Friday, June 17, 2016

Eggs

The birds at Haystack Rock are busy nesting. Have you ever wondered what the eggs look like that they're laying?

Common Murre 

The common murre lays one egg at a time. They lay their egg on a bare rock ledge on a cliff face. The egg is blue-green in color and is speckled. The incubation period for the common murre egg is 32 days. Once hatched, the young fledge on Haystack Rock for 20-25 days. When it comes time to leave the nest, they fall to the ocean at dusk or at night while following their father. 
Common murre egg




Notice the shape of the egg. What would happen if you tried to roll the egg? What path would the egg take?  How could this help in the success rate of the nesting pair in producing a chick?

Common murre egg that rolled off the rock



Black Oystercatcher

The pair of black oystercatchers nesting in the saddle at Haystack Rock were sitting on two eggs that were layed in late May. Unfortunately, those eggs were lost. There's still time for them to try again this summer. The clutch is usually 1-3 eggs, and the incubation period is 26-28 days. The eggs are tan in color and speckled. The chick is able to leave the nest after one day but will stay in the territory after fledging for 40 days. Like the murres, the oystercatchers lay their eggs on the rocks. The nest is a shallow bowl in the rocks into which they toss small pebbles and shell fragments with their beaks. 
Black oystercatcher egg

How does the shape of this egg differ from the egg of the common murre? 

Empty black oystercatcher nest

Saturday, June 11, 2016

Some interesting finds

While opalescent and shaggy mouse nudibranchs are fairly common at Haystack Rock, every once in awhile the staff and volunteers find some more obscure ones. One example, which was seen last week, is the alabaster nudibranch. As reported by Steve Grace, a volunteer, "This morning, after several months of searching, I finally spotted the alabaster nudibranch (Dirona albolineata). Its white lines glowed against a dark kelp background, its oral veil undulated in the current, and its translucent body seemed to be lit from within."
alabaster nudibranch
(photo courtesy of Steve Grace)

Steve also found a Christmas anemone (aka mottled anemone or painted anemone) Urticina crassicornis. While they've been seen at Ecola Point, this was the first one seen at Haystack Rock.

Christmas anemone
(photo courtesy of Steve Grace)

The intertidal area at Haystack Rock is ever changing. Sand comes in, sand goes out. Sometimes we have to look really closely to find some interesting things. How many different types of things can you find in this photo?

An area along the north wall
(photo courtesy of Gretchen Stahmer)