WESTERN BIRDS

Volume 14, Number 4, 1983

MARIN COUNTY HERON COLONIES: 1967-1981

HELEN M. PRATT, PointReyes Bird Observatory,4990 ShorelineHighway, Stinson Beach, California 94970

Like all birdsdependent on freshwaterand marine wetlands,members of the heronfamily are sufferingprogressive loss of essentialhabitat. In addition, agriculturaland industrialpollution threatens their capacityto reproduce. Great Blue Herons (Ardea t•erodia$)and Black-crownedNight-Herons (_Ny½- ti½oraxrwcti½orax) have declinedin partsof their range and have been placed on the NationalAudubon Society'sBlue List of species"which have recently givenor are currentlygiving indications of non-cyclicalpopulation declines or range contractionseither locallyor widespread"(Tate 1981). Most heronsnest in conspicuous,often widely separatedcolonies. Some colonysites are usedrepeatedly for many consecutivenesting seasons; others are desertedafter a few years and new coloniesare establishedelsewhere. Sites are sometimes reoccupied after several years of inactivity and the numberof birdsmay increaseor decreasedramatically. Evaluation of popula- tion trendsrequires knowledge of both the historyof activeand inactivecol- onieswithin a region and the populationchanges in individualcolonies. Thispaper presentsdata on the location,population level, and historyof 11 heron coloniesknown to have been occupiedbetween 1967 and 1981 in Marin County, California(Figure 1). Its purposeis to providea baselinefor future comparisonsby indicatingcurrent and past status. Marin County liesbetween approximately latitudes 37 o 50' and 38 ø 20' N, and longitudes122 ø 28 • and 123 ø 00' W. It bordersthe PacificOcean on the westand San FranciscoBay on the southand east.It isrich in tideflats and estuariessuitable for foraging herons and egrets.That Grinnell and Miller (1944) listed no Great Blue Heron coloniesin Marin County as of 1943 is probablybecause ornithologists were not as familiarwith the area as they are today. One Marin County heronry is known to have been occupiedsince at least 1941; the other sitesare of more recent or intermittent occupancy. WesternBirds 14: 169-184, 1983 169 MARIN COUNTY HERON COLONIES

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170 MARIN COUNTY HERON COLONIES

The speciesnesting in Marin Countyinclude the GreatBlue Heron, Great Egret(Casmerodius albus), Snowy Egret (Egretta thula), and Black-crowned Night-Heron.Great Blue Herons nest at 10 colonies,Great Egrets 5 colonies, and SnowyEgrets and Black-crownedNight-Herons only 1 colony. METHODS Estimatesfor the numberof breedingpairs at nine colonieswere basedon total activenests. Counts were made with binocularsand spottingscopes from hillsidesnear colonies where it waspossible to determinewhether or not nests wereactive. Nest counts were made by the authorexcept as otherwise noted. I estimatedthe sizeof the InvernessPark colonyfrom nestcounts augmented by reportsfrom other observers of the numberof flyingherons seen early in the season.At the West Marin IslandColony the estimatesfor 1965, 1979 and 1981 were of occupiednests. I alsoinclude counts from 1973 through 1981 of the maximum number of birdsseen on or feeding near the island. Thesecounts were made from shorewith a spottingscope at a distanceof ap- proximately1.2 km withonly one sideof the islandvisible. They maybe com- pared with each other to indicatepopulation trends but do not providean estimate of the number of occupied nests.

COLONY DESCRIPTIONS AND HISTORIES

AUDUBON CANYON RANCH Audubon Canyon Ranch (Figure 2) is a wildlife sanctuaryand nature educationcenter located on ShorelineHighway about 5.8 km north of Stin- son Beachon the eastside of BolinasLagoon (Figure1). Great Blue Herons and Great Egretsnest here in Coast Redwoods (Sequoiasempervirens). In 1969 about five pairsof Snowy Egretsalso nestedin the colony. It is impossibleto date the establishmentof thiscolony, but sincethe treesat Audubon Canyon Ranch were cut during heavy logging that started in westernMarin Countyin 1849 (Masonand Barfield1973) and the nestsare in secondgrowth, it probablydoes not predate the late 1800s. M. Galloway (pers•comm.), a former residentof the ranch, reportsthat the colony was well-established and active in 1941 and included both Great Blue Herons and Great Egrets.Although Great Egretswere known to breed in the San Joaquin Valley in the 1920s (Moffitt 1939), the firstrecorded observation of a Great Egret in the San FranciscoBay region between the time when they were almostextirpated by plume huntersin the 1880s and their reappearanceafter being protected, was in October 1924 (Stoner 1934). Stoner (1934) also reported an observationof seven Great Egretsat Bolinason 7 May 1929. Bolinasis 5 km from AudubonCanyon Ranch on the oppositeside of Bolinas Lagoonand egretscurrently sighted there at that time of year are known to be from the Audubon Canyon Ranch breedingpopulation. Because the Great Egretpopulation is usuallyat itsmaximum during May, the egretsreported in 1929 probablywere breedingat AudubonCanyon Ranch. Great Egretshave joined establishedGreat Blue Heron coloniesat other sitesin Marin County (seebelow), and they might well have done the same here. From 1967 through1981 the Great Blue Heron populationranged from 27 to 62 breedingpairs with a decliningtrend since 1973 (Table 1). The Great 171 MARIN COUNTY HERON COLONIES

