Pacific Chorus Frogs

A couple of nights ago, I was out watering the garden at dusk. It’s been quite hot here, and I’m finding that I need to water all my containers twice a day when it’s this warm. So there I was, making the rounds, when a little dark shadow popped up behind the seasoning celery/lobelia pot. At first I thought it was another black widow - the light was nearly gone and it was hard to see. I went inside to get my phone so I could take a look. Not a spider - a Pacific Chorus Frog!

Well, I was simply delighted, having never seen a frog in our garden before. We do not have a pond, only a water feature (a bubbling fountain with a large reserve of water underneath it). We do not have any excessively wet places, that I know of. We have found newts in the fountain area, and also under things like rain barrels, but that’s been infrequent. I don’t think of my garden as a good habitat for things that like cool wet places. So this was totally unexpected!

Pacific Chorus Frogs (also known as Pacific Tree Frogs) are found up and down the west coast, from British Columbia to Baja California, as far east as Montana; and from sea level to 10,000 feet, in anything from desert to redwood forests!

In this geographic range, there are two things that distinguish these frogs from other species: The presence of toe pads, and a dark stripe that extends from the nostril, through the eye, and past the ear. No other frogs found within the geographic range of the Pacific Chorus Frog have both of these characteristics. They are quite small, between 1-2 inches, though the females are larger than the males. Females have a smooth white throat while males have a wrinkly dark throat.

It’s hard to tell from my pictures, but I think this one is female. I’ve never heard any of the breeding calls this close to my house, and it’s also not breeding season, which is usually in spring through early summer. We do hear the males down near our creek, about 100 yards away from our house, at that time. They make quite a racket, but it’s a welcome racket!

Here’s the thing that’s really twisting my noodle: How did this frog end up in our garden? A neighbor a few doors down has a pond, but it seems like a long journey for such a little guy. Our water fountain’s water reserve is under 1/4” hardware mesh, so as far as we know, inaccessible. I suppose it’s possible that there’s a hole or something. I don’t know, it’s just a mystery! But I’m thrilled. This means our ecosystem here is healthy - it’s a good place to catch a meal. Lately I’ve been feeling very bummed out about the garden, because I have such little time to spend in it, but having a bit of a mess seems to be a good thing for biodiversity, which is cheering.

Reference: Michael F. Benard, Natural History of the Pacific Chorus Frog, Pseudocris regilla

Evaporative Cooling

I don’t think there is anyone who hasn’t experienced an extreme heatwave this past month. Rin, who is spending the summer in Savannah, experienced their first East Coast heatwave (with accompanying high humidity) a couple of weeks ago. Here in the West, we too have had our share of extreme heat, though not the humid kind. Our backyard weather station hit 116 degrees several times this week, and I instantly start sweating the moment I walk outside.

I have discovered recently that I am a ‘sweater.’ I don’t mean that I’m always sweating; but yes, when the circumstances are right, I will sweat more than the average person. I learned this because Tom and I have joined a local gym. The reason for joining began with injury recovery, but quickly morphed into something else - another tool to build our resilience. We are planning a month-long walking trip next summer for our 25th anniversary, so we are both working hard to build muscle, improve balance, regain agility, and increase flexibility. We’ve added all kinds of different exercises to our daily routine; simply hiking up a hill is not going to prepare us for hiking 16 miles a day for weeks on end.

So now we are in training. And man, when I train, I sweat. I mean not just in the usual places. When I’m done with, say, a spin class, my calves are slicked with sweat. And after a TRX class, my forearms are dripping. I suppose it could be embarrassing, but I don’t look at it that way - I consider it a sign of a healthy vascular system that is performing one of the jobs it has uniquely evolved to do.

Sweat is a beautiful human adaptation. Chimpanzees and macaques have sweat glands, but humans have 10 times the amount that they do and are the sweatiest among the great apes. Scientists have discovered that “the higher density of sweat glands in humans is due, to a great extent, to accumulated changes in a regulatory region of DNA that drives the expression of a sweat-gland-building gene.” This happened through repeated mutations and contributed to an evolution of higher sweat gland density in humans. We are meant to sweat! It’s our primary way of cooling ourselves. As the water in sweat evaporates, the surface of our skin cools. This is true of any evaporative cooling. A liquid will remove latent heat from a surface, and that evaporating liquid will cool the air around it.

