By Donald S. Heintzelman
Within roughly the last decade, a new branch of ecology has developed called stopover ecology.
The research focus of stopover ecologists is on the many locations along major songbird migration routes especially the Atlantic and Gulf coasts, Pacific Coast, and certain inland routes such as the famous Kittatinny Ridge in parts of New York, New Jersey, and eastern Pennsylvania, that biannually are used for a few hours or days by millions of songbirds. In other words, stopover habitats are vital refueling stations for migratory songbirds.
The scientific objectives at these locations are to learn more about how and why the fruits or nectar produced by native trees, shrubs, and flowers are vital to the survival of large numbers of migratory songbirds. Another goal is to determine which species of native plants are most useful for enhancing small, backyard habitats for the benefit of migrating songbirds.
Unfortunately, whats becoming increasing clear is that vast, natural stopover habitats already are lost to land development and the situation is becoming worse in some places, such as the Gulf Coast and parts of the Atlantic Coast.
As an ornithologist who has spent most of my professional life studying bird migrations (especially hawks), this is a subject of fascination and interest to me. Thats why, in my 16th wildlife book, The Complete Backyard Birdwatchers Home Companion, I discuss some aspects of this topic for beginning and novice birders. Id also like to share some of my thoughts with Wild Ones members.
In New Jersey, for instance, part of Island Beach State Park preserves the magnificent, pre-colonial maritime vegetation that once covered all of that states barrier beach islands. Now, however, most of the Atlantic coastline in New Jersey, and the other coastal states, has been modified by human activities. The result is fewer and fewer stopover habitats remaining with native, fruit-producing vegetation that migratory birds need for their survival.
A visit to the northern third of New Jerseys Island Beach State Park instantly reveals the magnitude of the loss along the coast. There one sees a floristic mosaic and zonation of plants extending from the ocean to the bay side of the island all beautifully adapted to the maritime environment. Included are Dune Grass, Beach Heather, Beach Plum, Bayberry, Sumac, American Holly, and Red Cedar.
Adding more emphasis to the natural versus the altered or destroyed is the shocking sight of very densely developed summer housing immediately outside the parks entrance. Its as if a giant took a knife, cut off part of the natural pre-colonial maritime vegetation, scraped the land bare, and planted houses. No contrast could be greater, more dramatic, or sadder astonishing testimony of the ecological ignorance, and arrogance, of the human species.
To try to offset this damage, there are various native plant species suitable for enhancing backyard habitats on these barrier beach islands. For seaside conditions, select Eastern Red Cedar (Juniperus virginiana), American Holly (Ilex opaca), Beach Plum (Prunus maritima), and Northern Bayberry (Myrica pennsylvanica). These species provide appropriate fruits that migratory songbirds eat.
At the southern tip of New Jersey, at Cape May Point, major concentrations of migrating hawks, songbirds, and other birds appear every autumn. Its one of the most impressive ornithological spectacles in North America and a critically important stopover area for these migratory birds.
Unfortunately, more than 40 percent of the native habitat in the lower 10 kilometers of the Cape May peninsula has been developed in the past 20 years. That means that vital stopover feeding and resting areas containing native trees, shrubs, and flowers that millions of birds depend upon annually no longer exist. Indeed, development pressure now is being applied to Cape Mays most ecologically critical stopover habitat areas.
To offset some of this serious habitat damage, stopover ecologists and conservationists encourage property owners to plant native trees, shrubs, and other plants to serve as mini-stopover habitats that songbirds can use to feed and rest in protective cover. The same species, and others, recommended for barrier beach islands can be used at Cape May and elsewhere along the Atlantic Coast.
Inland, along the famous Kittatinny Raptor Corridor in eastern Pennsylvania, an increasing amount of farmland, old fields, woodlots, hedgerows, wetlands, and other habitats are also being lost to development, and natural plant diversity replaced with grass and a few trees and shrubs (often exotic or introduced species). That means that migratory songbirds that use parts of this corridor during spring and autumn have less protective shelter and survival food available during these critical months.
Again, however, the solution to this problem is enhancement of backyard stopover habitats with native trees, shrubs, and flowers. For example, Mountain Ash (Sorbus americana) produces colorful reddish-orange fruits during autumn that migrating American Robins relish. Other birds, including various thrushes, Cedar Waxwings, and Evening and Pine Grosbeaks, also feast on these fruits.
People living within the Kittatinny Raptor Corridor, and elsewhere in eastern Pennsylvania and adjacent states, can also plant Pin Cherry (Prunus pensylvanica), Red Mulberry (Morus rubra), American or Climbing Bittersweet (Celastrus scandens), and American Holly (Ilex opaca) to provide fruits for songbirds.
Hummingbirds also live within, and migrate along, this same bird migration corridor. To help provide them with food, try planting Bee Balm (Monarda didyma) which apparently escaped from cultivation and Cardinal Flower (Lobelia cardinalis) from which hummingbirds secure nectar and tiny insects that represent their food.
American Wildlife & Plants: A Guide to Wildlife Food Habits by Alexander C. Martin, Herbert S. Zim, and Arnold L. Nelson (Dover Publications, Inc.) is an excellent reference book. It provides very detailed information about specific flora for various parts of the continental United States that can be used to attract specific bird species, plus equally detailed information about bird and other wildlife food habits. Much of the books information deals with native plants.
The new science of stopover ecology brings with it at least one vitally important message: By enhancing thousands of small yards with native vegetation, particularly species that produce fruits eaten by migratory songbirds, these mini-stopover habitats can help to compensate for the loss of larger habitats along North Americas major coastal and inland songbird migration routes.
Heres an ecological need begging for help and one in which Wild Ones can participate with gusto!
Donald S. Heintzelman has been staff photographer for the Bethlehem Globe-Times and Organic Gardening magazine. Later, after graduating from Muhlenberg College, he was associate curator of natural science at The State Museum of Pennsylvania, and for some years was curator of ornithology at the New Jersey State Museum. More recently, he was co-founder and president of the Wildlife Information Center, Inc. A wildlife consultant and writer, he has traveled widely in North America, the West Indies, South America, the Falkland and Galapagos islands, East Africa, and the Antarctic photographing and studying birds and other wildlife. He was also a wildlife film lecturer for the National Audubon Society, and served as ornithologist on the ecotourism ship M.S. Lindblad Explorer on expeditions to Amazonia, Antarctica, and Galapagos. He is the author of 15 previously published books, including A Manual for Bird Watching in the Americas, A Guide to Hawk Watching in North America, Autumn Hawk Flights and The Migrations of Hawks, and Guide to Owl Watching in North America. He has published more than 150 scientific articles and notes on ornithology, wildlife, and conservation in leading national and international journals and magazines. He is an award-winning author of a nature column published in several newspapers in eastern Pennsylvania.
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Updated: Jun 12, 2005.