Saturday, February 28, 2009

Egg of Newt

The male newts have been torpedo-ing around the ponds since November. With the heavy January rains, the first females arrived and each was quickly surrounded by many male admirers forming swirling, orange 'newt balls'. More rain fell, more females trekked across forests and grasslands and the sexual ratio in the ponds evened out. Now, pairs of newts are stacked and gliding about in broad arcs, tilting and rolling in shallow water, long tails trailing behind. With the entire pond as their ballroom, they don't seem to be in a hurry just now.

The males are sporting smooth, cloudy skin, swollen limbs and finned edges on their tails due to their extra weeks of immersion. They've also grown black, rough spots on their toes called nuptial pads which help them grip the female from above while mating.

After their paired swimming (called amplexus), the male deposits a spermatophore (packet of sperm) in the water which the female picks up with her cloaca (vent beneath the tail used for excretion and reproduction), and the eggs are fertilized inside her body.

The female newt lays the fertilized eggs in shallow water as a rubbery mass about the size and shape of a clear ping-pong ball. Each egg mass contains dozens of two-toned dots, the developing eggs. If the egg mass turns, the enclosed free-floating eggs will roll too so their dark sides face upwards where they will absorb more heat from the sun and develop faster. The pace is picking up, as the amphibian eggs are now in a race to hatch and develop from larvae into terrestrial-hardy adults before the rains stop and the pond dries out over the summer.

Does each female newt lay more than one egg mass per mating season and are the eggs in each mass fertilized by one male or multiple? I haven't been able to find this out yet. There certainly seems to be the opportunity during this annual pond congregation to mix genes in many different combinations, but I am not sure if newt biology and female patience works that way.

Over the next 2 to 3 weeks, the embryonic dots transform into commas and then elongate into miniature knives. The knives start twitching inside their jelly atmosphere and develop bumps and lines that define eyes, gills and tail. There might be some eggs in the mass that were not fertilized and those never develop past the round dot stage. If the egg mass rolls, the embryos flip themselves to keep their back side up.

Incubation takes 2 to 7 weeks, probably depending on water temperature. To hatch, the embryo wiggles out of its jelly-like egg sphere, cuts through the enveloping egg mass and emerges into free water. It may take several days for all the embryos to hatch out of the egg mass and each successful escapee leaves behind an air bubble.

The newly hatched newtlets (as I call them), are approximately 5mm long, and their mostly translucent bodies have 2 dark eyes, two dark streaks down their body and tail, and many small dark spots. Their gills are delicate branches waving behind the head. For a few days, their undersides bulge with the remaining egg yolk. They originally seem to have a lopsided sense of balance, and often rest or swim on their sides or upside down. Their forelimbs are present upon or soon after hatching but often tucked against their sides and not apparent. The likewise delicate hind limbs appear in a week or two.

In the next stage of their lives, the newtlets must survive as small sized predators among many other predators in the three dimensional world of the pond.

See also:

NOTE - Coast range newts contain poisonous neurotoxins that can cause death in vertebrates and humans. Sometimes they secret the neurotoxin through their skin, so either don't pick them up or wash your hands afterwards and certainly don't ingest them or let your dog eat them.

Coast range newt, Taricha torosa torosa  California Herps website
Gayle Pickwell, Amphibians and Reptiles of the Pacific States, Dover Publications, 1972.

Saturday, February 21, 2009

Night Life at the Ponds

Yesterday we started nighttime pond surveys. Before sunset as we geared up, we could already hear the Pacific treefrogs from ponds over a mile away.

By the time we hiked down in the dark, treefrogs were loudly calling their advertisement songs from every pond & puddle. They would fall suddenly silent when we first approached a pond's edge, but soon one frog would start trilling, and not to be outcompeted, the others would quickly join in.

<--- The local loudmouth, Pacific treefrog in the water. Notice its skinny waist.

Treefrogs spend the nonbreeding season in grasslands and brush usually near locations that hold water for at least part of the year.

<--- A treefrog heading to water.

They have adhesive discs on their toes that allow them to climb objects such as trees, even window glass.
When I find gelatinous egg masses inside of tall, straight-sided cattle troughs, I know the treefrog is the only local amphibian that would be able to suction its way up and into such structures.

