Page 16 - Sonoma County Gazette September 2019

Wonders of Bird Migration
Searching for Balance in an Underwater World Gone Upside Down
By Lisa Hug
September is a month when many birds are exiting cold northern latitudes and migrating to warmer and more food-rich southern areas. Bird migration is one of those marvels of nature that never stops fascinating us.
By Song K. Hunter
For many locals in our Northern California community, reading that we are
How do the birds know where to go, when to leave, how high to fly, or even when to stop? And, how can they go thousands of miles in one stretch without stopping to eat or rest? We can watch them; we can read books and scientific
in the midst of a devastating imbalance within our Pacific coastal intertidal zones will not come as a surprise. This is due to a chain of events spanning almost 200 years. This story is one of ripples, spreading ever outward: one imbalance leads to another, and another.
papers on bird migration and memorize all the facts and statistics. But, in the end, we come back to the same question:
To learn the history of Fort Ross is to know the plight of the sea otter
and to understand how the effects of our human practices can have long term, sometimes catastrophic results. The Sonoma Coast has had a regional extinction or extirpation of sea otters for the last 100+ years, since the Russian, American, and British over hunted the animals. These furs were so valuable that a hunter could earn a year’s salary with just one pelt.
How on earth can
they possibly do what
they do?
The sea otter is an apex predator. It consumes 20 to 30 percent of its body weight daily, helping to keep other species under control. The sea otter
has been gone from Sonoma Coast for over 100 years, but it was a series of subsequent events that caused our ecosystem to crash.
There is a bird passing by Sonoma County right now that is in the middle of the longest journey known in the animal kingdom. This is the Arctic Tern. Most
It started with a severe algal bloom, or red tide,
of us won’t see it, and won’t even be aware of it. But, at this moment, hundreds are flying southward just a few miles offshore from Bodega Head. They are flying from the Arctic Regions of Alaska and Canada to Antarctica. The Arctic Tern weighs about 4 ounces, and has about a 2 and a half foot wingspan. This
in 2011, during which Fort Ross’s abalone population was hit particularly hard. Then
in the summer of 2013, our coast was hit by one of the largest die-offs of sea stars that scientists had ever seen. For the next two years, 2014 and 2015, our coasts continuously saw the warmest water on record due to the “Warm Blob” and a strong El Niño. These warm waters led to a massive bloom in purple
small bird lives to be about 30 years old on average. And in that lifetime, it
will have travelled 1.5 million miles, enough miles to have made three roundtrips to the moon. I’ve been lucky enough to see these birds at sea during fall migration. And every time I’ve seen one, I knew I was intercepting a miracle in progress.
But, it isn’t necessary to go out to sea to witness birds that undertake amazingly long distance migrations. If you take a short drive to the coast, you can see the whimbrel. This is a shorebird that nests in Alaska and spends the winter along coasts from California to the tip of South America. They have been known to fly non-stop over the ocean for 75 hours and cover over 1850 miles in one stretch.
sea urchin.
All these events, individually, may not have had a great impact, but together,
But, in reality, we don’t have to travel at all to witness a bird on a fantastic journey. We can just look out our window on a pleasant September morning. There, we are likely to see the very common, humble, and drab-colored Golden-crowned Sparrow. Or,
we might hear it singing it’s mournful, descending “Oh dear me” song to itself. This bird has likely
just finished a 2000 mile journey from southeastern Alaska. Point Blue Conservation Science (based in Petaluma) discovered the exact breeding grounds of our local Golden-crowned Sparrows by radio-tagging individuals.
they’ve created what CDFW calls the Perfect Storm. Even today, our waters continue to stay far warmer than in previous years, leaving room for the wasting disease and urchin populations to thrive.
And then there is the problem of knowing when to take off and where to
go. The urge to migrate is controlled by hormones. Birds navigate by sensing the earth’s magnetic fields and by orienting to the stars at night. The Golden crowned Sparrow migrates at night. This sparrow only weighs about an ounce, and somewhere in its tiny brain, it has a sense of where stars should be at different times during the night and on different dates!?!
Sunflower Seastar © Paul Norwood 2009
September is the month with the most bird movement.
Bull kelp is a beautiful species of
seaweed that grows seasonally, at times in Spring, up to ten inches a day. Its canopy is focused at the ocean’s surface, as each stipe (stalk) ends in a gas filled bulb. Each bulb has many leaflike blades, sometimes over three meters long! It provides a sanctuary for fish and a food source to hundreds of species.
As each day becomes shorter, our environment sounds, looks and feels
different as new birds arrive and others slip away to places further south. These migratory birds are small but their feats are HUGE. These birds have senses that we don’t have. They can feel or see or sense magnetic fields that we are oblivious to. It makes you wonder how many different ways there are to perceive the world. Gosh, I guess there are as many different ways to perceive the world as there are individual organisms that have ever, or will ever live in it.
16 - www.sonomacountygazette.com - 9/19
These are very clear signs of our rapidly changing climate.
One of the main species hit by the sea star wasting syndrome was the
Sunflower Star (Pycnopodia helianthoides) and it was this species, along with the Ochre Sea Star (Pisaster ochraceus), that had been keeping the population of the Purple Sea Urchin (Strongylocentrotus purpuratus) in balance.
Since 2013, the Mendocino and Sonoma coasts have seen a 93% decrease in our Bull kelp forests. According to the Noyo Center’s Bull Kelp Recovery Program, “Fewer fish has meant that shore birds do not have enough food
for their chicks. This year, 90% of the local cormorant and 80% of the black oystercatcher nestlings failed to survive. Fewer young fish also means fewer larger fish for marine mammals, such as harbor seals and sea lions.”
SEARCHING cont’d on page 35
How can the Golden-crowned Sparrow, a bird that
weighs only a little over an ounce, travel such huge
distances? First of all, it accumulates huge fat reserves by feeding constantly in the weeks and days before it leaves. But, it also needs plenty of food-rich rest stops along the way.
With few remaining natural predators, the now massive urchin population has transformed the sea floor into what are called urchin barrens. These fields of urchins have decimated their favorite meal, Bull kelp (Nereocystis luetkeana).