Since most animals do not sweat, they have to cool themselves in other ways, and sometimes they too use evaporative cooling. During this heat wave, we’ve been closely watching the behavior of our backyard bees on our water fountain.

Bees use water to cool their hive. Some worker bees are tasked with finding, collecting, and bringing water back; it is spread in a thin surface over the surface of the comb and the bees then fan their wings to evaporate it. A hive may use a quart of water a day in the hot months for this purpose.

Honeybees are not the only ones who do this. Some wasp colonies (many wasps are social insects and, like honeybees, live in large groups) use water the same way. They collect it and spread it on the surface of their nests. Today, while filling the one of the water bowls at the school garden, I watched both paper wasps and yellow jackets collecting water from the edges.

This is one of the most important ways we can help insects; we can place shallow bowls of water around our gardens and yards. Put a rock in the bowl, or several rocks, so that the insects don’t drown (they have poor depth perception). If mosquitos are a worry, change the water daily or weekly (it’s good to do this anyway to keep the water clean). Birds will love this, too.

Many insects will also get water from the soil in your garden, so it’s nice to have a bare space which you keep wet for this purpose. Butterflies especially adore a muddy spot.

Another creature in our garden that appreciates evaporative cooling is the chickens. Chickens, like dogs, pant when it’s hot, and this past week they’ve been panting from dawn until full dark. I actually spray them with water, and though they seem to dislike me doing that, they really love when the ground in their run is wet. So when the temperature is over 100, I go out several times a day and spray them, and the dirt in the run, thoroughly. Immediately afterward, the chickens will congregate in the wet place, and they really perk up.

Chickens also dig holes in the dirt to find the cooler place under the surface. Many creatures do this, too. While dogs and coyotes pant, owls use something called ‘gular fluttering’ which is flapping the loose skin under the throat to move air over the throat cavity. Vultures urinate on their legs to keep cool, another form of evaporative cooling!

That last fact makes me appreciate anew the way we humans use sweat to keep ourselves from overheating.

Stay cool, everybody.

Special Visitors

Many years ago, I planted a line of three dogwoods (not our native species; rather, Cornus sanguinea) just outside our front porch. This is the part of the garden I call our ‘woodland’ garden, because it gets dappled shade all day from our mature trees. I have a lot of natives here (various Ribes, spice bush, coffee berries, etc, as well as some true geraniums, things that can handle dry shade). I wanted the dogwoods because of their bright red stems, but I haven’t been pruning them correctly I guess, because they have yet to show the flame color their name suggests.

Anyway, I can see them from our living room. Tom and I were sitting on the couch chatting yesterday and I was looking out at them and admiring the sun shining through their leaves when I realized - hang on a second, what am I seeing? - those leaves aren’t supposed to look lacy. But they do now, and for a very good reason - one that makes me super happy. They are being used to build the nests of leaf-cutter bees.

image credit: Planet Bee Foundation

Leafcutting bees (Megachilidae family) are solitary native North American bees who use soft leaves and flower petals to create nests for their young. The female bee finds a long channel or tube, for instance in wood or in a hollow stem, and painstakingly creates chambers for her larvae, depositing some bee bread (a little mound of pollen) and an egg in each one. Each chamber is separated by a wall made up of chewed leaves and mixed with resin or mud. The bees spend the winter as mature larvae in the chambers; in spring, they pupate, then chew their way out of the nest and go off to mate. The adults are active only in spring and early summer; most of their lives are spent in the cells as larvae.

We have at least 75 species of leafcutter bee in California. They are generally smaller than honeybees, tend to be more of a grayish color, and carry pollen on their bellies rather than on their legs like honeybees. They are wonderful pollinators, and in fact there is an introduced species that is a major pollinator of alfalfa and is economically important. The family Megachilidae also includes Mason bees and Wool Carder bees.

