Nature Notes from Big Creek, 1993

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January 1993 February 1993 March 1993 April 1993 June 1993 July 1993 August 1993 September 1993 October 1993 November 1993 December 1993

January 1993. About two weeks ago, our reserve steward Feynner Arias found a golden eagle eating a red-tail hawk. The eagle was all bloody and it was clear that the eagle had killed the hawk. We wondered if eagles actually hunt smaller birds like hawks, or was this an accident of some kind? I called Steven Bailey of the Pacific Grove Museum and he informed me that he had heard of eagles killing hawks, which were harassing them in mid air. Red-tail hawks often harass the larger eagles as they are flying, just like jays and other smaller birds. In one instance, the eagle was seen to flip over and grab the offending hawk out of the air. Maybe this is what happened here at Big Creek.
Apparently, among birds the smaller bird has an advantage in aerial fighting, presumably because of its greater agility. This explains why small birds display no fear when mobbing much larger birds, even predators such as hawks and eagles. It also may explain why male hawks (and owls) tend to be smaller than females (in most animals, as in humans, the males tend to be larger than the females). Male hawks defend territories by driving off their rivals, and the smaller hawks may have an advantage in this. I also have heard that when different species of hawk fight, the smallest is dominant and wins most often.
We have seen flocks of 5-20 band-tail pigeons on the north side of the reserve recently. They are eating the bay laurel fruits, which are very abundant this year. There seems to be very few acorns this year, the fewest I have seen (since 1986). This could potentially be quite hard on the wildlife since acorns are an important source of food for so many species (including acorn woodpeckers, deer, pigs, quail, pigeons, and squirrels). Perhaps the abundance of bay and coffeeberry fruits can make up for the loss. This won't help the acorn woodpeckers though. One large granary tree I have been watching is completely empty of acorns.
Other notes: The grass is growing beautifully after the rains, including lush patches of bunch grasses along the trails and ridge tops....Where are the fall monarch butterflies? I have seen relatively few here at Big Creek or at Esalen where there are usually huge numbers...Thank you to the people who called me with information about the wild goat I saw last month. My informants suggested Tahr goats or Barbary Sheep. When I looked these up in an animal encyclopedia, I immediately recognized the Tahr Goat as the animal I had seen. They have a stocky body with long legs like a Rocky Mountain goat, but horns like a juvenile ram, and are known for their agility on cliffs and rocks..(12/10/92)


February 1993. After the rains on January 7, Big Creek rose 4-1/2 feet above base flow. This flood was a good opportunity to measure storm runoff under the footbridge. We have excellent records of the "depth", or stage height, of the creek, since these are recorded automatically every hour. However, stage height is only an indirect measure of flow, and to make the correlation I need to make several measurements with a flow meter. Does anyone have access to such a device? It looks like a heavy boat propeller attached to a steel rod. Measurements are taken by lowering the propeller 6/10 of the way from the surface to the bottom, and measuring water speed by counting revolutions of the propeller. This is repeated every foot as you cross the stream, and with simple calculations you can estimate the flow rate quite accurately.
Feynner and I are assembling four new weather instrument platforms at Big Creek. These have been designed to make it easy to install and maintain weather instruments such as wind, temperature, and rain sensors. Each platform consists of a central "tower" 5-13 feet high and 6 feet in diameter, with a catwalk around the top. Each platform has three flat instrument stations and six instrument masts. Made of 1-1/4 inch galvanized steel pipe, the platforms are wired internally, with 10 wires connecting each instrument station to a central waterproof switching panel. The data logging computer and electronics fit in the same box as the switching panel.
We now have the prototype platform running at the gatehouse, one platform partially installed at redwood camp, another partially installed at Highlands Peak, and two assembled but not installed in the parking lot. These latter two will be installed at the Whale Point site and at a site up in the grasslands. It will be some time before all are up and running, but the plan is to have one instrument platform in each of five major habitats on the reserve: redwood forest, canyon coastal scrub, hillside coastal scrub, grassland, and upland pine/oak forest. These platforms are part of a long-term study of the effects of topography and climate on the vegetation. Daily summaries of the data will be available in a notebook and the raw data on computer disk.
We are having some rock fall with all the rain. In December a group of student volunteers working in the parking lot saw some deer dodging rocks on the slopes above. The next morning a small doe collapsed in the road, dead. We later found that she had died from a rock hitting her back, rupturing the liver. All of us in Big Sur should take this as a warning; it could just as easily happen to a person.
Where were the Harbor Seals? These seals usually return in November, after a two-month absence, to haul out on the beach opposite square black rock. This year they didn't return in large numbers until the first week in January. Does anyone have any knowledge of where the seals might go between August and November (this year: January?). (1/8/93)


