Visiting the seals

My monthly column about the seals appears in The Cambrian in the last issue of the month:
http://www.sanluisobispo.com/news/local/community/cambrian/cambrian-opinion/article196370769.html

You hear them as soon as you get out of the car. It’s pup time at Piedras Blancas. More than 5,000 pups will be born in the rookery, which extends from beyond the light station in the north to about two miles south of the viewpoint.

Most pups are born at night, but you might be fortunate enough to be watching when one is born on the beach.

Each pup is accompanied by a mother, and mature males hover, awaiting the opportunity to mate. It’s one of the busiest months on the beach, and the most active.

Females are still arriving to give birth. Look for seals that are urgently tossing sand on their backs. It doesn’t have much to do with the process, but seals seem to do it when they are stressed.

Gulls scream and flap around new births, so follow them to the newborn. They consume the afterbirth, part of nature’s recycling. The beach would be disgusting without them cleaning it up.

Once born, the pups need to start nursing. The first pup was born on the south end of the beach Dec. 16, so that pup will be the first one weaned. Look for rotund, fat pups. Some will learn to steal milk from other mothers, ballooning up to even more than the usual 300 pounds. Those 500-pounders are superweaners.

Although mothers and pups bond to each other at birth, barking and sniffing at each other, it’s far from a perfect system. Eighty percent of pups nurse on at least one mother other than their own. Not every pup survives, and those bereaved mothers may adopt one or more strays. Some mothers are particular and chase pups other than their own away, but most are tolerant. Elephant seal mothers have never been observed to give birth to more than one pup at a time.

Nursing more than one pup puts the nursing couple in jeopardy. Mothers don’t eat while they are nursing. They produce the milk from their blubber, losing two pounds for every pound the pup gains. Stray pups are nursing from a limited source.

It appears to even out. Around 95 percent of pups at Piedras Blancas survive to be weaned. Younger mothers may gain experience by nursing more than one pup. Pups of experienced mothers are more likely to survive.

As pups are weaned, mothers come into estrus, heat, like dogs. They mate before they return to the ocean, thin and in need of food. They’ll spend three moths feeding before they return to the beach with some of their blubber reserves restored.

Estrus and mating spark battles between males. Most dominance interactions are simple: a challenge and a retreat. But with breeding rights at stake, males are willing to fight. They bump chests and rip at each other’s chest shield, the crinkled skin around the neck, with their teeth. Battles can be bloody. Dominant males take no notice of pups or mothers as they chase each other across the beach. Pups can be separated from their mothers, a serious problem and the single most common cause of pup death. Pups can even be killed as males land on top of them in their determination to be the most dominant, or to mate with the mother.

Watch as two bulls challenge each other, and their conflict ripples through the rest of the seals. With new females arriving, pups born, pups being weaned, mothers mating and departing, the scene is constantly changing.

Molting

Ella continues to molt her blackcoat. And, from this photo, appears to be a male.

He's staying close to the edge of the bluff. That keeps him out of the way of mating, which is now frequent among the adult seals. As the pups wean, their mothers go into estrus and become receptive to mating. Females mate with more  than one male before they return to the ocean.

Females typically protest, whether they are in estrus or not.

Molting

Ella was difficult to find this morning, but I located her rotund form close to the bluff. She's out of the fray of newborns and their mothers here. She's molting the blackcoat she was born with, for her first mature coat.

She'll have countershading, dark on her back and light on her underside. It's an ocean camouflage that will help her blend in with the dark depths when predators above look down at her, or the light sky when those below her look up.

Between a high tide and high surf warning, the beach was inundated this morning. The seals were flustered, trying to get away from the waves, but not very effective in doing anything about it.

More rain is expected tonight. The rain isn't really a problem, but it does pool on the beach under the culvert pipes that drain from the ranch.

Some found dry land and rest, even in difficult times.

Ella is weaned

Diana Kramer, director of The Marine Mammal Center San Luis Obispo facility, which is actually in Morro Bay, Was out at Piedras Blancas and posted this report:

Today we found Ella who weaned this weekend! We were pretty confident it was her (or him) because she was right by post nine as usual and the only big fat weaned pup! 

She looks great, nice and robust and was enjoying resting on the beach. You can really see her size in the pic with the smaller pup in the background!  

Some elephant seal drama in her corner, though, with one big male lumbering through chased by another male. The losing male woke her up from her nap with a big bop to the head as he scooted through, but she made it through ok! 

It looks like Ella is aiming to be a super weaner, because we caught her (or him) checking out some other females to see is if she could get away with stealing some milk!

Rain

A major storm arrived in Piedras Blancas overnight. Rain doesn't faze the seals particularly. Ella is doing well.

The beach is now full of adult seals and pups. Some have commented that they seem late this year. I've looked at photos from previous years and am not sure there is much difference. Perhaps USGS Wildlife Biologist Brian Hatfield will have a report later on the timing of this year's birth season.

Aggression

The most dominant male, the beachmaster, gets breeding priority, but in these early days before the females come into estrus,  less dominant males are causing uproar among the mothers. Some are attempting to breed with the new mothers, even though they have not come into estrus yet. Their pups are small, and easily overlooked as the males attempt to bully a female into mating.

Kathleen Curtis made this video of a male harassing a mother.

Dominance reduces aggression on the beach, by sending aggressive but less dominant males packing. the females come into estrus at the end of lactation, and become willing to breed. None of the females has finished nursing yet, so none are yet in estrus.

Patrick Robinson, director of the Ano Nuevo Island Reserve, said as the females come into estrus, the dominant beachmasters should become more vigilant.

Pups can be killed, in the rough and tumble as the male tries to mate and the female tries to escape. The male may kill the pup by biting its head. The pup may be separated from its mother, which is the most common cause of pup death. Struggling with a bigger male uses the mother's limited store of energy (blubber), which she needs to feed her pup.

It's a tough life down there on the beach. Despite all that, over 90 percent of the pups at Piedras Blancas survive to be weaned.

Bulking up

On New Year's Day, I went to check on Ella. With a dozen or more newborn pups close by, I thought I might have lost track of her. No problem! She is far and away the fattest, most grown pup out there.

She's getting a nice crease at the back of her neck, an indication of good store of blubber.

I can't tell whether Ella is a male or a female. males nurse an average of a day longer than females and gain more weight. Males get teeth sooner than females, too. Ella probably has most of the 30 teeth she will get by the time she is weaned.

Ella has a solid relationship with her mother, but several pups nearby were separated from any nearby females. Maternal-pup separation is the most common cause of pup death, so it's a concern to see these pups alone.

Pups don't always stay with their own mothers. In one study only 22 percent of the pups nursed only on their own mothers. The rest all nursed on another female, at least occasionally. If a pup dies, the bereaved mother may adopt a separated pup, or even try to steal another mother's pup. At Piedras Blancas, over 90 percent of pups born on the beach survive to be weaned.

This youngster was doing well.

New Year's Day brought a rich migration of food fish to the waters. The waves boiled with dolphins skimming and leaping. Flocks of pelicans and gulls circled and dove into the feast. It was the most boisterous feeding event I've ever witnessed. Some landed on the water, and appeared to scoop up prey from there.

The viewpoint has been crowded with visitors during the holiday season. I hope they have come away with a new appreciation of the importance of protecting the oceans.