Sunday, August 30, 2009

Big Changes in Frog Town

--- Sierran treefrog tadpole with tiny leg developing in the tail membrane. ---

The Pacific treefrog tadpoles spent the summer transforming into mini-frogs. Meanwhile, their name changed to Sierran treefrog.

--- Big tail, small legs at Plum Pond, May 20th. ---

A treefrog tadpole completes its aquatic life from egg through tadpole to small frog in about three months - longer, if water temperatures are cool. Depending on when the eggs where originally laid, treefrog tadpoles typically metamorphose in California from June to late August.

-- The Plum Pond on May 11th with visiting black cows. ---

As the summer flies by, the Plum Pond shrinks but still gets enough spring seepage that it does not completely dry up. Depending on their seasonal rotation, the cattle may drink from this and other ranch ponds as late as mid-July. Frogs are plentiful at the Plum Pond, although hard to find on hot days.

--- The Newt Pond was shallow and muddy on May 10th. ---

The Newt Pond dries up every year, sometimes filling and drying several times in the year. This year it dried up for good by June 7th which is 56 days later than last year. Earlier, in anticipation of its annual demise, I collected a few treefrog and toad tadpoles from the Newt Pond and have been raising them in a fish tank. Because of the cooler conditions in my kitchen, the tank tadpoles are developing more slowly than those in the Plum Pond.

--- On June 13th in the kitchen tank, most of the treefrog tadpoles (top three) had legs,
but the California toad tadpole (bottom) did not. ---

In late May, the Plum Pond had treefrog tadpoles at several stages of development swimming about the warm, shallow water eating mostly algae. The youngest tadpoles had small rear limbs pushing out of the base of their tails. Frogs with larger legs used them to navigate through tangled vegetation.

--- Treefrog tadpole with muscular rear legs at the Plum Pond, May 20th. ---

On some Plum Pond tadpoles, the pair of front legs had burst out of a fold of skin in front of the belly. At this point, the tadpole is about to come out of the water and there are numerous internal changes also occurring. Its tail gets less finlike and more stump-like as it is adsorbed into the body. Lungs develop. The tadpole stops eating for a short time while its sucking mouth converts to jaws and its digestive system is converting from one that processes vegetable matter to one that breaks down animal matter.

--- Suction mouth and big, shiny belly of a tadpole in the kitchen tank on June 13th;
it also has new rear legs and soon the front legs will push through the bulge in front of the belly. ---

--- All 4 legs but still packing a stumpy tail at the Plum Pond, May 20th. ---

--- In the kitchen tank on June 26:
left - newly metamorphosed treefroglet,
right - treefrog tadpole. ---

With all 4 limbs, the metamorph creeps out of the water, although it quickly leaps back in whenever disturbed. Over the next 5 or so days, the stumpy tail disappears completely. Initially, the froglet looks dark and skeletal, much smaller than the tadpole of a few days ago, probably due to its temporary fasting during metamorphosis.

--- New treefrog at the Plum Pond on July 13th and only 3/8" from nose to rump. ---

--- The first treefrog to metamorphose in the kitchen tank is a rich copper color. ---

The young frog will use the suction-like discs on its toepads to climb pond vegetation where it will sit in wait for passing prey, mostly small, flying insects. If successful at its new hunting strategy, it will fill out into the more typical frog shape.

--- Adhesive toe pads allow the treefrog to climb up many surfaces, even glass. ---

Some herpetologists have recommended reclassifying the Pacific treefrog because of differences in its body structure from the eastern treefrog, and also because of subtle differences between the populations throughout its California range, including something to do with those fancy toepads. For this blog site, I've committed to using the nomenclature and taxonomy for reptiles and amphibians as designated by the California Herps website because I think it's a good resource that stays current with the experts and particularly with field biologists working in California. While the tadpoles were transforming this summer, Gary Nafis converted to the new treefrog names on his website and I am too. See the California Herps website for more details on this name change and distribution maps.