March 1993. Last month I attended a workshop in which we learned to use a device which, if certain security problems could be solved, would revolutionize field studies. It is a little walkie-talkie-sized "GPS" receiver, which tells the holder its exact location on the surface of the earth. It does this by means of signals received from 21 satellites orbiting the earth. The breakthrough for field work is that it becomes possible to record the exact locations of objects such as trees, bird nests, rare plants, etc., eliminating the need to tag items and flag them so they can be relocated. The savings in time are enormous (for field workers), and it becomes unnecessary to "litter" the landscape with tags, grid markers, flagging and other apparatus.
The reason this "dream device" is not currently operational is that the US Department of Defense views the system as a security threat and purposely degrades the signals so they cannot provide exact locations. I am told that the coast guard will soon be broadcasting correction factors over the navigation networks, which will enable craft to overcome the signal degradation, but this will probably not work in most inland areas or in the canyons such as we have at Big Creek.
Big Creek rose about 6' on the gauge during mid-January. It washed out the road near redwood camp, and it washed all the sand and gravel off the beach into the cove (the waves brought it back in later). The rains also triggered a collapse of one of the sheer cliffs upstream from my cabin. Two huge boulders fell in the creek (one was about 25 feet long and 15 feet in diameter) and a dozen others fell on the roadbed. Judging from the small number of similarly sized boulders in the stream, and the smooth weathered surfaces of these few, I would say we witnessed a rare event for Big Creek. Perhaps the cliff was weakened seventy years ago when the road was blasted out of the rock.
Spring is here. Millions of shooting star flowers are opening up on the ridges. In the canyon bottom the pink currants and the white milkmaids are in full bloom, and numerous other species are beginning to flower. The willow buds are opening and little twigs or catkins are growing out. The alders along the creek are still dormant but that will change soon. The creek is marvelously clear and the creek bed is scoured clean.
The rains have brought us a new student, Carlos Garza, from UC Berkeley. He will be studying the genetic variability of "meadow mice," or voles. These are short-legged mouse-like creatures with a long pointed nose and a short tail. They eat green vegetation and are capable of bearing huge litters every month or so when there is adequate food. We are expecting a population explosion this summer after all the rain we've had.
All populations of organisms (including voles) depend upon their genetic variability to overcome disease, environmental stress and other adversity. Nowadays, with so many plant or animal populations isolated into small pockets of suitable habitat, it becomes very important to know how such isolation will affect the genetic variability. Carlos' study will look at this in small isolated meadows at Big Creek and at the Hastings Reserve in Carmel Valley. The field work will consist of live-trapping the voles, removing a blood sample for analysis, and releasing them. In Berkeley he will analyze the blood and compare genetic types to measure the genetic diversity of each population. (2/16/93)