Treefrogs are small (up to 2" long not including the legs) and can quickly change their colors. The easiest way to identify them is by the black bar that runs from the tip of the snout through and behind each eye (the masked ranger frog). No matter what color the frog has changed to, the black mask will always be obvious on this small frog.

<--- Male treefrogs inflate vocal sacs to create their impressive chorus and call their mates.

As early-arriving treefrogs finish their reproductive duties, they leave the pond and more partying treefrogs arrive.
Thus, the treefrog breeding song can be heard several months throughout a rainy spring. Pacific treefrog calls have often been recorded as jungle background in Hollywood movies.

Male treefrogs clasp the larger female, called amplexus, and fertilize the eggs as she releases them into the water. The eggs are attached as loose jelly clusters on submerged vegetation.

<--- Treefrogs in amplexus ---

So far, I have only seen a few treefrog egg masses this year. I will post photos once I have some good ones. In the meantime, you can see good photos at California Herps.

Under the din of the treefrogs, we occasionally heard the low chuckling of the California red-legged frog. They start calling later in the evening. California Herps reports that red-legged frog calls last only 1 to 2 weeks at a location. Last year, we heard their calls from mid-February through early April at the Dipper ponds.

<--- Red-legged frog at the Mallard Pond. Photo by K. Greene. ---

We found a red-legged frog sitting in the shallows facing outwards at the Mallard Pond and another one similarly positioned at the Plum Pond.

The red-legged frogs are much larger (5.25" not including legs) than the treefrogs and not nearly as numerous. They have long folds of skin that look like a line running down each side of their backs. Since the red-legged frogs are rare and protected by state and federal laws, we do not pick them up or otherwise disturb them.

<--- Red-legged frog at Plum Pond. ---

California red-legged frogs could be confused with two other large frogs in our area - the native foothill yellow-legged frog or the large introduced American bullfrog. Check the California Herps site for details, however, yellow legged-frogs occur in streams, not ponds and do not have the above-described dorsolateral folds of the red-legged frogs; and bullfrogs can get quite large, usually with a smoother brown-greenish color to their backs, and a tympanum (eardrum that looks like a large flat disc behind the eye) which is larger than the eye. We have never seen or heard bullfrogs at the Dipper Ranch Ponds. This indicates these somewhat isolated ponds are in good shape since bullfrogs eat many of the native amphibians and reptiles.

<--- A red-legged frog egg
mass in the Plum Pond on February 8th of this year. ---

We did not see any egg masses last night, however, cloudy water from recent heavy rains may have been hiding them.

The egg masses float for awhile and then sink, so they are hard to find a few days after being deposited.
I expect the red-legged frogs are just getting started and we will see more of them in the next few weeks.

<--- Last year, I saw much larger red-legged frog egg clusters, the size of cannonballs, in the Plum Pond on February 16th. ---

[03/07/09 revision: I moved the video of the treefrogs to a new posting which includes further discussion of frog calls and a link to recordings of treefrogs and red-legged frogs at the Plum Pond on 02/20/09.]

See Also
  • The CaliforniaHerps site has more information on these frogs including audio recordings of different frog calls.
  • Gayle Pickwell, Amphibians & Reptiles of the Pacific States, Dover Publications, 1972. - although terminology and some information in this book are out of date, Pickwell taught at San Jose State University (known as San Jose State College when Professor Pickwell originally published this book), and provides many detailed observations in the Santa Cruz Mountains.
Pacific treefrog, Pseudacris regilla
California red-legged frog, Rana draytonii
Foothill yellow-legged frog, Rana boylii
American bullfrog, Rana catesbeiana

Tuesday, February 17, 2009

Fillin' & Spillin'

We've had one storm after another rolling in since Thursday. A low pressure system off the Pacific Ocean has been lining them up and aiming them onshore in a northeasterly direction. That's what the National Weather Station says and I independently corroborated this with my local weather station, a leaky window on the southwest side of the house. On a clear day, you can look out same window through gaps in the local mountain ranges to see the northernmost tips of the Santa Lucia Range, 200 miles further down the California coast. Hail pounding on that window on recent evenings reminded me that ocean-bred weather systems move inland through the same alleyways, and to put another towel on the sill.

