air flow at that time.”--George H. Lowery, Jr., 1974; (Louisiana Birds, Published for the Louisiana Wild Life and Fisheries Commission, Louisiana State University Press, Baton Rouge)

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