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| Alfred Hitchcock and feathered friends |
On August 18, 1961 the Santa Cruz Sentinel reported:
A massive flight of sooty shearwaters, fresh
from a feast of anchovies, collided with shore side structures from Pleasure
Point to Rio del Mar during the night. Residents, especially in the Pleasure
Point and Capitola area were awakened about 3 a.m. today by the rain of birds,
slamming against their homes. Dead and stunned seabirds littered the streets
and roads in the foggy, early dawn. Startled by the invasion, residents rushed
out on their lawns with flashlights, and then rushed back inside, as the birds
flew toward their light. . . . When the light of day made the area visible,
residents found the streets covered with birds. The birds disgorged bits of
fish and fish skeletons over the streets and lawns and housetops, leaving an
overpowering fishy stench.
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| A sooty shearwater in flight |
The Santa Cruz Sentinel also reported that film-maker Alfred Hitchcock
requested news copy of the mysterious event to use as research in developing
his latest thriller. Within a month he had hired screenwriter Evan Hunter (better
known as Ed McBain for his crime novels) to adapt Daphne du Maurier’s 1952 novelette,
The
Birds, to film. Set in du Maurier’s native Cornwall after World War ll,
it is the story of a farm community that is attacked by flocks of seabirds in kamikaze fashion.
The Mystery Deepens
In late 1987, a serious
outbreak of food poisoning in eastern Canada linked to cultured mussels
harvested in Prince Edward Island made front-page newspaper headlines when
three elderly patients died. All the victims, including the deceased, suffered
long-term neurological damage including memory loss so the malady was named amnesiac shellfish poisoning. The
mystery deepened as Prince Edward Island had never before been afflicted with
toxic algae and the unusual neurotoxin symptoms were very different from those
caused by paralytic shellfish poisoning toxins or other known toxins.
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| California Sea Lions |
In 1991, dead and dying
seabirds, including brown pelicans, began washing up on the beaches near Santa
Cruz and Monterey Bay, CA. It was discovered the birds had been eating anchovy
contaminated with domoic acid. In May and June of 1998, 400 California sea
lions died of domoic acid toxicosis. By 2002, it
became obvious that thousands of birds and mammals, including dolphins, sea lions,
seabirds, and endangered brown pelicans have succumbed to domoic acid
poisoning.
Why is this happening?
Since then, the mysterious
poisonings have lost a good deal of their mystery. They occur with almost predictable
regularity now, and the science behind them is becoming widely understood. When
conditions are right, the marine phytoplankton, Pseudo-nitzschia australis,
blooms and the tiny algae bloom, creating what is called “red tide”. The algae
produce domoic acid. As the toxin accumulates up the food chain, fish become
contaminated with the poison, and then the birds and marine mammals who feed on
them. The toxin enters the
bloodstream, then the brain, causing convulsions, coma, vomiting, seizures and
finally, death.
Wildlife centers like The
Marine Mammal Center in Sausalito and the International Bird Rescue Research
Center in San Pedro are often overwhelmed with dead and dying animals and
desperately try to save them. Experience has shown that animals quickly rescued
have a chance to survive if they receive massive fluid therapy, orally and
intravenously, to flush the toxin from their bloodstreams.
What causes red tides?
Scientists prefer to call red
tides Harmful Algal Blooms (HAB), and they have been reported along every US
coastal state. Their frequency appears to be on the rise. They are a concern
because they affect the health of people, wildlife and ecosystems—as well as
the health of local economies. Not all algal blooms are harmful, however. Most
blooms, in fact, are beneficial because they provide food for marine life. In
fact, they are the major source of energy that fuels the ocean food web. So
what causes the profusion of harmful red tides?
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| Red tide algal bloom |
The short answer is
fertilizer over-use. See this blog’s post titled The Problem with Fertilizer, December 30, 2014.
Natural upwelling from
the ocean’s depths of nitrogen rich nutrients are of limited duration. They
feed the algae and dissipate with minimal effect on other marine life since
their presence is not constant. Over-use of fertilizer provides a constant
stream of nutrients to algae and tips the balance from beneficial to harmful.
Back to The
Birds
It wasn’t until 2011 that the
1961 “bird attack” in Capitola was positively identified as a domoic acid
event. Researchers at Louisiana State University examined samples from plankton
and marine animals collected in 1961 and identified an unhealthy accumulation
of domoic acid which was found in 79 per cent of the plankton ingested by
anchovies and squid.
Over a short period, that
would become potent enough to cause fatal consequences for predators that
ingested the creatures. "Here we show that plankton samples from the 1961
poisoning contained toxin-producing Pseudo-nitzschia, supporting the contention
that these toxic diatoms were responsible for the bird frenzy that motivated
Hitchcock's thriller," says Sibel Bargu, lead researcher.
Although the usual suspect
would be pesticides from farmland, the researchers note that there was a
house-building boom in the area at the time, and posit that leaky domestic
septic tanks were instead to blame.
Life imitates art once
again. The picture-perfect California coast attracts millions who are inspired
by its beauty and the movie culture that springs up around it. In the movie, havoc ensues as birds attack to punish human excesses, but the reality turns out to be that excess is punished by Mother Nature in less theatrical but more
devastating ways.
More reading
The
Marine Mammal Center at http://www.marinemammalcenter.org/science/#.VKdVbCvF98E
The Poison Review at http://www.thepoisonreview.com/2011/12/30/angry-birds-or-domoic-acid-toxicity/
The International
Bird Rescue Research Center at http://bird-rescue.org/
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