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On the Move: Wildlife Corridors, the B2BE, and Migratory Birds!

Wildlife Corridors

We inhabit a world of many species, spaces, and needs for survival. To get from here to there, one must have a space of transition, connectivity, and available resources for safe passage and vitality. Wildlife corridors are home to many species of wildlife and act as a passageway for them to move about freely and safely. Housing developments and urban sprawl act as barriers to the natural roam of the wild. An important resolution is to plan for and create wildlife corridors where animals can move from place to place. Wildlife corridors are also referred to as “green corridors”, “nature highways and “wildlife bridges”. These transitional spaces can assist whole ecosystems in expansion with thriving wildlife populations even though humans and our structures are close by. Migratory animals use this in their travels, especially migratory birds. One of our local corridors, The Barrens to Bald Eagle Wildlife Corridor (B2BE), was placed into conservation by ClearWater Conservancy and numerous partners in 2010. This landscape in central Pennsylvania acts as an important pathway for species to move across different habitats throughout the year.

Uses of wildlife corridors are categorized by the dwellers and the passage users. The dwellers of a wildlife corridor may permanently or indefinitely live in the corridor. Trees, plant life, amphibians and reptiles, some mammals and insects are common dwellers. The passage users are the “hotel guests” in transit to their destination. These temporary passersby are small and large herbivores (deer, elk), birds, and medium to large sized carnivores (bears, coyotes, wolves) as well as migratory bird species.

Pennsylvania has a complex landscape with its topography and geographic position in the mid-Atlantic region. There are strong thermal currents and updrafts that make it possible for songbirds, raptors, and other bird species to travel along the Atlantic Flyway. Every fall and spring, millions of birds use this east coast flyway. Corridors throughout Pennsylvania are so important for this phenomenon! Bird migration is a special event for birders and outdoor enthusiasts alike to experience in awe.

Wildlife corridors have so many great benefits and are of the utmost importance, especially since they preserve wildlife habitat around human society. Animals must somehow mate, disperse, find resources, adjust to climate change, and avoid man-made dangers. The positive effects are that wildlife corridors provide a safe passage, promote genetic diversity, prevent habitat fragmentation, help plants thrive, minimize human-animal interaction and prevent wildlife encroachment amid natural calamities.

There are 2 types of wildlife corridors: natural and human made. Human made corridors focus on helping animals have a safe passage across the road. Organizations have been creating tunnels and bridges that act as a special road to go to across roads without meeting the traffic. Some corridor areas are developed from the ground up with major plantings. Natural corridors are conserved and restored to a healthy state for the wildlife inhabitants. Monitoring of threatened and endangered species is performed in effort to restore habitats specifically to conserve these at-risk species.

Barrens to Bald Eagle Wildlife Corridor

Thirty-nine acres of the 100+ acre Barrens to Bald Eagle Wildlife Corridor were purchased by ClearWater Conservancy and numerous partners in 2010 and is protected with a conservation easement held by Halfmoon Township. An additional 64 acres is owned by Barbara Spencer and Dan Dreibelbis, who enrolled their property in the Halfmoon Township Open Space Protection Program. The corridor connects the 6500-acre Scotia Barrens (State Gamelands #176) to the Bald Eagle Ridge. Scotia Barrens is a rare habitat, one of the largest examples of pitch pine-scrub oak barrens remaining in the Commonwealth. It has extraordinary value as a home for a wide variety of wildlife, a primary source of our groundwater supply, and a place to teach our children about the natural world.

There were several plantings of shrubs and trees including tulip poplar (Liriodendron tulipifera), gray dogwood (Cornus racemose), eastern white pine (Pinus strobus), quaking aspen (Populus tremuloides), oak (Quercus), hickory (Carya spp.), and viburnum (Viburnum spp.). These trees and shrubs provide nectar and pollen for pollinators, fruit and seeds for birds and animals, nesting and roosting areas, and winter thermal cover. They also provide plenty of other benefits and homes for insects, amphibians, reptiles and the whole ecosystem.

Part of the B2BE was a hay field in the past and was allowed to grow “free” into a grassland. Grass species present are timothy (Phleum pratense), orchardgrass (Dactylis glomerata), and smooth bromegrass (Bromus spp.). These hay grasses are not native, but they are common throughout Pennsylvania landscapes. These provide consistent nesting cover for birds: Red-winged Blackbirds (Agelaius phoeniceus), Savanna Sparrows (Passerculus sandwichensis), and Eastern Meadowlarks (Sturnella magna). If you stop harvesting a hay field long enough, native wildflowers will eventually naturally find their way into the field. Goldenrod (Solidago rugosa ), milkweed (Asclepias syriaca), aster (Aster alpinus), ironweed (Vernonia noveboracensis), pokeweed (Phytolacca americana), and white snakeroot (Ageratina altissima) are all present at the B2BE. Mountain mint (Pycnanthemum virginianum) and switchgrass (Panicum virgatum) were planted by stewards additionally to the existing grasses.

