DISCOVER MAGNIFICENT MORRO ROCK – Explore the beauty of Morro Rock and learn about its geology and history and the species that live on and around the rock. Meet near the rest rooms at the northeast parking lot in front of the Rock. Bring binoculars and a jacket. (E) .5 mi., 1-1.5 hours





I.                   INTRODUCTION AND THEME  (near the rest rooms)


        Welcome and Introductions

        Hand out binoculars

        THEME: Magnificent Morro Rock, standing as a sentinel at the entrance to Morro Bay harbor for centuries, supports a unique ecosystem and several endangered and threatened species that live in its shadow. Please enjoy your visit here and help us preserve its beauty and its many species for future generations to enjoy.

        The name El Moro or Morro means domed turban, knob or knoll and was given to the rock by Portuguese explorer Juan Cabrillo who sailed into Estero Bay in 1542.

        The nine sisters – the Morros of San Luis Obispo County

There are actually 14 peaks extending from Morro Rock to south San Luis Obispo near Tank Farm Road and the SLO airport but only 9 have names.

(If asked, they are:       Islay Hill, (775 ft.), San Luis Mtn. (1292 ft), Bishop Peak (1559 ft), Chumash Peak (1257 ft.), Cerro Romualdo (1306 ft.), Hollister Peak (1404 ft), Cerro Cabrillo (911ft.), Black Hill (665 ft.) and Morro Rock).

        Morro Rock is about 576 feet and covers about 55 acres, the small rock in front is Pillar Rock.

        Let’s move onto the beach area for a better look at the Rock on the north side.



(Move to Morro Strand State Beach near the rock and the water)

        Born 20+ million years ago in Southern California near Baja, California Rock est. - 22 million years, others older. The area was then undersea.

        Plate tectonics – offshore Pacific Plate moving under the North American Plate scraping rock forming the sisters and the coastal ranges. Plates moving past each other at San Andreas Fault (east of Paso Robles & Atascadero) causing earthquakes and moving the sisters northwest.

        When the seas subsided about 10 million years ago, the peaks became visible. No ones knows how active they were but the cones eroded over the centuries, rock dust filled crevices and seeds took hold sprouting plants to provide shelter for animals and birds.

        Dacite rock – Morro Rock is dacite, an igneous (volcanic) rock similar to granite. It is composed of potash, feldspar, calcite and quartz.

        The local Chumash Indians used the Rock as a navigational tool in their canoe trips along the coast but did not camp here. It was thought of as sacred in their culture. The closest village was near where the power plant is today.

        After Cabrillo’s visit in the mid-1500s, the next European explorer was Captain Don Gaspar de Portola travelling by horseback from San Diego to Monterey in 1769. Fr. Juan Crespi, the diarist for the trip noted in his journal that Rock was completely surrounded by water and about 200 meters offshore (photo of Morro Rock before blasting).

        Degradation of the Rock by man began about 20 years after the founding of the town of Morro when blasting of the rock began (1891).  (Info about planned tunnel and blasting party).It provided building materials for a breakwater at Port San Luis near Avila, the causeway to connect the Rock to the mainland (1933-35), breakwaters for Morro Bay and to repair the breakwater here (photo of blasting at Morro Rock and use of same plan as Long Beach harbor and result). About 1.2 million tons of rock  was blasted.

        Man’s devastation of Morro Rock finally ended in 1963, 70+ years after it began, after public outcry over the degradation to the rock and its environment. You can see significant damage from here and we will see more on the other side (photo after).

        In 1968, Morro Rock became a California State Historical Landmark and five years later an Ecological and Natural Preserve protecting the endangered Peregrine Falcon. Climbing has been prohibited since then.


