Portrait of our home

South side, as reflected in a California Scrub Jay’s eye:

There’s intelligence behind that reflection. The smarts and resourcefulness of jays, and corvids in general, are well known. Marla has “trained” a few of these guys to come into the backyard and beg for peanuts. She’ll toss three (in the shell) on the ground and watch one of the birds carefully decide which one to take. It will pick up and drop each one in succession, then maybe retest one or two, and finally make a decision and fly off with the “best” peanut. We think the decision is based largely on weight, but who knows, maybe there are other factors. We find the performance endlessly entertaining. Simple pleasures.

Segregated shrimp, sexual dimorphism, the law of small numbers

On our trip to the Big Island last July, Hai showed us a beautiful Marbled Shrimp tucked into a cauliflower coral on one of the pilings in (where else?) Kawaihae Harbor. It was a female. The shrimp was still there on our recent return to the island, and it had been joined by another one, also female.

On the February trip, Wendy showed us where another Marbled Shrimp had taken up residence along the quay at Mahukona. This one was male. Wendy said she’d seen other Marbled Shrimp at this site, all male.

Marbled Shrimp display considerable sexual dimorphism—biospeak for overt, non-reproductive differences between the sexes. This is a female we saw at Kawaihae. Females have conspicuous tufts (setae in biospeak) on body and legs, and their front pincers (chelae) are shorter than those of males. This little beauty is about an inch and a half long.

Here’s one of the males from Mahukona. Males have absurdly long chelae that they apparently use to fight one another. Though this species belongs to the broken-back cleaner shrimp family (Hippolytidae), they don’t engage in that family’s characteristic fish-cleaning behavior, but are instead opportunistic detritivores. The species is broadly distributed through the Indo-Pacific.

And now for some martini-fueled rambling:

It’s tempting to think that Marbled Shrimp generally tend to live in single-sex domiciles. One could invoke the law of small numbers to verify this if only there were a law of small numbers. There is not; there is only a law of large numbers. This statistical law basically states that if you flip a coin one thousand times you will get very nearly fifty percent heads and fifty percent tails. If not, you can conclude that the coin has been tampered with. But since there is no law of small numbers, five heads up coin tosses in a row mean nothing. And two same-sex Marbled Shrimp homes also mean nothing.

Irrational species that we are, we tend to believe in the law of small numbers. You see it all the time: “Two of my friends got the vaccine and they both got sick.” The result is that many of us embrace untruths, guided more by what we feel than what we know.

The difference between small and large number is not necessarily clear though. There are statistical tools for this, but there’s always a bit of subjectivity involved because you need to decide how sure you want to be. Very sure needs a much larger number of observations than just a little sure.

Anyway, maybe, just maybe, despite its biological unlikeliness, Marbled Shrimp actually do live sexually segregated lives, at least when they’re not reproducing. As lots of research papers (including a couple of mine) conclude: further study is needed.

The fish are still here—pretty much

We’re back in Hawaii for a couple of weeks. I’ve gotten into the water a handful of times, both snorkeling and diving. There are still lots of fish on the Kohala reefs, but they don’t seem quite as abundant or diverse as last time we were here in July. It seems that way every time we come here—fewer and fewer fish. Marla and many of our friends share this perception. But, with the exception of the aftermath of the devastating 2015 coral bleaching event, the decline has been fairly subtle and inconsistent. Maybe populations are indeed declining, or maybe it’s just a tendency to recall the past as better than it actually was. I hope it’s the latter.

There’s still plenty to see and photograph though.

A small Stout Moray at Mahukona. The mottling on the inside of the mouth—unusual in fish, or for that matter in any vertebrate—can help distinguish this species from similar eels. The trouble is not all Stout Morays share this feature. Hoover writes that these are the most abundant shallow water moray in Hawaii, but are not often spotted due to their “retiring nature.”