With 5.5 inches of precipitation in the last 48 hours, the creeks are flowing, ponds are filling and some are spilling over. I'm not complaining. We need the rain. I alternate between cheering the rain on and looking for gaps between storms when I can check the ponds. I don't mind hiking and working in the rain, as long as I am working hard enough to evaporate off whatever soaks through the layers. I just wasn't looking forward to sliding all the way down muddy roads to the ponds nor slipping across wet pastures on the way back.

--- Water flows down grassy hillsides to the Plum Pond --->

Yesterday, M10 came by with the mule to do road and water checks, so we drove down to the Plum Pond to check recent repairs. An old culvert had collapsed under a road and they replaced it with a different diversion setup. So far this winter, the pond hadn't filled enough to test the new spillway and culvert. Watching flow patterns during a rainstorm is often the best way to learn how a hydrologic system works. Indeed, earlier that day, I'd been hoeing out thistles in the farmyard in a light rain and mulling over water rilling down the driveway.

The Plum Pond is fed by a small spring, but in a rainstorm, you can see how gravity sends water sheeting and streaming down the surrounding grassy hillsides and bubbling up old gopher holes too. Yesterday, the pond was full of cloudy water with one end steadily pouring through the new culvert. The construction work looked intact and was functioning well. Straw placed on top of the repaired road was preventing any erosion.

<---Repair work at the Plum Pond holding up in heavy rains --->

The water in the Plum Pond was too cloudy to detect the California red-legged frog eggs I saw last week or spot any new clusters. We heard a few peeps from Pacific treefrogs. The coast range newts were paddling about the cloudy water unconcerned. They have been in the pond long enough now that they are all swollen and cloudy themselves.

<--- This newt was on his way to a pond in November and still had the bumpy, dark orange skin of the terrestrial phase ---

---After being in the water for a few weeks, newt skin gets cloudy and smooth and their limbs swell, the aquatic phase --->

Other ponds have also formed around the abandoned Monotti barn. The Donut Pond (so called because it was excavated in an oval shape with an island in the middle) has shallow water on one side. A low spot in front of the barn (I call it the Barn Pond) is filling. The Barn Pond is so ephemeral, I rarely see any water there, but with more rain today, I can now see the Barn Pond all the way from the house.

--- Donut Pond and Barn Pond,
shallow and muddy ---

The Newt Pond is three-quarters full with water pouring into it via a piped diversion placed at a nearby spring and drainage up the hill. I saw one newt along the water's edge but it was too cloudy to detect any others.

<--- Newt Pond

Diverted water pouring into the Newt Pond --->

Interestingly, the Woods Pond has very little water. The adjacent drainage is streaming down a steep section (the cattle operator just cleaned out a culvert above), and the pond's narrow spillway is draining, but not much water is actually settling in this pond. I haven't figured out its hydrology.

<--- The Woods Pond still has little water ---

After all this filling and spilling, last night, the tree frogs started their breeding din. I have heard a few tree frogs calling in the evening for the last few weeks. Mostly individual frogs setting up shop and testing out their voices. One clever fellow took over the metal cattle trough and has quite an echo going. But it was only last night that I can report the voices of many tree frogs joined into their annual "chorus" of breeding frenzy. They switch from a variety of notes to their "advertisement call", the repeating of two notes (kreek-ik) over and over again, egging each other on to get louder.

I did not make it to the Mallard Pond during this set of storms. I can imagine that it is spilling and the frogs are trilling. With my hardy core of curious volunteers, I expect to be checking the Mallard and other ponds for night-time frog surveys in the next few weeks.

--- Later ---
See Also:
Coast range newt, Taricha torosa torosa
Pacifc treefrog, Pseudacris regilla
California red-legged frog, Rana draytonii

Hear audio tapes of California frogs and toads at California Herps website.