        Peregrine Falcons (photo) nest on the rock every year from late February through June or early July. They have nested here for centuries. The Chumash revered the Peregrine as a god. There were two nests (called eyrie) on the Rock this year, one on the southwest side and one on the northeast side. The falcon is a medium sized bird about 18 inches (female, male 2 inches shorter) long with a wingspan of over 3 feet. They weigh 1.5-2 lbs. It has a dark gray back and gray and white barred under parts and a squared-off tail. The head is black above and white below and it looks like it has sideburns! The young fledglings are tiny when born (1 oz.) and have white down but at a month they start sprouting their brown and white feathers. The falcon is the fastest animal in the world, diving at 200 mph for prey that it catches in the air. They were once fairly common along the coast but suffered from the introduction and widespread use of DDT beginning in the 1950s, which caused thin eggshells that did not hatch successful young. Although DDT was banned in the US in the early 1970s, it is still sold in Mexico and Central America where the falcons prey live in the winter and it is still present in the food chain. Extinction was averted with the help of the Santa Cruz Predatory Bird Research Center at UC Santa Cruz and other research facilities in the Mid West and East Coast where baby falcons were hand-raised and replaced thin and broken eggs in the nests. Many local bird fanciers in Morro Bay also helped by guarding the nests. Today the falcon is making a comeback. There were two nests on the Rock with 4 fledglings in 2001 and 2002. The birds use a different nest site each year in the same area and when they form a pair they will often close to the areas where they were born. Males claim territories, generally large ones of several miles so it is unusual to have 2 nests on Morro Rock even though they were on opposite sides.


What can we do to help the Peregrine Falcon? Please make sure you properly dispose of dangerous household and agricultural chemicals so they do not get into the environment where they can affect wild animals as DDT did to the Peregrine Falcon. Also make sure you do not drop lit cigarettes near the rock as the vegetation that we will see on the next stop is very dry particularly in summer and can easily catch fire.



        There is another threatened species nesting further up Morro Strand beach and on the sand spit across from the rock that we will see later – the Western Snowy Plover (photo). This small shorebird weighs about 1 to 2 ounces and is approximately 6 to 6.5 inches long. It is gray-brown, white, and black. The Plover nests from March-September on the Pacific coast beaches. There are only about 1500 left due to the degradation of their nesting grounds and interference from man and his pets. (No dog signs) (Birds & Nature at Morro Strand)


        There is a small tide pool at the base of the rock facing the beach that is visible at a minus tide. There you can see surf grass, sea stars, mussels, anemones, snails, algae, small fish and many other tiny creatures. Now let’s move closer to the rock on the causeway. (Other tidepool walks)



 (Move to the path head on the northeast side of the rock)


         The vegetation on and around the rock is chaparral that is tolerant of the windy, salty and sometimes dry conditions. Plant life here includes white and golden yarrow, fennel, California sagebrush, nightshade (white and purple), black mustard flower, blackberry, fog lichen (on the rocks), sticky monkey flower coast salt bush, chamise, arroyo willow, cactus, sea rocket and poison oak. Sometimes we will see butterflies, moths and dragonflies in these vegetated areas. During the winter breeding season, the Monarch butterfly (photo) is often seen here. What can we do to help the butterflies and other insects? You can see how dry the vegetation is here – a real fire hazard so be careful with lighted cigarettes. Plant native plants that butterflies & other insects can nest upon.  They visit our garden flowers to collect nectar but nest on native plants.  And remember not to step on caterpillars – they turn into beautiful butterflies.

        Gull and cormorant nests are visible here and cormorants (Brant and pelagic) out on Pillar Rock. Males of these species vie with each other for the best, most protected nesting sights and this can lead to some loud fights, conducted in the air. The cormorants are great fishing birds with heavy bones so they can stay under water longer but need to dry out their wings by spreading them when they land on the Rock..  Double crested cormorants we see flying and fishing here near the rock nest at the rookery.

        We can now see the Dacite (igneous) rock –Let’s examine it closely. You can clearly see the colors of the dacite here when wet and dry. The orange highlights are iron oxides. We can also see clearly and up close the scars of the seventy plus years of blasting.

        Let’s move to the other side of the causeway.  (Stop by plaque on way and point out falcon nest on South side.)