I was surprised at how common Ornate Butterflyfish were on this trip, especially at depth. This luminous pair was serenely meandering among the coral at about 60 feet. The Ornates feed only on living coral, but are less particular about the type of coral than most butterflyfish. Despite their feeding habits, they apparently do no harm to the reef.

Some birds for the new year

Winter, such as it is here on the mild, frost-free Central Coast, means birds, birds, birds. Migrants of all sorts are down from their breeding grounds up north, and even the year-round resident species seem more abundant than in the warmer months.

There’s also the upcoming weekend’s Morro Bay Winter Bird Festival. Not the kind where people dress up as birds and flap their arms, the other kind. This one involves four days of birding field trips and lectures. It’s a big deal, supposedly the largest such event in the country, with many of the nation’s top bird authorities in attendance. Marla and I plan to spend a lot of time there, including some volunteer organizing.

Anyway, I thought I’d post a few recent bird shots in recognition of the Festival and of the new year. None of these birds are rare, or even uncommon. Just beautiful.

A Song Sparrow proclaims his supremacy from a silver lupine at Montaña de Oro State Park. These guys are ubiquitous throughout much of the U.S. and Canada, but rather oddly we never see them at our backyard feeders. This in contrast to the White-crowned, Yellow-crowned, and White-throated Sparrows that swarm our feeders almost year round.

We ran into a small gang of Blue-gray Gnatcatchers foraging for insects at MDO. They’re more gray than blue to my geriatric eyes. Apparently they tend to be bluer in the eastern part of their range.

This one has spotted a bug (or maybe a spider) hanging near the base of the side branch.

A moment later, the gnatcatcher flies off with the bug in its beak. (Notice that the bug is now missing from the branch.)

A Bewick’s Wren, again at Montaña de Oro. These delightful, feisty little birds are the most common of four wren species found in this area. We see them in our backyard quite often, either dining at our suet feeders or looking for insects in the garden. To me, the eye bar and long, curved bill lends them a certain fierce look, and they are indeed fierce—from an insect’s perspective.

A Common Loon stretches its wings in Morro Bay, near Morro Rock. These big, robust birds breed far to the north, but some individuals apparently forgo breeding and remain in this area year round. Loons are so highly adapted to a watery life that they can barely walk on land—their legs are set too far back. They cannot take off from the land, requiring a substantial stretch of open water to take flight.

Cabo Pulmo fish geekery

Our trip to Cabo Pulmo was the first time we’d dived in the tropical East Pacific. A lot of the fish we saw resembled those we’d seen in Hawaii, Bali, and Samoa, but were just a bit different. Due to the vast, mostly islandless expanse of the tropical Pacific east of the 130th meridian the west coast of the tropical Americas is biogeographically distinct from the Central and West Pacific, so fishwatching in Cabo Pulmo left us feeling like beginners. Fortunately, the Smithsonian Institute offers a free app describing over a thousand East Pacific fish species. It’s aptly named Fishes: East Pacific. I don’t know how we’d have begun to identify the fish we saw without this comprehensive guide.

Delightful little Pixy Hawkfish (also called Coral Hawkfish) were everywhere you looked. Every coral head seemed to house at least one, and often several of these fish. While the majority of reef fish found in the East Pacific do not occur in the Central and West Pacific, the Pixy Hawkfish is an exception—it’s found all the way west to the Red Sea. This fish is very similar to the Dwarf Hawkfish I photographed in Bali in 2018: https://onebreathkohala.wordpress.com/2018/11/25/back-to-bali/

Someone familiar with Hawaiian and West Pacific reef fish might identify this head shot as a Fivestripe Wrasse, but they’d be wrong.

Here’s the whole fish. It’s a Sunset Wrasse, found only in the East Pacific. Its head resembles the Fivestripe Wrasse, while the body looks more like a Saddle Wrasse. Here are photos of the Fivestripe and Saddle I took back in 2015: https://onebreathkohala.wordpress.com/2015/05/14/fivestripe-wrasse/. (Man, my photos were pretty sucky back then.) All three of these species are closely related. The Saddle Wrasse is endemic to Hawaii, while the Fivestripe ranges widely through the Indo-Pacific region.

