Tuesday, May 22, 2007

Humpback Whales, Delta and Dawn in Sacramento

I’ve been wondering if Delta and Dawn are related to Humphrey?

If you haven’t been catching the news this past week, you may not have any idea what the heck I’m writing about. Delta and Dawn are names given to two wayward humpback whales, a mother and her calf, who have wandered inland more than ninety miles to the port of Sacramento, CA. Humphrey is the 40 foot, 40 ton, humpback whale who made nearly the same excursion in 1985. He went as far as Rio Vista, twenty miles or so south of the port of Sacramento. He wondered around the deep channel for nearly a month before swimming back to the Golden Gate area and out to sea. Then in 1990 he was spotted again inland at the Bodega Bay area. His adventure nearly ended when he beached himself in the mud in San Francisco. He was last seen in 1991. There is a plaque at Rio Vista honoring Humphrey’s Sacramento River journey. Many of the people out observing Delta and Dawn are children and grandchildren of those who saw Humphrey on his travels.

Delta and Dawn, names picked by choice of local television viewers, were spotted in the Sacramento River up stream of Rio Vista, May 14. Take a look at a map and see how amazing their journey has been from the Pacific Ocean to Sacramento. The deep channel is not very wide at all. When they arrived at the port area the other day, they swam in circles, unable to go further north because of locks. On Friday, the coast guard and marine mammal people used whale sounds in the hopes of tempting them to start a swim south but that did not work. They decided to leave them alone for the weekend and then on Sunday they started to move south and went as far as the Rio Vista bridge, but then turned around and headed north again. The Coast Guard, Fish and Game, and County Sheriff’s put a floatilla of about 25 boats in action today to discourage their movement north but by late Monday afternoon they were about five miles north of the Rio Vista bridge heading toward the port again. The experts believe the bridge may have stressed them, with the vibrations of traffic crossing, etc., causing them to reverse their course again.

Monday they had hoped to insert a tag tracking device in Delta but put that off until Tuesday. They did take a tissue sample for genetic study from her to check her health and identify what pod they may be from. They also began banging on pipes underwater from the boats to encourage their movement away, and plan to use that device again Tuesday morning.

Another question I have is what would make whales leave their migration route and stray so far from the ocean? I don’t think the scientist can answer that unless a reason is that the mammal is ill. So that leaves another possibility: maybe some time back, Humphrey mentioned his adventures and this mother had nothing else to do but do some inland exploration. Let’s hope she hasn’t got herself and her young calf into a situation she cannot get out of.

Oh, one more question comes to mind. How do the experts know that Delta and Dawn are female. They said that from the beginning of the sighting. I assume the calf swims with the mother but they have stated the calf is female. Does it have to do with coloration? Or?
For some great video of the adventures of Delta and Dawn check out the Sacramento Television station web site. They’ve had great coverage.

The natural migration of birds, butterflies, and mammals has always fascinated me. The swallows returning every March 19, St. Joseph’s Day, to San Juan Capistrano Mission; the Monarch butterflies to Pacific Grove in Northern CA; the whales; the birds. And I believe they communicate with each other. You know how it is: put out bird seed when not a single bird is in sight, and soon you have one bird, and within minutes a whole flock arrives to scatter seed!

~ Linda

1 comment:

Tamara said...

hi everyone!!!!!!!!!!!!!!!