(Move to the parking area on the side of the road facing the harbor near the kelp beds)


        {Sea otters may be present fishing in the channel or resting in the kelp beds.} The sea otter is a member of the weasel family who took to the sea millions of years ago (photo). This marine mammals relatives include the river otter, the weasel, the American badger, the mink and the skunk (yes the skunk!). This animal was hunted nearly to extinction for its beautiful warm fur coat which helps it to stay warm in our 50 + degree water. Other marine mammals have a layer of thick blubber to stay warm but the otter‘s fur, which it keeps well groomed, serves this purpose. It also must eat a lot of food to help stay warm – more than 20% of their body weight each day (60-80lbs average weight of adults)! It is listed as a threatened species as there are only about 1900 – 2000 left in the Central California range, extending from near Santa Cruz to South of  Pt. Conception. There is another colony of slightly larger size in Alaska and a small one offshore Russia.  Sea otters swim on their backs, eating clams, abalone, sea stars, octopus, sea urchins and other crustaceans. They help keep the kelp forests healthy by eating the urchins that destroy the kelp beds. Sea otters are one of only a very few mammals to use tools, rocks to pound clams and abalone shells off their rocky resting-places and to open clams and other bivalves. We often see otters here in the kelp beds near the causeway and feeding in the harbor channel. Many are males but sometimes a female with a pup will appear near the Embarcadero area across the Bay. Other places to see sea otters are offshore off Montana de Oro, in the kelp beds north of Cayucos, sometimes offshore of Morro Strand Beach and near the rocks and kelp beds close to the Sea Otter Research Station at Piedras Blancas Lighthouse north of San Simeon. (Sea otter and forest walk) 

        What can we do to help the sea otters and other marine mammals? Please pack your trash when you go to the beach clean up after your pets on the beach; be careful when disposing of chemicals and used oil and do not harass or try to feed these lovely wild animals. They, like all sea mammals, are very sensitive to oil spills so if you are boating, make sure your engines are well maintained and use public restroom pumping stations at the wharfs. Many of these charming animals from the Alaska population were killed during the Exxon Valdez oil tanker spill when oil fouled their coats and they died from exposure and ingesting oil.  They are also very susceptible to diseases carried by improperly treated sewage and animal wastes.


        Another sea mammal often seen feeding in Morro Bay is the harbor seal (photo). There is a resident colony south of the marina in Morro Bay State Park. They can also be found at Port San Luis near Avila Beach, hauled out on the rocks at Corallina Cove in Montana de Oro State Park and also on rocks north of Cayucos. Harbor seals are gray with darker spots and a rounded cat-like head. They have their young on sandbars or mud flats and the pups can swim within a few hours of birth.

         Franklin Riley founded the town of Morro (now Morro Bay) across the Bay from where we are standing, in 1870. Another early settler and town father was the Rev. Alden B. Spooner I who ministered to the Protestant population in the region, served as town constable and piloted ships entering treacherous Morro Harbor. He died outside the harbor entrance in 1877 while trying to pilot a ship into harbor. The town was incorporated as a city in 1964.

        The large electricity plant with the 3 tall stacks in front of us is the Duke Energy, constructed by PG&E in mid-1950s, sold to Duke in 1990s.

        The Sand spit across the harbor entrance is the 7 mile long Morro Dunes Natural Preserve (another snowy plover nesting area and usually has lots of brown pelicans on the beach resting).

         Discuss other birds visible

         Brown & white pelicans fly overhead and rest on the sand spit (brown) and Grassy Island near the marina (white). (photos)

         Great & Snowy Egrets & Great Blue Herons are often seen flying (photo)  overhead or feeding in the bay as they nest in the Heron rookery across the Bay near the Museum. Nesting season is January- June.

         The annual Audubon Christmas count shows many bird species using the Rock and surrounding beaches as this is part of the Pacific flyway for birds migrating from Mexico to the Arctic. These include the black crowned night herons, double crested Brant & pelagic cormorants, red shouldered hawks, surf and black scooters, the common loon, grebes, oyster catchers, several species of owls, gulls and shorebirds and many land species such as chickadees, finches, wrens, warblers, bushtits, cliff swallows and even turkey vultures.