Saturday, February 14, 2009

Thistle Logic

--- Thistle seedlings germinating in a group.
A seedhead probably fell here in a previous year. ---

Now is the time to control thistle seedlings. In this posting, I will describe basic strategies to thistle control, especially early season methods, and share some photos of thistle seedlings. Beware: thistles will bore you to tears! It's part of their sneaky plan to take over the world.

---ITALIAN THISTLE seedlings have leaves with narrow greenish-white upward slanting lines and a bright white dot beneath each thorn on the leaf edge. I think of the line and the dot as being the "i" in Italian. They are one of the earliest thistles to germinate in the winter. --->

Thistles can be weeds in yards, gardens, crops and rangelands. In natural areas, non-native invasive thistles spread on their own, take over and reduce native plant diversity. Depending on the type of thistle, time of year and site conditions, effective thistle control can consist of digging, pulling up by hand, mowing, mulching, careful use of herbicides, or more exotic methods like grazing by molasses-bribed cattle or burning. Often, you will switch between methods on the same stand of thistles as the season and your efforts progress.

January through October, I usually spend some of my weekend hours controlling one species of thistle or another in the farmyard, in sensitive areas of the ranch or on other nature preserves. I will share my thistle logic throughout the spring and summer months to help you decide what to do when. Maybe I will even start a thistle cam. Doesn't that sound boring? See, I told you thistles are sneaky.

<--- A brown seedhead from last year easily recognized as MILK THISTLE because of its large size (often greater than 2 inches in diameter) and huge curved spines ---

--- Underneath and nearby are the MILK THISTLE seedlings just starting to get robust leaves with broad 'splashes of milk' running horizontally across the blade. Milk thistles germinate in the winter. --->

Thistle Seedling Identification - With the arrival of winter/spring rains in the Santa Cruz Mountains interspersed with many sunny, warm days, the seeds are germinating and young thistle plants are starting to claim ground. Now is a great time to start popping out young thistles with a hoe, pulaski or whatever is your favorite digging tool. How do you recognize a thistle seedling? Usually, it has leaves with wide flat stems (often whitish) and oval-shaped blades with spiny edges. Use the photos in this blog or links below to help with identification. Look underneath big, brown, spiny thistle plants from last year, and you will start to consistently see the same small green plants which are their newly germinated seedlings.

<--- Cotyledons joined by the first spiny true leaves of a thistle seedling. ---

The first leaves to germinate from the seed are a pair of thick paddles from which the young plant derives its initial nutrition. These first leaves, called "seed leaves" or cotyledons, might be hard to recognize at first. Look for nearby plants which have the same cotyledons but also have their next sets of leaves which should be shaped and colored more like ones you might recognize on the adult plant.

Thistle leaves usually come out of the ground in a neatly organized swirl called a rosette. Much later, a stem will bolt up from the center of the rosette and eventually bear flowers then seeds. Controlling the thistle plant at the rosette stage is a good strategy. It is easier to get enough of the root at this stage to kill the plant and this early action ensures that no seeds will be produced. Some people get good at recognizing thistle seedlings early and pluck them out by hand at the cotyledon stage. Some people eat young thistles.

Control by Digging - Digging or other methods of weed control that turn the soil are sometimes referred to as 'cultivation'. I will be addressing digging methods with hand tools, although in fields or other large tracts of thistle invasion, tractor-pulled cultivation implements could be considered. Start by sharpening the blade of your digging tool. I keep a file near my hoe and pulaski and touch up the edge every day I use the tool. Wear gloves even during the sharpening process. Aim your sharp-bladed digging tool to the side of the plant and strike into the ground beneath it. Your blow or blows into the soil need to sever the root underground several inches below the surface. If you just slice off the leaves or the very top of the root, thistle plants are likely to resprout from the base and you'll just have to rechop out that plant later. Note that purple starthistles in particular need to be cut at least 3 or 4 inches underground or they will slowly resprout.

--- PURPLE STARTHISTLE rosettes have tightly packed, deeply lobed leaves with whitish fuzz in the center. This plant is a biennial with a large root that needs deep grubbing to keep it from resprouting. Purple starthistle plants germinate from early summer through fall. --->

If you dig up a whole thistle seedling and look closely at the shape of the root, you will see a fat part at the top (like a carrot) that transitions into a narrow section or subsections. If you chop the root several inches below where the leaves join the fat root, you sever the active growing buds and won't get resprouting of that plant.