While the East Pacific has several species of butterflyfish, members of this family are not as abundant at Cabo Pulmo as we’re used to seeing in Hawaii or the Indo-Pacific. This one, the Blacknosed Butteflyfish, also called Barberfish, was the most common. The scientific name for this species is Johnrandallia nigrirostris, honoring the late Jack Randall, a true giant in the field of reef fish studies. Johnrandallia is a monotypic genus—nigrorostris in the only species. It’s another species confined to the East Pacific.

The lower fish in this photo was a special find. It’s a Clarion Angelfish. The primary range of this species is restricted to the tiny, remote Revillagigedo Islands, about 300 miles southwest of Cabo San Lucas. Only a few stragglers ever make it to the Baja Peninsula or Mexican mainland. This one makes a pretty pair with the adult King Angelfish above it. The smaller fish cluttering the photo are Scissortail Chromis.

Why there are marine preserves

I started diving in the Florida Keys in the early eighties. There were a lot of fish there at the time, but not all that many large ones. The old-timers would tell me “you should have been here twenty years ago.” Fishing pressure had reduced numbers and average size. In the nineties I had the chance to dive in Curaçao. I was excited—my first dive in the Caribbean—there had to be lots of great fish, including lots of big ones. Well, not quite what I’d expected. Once again, I was told I should have been there decades ago. Since then we’ve done a lot of diving and snorkeling in Hawaii, Samoa, and Bali. We were always told the same story—it was way better years ago.

The other week Marla and I dove in Cabo Pulmo, about sixty miles northeast of Cabo San Lucas on the Sea of Cortez*. This time it was a different story. It was made clear to us that there were far fewer fish there in the past. The reason: Cabo Pulmo was designated a Mexican National Marine Park in 1995. The region had been seriously overfished in the past, but fishing of any sort has been prohibited since the National Park designation. Fish have responded accordingly, both with respect to abundance and average size. Cabo Pulmo provided some of the best diving we’ve ever had.

Large schools of fish everywhere you looked. Those are Mexican Goatfish on the upper left and Graybar Grunts on the lower right. There are only a few species of goatfish in the eastern Pacific, in contrast to Hawaii and the other side of the Pacific. Grunts are well-represented in the eastern Pacific as well as the Caribbean and tropical Atlantic, but are replaced by their close relatives, the sweetlips, in the western Pacific.

Lots of big fish, too. This largish Leopard Grouper—I estimate it was just short of two feet—swam up and gave me the eye. We saw many other large groupers, some up to four feet in length. I got a few photos but managed to accidentally delete them, along with a pile of other photos.

It’s been well established that allowing fish to grow large benefits fisheries outside the protected area. Large fish produce many more offspring than smaller fish, with the excess moving to adjacent areas where they’re fair game.

A better look at some Graybar Grunts. To me these guys look a lot like emperors or snappers, to which the grunts are related.

Panamic Pigfish, another species of grunt. Superabundant on Cabo Pulmo reefs.

This is a young King Angelfish. There are only four species of angelfish in the eastern Pacific, but they’re all big and showy. More on angels and general fish geekery in the next post.

* Mexico has just moved to change the name from Sea of Cortez to Gulf of California because Cortez was not a nice man.

Big cleft? Little cleft?

Stumbled across some leftover photos from our July Hawaii trip:

They’re beautiful, weird, and ubiquitous on tropical Pacific reefs. We see Longnose Butterflyfish wandering nonchalantly over the reefs on pretty much every one of our snorkel and dive outings. There are two species that go by the name Longnose Butterfly: the common Forcipiger flavissimus and the somewhat uncommon F. longirostris. John Hoover (hawaiisfishes.com) calls flavissimus Common Longnose Butterflyfish and refers to longirostris as Big Longnose Butterflyfish. Other authorities, such as Keoki Stender (marinelifephotography.com), refer to the respective species as Forcepsfish and Longnose Butterflyfish. Flavissimus is also sometimes called Yellow Longnose Butterflyfish and longirostris is sometimes called Big Forcepsfish. Confusing to you? Me too. Do you care? Well, I do.

