Pelican Beaks

Q: Do you remember this old limerick?
A wonderful bird is the pelican,
His mouth can hold more than his belly can,
He can hold in his beak,
Enough food for a week!
I’m damned if I know how the hell he can!
—Dixon Lanier Merritt

So is it really true?

A: The pelican’s pouch, more properly referred to as the gular sac, has several different functions. The first and most obvious is to procure food. The brown pelican we see along our coast hunts by plunging into a school of fish from a few dozen feet in the air; the greatly distensible sac opens upon impact and two and a half gallons of water (and any fish nearby) are immediately sucked in. The bird closes its beak, hanging its head down and letting the water drain out the sides, and then flips the beak up and swallows the fish. Apparently the bird’s beak can hold three times as much as its stomach, but I doubt if one gulp will last it for a week. Nesting pelicans also carry partially digested fish in their pouch to feed their young. Finally pelicans, like all birds, cannot sweat but dissipate heat by rapidly vibrating their throat sacs. This is called gular fluttering.

There are eight species of pelicans, with some on every continent but Antarctica, but only two feed by plunge diving—the brown and the Peruvian pelican (formerly considered a subspecies of the brown pelican but now given full species status). These two are also strictly saltwater species. The other species of pelican we regularly see in the Bay Area is the American white pelican. But unlike the brown, white pelicans fish by floating along the surface, often in formation, and scooping small fish out of the water with their beaks and into their large gular sacs. These birds nest in northeastern California and at Pyramid Lake in Nevada and are here during the non-breeding time of year from August to March. Their claim to fame is their 9-1/2 foot wingspan, and they are often seen soaring high in formation with striking black and white wings.

The brown pelican used to commonly nest in the California but due to eggshell thinning (from DDT) and the collapse of sardine populations, they now mostly breed in Baja California, though small breeding colonies have recently appeared on Anacapa and Santa Barbara islands. The federal government recently announced that the brown pelican is no longer considered endangered—good news indeed and proof that the Endangered Species Act works, so it looks like we’ll get to watch those gular sacs gulping and fluttering for a long time to come.

Quicksand

Q–What is quicksand? Is there any in the Bay Area? Is it true that an earthquake can turn some land into quicksand? Has anyone ever been sucked into such soil? [Chantal, San Francisco]

I have had two personal encounters with quicksand and neither happened in the Bay Area. The first was along the Amargosa River near Death Valley and later on the bank of the Colorado River in the Grand Canyon. Fortunately like everyone else who steps in quicksand, I survived! Classic Western movies, of course, have portrayed an entirely different outcome. Usually bad guys are sucked down into the muck with only their black hat remaining on the surface as witness to their justifiable and righteous death.

“Quick” in this sense does not mean fast but means alive which is the original definition of the word. The use is similar to the word –quicksilver- for the metal mercury’s liveliness in the liquid state. Basically quicksand is made up of small particles (technically not sand but finer grains referred to as silt by geologists) that are saturated with water. The friction between the silt particles is so reduced that the entire mass is a semi-liquid that cannot support any weight. Most quicksand is only a few feet deep but if you happen to find yourself floundering in it, don’t panic (yeah, right). Your body is less dense than the quicksand and you can swim to the nearby bank. All of your movements should be slow and deliberate like you are swimming in a big vat of molasses.

However there is a closely related phenomenon, which is present in the San Francisco Bay area – liquefaction. You can demonstrate this on any beach. Find some wet but firm sand and jump up and down on it. Soon the entire mass will become more and more liquid and unstable as your feet sink down into it. You have just demonstrated what can happen in certain areas during an earthquake. Much of our infrastructure in the Bay area is built on fill or young sediment, which is very near the water table. During an earthquake the ground shakes and the underlying sediment can quickly become saturated with water. It becomes unstable and unable to support the overlying structures. Buildings, roads and bridges collapse just like we saw during the Loma Prieta earthquake in the Marina District. And this my friends, is not a movie.

Michael Ellis – Ask the Naturalist- Bay Nature Magazine

Longest Bird Migrators

Q: Which bird that migrates to or through the Bay Area travels the farthest to get here from its breeding grounds? Where does it come from and where does it go? [Jason, Oakland]

A: In October 1977, during my first pelagic birding trip in the middle of foggy Monterey Bay, I was carefully studying the drawing of a bird I had just seen (a south polar skua) when Rich Stallcup, the boat naturalist (now with PRBO Conservation Science), suddenly shouted something I couldn’t make out. “Did he say ‘comic’ tern?” I asked the elderly woman next to me. “Yep” she replied. Even Rich, one of California’s premier birders, could not distinguish at that foggy distance between the common and the arctic tern. They look a lot alike, especially in autumn plumage and from the deck of a rolling ship. So we had to make do with the combo “comic” tern. Not something to add to your life list, but I think of it as my first possible sighting of a champion migrator.

Terns are closely related to gulls. I like to think of gulls as basic Ford pick-up trucks—durable, tough, long lasting, but not too fancy. Terns are more delicate, can turn on a dime, and hover nicely in place, a bit more like Porsches. Like all terns, arctics mate for life and usually migrate together.

