EATS BIRDS IS NEWS
paraphrase the journalistic aphorism: Bird eats insect is not news;
insect eats bird is. And that news has been confirmed by Martin Nyffeler
of the University of Basel in Switzerland with his colleagues Michael
R. Maxwell of National University, La Jolla, Calif., and J. V. Remsen
researchers have recently uncovered many examples of these predator-prey
surprises. This edifying scientific paper is one of those that can change
our perception of the way the natural world works.
are the prey. Large praying mantises are the predators. The scientists
accumulated records of these voracious ambush hunters attacking birds
in a variety of situations on every continent except Antarctica.
of praying mantises at the South Pole and the large size of penguins
makes a forthcoming report unlikely. Nonetheless, in warm regions of
the world where these carnivorous insects live, numerous accounts exist
of mantises eating birds.
mantises look like something you might find at a Star Wars battle. Their
huge eyes framing a triangular head give them a decidedly alien appearance.
The front legs are held in an upright position with spines on the inside
of what would be functionally equivalent to a claw and a long wrist
that folds toward the forearm, also with spines.
two parts of the leg are pulled toward each other, the prey is held
tightly in a thorny vice grip. Praying mantises are so effective at
holding on to prey that, when humans did not intervene, about 98 percent
of the captured birds were eaten by the mantis. As if this were not
enough of a horror scene, a mantis first attacks the birds head
and then eats the brain of the victim.
documented the capture of two dozen different species of small birds
from 13 countries by a dozen kinds of mantises. More than a hundred
of the records were from the United States, and the ruby-throated hummingbird
was the most common victim. Considering the size differential between
most insects and most birds, the favored bird prey by a praying mantis
is not surprising.
in favor of the mantis are further increased when the crafty mantis
learns that the underside of a hummingbird feeder is an ideal spot for
an ambush predator to hang out. Some bird enthusiasts will be pleased
to know that records also exist of avian species turning the tables
by eating mantises. Crows, owls and kingfishers have been reported to
eat praying mantises in other countries and would presumably do so here.
But again, bird eats insect is not news. Insect eats bird is.
common praying mantis native to North America is the Carolina mantis,
so-called because the first specimen was described in South Carolina
in the 1700s. They are typically green, which serves them well when
camouflaged in vegetation, or brown. Carolina mantises get as long as
2½ inches and are widespread across the Southeast. As with many
kinds of native plants and animals, Carolina mantises are sometimes
overshadowed by introduced species from other continents.
and European praying mantises are larger than our native species. The
Chinese mantis can be more than 4 inches long. The introduced praying
mantises were first reported in the United States in the 1890s from
what is presumed to be accidental introductions, probably by eggs attached
to horticultural plants.
some garden outlets actually sell eggs of praying mantises for people
to put in their gardens to control insect pests. The researchers end
their article with a warning: The predation risk that [praying
mantises] pose to some bird species, particularly hummingbirds, lead
us to recommend caution in [their release] into North American gardens.
is for certain, we can all take comfort in the fact that praying mantises
do not grow large enough to pose a threat to humans. Otherwise, living
in Antarctica might become appealing.
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