After dislodging a thistle plant, sometimes I reach down with my gloved hands to grab a leaf and flip the plant upside down or into a pile or bucket. This makes it easier to keep track of what plants I have already attacked. If, when I grab the cut plant, it falls apart into many separated leaves, then I know I probably didn't chop deep enough and I aim my tool at the developing hole again. If I grab one leaf and the whole set of leaves comes attached, then I know I probably chopped the root low enough. I shake off most of the dirt clinging to the roots to make sure the plant will dry out and die sooner. If you are chopping out a large rosette, you might discover there are smaller thistle seedlings hiding under the big one's leaves. Get those little guys too.

<--- YELLOW STARTHISTLE leaves change in shape several times as the plant grows. The initial leaves are unlobed, but within a few weeks the leaves are deeply lobed with the terminal lobe in an arrowhead shape. The plant has a distinct flat yellow green color. It germinates in winter but stays small until mid- to late-summer. --->

Persistence - The annual seed germination period of some thistle species does not occur all at the same time and can be spread out over several weeks to months. So don't be surprised if after thoroughly clearing a location of thistle seedlings, more appear a few weeks later. It's not that you need new glasses. Many of those seeds probably germinated after your initial attack because you cleared out a nice open space for them without competition from their older siblings. You will need to pass back through your control area several times during the spring and summer to get the late comers. Don't be discouraged. Many of these late germinaters would have had to wait another year or so before their turn. You are actually stimulating more of the seeds in the ground (referred to as the "seed bank") to germinate in the same year so that the total length of time you have to control thistles at that spot will be less.

<--- BRISTLY OX-TONGUE likes moist soils. It is easily recognized by the white zit-like blisters on the top of the leaves from which the bristles emerge. It germinates mid- to late summer. ---

Several species of thistles can occur in the same general area. You may just finish getting all the rosettes of the early germinating thistles (Italian thistle, milk thistle) when seedlings of the next round show up (yellow starthistle, bristly ox-tongue). Bull thistle is a late summer germinator and bloomer. Purple starthistle keeps germinating for much of the summer, and even seems to increase its germination rate in the fall.

If you start to get overwhelmed, go after the largest plants first to keep them from going to seed, recharge, and then return to the same location in a week or so and go after the largest plants again. Repeat until there are no thistle plants standing. As the season progresses, there are other methods you can use which I will discuss in future blogs.

More Than One Year - How long will it take you to get rid of the thistles? It mostly depends on how many prior years thistle plants have been allowed to mature at that location and drop seed into the soil, and your thoroughness. A seed which was produced one year may germinate the next year, or it may stay dormant in the soil for many years. Some thistle seeds may stay inactive in the soil for as much as 8 years, and still germinate once the right moisture and sun stimulation occurs. A big seed bank takes more years to deplete.

--- BULL THISTLE germinates in late summer and has a soft fuzzy appearance in addition to stiff yellow spines on the leaf edges. --->

Don't be discouraged. Thistle control, indeed weed control or the overpowering of any evil force, takes persistence. You can start humming Dylan's "Where have all the flowers gone?" at this point. When developing your thistle campaign, I encourage you to pick an area that is small enough for you to stay on top of the first year and don't let any thistle plants go to seed in that area ever again. It will be more work than you expected, so start small. Check that area several times during the spring and summer and get any missed plants or late germinaters.

Attack the same area the next year. It actually may seem like more work the second year because all your hard work the previous year is just tricking more of the seeds in the ground to germinate faster. By year 3 or 4, you will probably see a substantial reduction in the number of seedlings and now you are getting the upper hand. As the amount of work declines in your initial attack zone, you can expand your thistle control into surrounding areas, but always try to keep your control area small enough that you have time to prevent any thistle plants from going to seed.

Thistle Logic In Sum - pick a small initial attack area, learn what thistle seedlings look like, use sharp tools, chop out enough of the root in the rosette stage, repeat visits during the growing season, don't let any plants go to seed, attack the same area for several years in a row. You may find that family, neighbors and co-workers ridicule your thistle control aspirations. Just remember these basics to outsmart the thistles and be persistent.