April 1993. The land is turning green this spring, and there are a lot of flowers. I have been admiring the lush tufts of bunchgrass growing on the ridges, and the vigorous growth of the shrubs and poison oak. The deer I have seen look fat and healthy, with the bucks just beginning to sprout new antlers and the does heavy and pregnant. We saw a golden eagle the other day soaring up the canyon, and the song sparrows and canyon wrens sing all day long. Spring is here.
Insects are out in abundance (no biting ones yet, though). Right now there are lots of pretty black and white moths flying in the canyon. These moths lay their eggs on redwood sorrel, the sour "cloverleaf" plant that grows under the redwoods. The little caterpillars eat semi-circular "bites" out of the leaves, but are very hard to see because if you disturb them they stand straight up and look like a dead stick or tiny twig. This caterpillar, a kind of inchworm, was "discovered" here at Big Creek during a research project on understory insects. Actually, the adult moth was known already but no one knew what the caterpillars ate or what they looked like.
Please come to our open house Saturday April 3. We will lead hikes and drives around the reserve. The star attraction at the open house will be presentations by the science students from Pacific Unified School in Pacific Valley. All this year they have been working on marine studies projects, and each student has tried to become a "local expert" on their topic.
The students will be writing their reports for a book "Catch a Wave." The material from last year's "Stoked on Oaks" unit has already been compiled, and a draft will be on display at the open house. Kim Smiley attended a meeting last month and presented the program to the environmental science committee of the state department of education. They recognized the unique work that the school is doing, and have suggested that other schools can use the program as a model for developing their own science curriculum. Kim got a grant and will be taking a sabbatical leave from teaching next year to finish compiling the books.
Another reason to come to the open house is to walk the reserve roads. You will appreciate the kind of road work done by Feynner, our land steward. The roads are not always smooth, having erosion controlling water bars every 1-2 hundred feet, but they are fine for slow travel. In many areas they are very attractive. Feynner mows the roads and banks with a brush cutter, and uses the tractor blade to grade and fill only where the bank has caved in or erosion has occurred. As a consequence the roads are lined with flowers and other plant cover on both sides, and there is no open ground for weeds to take hold in. They have the appearance of grassy tracks winding along the hillsides. (3/19/93)


June 1993. Our April 3 open house seems ages ago, but it was well-attended and I would like to thank the 100+ people who visited the reserve. It was a beautiful day. Many visitors were treated to a wonderful "Catch a Wave" experience by the students and staff from the school in Pacific Valley. The projects, activities and skits were very well done.
Spring came very quickly this year, with a tremendous burst of growth. The lilacs seemed to grow about 3 feet overnight, as did the poison oak and rest of the shrubs, herbs, and grasses. The creek developed a substantial algal bloom after the winter flood waters subsided, with strands of algae about 8" long. In mid-May the roots of Coulter's willow, which dangle in the creek, turned bright red. I have not discovered the why this happens nor when to predict its occurrence.
We saw only a couple of steelhead trout in the creek this spring. This makes the third year in a row with greatly reduced numbers of these fish. We did find a Pacific Lamprey nest. This jowls, eel-like fish had cleared a 1 square meter area of algae and was "working" as I watched, poking at the bottom with its snout. It was green-brown, the same color as the algae coating the rocks. It moved slowly and deliberately, occasionally floating down, turning around, and realigning with the flow. It was about 15" long and 1 1/2" in diameter.
In early May I saw a Bald Eagle at the seal beach opposite square black rock. It was standing on a rock with fresh blood on its beak and a pile of small intestines at its feet. The Harbor Seals were whelping their pups and the tiny babies may be vulnerable (some are only about 15" long). Others have suggested to me that the eagle may have been scavenging the afterbirth, but in this case I think a baby was killed. The eagle was a juvenile with partially white-feathered head. I saw it on and off for the next two weeks at the same site.
While kayaking, Feynner saw a Golden Eagle flying low over the water about a mile offshore, apparently looking for fish. This is also unusual behavior, so I am told. Big Sur eagles seem to be unconventional birds.
Sam Stroich, a class instructor and owl expert visited us. He was camping at Highlands camp and I asked him to listen for Spotted Owls since I have heard them before on the reserve and wanted his confirmation. The next day he came down and said he heard one right near camp. A few days later I told this to some botanists staying at the reserve. They said that they had been up below the camp that same night, playing tape recordings of spotted owls to see if they could get an answer. Its too bad Sam didn't answer back or the confusion could have been complete! I guess this is a lesson showing the necessity for good communication among researchers. (5/21/93)