        Other animals include many ground squirrels, lizards and insects, including moths, butterflies and dragonflies.

        Let’s move to the south side near the beach.



(Walk to rocky area above the beach and near the breakwater – point out falcon nest)

        The harbor entrance and breakwater areas are very dangerous places because of the high waves and strong ocean currents. Often there are “rogue waves” that crash over the rocks and breakwater even on a seemingly calm, sunny day. Many sailors have lost their lives in boating accidents here and other people have been washed out to sea from the rocks near the breakwater and the south area of the Rock. Wave trains come down the coast from the Gulf of Alaska and their impact on the breakwater can be 3000 lbs. per square foot of breakwater. A wave train can take 2 days to travel the 2000 miles over deep water.

        Morro harbor is 4 miles long by 1.75 miles wide and includes about 1450 acres of mud flats, eelgrass, pickle weed marsh and salt marsh. It is one of the last relatively unspoiled estuaries on the Pacific Coast.  The harbor entrance is dredged every 2-3 years due to the positioning of the breakwaters, the closure of the north entrance, silting from creeks entering the Bay and sand blowing from the sand spit. The harbor entrance was dredged last winter (2001).

        Gray whales (photo), the California marine mammal, pass Morro Bay from December to March on their 12,000-mile journey from the Arctic to Mexico and return. They are usually not visible from the Rock due to the fog but it is fun to go out on a whale watching boat from Morro Bay.

        Sea lions (photo) can sometimes be seen in the harbor especially in the fall during the anchovy season (July & August). They can also be seen offshore on rocks north of Morro Bay. The humpback whales (photo) also come from Hawaii to feed on the anchovy.  We can see them blowing from the rock and the beach and again from the whale watching vessels.  The huge elephant seals (photo) haul out on the beach near Piedras Blancas lighthouse north of San Simeon and it is worth the trip to see them.

        On this side of the Rock we can see many holes formed from erosion by sand and wind. The nesting birds take advantage of them by building their nests in them since they are better protected from the weather than those on the ledges. The bird droppings we see aid in fertilization of plant material growing on the rock here. 

        What can we do to help the birds and animals on and around the rock? Remember to pack your trash and be careful with lit cigarettes. Please do not feed the birds and animals, french fries and bread are not a normal part of their diets and some of our foods might make them sick. The many ground squirrels here may carry fleas that can transmit plague so keep your children away from them.  If you come to the Rock or the small beach here with your animals, please keep them leashed and pick up after them. Don't throw rocks or other objects at the sea otters, birds or other animals and certainly do not shoot at them.



(Return to starting point or at harbor entrance area)


        Thank you for visiting Morro Rock. Remember that the Rock supports a unique ecosystem and several endangered and threatened species. Please enjoy your visit here and help us preserve the Rock and its many species for future generations to enjoy. We hope you’ll come again. We ask that you take only photos and leave only foot prints.

        Retrieve binoculars, answer any other questions

        Handout CCNHA newsletter, application

        Other handouts (Welcome map. Morro Bay National & State Estuary)

        Encourage a visit to the museum – give directions





Gates & Bailey, Morro Bay’s Yesterdays

Krause, Anthony, Wildlife Watches Guide to San Luis Obispo County

Dickerson, Sharon, Mountains of Fire


Items needed:

(Refer to the Morro Walk photo archive (this is a password protected directory only, no web page) of photos for docent training and visitor education for Morro Rock walk (docents can request a user-id and password to browse this directory))

Photos of:

        Peregrine falcon

        Snowy plover

        Sea otter

        Harbor seal

        Gray whale/ Humpback whale

        Sea lions & elephant seal

        Blasting at Morro Rock

        Morro Rock without causeway and breakwaters

        Morro Rock after


CCNHA newsletters

Other handouts Docent Pages
Revised Monday, February 18, 2008 01:27:44 PM