The ‘damage’ to the margins of the leaves is quite slight and doesn’t hurt the plant at all. The bees are extremely gentle and in fact, in all my years of taking pictures of bees in my garden, I’m not sure I’ve ever gotten a photo of one. I’m delighted to find this evidence of their existence in my little ecosystem and I hope I get the privilege of finally meeting one.

California Kingsnake

Today, Tom and I were out in the garden looking at some flowers and cutting herbs for drying, when all of a sudden Tom hollered “Holy Cow! A big snake!”

It was a California Kingsnake (pictured above in its full glory; below is the smidgen of it I actually saw), a fabulous creature to have in the garden. It’s non-venomous and eats rodents (YES), lizards, and even rattlesnakes!

Ok, so we never saw its face

Our snake is between 1-2 feet (these snakes never get super large: according to CA Herps, they are most commonly 2.5-3.5 feet) and seems happy in a protected spot underneath a hedge of flowering woody perennials. Hopefully it’ll find a mate and lay some eggs around here. Kingsnake babies! Squee!

As you know, I’ve been trying to attract snakes to the garden for years. It’s quite possible that we have them and never see them. The only other snake we’ve ever seen here is pictured below - a sharp-tailed snake, about the size of my palm, which eats snails and slugs. Also fabulous, but maybe not quite as arresting as a California kingsnake!

Wasps: One Sign of a Healthy Ecosystem

When I started teaching at Merritt College, I was “given” the Environmental Center property as a place to hold my labs - basically, as a place to grow a garden. In years past, it had been used for that purpose (though, I would argue, not to its full potential), and even held a few remnants of the old raised beds. But it had long been abandoned and unused; my co-workers had several truckloads of junk and trash hauled away, which revealed a rather shabby and sad space. The ground was either rocky, or covered in weeds. The outbuildings were mostly being taken over by nature, with mushrooms growing out of roof tiles and critters nesting in walls. Invasive Himalayan blackberry vines covered every corner. The first lab I held there, I had the students spend an hour just being in the space, mapping it out, taking an inventory of what was there, noting how the sun might move across the sky, how the wind moved through the space, and what they thought could be done with the property to make it a ‘real’ farm. On that day, I watched them move through what would eventually become our garden, and took my own inventory of the space. And I realized something that day. I realized that there were no bugs.

A female (identified by the curled antennae) tarantula hawk-wasp taking a break in the Environmental Center garden, on my newly formed paths

Actually, no birds either, except one curious scrub jay. No scuttling lizards. Nothing zooming past, not even a pesky fly. Now, sure, it was late January, but that’s no deterrent in coastal California. If it’s above 50 degrees (and it was, that day, as it is nearly every day of the year in Oakland), bugs are generally out getting some stuff done. But not at the Environmental Center.

My feeling was that the space had been abandoned so long, and was so full of invasive (rather than native) plants, and was so crowded with non-flowering weeds (mostly exotic grasses), that nothing really wanted to live there. This is not an uncommon thing. Urban spaces are increasing across the globe, destroying valuable habitat for all kinds of creatures. How can an insect live in a place with only concrete, glass, and steel? Urban spaces not only lack flowering plants, they also often devoid of any kind of slow-moving water, crucial for drinking but also for many insect nurseries. Cities trap heat to become even hotter than their surroundings, becoming ‘urban heat islands,’ uninhabitable to many species. Vehicles rush around, creating dangerous circumstances for any surviving insect just trying to get from here to there. And people are fearful of insects, generally, and are quick to squash and kill anything they don’t understand.

As I’m sure you’ve heard, insects are absolutely vital to our human lives. Not only do they provide pollination services, they are a critical food source for so many animals that live further up the food chain. Many, like wasps, are also important biological controls, keeping a check on other insects, feeding them to their young. And others, including yellow jackets, are valuable detritivores, cleaning up dead animals and other organic matter so that we are not buried in refuse.

