HABITAT Northern United States and Canada
THREAT PestsThis small, robin-size
shorebird flies 19,000
miles per year in its
sweeping migration
from Tierra del Fuego,
at the very tip of South
America, to the Canadi-
an Arctic tundra, where
it breeds, and then
back again. To fuel this
epic journey, the knot
carefully times its spring
break with horseshoe-
crab mating season in
the Delaware Bay, where
it stops to feed on the
crabs’ pebble-like eggs,
doubling its weight in
the process. But warmer
temperatures are now
prompting horseshoe
Weighing in at around
1,800 pounds, with
antlers that can span
six feet from end to
end, adult bull moose
have few predators to
worry about. But thanks
to milder winters, a
deceptively small pest is
threatening their young.
With less snowfall and
warmer temperatures
over the past 10 to 15
years, ticks are thriving.
A study tracking moosecrabs, already strug-
gling due to overfishing,
to lay their eggs earlier
in the year. By the time
the knots arrive, they’re
left with scraps. And
the crab-egg feast isn’t
the only meal these
birds are missing: In
Virginia, rising ocean
acidity is depleting
the population of blue
mussels that knots feed
on, and in the Arctic,
warmer temperatures
are causing insects to
hatch earlier, depriving
knot chicks of their first
meals. In 2014, after its
population bottomed
out at just 12,000calves in New Hampshire
and Maine counted an
average of 47,000 of the
blood-sucking parasites
on any given calf — a
problem that puts them
at severe risk of death
by anemia. Seventy
percent of the calves
being tracked perished
over the course of three
years. Moose popula-
tions in the U.S. are de-
clining, and “the abun-
dance of pest species isbirds, the rufa red knot
was listed under the
Endangered Species
Act, the first bird to
have climate change
named as its “primary
threat.” According to
the National Audubon
Society, two-thirds of
North American birds
are threatened from
global temperature rise.
“Birds are important
indicator species,” said
Audubon’s director of
climate watch, Brooke
Bateman, in a report on
the study, “because if an
ecosystem is broken for
birds, it is or soon will
be for people too.”seriously concerning,”
says the IUCN’s Foden,
who notes that warmer
weather in Hawaii has
brought malaria-carrying
mosquitoes to higher
elevations than before,
and proliferating tsetse
flies have rendered large
parts of Africa unfit for
cattle farming. “The
stress of climate change
will make all species
more susceptible to
diseases and parasites.” RUFA RED KNOT
HABITAT Annual migration from the southernmost tip of South America
to the central Canadian Arctic THREAT Food scarcity
CLIMATE CRISIS
82 / ROLLING STONE / APRIL 2020
MOOSE