Egret population increasedduring the same period from 70 pairs to 148 (Table 2). Details of nesting successfor 1967 through 1973 have been publishedpreviously (Pratt 1970, 1972a, 1972b, 1974). DA SILVA ISLAND The Da Silva Islandcolony is on the southside of a hill known as Da Silva Island,which borders at the north end of the RichardsonBay bridgein Mill Valley (Figure 1). The hill is approximately95 m from U.S. Highway 101, and though not an island now, may have been one before developmentof the area. It isprivately owned and there are severaldwellings closeto the colony. Great Blue Herons nest here in Eucalyptussp. The colony was first oc- cupiedin 1979 by fivepairs and wasoccupied again in 1980 and 1981 (Table1). HOME BAY Great Blue Herons nestedin live oaks (Quercu$sp.) on the northwestside of the southfinger of Home Bay, a branchof Drake'sEstero in the PointReyes National Seashore (Figure 1), in 1968 and 1969 (Table 1). There are no reportsfor 1970-1978. In 1979 there was an unverifiedreport of two or three nests. I was unable to find nests there in 1980 but found one in 1981.

INVERNESS PARK Thiscolony is on privateland in a clumpof Douglas-fir(Pseuclotsuga men- zie$ii) (Figure3) growingat the edge of Sir FrancisDrake Boulevard 2 km south of Inverness(Figure 1). It was first reported occupiedby Great Blue Herons in 1972 by the residentof a houseopposite the colony. It may have been inactivein 1973 but was occupiedagain at leastby 1975, the year that Great Egretsfirst nested there. Estimatesof breedingpairs are highlytentative

Table 1. Numbersof breedingpairs of Great 131ueHerons at Marin County colonies from 1967 through 1981. Dashesindicate known absenceof birds. U = Nest counts unavailable;herons may or may not have been nesting.

1967 1968 1969 19701971 1972 1973 1974 1975 1976 1977 1978 1979 19801981

Audubon Canyon 50 62 55 50 44 46 58 48 45 40 41 43 35 33 27 Da Silva Island 5 5 3 Home Bay U 2 a 3 a U U U U U U U U U U -- 1 Inverness Park U U U U U 16 -- U 4 3 4 3 U 12 8 Nick's Cove U U U 23 a U U U 23 28 23 24 16 a U 18 15 No San Pedro Rd 1 1 1 1 2 1 4 4 3 Olema U U U 26 a U 19 b -- Sand Poin! U U U U U U U 25 7 U U U U U 16 SchoonerBay A & B U U U U U U 15 15 12 9 -- 7 7 7 3 Stafford Lake 8 a U U 5 a U U 5 c 14 21 U 21 19 16 27 23 aCaliforniaDep. of Fish & Game, unpubl. data bRichardBrown (pers. comm.) cAlice Williams (pers. comm.)

172 MARIN COUNTY HERON COLONIES

Figure2. Audubon Canyon Ranch Egretsare visibleoccupying nests in treesbehind the ranch house Photo by Clerin Zumwalt

173 MARIN COUNTY HERON COLONIES because the nests are unusually difficult to find. The Great Blue Heron population has probablybeen as high as 16 pairs and as low as 4 (Table 1). There have been as many as 12 Great Egretpairs but usuallyfewer (Table2). NICK'S COVE This colony is on private land in a eucalyptusgrove about 0.5 km east of Nick's Cove on Tomales Bay (Figure 1). I have no recordsprior to 1970, when the colony contained23 Great Blue Heron nests,but it had likely been occupiedbefore that date. Great Egretsnested there in 1974, with five nests, probablyfor the first time. Their late arrivalthat year (early June compared with late April in 1975 and 1976) suggeststhat they moved to Nick'sCove after experiencingnesting failure at another colony. The Great Blue Heron population has remained fairly stable (Table 1). The Great Egret nest count has fluctuated between 5 and 15 (Table 2). NORTH SAN PEDRO ROAD The North San Pedro Road colony (Figure4) is on private property at the edge of about 3 km southeastof the Marin County Civic Center (Figure 1). Great Blue Herons nest here in live oaks and Madrone (Ar- butus menziesii). One heron pair nested here for the first time in 1971 (L. Boyd pers. comm.). Exceptfor 1974 and 1975, when no heronsreturn- ed, there were between one and four neststhrough 1981 (Table 1). OLEMA This colony was locatedin the Point ReyesNational Seashore in Douglas- firs about 1.5 km northwestof the SeashoreHeadquarters at Olema (Figure 1). The colony had 26 Great Blue Heron nestsin 1970 and 19 in 1972 but has been inactive since then.

