Why,
since rails are widely distributed, are many of them absent
from life lists of most birders? It is not because rails
have especially sparse populations; six of the nine species
breeding in North America are so abundant that hunting them
is legal; only King, Yellow, and Black Rails are protected
in the United States. Rather, many members of this family
are so secretive that they move about unnoticed; when
necessary, rails can melt into the marsh vegetation without
causing much of a ripple. In situations where other marsh
birds take flight and depart emitting harsh calls, rails
often move silently. As Audubon wrote of the Clapper Rail in
his Birds of America (1842): On the least appearance of
danger, they lower the head, stretch out the neck, and move
off with incomparable speed, always in perfect silence ...
they have a power of compressing their body to such a degree
as frequently to force a passage between two stems so close
that one could hardly believe it possible for them to
squeeze themselves through. Unlike highly visible,
skittering shorebirds that run and pause in pursuit of the
tide line, deliberate stepping, cryptically colored rails
are usually hard to spot against their noncontrasting
backgrounds. Indeed, rails may consider themselves
invisible, for even on the rare occasion when they are in
the open, they often act as though they cannot be seen. Such
apparent indifference to discovery is sometimes mistaken for
boldness, but more likely indicates that they do not
recognize a human being 20 yards away as a potential threat.
Even their fibrous, domed nests fade into the grass. Their
generally elusive behavior causes difficulty for
conservationists trying to census rail populations to learn
enough about their ecology to implement effective management
practices. For seventy years mystery
surrounded the calls of the rails and, for a while, their
voices were misdescribed and misattributed. Since rails are
rarely heard and more rarely seen, it remained difficult to
positively identify the producer of a call until the use of
tape recordings to attract the bird became practical. Many
rails limit calling to the breeding season, often awaiting
the break of day or onset of darkness. Besides the
infrequent acoustic advertisements, telltale evidence of
rails consists of little more than their tracks, pelleted
remains of meals, and inch-sized white splatters of
droppings. Rail disappearing acts also
work in water. They can readily submerge their normally
buoyant bodies, dive when pressed, and speed their paddling
by using wings underwater. So effectively do they maintain a
low profile that their main nonhuman predators are pike,
black bass, and other predatory fish which feed on their
young. Not only do rails usually
elude their predators, they seem to delude their prey.
During a tail-jerk display a rail's tail is cocked upward
and its head (which usually bobs as it steps) is frozen
still. This posture is thought by some to permit a steady
view of the foraging area while misleading small prey to
mistake its tail for its head. Many birders hope to spot
rails at dawn or dusk low tides when the birds reputedly
come forth to bathe and preen at the water's edge or to
forage on temporarily exposed mud-dwelling prey. Other
enthusiasts venture to marshlands when very high tides
compress the amount of space and covering vegetation
available to both rails and stalk-climbing snails that rails
eat. Along the Atlantic coast, hunters of Clapper Rails
(Marsh Hens) usually await the first full-moon tide of
September. When this tide is pumped by a north wind, which
forces the water level exceptionally high and pushes the
birds to even higher ground, it is known as Marsh Hen
Tide. Rails are subject to
periodic calamities; floods destroy nests and young, and
during their nighttime migrations, heavy fog can take them
off course, even into cities. In 1977 a storm brought an
early freeze and reduced by two-thirds the breeding success
of Clapper Rails in New Jersey. In 1940 one hurricane left
an estimated 15,000 of these rails dead in South Carolina,
and in 1976 another storm killed some 20,000 in New
Jersey. Ironically, the remarkable
ability of rails to reestablish after natural disasters
could lead to their demise, for their ability to respond to
nature's inconstancy may promote false confidence in
marshland managers who assume rails will recover from human
interference with equal success. Pollution in salt-marsh
habitats cannot necessarily be counterbalanced by the
apparent physical hardiness of rails. In Georgia, for
example, 95 percent of rails tested in one area near an
industrial plant had unacceptably high concentrations of
mercury in their muscles -- levels high enough to make
eating them ill-advised. It would not be surprising if
searching for these furtive creatures proves ever more
frustrating. The disappearance of a rail seen ambling amid
the marsh grasses may be illusory, but the disappearance of
high-quality rail habitat is not. SEE: American
Coots;
Metallic
Poisons. Copyright
® 1988 by Paul R. Ehrlich, David S. Dobkin, and Darryl
Wheye.