Besides being inconsistently named, the two species can be difficult to tell apart. Longirostris tends to be a bit bigger, with a longer snout, but there’s some overlap in size. Two features are generally used to distinguish the species in the field. The first is coloration: I usually look for tiny black dots on the fish’s chest—longirostris has them, flavissimus doesn’t. Trouble is, you have to be close and have good eyesight (and a non-fogged mask) to see this. The second is mouth shape: Flavissimus is supposed to have a deeper oral cleft than longirostris, but I can’t tell the difference, at least not on a living, moving fish. Photos make it a little easier. Like these:

This is F. flavissimus. No chest spots and a slightly deeper oral cleft.

F. longirostris. Tiny black spots on the chest, and the oral cleft is a bit shorter than in the previous photo.

These two very similar species share the same habitat throughout much of the Indopacific, but they don’t directly compete. Flavissimus is a dietary generalist, eating all sorts of small invertebrates, and, rather oddly, often plucking off the tube feet of echinoderms such as urchins and sea stars. (The echinoderms have plenty of feet to spare, but it still sounds painful.) Longirostris on the other hand specializes in picking tiny shrimp from deep inside coral heads.

Anyway, there’s your fish minutiae for the day.

The season has begun

Fall is here and the migrating warblers have arrived in our backyard. More accomplished birders have been reporting their arrival for a few weeks, but we dilettantes have only begun seeing them this week. Several warbler species migrate here each fall from their breeding grounds in the northern coniferous forests. Many stay through the winter, while others continue south into Mexico and beyond. The three species shown below are frequent visitors to our backyard.

A male Townsend’s Warbler searches the underside of a limb for insects. These gorgeous birds spend a lot of time at our suet feeders. They’re surprisingly tame.

The Yellow-rumped Warbler (I think this is a female) is the most common warbler throughout much of the US. In addition to our backyard, we often see them on our beach walks feasting on kelp flies.

An Orange-crowned Warbler at one of the several suet feeders Marla keeps in our yard. These plain little birds (the orange crown is inconspicuous, and often absent altogether) are considerably less common here than the Townsend’s or Yellow-rumped, so we’re always pleased when one makes an appearance.

Here’s the Townsend’s right side up.

Small, fierce, and splendid

When I was a kid I owned several volumes of the Peterson’s Field Guide series—birds, reptiles and amphibians, butterflies, insects, and mammals—to identify any new species of animal I’d come across. Back then they were the gold standard for identifying animals in the field. I used them all, but I used the mammal book least. That’s because I’d only ever see a handful of mammalian species: the usual suspects—Whitetail Deer, Raccoons, Cottontail Rabbits, Gray Squirrels, Eastern Chipmunks, Striped Skunks, Opossums. Sometimes a Woodchuck, and on rare occasions maybe a Red Fox. No need for a book to ID any of those. The part of New Jersey where I grew up also had a large number of small, not so easy to identify mammals—rodents, shrews, moles, weasels—that, despite spending a lot of time in the woods, meadows, and wetlands, I never encountered. That’s the trouble with mammals: most of the smaller ones are secretive and/or nocturnal, while the big ones are wary and, in New Jersey, absent. Nonetheless, I’d sometimes pore over the mammals field guide and dream of one day seeing a shrew, or maybe even a weasel.

Up until the other day I’d never seen a weasel in the wild, nor did I expect I ever would. But on a recent afternoon Marla and I were taking one of our usual walks on Bluffs Trail in Montaná de Oro State Park when we heard a conspicuous rustling in the grass about thirty feet off the trail. We looked over and there was a weasel looking back at us. The gorgeous little animal spent about a minute regarding us with great curiosity before retreating into its burrow.