July 1993. This year our marine life seems to be faring poorly. For example, I have seem several emaciated sea lions in the past month, and a young one crawled up our road from the beach and died. Many of the she sea lions resting on square black rock are also very skinny, and several had rows of deep gashes on the side of their bodies. By contrast, the harbor seals seem fat and healthy. The only sign that something might be wrong with them is they had fewer pups this year than in previous years. The other day I counted 230 seals on the reserve, with only 41 pups. In other years the total would have been more like 70.
The cormorants and gulls failed to nest on the rocks around the Big Creek cove, and the pair of black oystercatchers abandoned their nest last week without hatching any chicks. The fishermen report that the fish have empty stomachs, and that the recruitment of new fish is minimal in the kelp beds. It seems as though the weather conditions which brought us rain have "let down" the marine food chain along the coast, and most creatures there are going hungry.
I have been following our young red-tail hawk chicks this month. We first saw them as fuzzy white "tennis balls" about a month ago, and this week the two birds are just learning to fly. They are beautiful animals, with creamy white throat patches and striking patterns of brown, white and gray on the rest of the body. They cry out "Kee," repeated every 2/3 second, and flutter about seeming very clumsy as their parents show them awesome dives and other flying demonstrations.
Last week three students watched a bobcat bring down a young deer and try to kill it! The bobcat was wrestling with it in the trail and biting its throat as it screamed for help. When it saw the students the bobcat ran off leaving the deer panting by the side of the trail. When I went back to look the deer was gone. The bobcat could have carried it off or it may have run off on its own. A few weeks earlier, in the same area, Feynner heard a young deer screaming as though being attacked. In this case he saw three adult deer run to the rescue and apparently succeed in driving off the attacker. Could it have been the same bobcat? It seems quite possible. (6/19/93)


August 1993. Feynner and I have been watching several aerial hornet nests along roadsides in the reserve. Hornets or "Yellowjackets" make nests of paper and live in colonies of a few to several thousand individuals. One common species makes a hanging, or aerial nest, while some other species make ground nests. Each nest has a queen who lays the eggs in paper "cells" which look like honeycomb. The grubs hatch and are fed by the workers (who are older sisters), who feed them caterpillars and other soft-bodied prey. The nests grow steadily during May and June, harvesting the abundant prey available then. Smaller nests mainly produce workers, but as the nests grow the grubs begin to develop into large "reproductives" which may be male or female.
The nests are delectable food for any predators who can deal with the stinging workers. During a single week in mid-June, predators destroyed seven of the eight nests we were watching. The surviving nest was protected under the eaves of the office shed. Nest activity has greatly declined in this nest, indicating that it has "matured," perhaps ready to send out reproductives. (7/3/93)


September 1993. I recently read "Mule Deer Country" by the Canadian wildlife biologist Valerius Geist. According to the book, our coastal "columbian" black-tail deer are derived (long ago) from a form of the white-tail deer. True mule deer, which are the most common deer in the western states except along the coastline, are in fact of hybrid origin between male black-tail deer and female white tail deer. The biologists figured this out because the DNA found in mule deer mitochondria (little energy factories found in every cell of the body, inherited only from ones' mother) is identical to that found in white tail deer. By contrast the regular DNA in mule deer is about a 50:50 mix between the white tail and the black tail species.
The hybrid origin of mule deer fits with another interesting theory about the large animals of North America. Between 10 and 20 thousand years ago there was a very diverse group of large animals including camels, horses, donkeys, ground sloths, dire wolves, saber-tooth cats, as well as bison, black- and white tail deer, mountain lion and coyote. About 10,000 years ago most of these went extinct, perhaps because of human hunters. The survivors altered their habitats and behaviors to take advantage of the lack of competitors, and spread widely into areas to which they were ill adapted. In addition, many new species invaded from Asia including wolves, elk and moose. As a result the current set of animals are not yet adapted to their present conditions, or to each other. For somewhat technical reasons such conditions are suited for the spread of hybrid species. (By contrast, our black tail deer and mountain lions are both "ancestral" North American species and we might expect them to be very well adapted to each others' presence.)
The book pointed out some very interesting differences between mule deer and white tail deer. For example the latter escape from predators by outrunning them along well established trails. Mule deer (and to a lesser degree, our black-tails) escape by "stotting," that is, jumping over obstacles and uneven ground in such a way that a predator has a hard time following. They also stop to look back to see if their escape worked. Another difference is that mule deer will defend themselves and their young against predators rather than just trying to outrun them. The author also thought that Rocky Mountain mule deer had little defense against mountain lions.
Our observations suggest that black tail deer have effective defenses against lions. In spring I described an incident in which some black tail deer drove off a predator, either a bobcat or a mountain lion, which was attacking a young deer. Last month Feynner (the Big Creek steward) watched two large bucks drive a predator out of a clump of lilacs, scattering smaller deer in the process. Later when he checked the site there were tracks of a fairly large mountain lion. This suggests that aggressive defense against predators (including lions) is common in the black tail deer, and that large deer will actively protect smaller ones.
Valerius Geist also suggested that black tail deer may live in clans, which defend territories against other clans. In other deer the females will defend areas against other female groups, but our deer are apparently the only ones in which males and females form exclusive groups. I have never seen this behavior but clan behavior fits well with the dissected topography and mild climate that we have in coastal California. Does anyone have deer stories in which groups seem to aggressively fend off other groups? I would also like to hear of any observations in which deer drive off predators. (8/21/93)


