Birds on the rocks – 2018

Pelican and cormorant on top of jetty at entrance to Seaplane Lagoon.
California Brown Pelican, juvenile, one or two years old, as indicated by all brown head, with Cormorant on Seaplane Lagoon jetty.

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Osprey Family Thrives in Face of Adversity

Ospreys returned again this year to nest at Alameda Point’s Seaplane Lagoon.  But midway through the rearing process, the female became the sole provider and protector of her three chicks, after the male became entangled in fishing line.  Such osprey single parenting is unheard of.

Male osprey with fishing line and bobber. Credit: Phil Dauber.

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Bottlenose dolphins visit Breakwater at Alameda Point

Bottlenose dolphins do not usually come to mind when thinking of wildlife at Alameda Point.  In fact, only three have been observed there in recent years, and those sightings were from canoes and kayaks.  But on July 24, two more dolphins were observed with two regulars meandering around next to Breakwater Island.  The standalone rock wall, or breakwater, is visible from Pier 3 where the USS Hornet Museum is berthed.

The first-time visitors were from Monterey Bay and identified by researchers with Golden Gate Cetacean Research (GGCR).  The group tracks the dolphins using a catalog of 91 dolphins showing individual markings, some with names. Continue reading “Bottlenose dolphins visit Breakwater at Alameda Point”

Great Egret fishing at Breakwater Beach

Photos of a Great Egret foraging for Yellowfin Gobies in the shallow mudflat next to Breakwater Beach at the southeast corner of Alameda Point.  After catching a Goby, the Egret would then have to fling the little fish into the air to maneuver the fish back to its mouth.  Photos are from Friday, February 9, 2018.

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Harbor seal numbers spike during herring spawning

Alameda Point’s harbor seal population fluctuates between single digits and 50 during most of the year on the specially-built harbor seal float.  But when the Pacific herring arrive in the winter to lay their eggs, many more seals arrive to feast on the herring, causing a sudden spike.  Last winter, a spike in seal numbers to a record 70 came on January 5, 2017, in the midst of the herring run.  This winter, the herring arrived sooner, in December, and so did more harbor seals, causing a spike to a new record of 73 on Christmas Eve and Christmas Day.

In the brief time span since the new harbor seal float was set in place, local monitors have assumed that it was simply the colder water temperatures that enticed greater numbers of seals to use the float in the winter.  But in fact, they discovered it’s not the full story.

It turns out that dropping water temperature indeed has an effect, but the effect is on the herring.  Ideal water temperature for herring spawning is between 50 and 53.6 degrees Fahrenheit.  The water temperature at Alameda Point dropped below 54 degrees the afternoon of December 16 and continued dropping another 2.3 degrees, according to data collected by the National Oceanic and Atmospheric Administration.  This brought on the herring run and, in turn, the voracious seals.

National Oceanic and Atmospheric Administration graph of water temperatures at Alameda Point between December 15, 2017, and January 5, 2018, with harbor seal graph added by Alameda Point Harbor Seal Monitors. Click on image to enlarge.

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No vacancy on float for harbor seals

The rain ended, the sun came out, and so did the harbor seals at Alameda Point.  So many of them came out of the water to warm up on their new float on January 5, hardly any of the structure was visible.  The number has many observers asking for a second float.

Seventy harbor seals rest on new float at Alameda Point on January 5, 2017.
Seventy harbor seals rest on new float at Alameda Point on January 5, 2017.

The regional ferry agency installed the new float after removing an old Navy dock used by the seals, in order to make way for a ferry maintenance facility.

“I nearly keeled over when I saw the platform,” said Lisa Haderlie Baker, harbor seal monitor and Alameda resident.  “So many seals packed cheek by jowl, literally, that I had to count them four times using binoculars to make sure there were 60 of them, at least, basking in the sun, which I knew had to be close to a record.  It was a tremendous thrill.”  Continue reading “No vacancy on float for harbor seals”

Ospreys nest successfully in 2016 at Alameda Point

Location, location, location! But for a fenced-off dilapidated navigation light stand on a jetty at the Seaplane Lagoon, ospreys would not have had a successful nesting season this year.

In late August two adult ospreys took flight from their Seaplane Lagoon perch for parts unknown with two healthy offspring. It was a welcome sight because for the past three years a series of frustrating avian soap operas featuring other ospreys and unwanted nesting attempts aboard the maritime ship Admiral Callaghan were marked with failure. Previously in 2012 they had raised one chick, the only other recorded case of osprey reproduction at Alameda Point.

Two young ospreys on June 8, 2016, at Alameda Point Seaplane Lagoon.
Two young ospreys on June 8, 2016, at Alameda Point Seaplane Lagoon.

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