When we got home I went straight to the web to figure out what kind of weasel we’d seen (it’s the 21st century after all), and learned that it was a Long-tailed Weasel. (There are four species of weasel in the US—Long-tailed, Short-tailed, Least, and Blackfooted Ferret—but it turns out only the Long-tailed is found in this part of California.) Then I pulled my sixty year old copy of Peterson’s from the shelf. All of the series have checklists in the back where the reader can check off the species that they’ve observed. With satisfaction I checked Long-tailed Weasel, the first new mammal species I’d seen in years. The afterglow lasted for days.

What a splendid animal—look at those curious, intelligent eyes! Weasels are known for their fierceness and tenacity. Annie Dillard, in an essay admiring the weasel’s single-mindedness, recounts the story of a biologist who had to submerge a weasel in water to get it to release its bite on his hand. They regularly attack and kill prey substantially larger than themselves. They’ve even been know to take down full grown moose. (Okay, I made that up, but there are—perhaps apocryphal—accounts of the weasel’s larger cousin, the Wolverine, doing this.)

How cute can you get? Based on size and facial markings, this is a male.

As I’ve noted in previous posts, taxonomists have a way of confounding us old guys. I’ve always known the Long-tailed Weasel as Mustela frenata. But that’s apparently not good enough for those taxonomist busybodies. Now it’s Neogale frenata, which in this curmudgeon’s opinion doesn’t have as nice a ring. Oh well, gotta change with the times I guess..

More nudibranch procreation and another record

We saw a couple of noteworthy nudibranch (or if you prefer, sea slug) events on our recent trip. Kawaihae Harbor of course.

A couple of Goniobranchus alboputulosus mating on a piling in the harbor. Like most nudibranchs, the species is hermaphroditic. Also like a lot of nudibranchs, there’s no broadly accepted common name for this species; Hoover calls it “Purple-edged Nudibranch” in the 1998 edition of Hawaii’s Sea Creatures, but changes that to the to me less useful “White-bump Nudibranch” in the 2006 edition. Neither of these helps to distinguish it from the similar Trembling Nudibranch, but that’s the way common names go. This species, while not endemic to Hawaii, has a fairly limited distribution, occurring only in Hawaiian archipelago and the remote Marshall Islands.

This is another species with no agreed-upon common name. Two,” Mourning Nudibranch” and “Funeral Nudibranch,” seem appropriate. More boring is “Polka-dot Nudibranch.” The Latin name is Jorunna funebris—I’m guessing the second term refers to funerals. Anyway, this specimen is in the process of laying eggs, that stippled ribbon to the slug’s left. A lot of nudibranchs deposit their eggs in these looped ribbons. Why loops? As Geoffrey Rush would say, “it’s a mystery.” I was with Hai and Wendy when we found these nudis—there were several of them scattered on the pilings. Hai being Hai noticed that some were kind of big, so he took a photo one with a dive knife next to it to serve as a measurement reference. Sure enough, the animal measured about 70mm compared to the 50mm maximum length posted on the authoritative seaslugsofhawaii.com. Cory Pittman, primary curator of the site, and invaluable resource for us amateurs, has since updated the site with the new maximum. Another obscure record! This species is broadly distributed in the tropical Pacific. It’s unclear if it’s native to Hawaii or introduced.

I’m far from alone in my fascination with nudibranchs—the web is full of nudi fanciers. A lot of it is the phantasmagoria of colors and color schemes, but to me it’s also the hostile, alien environment these little slugs inhabit. They go about their colorful, sluggish business in a world full of stinging hydroids and poisonous sponges (both of which the nudibranchs eat), noxious bristle-worms, and sundry other unlikely creatures. Someone please pass the mushrooms…wait, no need.