SAND POINT The Sand Point colony is on private land on the east side of Tomales Bay between Sand Point and Tom's Point about 2 km southeast of Dillon's Beach (Figure 1). Great Blue Herons and Great Egretsnest here in eucalyptustrees. Heronshave occupiedthe colonysince at least1974 (Table 1) and the egrets joined them sometimebetween 1976 and 1981 (Table 2).

Table 2. Numbers of breeding pairs of Great Egrets at four Marin County colonies from 1967 through 1981. Dashesindicate known absenceof birds. U = Nest counts unavailable;egrets may or may not have been nesting.

1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981

Audubon Canyon 70 74 86 85 85 96 99 96 85 65 84 88 98 103 148 Inverness Park 3 4 12 2 U 1 -- Nick's Cove U U U -- U U U 5 15 13 6 12 a U 6 5 Sand Point U U U U U U U U U U U U 6 aCaliforniaDep. of Fish & Game, unpubl. data

174 MARIN COUNTY HERON COLONIES

Figure3. InvernessPark heronry. Photo by Helen M. Pratt

Figure4. NorthSan PedroRoad heronry.Nests were in the treesbehind and to rightof the large tree in left foreground. Photo by Helen M. Pratt

175 MARIN COUNTY HERON COLONIES

SCHOONER BAY A AND B The Schooner Bay A colony is about 0.5 km south of Sir Francis Drake Boulevard behind the dwellings at the Johnson Oyster Company on the northeastshore of Schooner Bay, a branch of Drake's Esteroin the Point ReyesNationa! Seashore (Figure 1). Great Blue Heronsnest here in eucalyp- tus trees. This colony was first occupiedin 1963 (C. Johnson pers. comm.) and exceptfor 1977 hasbeen active every year through 1981 {Table1). The Schooner Bay B colony (Figure 5) was first reported to me in 1981 (D. Shufordpers. comm.). It is directlyacross the bay within 0.5 km of Schooner Bay A. Of the five nestsin 1981, two were successfulGreat Blue Heron nests. The other three were unoccupiedat the time of my 24 June visitand showed no signsof heron occupancysuch as splashor eggshellson the ground. They may have failed early or were builtthe year beforebut not usedin 1981. The Schooner Bay sitesare so closetogether that I currentlyconsider them to be one split colony. STAFFORD LAKE This colony (Figure6) is on the islandin StaffordLake about4.5 km westof Novato on South Novato Boulevard (Figure 1). The lake and island are owned by the North Marin Water District.Great Blue Heronsnest here in live oak and California Bay (Umbellularia½alifornica). They first nested here in 1962 (W.H. Melson pers. comm.) and the colony has become one of the three largestGreat Blue Heron coloniesin the county (Table 1).

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Figure 5. Schooner Bay B. The heron nestswere in the small grove of trees on the far side of the bay. Photo by Helen M. Pratt

176 MARIN COUNTY HERON COLONIES

Figure6. StaffordLake heronry. The nests were concentrated intrees on the left third of the island. Photo by lan Tait

Figure7. West Marin Islandheronry. Photo by lan Tait

177 MARIN COUNTY HERON COLONIES

WEST MARIN ISLAND West Marin Island (Figure7) is one of a pair of smallprivately-owned islands in San FranciscoBay about 1.5 km offshorefrom Loch Lomond Yacht Har- bor in San Rafael (Figure1). Great Egrets,Snowy Egretsand Black-crowned Night-Heronsnest here in CaliforniaBuckeye (Aesculus californica), live oak and coastalscrub. This sitewas not mentionedby Grinneland Miller (1944) but it was activein 1957 and had been "growingfor many years"(Ralph and Ralph 1958). Stoner (1934) reportedoccurrences in the early 1930s of Great Egretson the southernand easternshores of San FranciscoBay but none north of the . Judgingby thisreport Great Egretsdid not colonizeWest Marin Islanduntil at leastthe late 1930s or early 1940s. Snowy Egrets,like Great Egrets,were almostwiped out by plume hunters and were thoughtto be extinctin Californiaby 1900, but by 1908 they were beingrecorded again and in 1943 were consideredfairly commonin suitable habitat (Grinnell and Miller 1944). They had been nestingon West Marin Islandfor at least5 yearsin 1957 (Ralph and Ralph 1958). At that time it was the northernmostbreeding site for Snowy Egretsin California. Black-crownedNight-Herons could have been nestingunobserved on West Marin Islandbefore either of the egretsarrived. Grinnelland Miller (1944) describedthem as "varyinglycommon almost throughout (the) state."There was a colony of Black-crownedNight-Herons on BelvedereIsland in 1938 (Moffitt1939) butdevelopment forced them to move. They may havegone to West Marin Island, perhapsjoining an establishedcolony. In 1957 Ralph and Ralph (1958) estimatedthat there were 1000 Great Egrets, 400 Snowy Egrets and 600 Black-crownedNight-Herons on the island.Although not stated, this estimateprobably included both adultsand young. According to an unpublishedCalifornia Department of Fish and