See also:

Sierran treefrog, Pseudacris sierra - formerly called Pacific Treefrog, Pacific chorus frog, Hyla regilla or Pseudacris regilla.

California toad - Bufo boreas halophilus

Friday, August 14, 2009

Bee the Corn

I just spent two weeks in the Midwest, and although my eyes were opened to the wonders of the prairie and corn field, the internet services weren't so great. I will be replacing the deer photos recently posted to better quality versions soon.

August 16th: deer photos have been reposted.

Saturday, August 8, 2009

Bump and Button

--- Button on the left background, Bump on the right background ---

This is the third in a series about summer deer families on the Dipper Ranch. Today's blog is about Bump and Button.

BUMP - this doe has a large mole-like bump on the inside of her left foreleg (see photo above). It is about 2" x 1" , dark grey, and has no antennae. She doesn't seem to scratch it or limp on that side, so I assume it is some type of harmless dermatological irregularity. Who knew deer had beauty spots? Bump has no cuts in her ears.

BUTTON - Bump is usually attended by a young buck, Button, who has 1" long antler buttons. Button has clean-margined ears and I assume he is a yearling. The 2009 Bump & Button pair may be the same doe-male fawn pair I saw frequently in the Fall of 2008. I hadn't trained myself to distinguish individual deer then, but I have observed similar feeding and bedding behavior between the years. Most young bucks disperse at about 16 months of age. I would expect Button to separate from Bump this fall during the breeding season.

--- This summer, Button has an adult-sized body, but his antlers are short. ---

The Columbian black-tailed deer of central coastal California is a subspecies of mule deer which range across large areas of the western US and Canada. The various mule deer subspecies survive in different environments and have somewhat different physical features and behavior.

Only the males carry antlers in mule deer. The velvet-covered antler bulbs appear on the top of their head every spring and may grow as much as 1 centimeter per day in the summer. The antlers stop growing and the velvet dries and is rubbed off in late August and September as the bucks prepare for the annual rut. Antlers are used for sparring between bucks, with dominant bucks getting more access to does for mating. The antlers are shed in late January or early February.

--- Last fall, a young buck, possibly Button, browsing in the farmyard ---

Yearling male mule deer with adequate diets normally have 2 points on each side of their antlers and 2-year old bucks typically have 4-point antlers on each side. Thereafter, subsequent annual growth may be more in the diameter and length of the antler and not an increase in the number of points, thus the age of a deer cannot be determined by its antler points. Nutritional conditions of the buck largely influence the growth of its antlers.

Button's antlers seem small for his age and body size. The black-tailed subspecies living in the mild climate of coastal California is generally smaller and starts its annual cycle sooner than many of the other subspecies of mule deer. Button still has another 1 to 2 months of antler growth this summer to see if he gets any divided points.

I am not sure why Bump does not have a new fawn this year. Possibly, she is a young doe which do not conceive every year, or she lost a fawn earlier in the year before bringing it out of hiding. In mule deer populations, 25 to 30% of the fawns are lost by the fall months, and 75% do not make it to their first spring (Feldhamer, et al.). Again, the nutritional level is a primary influence on deer survival.

--- Button is waving his head, but showing his size compared to Bump. ---

See also:

Thursday, August 6, 2009

Fly & Squirt, Puck & the Bucks

--- Fly, a doe with several cuts on her right ear ---

This is the second in a series about summer deer families on the Dipper Ranch.

FLY - this doe has 2 cuts on the inside of her right ear and a small one on the outside of the same ear. She has one fawn, SQUIRT, with a stumpy nose. Squirt seems smaller than Dot 1 and Dot 2, so maybe its nose will unwrinkle with time. So far, these two families have not mixed, so I haven't been able to compare sizes directly.