In the Bay Area, arctic terns are usually only seen far offshore and during the autumn. They fly south from nesting grounds well north of the Arctic Circle all the way to southern Chile, traveling as far as 15,000 miles. In its average 25-year life span, an individual arctic tern may fly over a half a million miles! (The Earth is only 25,000 miles around.) Arctic terns spend more time in daylight than any other species on earth and for many years were considered the premier migrators on the planet.

But in 2005 that changed. Research biologist Scott Shaffer and his colleagues at UC Santa Cruz outfitted some sooty shearwaters with radio tags and tracked them for over 200 days. The sootys (relatives of albatrosses) leave their New Zealand breeding colonies and travel all the way north to California to spend the austral winter in our summer. Here they feed just offshore on krill and squid in our nutrient-rich waters. They molt their flight feathers in the process (an energy-intensive event). In the fall they funnel back south to New Zealand, covering a total of more than 40,000 miles!

Arctic terns are too small to be electronically tagged, so we can only estimate the distance they migrate. Sooty shearwaters go the farthest but arctic terns still win the sunbathing contest. Your best chance of seeing either in California is on a pelagic bird or whale-watching trip, though sootys sometimes congregate in huge flocks resting on the water close to the coast.

Michael Ellis – Ask the Naturalist- Bay Nature Magazine

Slime Molds on the Move

Q: I’ve heard slime molds are neither plant nor animal, and that despite being single-celled they can move and even navigate a maze! How can this be? Are there slime molds in the Bay Area? [Michele, a frequent visitor from Toronto]

A: Strolling through a local redwood forest years ago, I came across a huge, bright yellow mass of a slime mold. I vaguely recalled reading that you could grow slime molds on a medium of oatmeal. I brought a bit of the yellow goo home and tried it. My experiment failed miserably; the slime mold shriveled and died horribly. My calling as a pet owner was finished.

Slime molds are weird, but not uncommon. There are two types in the Bay Area. The plasmodial slime molds are nothing more than gigantic single-celled life forms with thousands of nuclei. They develop when tens of thousands of single cells, all with a whip-like appendage called a flagellum, throng together and fuse into one giant cell with a single membrane. Worldwide there are about 500 species; they are often orange or yellow and are probably the easiest single-celled organisms to see with the unaided eye. They can be several inches across and cruise around on the forest floor like giant amoebas engulfing microorganisms such as bacteria and yeast. They also devour decaying vegetation, but apparently not oatmeal!

There are only about 65 species of the cellular slime molds. They are also single cells, but microscopic—they do not form huge plasmodia. They too feed amoeba-like, engulfing mostly living bacteria found in the leaf litter. When they exhaust the local food supply a remarkable event occurs: A chemical signal released by several of the cellular slime molds causes all the surrounding ones to stream together to form a larger colonial organism. Slug-like in appearance, this new mass moves toward sunlight; then fruiting bodies pop up and bear spores. These mature and are released, enabling the slime molds to drift to a new promised land, hopefully full of more edible bacteria. Yummy…

Slime molds’ spore-based reproduction strategy first led biologists to lump them with fungi, along with familiar household molds. But things are not so simple: Slime molds behave like animals when they are feeding and growing, and then more like plants or fungi when in the immobile, reproductive phase. So now they are classified in the kingdom Protista. This diverse group includes many “leftover” organisms that just do not fit into other kingdoms. They are mostly single-celled, like amoebas and dinoflagellates, but also include the multicellular seaweeds.

So on your next winter walk in any deep, damp forest, watch for bright yellow or orange blobs. Just don’t try to feed them oatmeal.

Michael Ellis – Ask the Naturalist- Bay Nature Magazine

The Paranoid Jay

Q: A blue jay has been flying against the windows of our house and poking at them. I thought it might be territorial, but I put out rice that the jay ate peacefully with another jay! Why is the jay doing this? What can I do to deter it? [Venkat, Union City]

A: I get a variation on this question every year. First, the jay that you are referring to, while its dominant color may be blue, is not a “blue jay.” Blue jays are common to the eastern United States but do not normally cross the Rockies, though they are expanding their range into Washington and Idaho. In the Bay Area, we have two widespread species of jays. Look for scrub jays (mostly blue and gray) in suburban yards, chaparral, and scrubland. Steller’s jays (bluer with a large crest) live in forests and wooded yards.

The behavior you witnessed is clearly related to breeding. These jays are defending their territory. The jay sees an image of itself in your window and assumes that it is a stranger invading his turf. In defense, he attacks. It is usually the male doing this, though in a monogamous pair of birds, the female can also get aggressive. The communal feeding behavior you saw was likely the happy couple sharing resources and reinforcing their pair bond. Mating could follow. The same thing happens in humans. A nice dinner out followed by . . . .

The only way to prevent the bird’s attacks is to do away with the reflections. That’s more easily said than done. Putting a paper covering or perhaps a silhouette of a falcon or accipiter hawk on the window may work. Eventually the testosterone will wear off and the bird will cease that behavior at the end of the breeding season. And hopefully both the bird and your window will still be intact.

Michael Ellis – Ask the Naturalist Column- Bay Nature Magazine