Tuesday, July 20, 2010

Elephant Seal prey

Humboldt Squid are a frequent prey hunted by elephant seals. They are a warm water species, but National Geographic reports in the August issue that their range is expanding. The map shows their range in 1984, 2001 and 2005.

The research is being done by William Gilley of Stanford University's Hopkins Marine Station, http://www-marine.stanford.edu/. I met him when he led a squid dissection at Camp Ocean Pines in 2008, http://www.topp.org/blog/slimy_squid_science. That workshop was so successful that it has been expanded into Squid for Kids, http://gilly.stanford.edu/outreach.html. They'll send free squid to any group that wants to dissect them, along with lesson plans and other support.

The expansion of the squid's range could affect other fish and marine mammals. This species is a fierce hunter and voracious eater, growing to as large as six feet long and weighing up to 80 pounds. The one I'm working on in this picture isn't that large, but it was big enough to make an interesting dissection.
National Geographic Channel will broadcast a documentary about them July 30, Dangerous Encounters: Cannibal Squid.

Wednesday, July 14, 2010

Other marine mammals

Blue whales share the ocean with elephant seals. Some were sighted recently in Monterey Ba, less than 100 miles north of Pedras Blancas, http://www.youtube.com/user/PrincessMonterey. Humpback whales also live off the Central Coast, and were sighted in the bay, http://www.youtube.com/user/PrincessMonterey.

Lots of seals were swimming in the water at Piedras Blancas on Monday. Seeing them surface reminds you how much is going on beyond our awareness. This picture shows a pile of large adult and sub-adult males at the south end of the bluff, with one recent arrival resting close to the water.
It's been very busy, both on the beach and with visitors on the boardwalk. America's on vacation! Lots of European tourists, too. The experiences they have on the Central Coast return home with them.

Tuesday, July 6, 2010

Molt in North American Birds

This new book by Steve N.G. Howell is one of the Peterson Reference Guides, http://www.houghtonmifflinbooks.com/catalog/titledetail.cfm?titleNumber=1051920. My first reaction was that molting was a niche topic that an informal birder like myself would not find interesting. I discovered that it's invaluable!
Unlike elephant seals, birds are always be in one stage of molt or another. In our area, where gulls are so prevalent, their plumage is very confusing. This book has really helped me sharpen my observation, educated me as to how to use plumage to identify birds.

I'm using those skills on a new site for recording bird observations, eBird, http://ebird.org/content/ebird. It's easy to use and I'm enjoying it.

Inevitably, I'm watching birds as I watch elephant seals at Piedras Blancas. This flock of Heerman's Gulls, up from Mexico for the summer, and Western Gulls was on the beach last week. It's such a great place to birdwatch.
Mr. Howell points out that Heerman's Gulls typically molt only some head and body feathers, sometimes some upper wing coverts. Very southern locations are different, so we wouldn't observe those on the Central Coast. Juveniles have an all-black stage. I'll be on the lookout for that. I rely on obvious markings, such as the Heerman's red beak, to identify them. Mr. Howell's book is giving me more clues to use. The more we know, the better our observations are.
Thanks for helping me with this book, Mr. Howell.