October 1993. Last month I was alerted to a potential health threat in rural areas of California. Known as the "Four Corners Disease" (it killed about 15 people in the four corners area of the Navajo Reservation), the disease has been identified as a new type of hantavirus, which affects the lungs. Hantaviruses are a serious problem in China and Scandinavia where they cause liver disease. Most of the victims in the Four Corners area had been exposed to mouse-infested rooms and sheds. It seems that breathing dust in such areas may cause the disease. Last July in California a university researcher working in the Eastern Sierra Nevada and a ranch worker in Santa Barbara county both died from the disease. Both had been handling deer mice, got flu-like symptoms, and died very quickly from fluid in the lungs.
Deer mice are the most common mouse in our area. They are gray-brown, with pretty white hands and feet and their tails are "two-toned" (light colored below and gray on top), all they way to the tip. They nest anywhere they can find food and nesting material. All of us probably have daily contact with these mice in some way or other, in woodsheds, tool sheds, vehicles (they often make nests in our vehicles if they can get in).
What is the threat of catching the hantavirus disease? Probably quite small. The California Center for Disease Control is studying the problem, but has yet to determine if there is a serious state wide threat. They are catching wild deer mice and surveying them for presence of the virus. In the interim they are recommending that people use caution and try to minimize contact with wild rodents. The most important protection is probably not to breathe or ingest the dust when cleaning mouse-infested areas. Common bleach is known to kill the hantaviruses, so they recommend rinsing everything with bleach water.
At Big Creek Reserve we had to react more strongly since one of the two California deaths happened to a university researcher. We surveyed our facilities for mice and "mouse proofed" one vehicle and one tool shed. The other facilities were mouse-free, thanks in part to the house cats and our "open" building and shed design allowing cat access. I am on a mailing list for Hantavirus bulletins and will pass any new information along that I receive.
Other notes: The fish in the kelp beds offshore made a strong comeback in August. Lots of juvenile rockfish recruited into the kelp beds, 2-3 months later than usual. Apparently the upwelling got going very late, bringing in the juveniles and getting a plankton bloom started. This happened just in time for the fish researchers, who were beginning to worry that they wouldn't have any subjects to study this year. The sea lions finally had fish to eat and look much healthier than they did in the spring. The red tail hawks that fledged from the Whale Point nest have moved away from our immediate area. However, Feynner saw two adult hawks, possibly the parents, chase a golden eagle away from the canyon. They may have been protecting the young ones. (We have seen instances of eagles consuming red tails at Big Creek.) Small flocks of pigeons are common on the reserve. Many are eating the coffee berry fruits. It looks as though there also will be a good crop of bay fruits this fall. (9/22/93)