--- Squirt, a single fawn, whose ears are bigger than his nose ---

In a Montana study, pregnant mule deer does carried twin fawns 55%, single fawns 44%, and triplet fawns 1% of the time on average over 12 years. Mule deer does in their first year of adulthood are more likely to carry a single fetus than twins, so perhaps Fly is a young doe. The reproductive potential of a doe is primarily influenced by her nutritional status in the year before the birth, especially in the last 2 to 3 months of pregnancy (Feldhamer, et al.).

Fly is flighty. She bolts quickly, even at the sound of water running in the bathroom sink. Squirt has a hard time keeping up with her during her quick retreats, although the fawn steadily follows her path through the tall grass. One night, I saw Squirt catch up with Fly at a fence line. Fly folded her forelegs and ducked her head under the bottom strand. As Fly's long, flexible back swept low, and her rear legs folded to the ground, tiny Squirt stepped right through the bottom gap in the old fence, and caught up as the doe unfolded her body accordion-like on the other side of the wire.

--- Squirt running to catch up with Fly ---

I often see Fly and Squirt creep out of the willow thicket west of the house at dusk. When the plums were dropping, Fly would stand drooling in the orchard as she ate unripe fruit. I usually didn't see Squirt during her orchard visits. The small fawn might have been screened by the tall grass, but I think Fly tucks Squirt into a nearby stand of canyon live oaks while she wanders about.

PUCK - on occasion, I see another young buck, Puck, with velvety, unbranched antlers about 4" long. I have not detected him as part of any of the other families and have not been able to photograph him yet.

I don't see many bucks this time of year. I did see one with 3 tines on his left antler and 2 tines on the right in early July in the John Deere meadow. The does with fawns have claimed the high ground near the farmyard with more regular water and a variety of food choices, and the bucks are lower down along the forest edges.

--- Mixed deer herd in February ---

At other times of the year, the deer mingle together in mixed herds. They often browse as a herd in the early morning and evening. When the calves first arrived on the Dipper Ranch in January, the deer initially disappeared, but within a few weeks, deer and cattle were sharing the pastures. Both cattle and deer are ruminants or cud-chewers. In the first two chambers of their stomach, the fiborous cellulose of their plant food is partially broken down by symbiotic bacteria. When the ruminants bed down, they regurgitate the cud, chew and mix it with more bile, and then reswallow it to be further digested and absorbed in the other two chambers of the stomach.

Mule deer have a relatively short gut length for their body size compared to other ruminants. Thus, they tend to be selective and eat smaller volumes of food such as young, tender twig tips, leaf buds and other plant tissues which are of higher nutritional quality and easily digested. I've also noticed that deer tend to sample the outside tips of whatever is newly growing along their regular trails. Cattle, on the other hand, will eat and process large quantities of grass and don't sample as much from the woody plants. One study found that Columbian black-tailed deer eat as much as 62% newly germinated annual grasses in the winter in the oak woodland/annual grass ranges of northern California (Feldhamer, et al.). Moderate, seasonal grazing at the Dipper Ranch seems to accommodate both the deer and cattle.

---These deer exhibit the characteristic tail of the black-tailed subspecies of mule deer:
black along the entire length of its dorsal side.
In the background, cattle are chewing their cud.---

See also:
  • Wild Mammals of North America, George A. Feldhamer, Bruce C. Thompson, and Joseph A. Chapman, editors, John Hopkins University Press, 2003.

Tuesday, August 4, 2009

Deer Pelmanism

--- Fawn chowing down on dry buckeye leaves ---

The does are bringing their fawns into the farmyard. They are drinking out of the cattle troughs and birdbaths, and eating rogue fruit falling in the old orchard. Their favorite snacks currently are the dropped leaves and flower stalks from the native California buckeye trees.

--- California buckeye tree dropping its leaves in July ---

California buckeye trees have an unusual adaptation to California's dry summer - they are summer deciduous. They drop their leaves in the summer drought period and are the first trees to bud out in the late winter. In the early spring, they are covered with large white blossoms.

