Park Wavelengths - May 2008

2008 Archives

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May 20, 2008

For early risers, some of the lowest daylight tides of the year are just a few weeks off with the new moon on June 3:

Wednesday, June 4	6:09 am	-2.0 feet
Thursday, June 5	6:59 am	-2.0 feet
Friday, June 6	7:50 am	-1.8 feet
Saturday, June 7	8:40 am	-1.4 feet
Sunday, June 8	9:32 am	-0.8 feet

Plucky little snowy plovers are hard at work nest building on the Great Beach, 11 nests have been identified this year but 6 nests have been lost to predators and wind.

A word on coyotes, often seen along Limantour and Bear Valley Road. This time of year, the pups are in the den, and parents range far and wide for extra food and may behave a little more defensively if near their dens. Point Reyes is abundant - gophers, rabbits, lizards, frogs, quail eggs, etc. so it is rare that they might attempt to get food from human sources (garbage, picnic leavings, pet food left outside. etc.) in this area. However, south of Point Reyes - in Golden Gate NRA, coyotes are making their way into neighborhoods abutting parklands. Rule of thumb is not to leave food of any kind out - secure garbage cans; put away pet foods, never leave food out in camp or picnic areas. If an animal is approaching, unusual behavior, create a bad impression - yell, throw dirt, back away and do not run. Report at park visitor centers if you are approached!

Fire season has officially begun at Point Reyes. Beach fire permits are not issued in advance and must be picked up the day you plan to have a fire at the beach.

Marin County Open Space rangers lead a hike this Thursday, May 22 "Flowers of Bull Point". Dress warmly and meet at the Bull Point Trailhead off Sir Francis Drake Highway just before the North Beach turnoff.

All park visitor centers are open on Monday, May 26, Memorial Day. A short service is planned at the historic cemetery of Sir Francis Drake Highway from 2:00 pm to 3:30 pm. A permit is out for a wedding for 50+ people at Drakes Beach on Saturday May, 24, 5:00 pm - 10:00 pm; expect parking congestion near the visitor center.

Special event on Saturday, May 24 at Bear Valley Visitor Center - Aerial photographer Robert Campbell will be showing slides and autographing his new book "Above Point Reyes" at 12:30.

A permit has been issued for a bike ride on Bolinas Ridge Trail on May 31st; 90 riders in three groups will be traveling by bike from Olema Campground along the trail to Bolinas Fairfax Road.

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May 20, 2008

Forwarded to Park Wavelengths subscribers

PORE Ocean Update 1.6

White Sharks at Point Reyes National Seashore

Have you ever seen a white shark at Point Reyes? How about one feeding on seal carcasses near the headlands? Would you like to know where and how often white sharks are seen, and what they are usually seen doing? This may be useful information if you dive or surf in open water at PRNS!

Scot Anderson, Ben Becker and Sarah Allen published an article in the January 2008 edition of California Fish and Game on observational sightings of white sharks at Point Reyes National Seashore over 23 years and decoy surveys over 11 years.

Where are they seen? Most observations were clustered in three areas: Point Reyes Headlands, McClures Rock, and Tomales Point. White sharks are mostly seen close to shore, in water depths from 5m to 30m. This is likely because they need to keep sight of the surface where they capture their prey.

When are they seen? White sharks are observed at PRNS most frequently in the late summer and fall (August, September, October), which coincides with the seasonal peaks of pinnipeds: California sea lions congregate in the area when males migrate north in the fall, and northern elephant seals juveniles haul out in the fall. When Scot Anderson used decoys to track the frequency of white shark appearances, he found that they were seen approximately once every 6 hours at PRNS! However, this frequency is still less than the frequency in which they are sighted at the Southern Farallon Island: once every 1.9 hours.

What do they eat? At Point Reyes National Seashore, white sharks prey on pinnipeds that congregate onshore and they also scavenge on marine mammal carcasses (especially whales). At the Farallones and A ñ o Nuevo, the pinniped population that white sharks primarily feed on are the northern elephant seals. However, this is not what Scot Anderson found at Point Reyes—the white sharks here seem to be feeding mostly on harbor seals and California sea lions. White sharks also scavenge off of marine mammal carcasses. Large dead marine mammals such as sperm whales, baleen whales, and northern elephant seas can leave an odor trail that can be carried for many kilometers. White sharks can track these “odor corridors” and follow them to the source. In 2004, when a dead sperm whale drifted to PRNS, as many as four white sharks came to feed on the carcass at one time. A large white shark (~943 kg) can survive up to 45 days after feeding on 30 kg of blubber from a dead cetacean!

Should I be concerned about attacks on humans? There were five human attacks by white sharks at PRNS over 23 years, all of which occurred in the fall season close to shore in water <10 m deep. All the victims survived. Those highest at risk appear to be people who dive for abalone, spearfish, or surf in open water in or near areas where sharks have been sighted, or near seal colonies. Please be careful, and report any white shark attacks to Law Enforcement (415-464-5170).

If you would like more information, Scot Anderson is currently working as a seasonal with the Trails crew. Contact Bill Michaels at 415-464-5157. For electronic copies of the article, contact Ben Becker.

Jessica Luo
Ocean Education and Outreach Coordinator
Pacific Coast Science and Learning Center

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May 6, 2008

The full moon rises May 20 with a few early morning daylight low tides:

Tuesday, May 20	6:02 am	-0.8 feet
Wednesday, May 21	6:37 am	-0.8 feet
Thursday, May 22	7:13 am	-0.8 feet
Friday, May 23	7:51 am	-0.7 feet
Saturday, May 24	8:33 am	-0.6 feet
Sunday, May 25	9:17 am	-0.4 feet

For Nunamiut Alaskan natives it is 'the moon when the ice goes out of the rivers' while further south at San Ildefonso Pueblo it is 'the planting moon'.

Spring surveys and studies are beginning on harbor seals and spotted owls. One spotted owl nest has been observed so far; it is hoped more will be noted in the mature forests along Inverness Ridge.

Armchair wildlife viewing along the Bear Valley Road corridor - Wednesday, a river otter seemed to be scoping out the creeks and dropping in at the Red Barn Classroom; soon followed by a coyote. Two young male black tails, their antlers in velvet, put on a boxing match along the road. Further afield, the last of the northbound gray whales have been rolling along Drakes Bay, mother and calf pair observations were made on Thursday and Saturday.

Poppies are out all over Bear Valley pastures, along Abbots Lagoon, patches along local highways. Large, white blooms along roadways are Cow Parsnips - they always look like cauliflowers and the stalks can be 5 feet high.

International Migratory Bird Day will be observed this Saturday, May 10 at Muir Woods NM. Educational activities begin at 7:00 am (birdbanding demonstrations) and go through 12 noon. Other activities include smolt trapping, habitat restoration, and bird walks. A free shuttle will carry visitors between Muir Beach and Muir Woods. More information at [phone].

Brown Bag Lunch seminar coming up on Thursday, May 15 at 12 noon in the Red Barn Classroom is "Nutrients and Benthic Invasion Dynamics in northern California estuaries" This free talk is open to the public.

Reminder: A public meeting on the suggestion for a bridge over Lagunitas Creek from White House pool to the Giacomini wetlands is scheduled for May 14 from 6:30 pm to 8:30 pm at the Dance Palace Community Center in Point Reyes Station.

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