Mowing different sections every few years is essential to maintain the grassland habitat for wildlife that live in this habitat type or it would change into scrub-shrub land on its way to becoming a young forest, and invasive plant species would become a problem as well. Mowing is done after nesting season in August through September to ensure the survival of the multiple herbaceous species.

Enough of the plants will grow back before winter to prevent soil erosion. Pollinators such as honeybees (Apis spp.) and monarch butterflies (Danaus plexippus) are naturally attracted to the flowers at the B2BE. Pollinators not only benefit themselves by eating the sweet nectar, they spread the pollen from the male structures (anthers) of flowers to the female structure (stigma) of the same plant species. This is necessary for an array of plants to reproduce.

The grasslands are filled with milkweed at this time providing resources for the monarch butterflies to lay eggs, leaves for the caterpillars to eat, and habitat where they transform. In fact, monarch caterpillars only eat milkweed. It provides necessary nourishment to transform into a beautiful butterfly. When the adults lay their eggs, they will need an abundance of nectar to gather energy for their upcoming migration. Providing milkweed and wildflowers at the Barrens to Bald Eagle Wildlife Corridor as well as other plants and nest sites is crucial for the lives of migratory species.

Migratory Birds

Fall migration on the northern hemisphere varies based on your altitude, climate, and geography. Usually this starts in mid-September through mid-to late November or early December. It is one of the world’s wonders in how birds rely on different factors and intuitively know that it is in fact time to get together in flocks and migrate. Several changes in the environment cue this movement.

When the seasons start to change, light levels of the sun start to shift, and the days begin to grow shorter. The temperature starts to get cooler and, in some areas, it starts to rain more frequently. The summer crops get eaten up and plants begin to die, leaving less food for birds and other animals. These factors urge birds to start to migrate in search of a warmer and abundant land with more available resources. Some birds also hold off on departure until their offspring are old enough to begin their journey. The time of fall festivals usually coincide with migration, as well as hunting season for migratory game birds, including ducks and geese.

Numerous migratory birds, such as swallows and swifts, will form huge flocks before leaving to migrate. When you notice these flocks on roosting areas, migration is close. Male songbirds, for example the American Goldfinch (Spinus tristis), change into a non-breeding plumage that is duller than when they are trying to attract a mate to breed. Young birds also start to look more like adults when migration season is about to begin. Some of these young birds are warblers (Dendroica spp.), flycatchers (Empidonax spp.), and thrushes (Turdus spp.) who migrate in September and October after their parents left in late August. In some bird species, one gender leaves the other behind in migration. Rufous Hummingbird (Selasphorus rufus) mature males migrate a couple weeks before females do. Flocks of Broad-winged Hawks (Buteo platypterus) line major ridges around the end of September into October. Merlin (Falco columbarius), Kestrel (Falco sparverius), and Peregrine Falcon (Falco peregrinus) can be sighted during early October. Golden Eagles (Aquila chrysaetos) start moving during this time and are seen in Pennsylvania. Seed eating birds can start heading south during October. Waterfowl such as geese (Anserini spp.) move onto ponds and lakes from breeding areas in the north during October and November. Bald Eagle State Park, Scotia Barrens, as well as the Barrens to Bald Eagle Wildlife Corridor are excellent viewing areas of migratory birds that stop to rest and feed.

The Barrens habitat is an ecological treasure since the surrounding ridges trap cool air, forming “frost pockets” of stunted vegetation, and because of sandy, well-drained soil, forest re-growth in the Barrens is slow, and a distinctive scrub-shrub habitat results. Approximately half of the most common bird species found in the Barrens are dependent upon scrub-shrub habitat, and they come in great numbers to feed during the migration seasons and breed in the summer months. The Barrens is to host to several extremely rare species including the Golden-winged Warbler (Vermivora chrysoptera), Appalachian cottontail (Sylvilagus obscurus), northeastern bulrush (Scirpus ancistrochaetus), and it supports a large diversity of migrating and breeding Neotropical migrant songbirds. This area of land is a local treasure and wildlife experts agree that without the habitat provided by the Barrens, many species would disappear from our region.

There are various things you can do at your own home to help migratory birds

  • Make your landscaping bird friendly ahead of time and have flowers that bloom late summer and early fall so they can provide nourishment to migrating populations.

  • Encourage an area of your yard grow wild with wildflowers and grasses.

  • Allow berries, fruits and seed-bearing flowers to stand. These provide a refueling stop and animals living here in the winter will benefit from them too.

  • Stay away from pruning many shrubs or trees, especially if they provide cover to the ground. These act as shelter. If you do prune, make a brush pile in your backyard near other cover, that some wildlife can use as cover.

  • Let leaves (leaf litter) stay on the ground in certain areas so that ground feeding birds such as sparrows, thrushes and doves have a foraging area.

  • Winterize birdhouses by making them into roosting boxes by plugging vent holes to keep the wind out. Remember to reverse this in spring before nesting season.


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