A common blue mud-dauber wasp dragging a spider to its nest to feed its larvae, at the Environmental Center

I know that over the (almost) ten years I’ve been writing this blog, I’ve given some mixed messages regarding pests. I have used yellow jacket traps in the past. I mean, yellow jackets are annoying as hell, there’s no question about that. Eating outdoors is one of the absolute joys of summer, and some yellow jackets make that next to impossible. They also bug my chickens and my honeybees, which I don’t like. So for many years, I rationalized my trapping, until I started to read more about general insect decline and the way that decline affects us. (By the way, if this is something you’re interested in learning more about, I’d recommend checking out Dr. Dave Goulson, or Dr. Doug Tallamy.) Now, I make it a practice not to kill any insect on purpose, and rather to learn as much about them as I can. I find that when I learn more about something, I become fascinated with it, and that in turn leads me to appreciate it fully.

This point was driven home to me when my folks shared that they’d recently read an article in the Wall Street Journal about how beneficial yellow jackets really are. I had been talking about insects in a positive light for years, but it wasn’t until my parents read an article for themselves that they had greater fascination for the subject. This made me realize that, though I’ve written on this subject before (here, and here and here, among others) it really bears writing about again.

There are several different kinds of yellow jacket wasps in California. They are generally either in the Vespula or Dolicovespula genera. Some nest in the ground, in old rodent burrows, and some nest in walls or trees; some that are strictly insect-and-nectar eaters, and some which are scavengers. The scavengers are the ones that annoy us at picnics. They are also the ones who generally will enter a trap. However, the others are great for ecosystem health, and deserve our respect and admiration.

A yellow jacket pollinating at Poppy Corners

And there are many other interesting wasps, such as the ones in the photos near the top of this post. Many wasps, such as the tarantula hawk-wasp and the common blue mud dauber wasp, take other bugs home to their nests to feed their young. The tarantula hawk-wasp, for instance, stings a tarantula between the legs (!) and drags it back to the nest, where it then lays one egg on the spider, takes pains to keep the spider alive until the egg hatches into a larva, which then feeds on the living spider until it pupates. I mean, the stuff of nightmares, yes? And yet also intriguing. Other predatory wasps do this with the very caterpillars that threaten to eat our crops.

In fact, in a 2021 study by the University of London, it was shown that “predation by insects -- as biocontrol to protect crops -- is worth at least $416 billion (US) per year worldwide,” and that wasps actually regulate populations of agricultural insects. This is a priceless service.

Another priceless service that wasps perform is pollination. Many wasps use nectar for their primary source of daily energy (the ‘meat’ is for larval development only), and the study states, “pollination by insects is vital for agriculture, and its economic importance has been valued at greater than $250 billion (US) per year worldwide.” These are not small numbers. Our food supply is already under threat, for oh so many reasons - so let’s use any and all of the free ecosystem services that nature provides us, shall we?

an old paper wasp nest in the eaves of our train shed at Poppy Corners

With all of these services firmly in mind, at the Environmental Center, one of the first jobs I gave the students was to plant a pollinator garden. I had obtained a grant for seed from Pollinator Partnership, and they sent us a large bag of various native California wildflower seeds. We knew that our vegetable and fruit plantings would attract pollinators, but we wanted to ensure as much diversity as possible, and that seed grant gave us another 30 species of flowers with which to attract and feed insects. (Also deer, but that’s a story for another time.) And once the goldfields started coming up, and the tidy tips, then the gilia and the poppies, the bugs started arriving - hover flies came first, then honeybees, then butterflies, and finally now, on these hot summer days, I’m finally seeing the wasps. I’m delighted. Now that there is the buzzing and zooming in the air, I’m starting to see lizards, and skinks, and snakes. Birds of all kinds have found us. Each of these species brings a new set of challenges, but that’s ok - we know that having a healthy ecosystem brings far more benefits than it does problems.

As the garden evolves, my plans for it does, too. I intend, this fall, to have one class build an herb spiral and plant fruit bushes and trees, which will attract even more pollinators. Another class is going to create a garden full of traditional, cultural crops, which should bring in even more native insects. I look forward to seeing the ecosystem develop and create a closed loop, where everything within the loop thrives, including the humans who eat the food grown there.