Bird Photos
Species Accounts
Conservation Issues
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The Importance of Migratory Stopovers
Delaware Bay, New Jersey
General Information
Stopover habitats are essential to successful bird migrations. Migrating
birds need these critical stopover locations in the same way we need gas stations,
restaurants, hotels and rest areas when we take long trips. Strategically located patches
of woods, wetlands, mudflats, and beaches with adequate food and shelter ensure the
survival of a species. As development continues to remove such habitats from our
landscape, it becomes increasingly difficult for exhausted migrants to find suitable areas
to rest and refuel.
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Reed's Beach, and a few other stretches of
beach along the southern shores of Delaware Bay, are one such migratory stopover. In the
spring, millions of shorebirds leave their winter homes in South America and time their
arrival on these beaches to coincide with the prehistoric mating ritual of the Horseshoe
Crab. As seen in this photo, vast numbers of shorebirds compete for space and food where
development has already occurred.
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Figure 1 - Reed’s Beach,
Delaware Bay, New Jersey
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Figure 2 - Horseshoe Crabs -
Male and Female
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In May, coinciding with the high tides that
accompany the full moon, Horseshoe Crabs respond to a primitive urge to leave the depths
of Delaware Bay and move to the shallows to mate and lay their eggs.
Bird banding studies show that each year, with impeccable timing, virtually the entire
east coast population of Sanderlings, Semipalmated Sandpipers, Ruddy Turnstones, and Red
Knots, leave their South American homes and arrive on these beaches on their journey to
their breeding grounds in the far north. Estimates are that the survival of 4/5ths of the
east coast population of Red Knots is dependent on the abundance of Horseshoe Crab eggs
found on these few miles of beach.
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Shown here among the sand grains and shell
fragments are the small green eggs of the Horseshoe Crab. Billions of these eggs, laid in
the sand, become the food for migrating shorebirds. Those eggs that survive this feathered
banquet become the crabs for future generations.
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Figure 3 - Horseshoe Crab Eggs in Sand
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Figure 4 - Gulls in a Feeding Frenzy
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The Laughing Gull has an unusual and comical
feeding strategy. Instead of digging or probing for Horseshoe Crab eggs, they stand in one
place and quickly stomp their feet up and down to force the Horseshoe Crab eggs from the
sand. They then sip the eggs from the water.
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Horseshoe Crabs stranded above the tide line
can survive the exposure until the next high tide, but they often become prey to foraging
birds such as this Greater Black-backed Gull. |
Figure 5 - Greater Black-backed Gull
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Figure 6 - Underside of Horseshoe Crab
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Although the many sets of claws look
formidable, the Horseshoe Crab is harmless, and quite helpless when stranded. |
Many migrating birds that do find suitable
beaches to feed and rest suffer harassment from beachwalkers, joggers, pet dogs, off-road
vehicles, fishermen and even well meaning birdwatchers. These birds, on an already tight
time and energy budget, must continually interrupt their feeding to flee, then return to
resume their feeding.
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Figure 7 - Shorebirds in Flight
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Figure 8 - Efforts to Protect Critical Habitats
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The importance of Delaware Bay Beaches and
other migratory stopovers are now recognized. Educational efforts to minimize disturbance
to migrating birds have met with success, but much more needs to be done. |
Volunteers from the Cape May Bird Observatory
explain these critical ecological relationships to visitors. |
Figure 9 - Conservation Programs to Educate
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Figure 10 - Piping Plover
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Some species, like this Piping Plover, are
dependent on quiet beach habitats for breeding. Their preference for nesting on open
beaches has brought them into conflict with man’s summertime beach activities, and
this species has been driven close to extinction. As man’s beach-loving activities
increase, many nests are destroyed by pets, off-road vehicles and other forms of
disturbance.
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Another beach nester, now endangered in some
areas, is the Black Skimmer. These birds prefer open beaches and sandbars, making them
vulnerable to human disturbance. Reproductive success is reduced by even slight human
disturbance. These magnificent birds, with their ability to flawlessly skim the surface
even in high winds over rough seas, have written their own chapter into the annals of
flight. There are only three species of skimmers in the world. It would be a tragedy
indeed if future generations lost the opportunity to witness this unique spectacle.
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Figure 11 - Black Skimmers
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Figure 12 - Laughing Gulls Mate
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The lengthening days of spring, and the
abundance of food, signals the time to renew life. These Laughing Gulls will soon be
raising a brood.
We have within our grasp the knowledge and the ability to preserve these interesting
creatures that share our planet. Many are now working toward that end. Whether or not
enough of us have the will to exercise this knowledge as good stewards of our world awaits
to be seen. Those of us alive today may not know if our efforts were adequate, but future
generations will know how we did.
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