--- Dot, a doe ---

I don't believe in feeding wildlife. Feeding wild animals usually leads to conflicts with humans. The fed animals may get too close to humans and start consuming landscape plants or pets not originally intended as wildlife food which usually means trouble. They may wander onto roads where they are hit and killed. The food provided by humans may be nutritionally unbalanced or only available at irregular intervals. Often, a fed wild animal is eventually a dead animal. The California Department of Fish and Game says it well, "Wild animals don't need your handouts. They need your respect."

As usual, the Dipper Ranch turns my former beliefs on their head. I realize the deer are attracted to the yard partially by the fruit in the orchard, especially since the fruit starts dropping just as the does are ready to bring their fawns out of hiding and introduce them to browsing. I would prefer they leave the fruit for me. I have flashing to put on the trunks of the fruit trees, and this winter, I will be installing a deer fence around my future garden. On the other hand, the fruit trees have been here a long time, maybe 50 years. For much of the last decade, the property was uninhabited by humans or neglected. These very same does probably visited these fruit trees when they were fawns, well before I took up residence in the ranch house.

--- Dot's right ear nick ---

I am trying to teach myself how to identify the deer as individuals and as families. In the next few blogs, I will introduce the local deer families. Today, I would like to introduce you to the Dot Family.

--- Dot's left hip scar ---

DOT - a doe with a black dot on her right side near the top middle of her back. On close inspection, she has a small nick at the 11:00 position on the outside of her right ear. Her left hip is preceded by a small diagonal scar pointing SSE.

--- Dot and the spots on the right side of Dot 1 and Dot 2 ---

Dot has two fawns and I am still trying to tell them apart. Unlike the adults, the fawns don't have scars to readily distinguish them. Recently, I realized not all of their spots are identically arranged, so I'm trying to memorize their individual patterns. This will only work through the summer because they lose their spots when they shed into their winter coats. For now, in the Dr. Seuss fashion, I call the fawns Dot 1 and Dot 2. I first met Dot 1 and Dot 2 in late May while cursing my brush cutter.

--- Spots on the left side of either Dot 1 or Dot 2 ---

The Dot Family visits the farmyard everyday between 6 and 9 AM and again between 6 and 9 PM. Currently, they are bedding down in the willow thicket below the Ortega corral. Dot 1 and Dot 2 are often within a few feet of each other. I think one might be the leader, foraging ahead of the other and wandering the farthest from the doe. As with all twins, the behavior of one is often attributed to the other. They are curious about noises and the cat, but will scamper away at any sudden movement towards them.

--- Spots on the left side of the other Dot ---

If you want to see fawns this time of year, I recommend you stake out a California buckeye tree that is dropping its leaves. Settle in a good viewing spot with binoculars about 1/2 hour before dusk. A deer family will likely come by to pick up the leaves that have fallen in the past day. If you are at least 30 feet away and quiet, the deer may freeze at first when you slowly move your binocular hands up to your face, but will probably go back to crunching the dry leaves if you are as still as possible. The new deer families seem to follow a daily routine, so if you spot them once, it might be a good viewing spot for much of the summer.

Next up - Bump and Button.

See also:

Columbian black-tailed deer - Odocoileus hemionus columbianus

California buckeye - Aesculus californica

A couple of hints on how I describe locations on a deer:
  • For hour designations or compass directions (11:00 or SSE), imagine the center of the clock or compass is the center of the deer's body as you look at it. Eleven o'clock is to your upper left. SSE stands for south-southeast on a compass or generally to your lower right.

  • When referencing the deer's right or left side, it is from the animal's perspective, not the viewer's. Thus, if I say left foreleg, it is the front leg on the left side of the deer, however, if you are facing the deer, that leg will actually be on your right.
Pelmanism is the memory game, also called Concentration, in which you turn up cards and try to match related sets.