<---A Pop Quiz: Can you tell the difference between the Italian thistle and milk thistle seedlings?

Congratulations on making it all the way through this thistle logic posting. A thistle-filled world is a bore, so do not succumb to the opiate effect of thistle tyrants and save the wildflowers. Here are a few entertaining thistle quotes for your persistence.
Abraham Lincoln: "All my life I have tried to pluck a thistle and plant a flower wherever the flower would grow in thought and mind."
Proverbs: "Who gathers thistles, may expect pricks."
See also:

Thistle Identification & Photos
  • CalPhotos
  • The Nature Conservancy's Global Invasive Species Team
  • Weeds of California and Other Western States, Joseph M. Ditomaso, Evelyn A. Healy, 2007, University of California, Division of Agriculture and Natural Resources. Great photos and descriptions in this new 2 volume set. Expensive but available at some County Agricultural Departments and Weed Management Areas.
  • The Grower's Weed Identification Handbook, Bill Fisher, 1996 with updates, University of California, Division of Agriculture and Natural Resources. Out of print, however, may be available at Univ of California Cooperative Extension Service offices. Includes photos of seedlings, compares to similar plants.
  • A table comparing spiny-leaved thistles from the California Department of Food & Agriculture

Control Methods:
  • Invasive Plants of California's Wildlands, Bossard, C. C., J.M. Randall, and M. C. Hoshovsky. 2000. University of California Press. Berkeley, CA. Complete text available online at the California Invasive Plant Council website.
bristly ox-tongue, Picris echioides
bull thistle, Cirsium vulgare
Italian thistle, Carduus pycnocephalus
milk thistle, Silybum marianum
purple starthistle, Centaurea calcitrapa
yellow starthistle, Centaurea solstitialis

Sunday, February 8, 2009

Frog Alert

I found the first cluster of California red-legged frog eggs in the Plum Pond today.

Saturday, February 7, 2009

Mr. Accipiter

This small hawk was sitting on a fence post as I motored up the drive this morning. Birds often ignore the car, even if it is moving, however, they flush as soon as I get out of the car. When I saw the hawk, I eased the car near the post, set the hand-brake and crawled back through the seats of my station wagon to get my camera. Good thing I took that yoga class on Friday.

Even when I unrolled the window, he didn't budge. Mostly, he was scanning the pasture below the drive with an occasional slight head rotation and dark eye cast at my car. I guess a small black car with mud on it probably looks like one of the cows. It's an Angus car.

We've had two days of blustery rain (yeah, keep it up until May!) with sunny breaks. This morning, loose white clouds were drifting under a dense dark mid-altitude band of clouds, and perhaps the little birds and their predators were getting a few bites to eat between storms. Or they could have been blown in by the storm front.

Accipiters are small hawks that make quick dashing flights among brush and branches to capture smaller birds - aerial pursuit. We get both sharp-shinned hawks and Cooper's hawks and I can't tell the difference. I was feeling frustrated until I read 3 pages in Hawks in Flight on how to tell the two apart, including "Arguments about identification of accipiters may well account for more broken friendships and more failed marriages between hawk watchers than all other causes combined." There's a lot of trouble packed into those little raptor bodies.

My guess is that Mr. Accipiter is a sharp-shinned hawk since he seemed ridiculously small for a savage raptor and his folded tail had a notch in the end. He also did not have the extremely long tail of a Cooper's hawk that often makes me think, "Is that a raptor or a military drone that just flew by?" My reference to "Mr." for this bird is only creative license. I make absolutely no claim to being able to distinguish whether this is a male or female bird. Although they look nearly identical, there is enough size difference between sexes within each accipiter species (males are about 1/3 smaller), that female sharpies are almost as large as male Cooper's. As a lone birder this morning, I can make these claims without offending anyone. You are welcomed to share your assessment in the comments, but no complaining about my hawk photography or our friendship might just teeter under the weight of this "Artful Dodger" (Dunne).
See also:
Hawks in Flight, Pete Dunne, David Sibley & Clay Sutton, Houghton Mifflin Company, 1988.