November 1993. Last month I received a copy of Cheryl Briggs' dissertation report. She won an award at UC Santa Barbara for the best dissertation project of 1992. Cheryl did her field work at Big Creek looking at gall midges on coyote brush. I wrote about her study a couple of years ago, just as she was getting started. Her studies are important since they help tell us how to control pests using biological agents rather than pesticides.
Gall midges are tiny insects that lay eggs on the growing shoots. The eggs hatch and the little grubs bore into the plant, somehow stimulating the plant to grow a swollen, fleshy gall. The grubs live and grow inside the gall, finally producing an adult midge which crawls out, mates, and starts a new generation. Midges eventually kill the plant if their numbers grow unchecked. This seldom happens because tiny wasps attack the midges. One species attacks the midge eggs (it is really small) and the other attacks the larvae in the gall. Based on these and other facts about the wasps Cheryl predicted that the egg-attacking wasp would control the midge much more effectively than the larva-attacking wasp. She set up cages over coyote brush plants to test her ideas, putting midges and wasps in each to see the effects.
Despite 500 hours sitting in cages and counting tiny insects (in all kinds of weather), Cheryl's experiments didn't work as planned. The tiny wasp found its way into all the cages, and the larger wasp could not establish in any of the cages. However, she had recorded detailed information about what happened inside and outside the cages at Big Creek, and she was able to use the data to study a related problem: what happens when midges are unable to travel between plants? What she found is that galls and wasps on uncaged plants were synchronized, with a peak in numbers half way through the study. This happened because the insects could travel between plants, leveling off any variation in numbers that might start to appear. By contrast the abundance of insects on the caged plants was extremely variable and unpredictable. Cheryl was then able to fit her data to what is called a "metapopulation" model, a mathematical formula developed by workers studying subdivided biological populations.
Cheryl's success derived from the fact that she took her data carefully and thoroughly, even when things weren't working very well, and that she was clever enough to adapt her study to a different end. She also learned a hard lesson about field experiments: they seldom work the first time. It's a fact that most scientific field studies must be repeated two or three times before the "bugs" are worked out. Cheryl is now living in England working at a laboratory which specializes in these kinds of questions.
Other notes: Feynner, our reserve steward, watched a golden eagle try to kill a deer. It kept swooping on the deer, driving it up the canyon walls. When the deer was in a precarious place the eagle "sneaked" up the slope, turned around and came down the slope flying low and fast. It hit the deer on the flank and knocked it down. The deer tumbled about 20 feet, sprang to its feet and ran into a thick patch of lilacs. The deer could easily have broken a leg, in which case the eagle would probably have had a very large meal. The deer weighed perhaps 100 pounds and would not normally be vulnerable to a ten pound predator. However, golden eagles are known to sometimes kill large prey stranded in the open, lacerating the back with beak and talons. (10/19/93)



December 1993. Spring is here! Sort of. Our first rains along the coast really are a kind of California pre-spring. Seedlings are germinating and the land is beginning to green up. The buckeyes will put out leaves, and hordes of migratory birds will descend on our insects, seeds, and berries. Today I saw dozens of flickers, which are ground-feeding woodpeckers. They peck holes in the ground, looking for ants, termites, and other insects. The holes cone-shaped and usually about 1" deep. In one case I found a long row of holes where a flicker had followed a termite tunnel. The holes were about 9 inches apart, which is about twice the length of a flicker's tongue. I also have seen hundreds of hermit thrushes, one of our most abundant winter residents. They skulk around in the undergrowth, eating bugs and berries. I also saw some up in the madrone trees eating the berries.
This is the best crop of madrone berries I have seen since moving here in 1986. The wild band-tail pigeons have been eating the berries in quantity. The acorn crop this year seems average, much better than last years'. The acorn woodpecker granary trees are 50-75% full, whereas last year they were virtually empty. Interestingly, the woodpeckers seem to have passed the bad year fairly well, since the colonies seem intact. Perhaps they were able to switch to other foods. Woodpecker colonies in Carmel Valley (at the Hastings Reserve) have been known to fail during years when the acorns fail.
The proposed Big Creek Marine Reserve seems to be on track for official designation January 1. This will make official a cooperative program we started about five years ago to set aside a marine life refuge for research and teaching. We are now working on plans for some new research projects in the reserve, and will continue the projects underway. The combination of pristine marine and terrestrial habitats is unique, and is something to protect and be proud of.
We also had a meeting with our local hook-and-line fishermen (at Pacific Valley school) to discuss the cooperative fishing project. The goal of the project is to see how well fishermen can monitor the fish populations they are harvesting. The primary method is to get them to save the first five fish of each days' catch, and then to identify, weigh, and measure the fish. The sizes are then plotted on graphs and the results compared from place to place and year to year. After two years' data it is clear that good estimates for six of the more common species may be obtained from about 60-80 samples. Biologists from the Department of Fish and Game also attended and were very interested in the project. The long term goal is to develop techniques, which can help fishermen harvest their fish in a sustainable way. (11/19/93)


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