Our three newest black oystercatcher chicks are doing quite well. They’ve left the nest and are now in the rocky area just beside the jetty. There are several other families on this side of the island, notably one beside the winch house and one in the east bay. There’s also a family or two over in the west surge channel. Most gulls have now settled down into their nests with mating coming to a close. Pam reports a nest up near the fresh water pool is about to hatch; be sure to keep your eye on that one over the next few days! I’ve noticed on several occasions some broken eggs scattered on the grass around the island. Probable cause: the otter. I saw it scampering across the winch pad the other evening, much to the gulls’ discontentment. There’s also a dead gull up beside the base of the tower; it’s been there for a few days now considering the state of decomposition. I expect that it was killed in a territorial fight. Gulls are very territorial birds and will aggressively defend an area of about one metre in radius (with exceptions) around their nest. Any other gull who infringes upon this territory will be the subject of an intense attack (http://www.flickr.com/photos/adamharding/3858558278/in/set-72157622022028013/) by the owners of that piece of waterfront real estate. Territorial defence is actually one of the reasons why it is important to keep human traffic down in the reserve during gull season: once chicks hatch, any disturbances that cause them to stray from their native territory into another family’s territory will result in retaliation by the adults of that foreign territory. Chicks are usually helpless to the attacks and will be ruthlessly killed.
We have three elephant seals hauled up on Great Race: Misery is up near the engine room, Bertha is behind the tank room and #4252 is on the concrete area at the top of the jetty. 4252 seems to be a bit unwell these days; I’ve recently observed her breathing heavily and coughing, and her spittle is often flecked with blood. Garry suggests that she could be going through her moult; however, females typically moult in April and May, sub-adult males moult in May and June and adult males moult in July and August. Considering that Misery has now completed his moult and is a breeding male, I’d expect that 4252, a young female, certainly would have by now. I’ll be keeping my eye on her over the next bit. There is still an elephant seal out on Middle Rock. Bertha is now most likely approaching the beginning of her seven month gestation period. Female elephant seals come into heat 24 days after giving birth. However, after mating, the fertilized egg does not implant in the wall of the uterus for up to four months, a rare phenomenon called “delayed implantation”. The currently favoured theory is that the female is to weak after giving birth and nursing that she doesn’t have enough energy to nurture the egg. However, once implantation does occur, the actual gestation period is seven months. This gives a total of eleven months and explains the yearly cycle we see. So, if Bertha gave birth and mated in late February, her egg is most likely reaching the implantation stage right now, late June. I expect that in a few weeks gestation will be well underway. I saw a hummingbird pass by my window this morning. I’m not sure how common they are around here. Unfortunately I couldn’t get a picture as it only briefly flew by.
Sea lions are at a seasonal low right now as the California variety move south to breed for the summer while most of the northern variety move northwards for the summer.