Nature Notebook, January 11, 2018

01/11/2018

Morning tides remain in the six-foot range as the new moon approaches on Tuesday, Jan. 16. There will be a window of daylight minus tides in the late afternoons, occurring just before sunset and darkness, from Jan. 12 through Jan. 18. Some good days for tidepooling will be afternoons across the Martin Luther King, Jr. holiday weekend. As always, do not turn your back on the water!

All the adventure and excitement is out at the Headlands as Northern elephant seal breeding season moves into full gear and the colonies grow. Over 200 females, called cows, have arrived on park beaches and the first pup birth of the season was noted on Dec. 26. If you have binoculars, look for the senior dominant male (or alpha) that has been dye marked D-1. He may appear to be napping, but if challenged with plenty of noise from a rival male, you may see him leap up and sprint toward the threatening sounds. Sometimes the sound of the alpha male, made through his floppy nose or proboscis, is enough to send the rival packing. Alternatively, they may move toward each other with a full-on wrestling match. The heavy callus of skin on their chest, called a chest shield, protects against bites reaching vital organs. The smaller females try to stay out of the way, but add to the chorus of sounds in the colony. If separated from their pup, they emit a unique song in order to reunite with the pup. Park researchers report 670 seals as of Jan. 5.