Table 3. Maximum numbersof individualsof Great Egrets,Snowy Egretsand Black- crownedNight-Herons seen on or feedingnear WestMarin Islandfrom 1973 through 1981. Data providedby RosaroundDay.

Black-crowned Great Egret Snowy Egret Night-Heron 1973 125 418 105 1974 148 674 30 1975 139 332 140 1976 116 369 125 1977 115 315 70 1978 136 874 67 1979 120 494 98 1980 135 570 90 1981 168 640 62

178 MARIN COUNTY HERON COLONIES

Game report(Anon. 1965), the colonycontained 100 Great Egret,25 SnowyEgret and 100 Black-crownedNight-Heron nests in 1965but it had beeninactive for severalyears prior to that date.My estimatesmade from a boatcircling the islandin May 1979 were58 GreatEgret, 262 SnowyEgret and 98 Black-crownedNight-Heron nests. On a similarsurvey on 20 June 1981, I estimated75 GreatEgret, 325 SnowyEgret and 109 Black-crowned Night-Heron nests. Table 3 shows counts made from 1973 through 1981 of maximum numbersof individuals,including both adultsand fledgedyoung, seen on or feedingnear the island.Counts for allthree species varied during this period without showingclear trends. An adult Little Blue Heron (Egrettacaerulea) was seenon West Marin Islandin August1965 (Chaseand Paxton 1966). Nesting was suspected but not confirmed.Dead young first identified as LittleBlue Herons were later foundto be SnowyEgrets (Unitt 1977). I knowof no subsequentreports of Little Blue Herons nestingthere. On 4 July1981 fire burned the nesting substrate over about 1.5 acresof the northwestslope of the island.An estimated100 youngSnowy Egrets and Black-crownedNight-Herons died. The GreatEgret nests were apparently spared.At this writingthe consequencesfor the 1982 nestingseason are unknown.

DISCUSSION Heron coloniesare characterizedby wide variationsin populationlevels fromyear to year. (e.g.Thompson and Littlefield 1980). Thefluctuations are far in excessof whatcould be explainedby mortalityor variationsin breeding successand are probably the resultof shiftsof breedingbirds from one colony to another.In addition,Marin County heron populations are not necessarily self-containedbut probably intermingle with those of othernearby counties in the San FranciscoBay region.The countsin Marin County, therefore,may not be indicativeof more generalizedtrends and shouldbe interpretedwith caution. The largestMarin County Great Blue Heron colony,Audubon Canyon Ranch has showna decliningpopulation trend since1974. The Schooner Bay colonyhas alsodecreased in sizebut the StaffordLake and Inverness Park colonies have increased (Table 1). Two small new colonies were establishedat North San Pedro Road and Da Silva Island. It is difficult to draw conclusionsabout Marin County Great Blue Heron population trends because accurate nest counts at Inverness Park and Sand Point were not availablefor mostyears, but there has been no generaldecline. The California Departmentof Fishand Gamestatewide surveys of heroncolonies taken in 1969, 1970, 1971, 1972 and 1978 show a steadyincrease in active Great BlueHeron neststhat is believed to be boththe resultof discoveryof morecol- oniesand an indicationof populationincrease (Belluomini 1978). The GreatEgret breeding population increased at AudubonCanyon Ranch from 1967 through1981 and the egretsappeared in three colonieswhere they had not nestedpreviously (Table 2). GreatEgrets have clearly declined on West Marin Island sincethe count of 1000 individualsin 1957 (Ralph and 179 MARIN COUNTY HERON COLONIES

Ralph 1958), and the nest estimatesof 58 in 1979 and 75 in 1981 show a declinefrom the 1965 level of 100. Countsof egretsseen around the island since1974 (Table3) suggestthat in spiteof yearlyfluctuations the population hasrecently been fairly stable. The CaliforniaFish and Game surveysshow an increasestatewide in the numberof Great Egretnests from 401 in 1969 to 853 in 1978 (Belluomini 1978). The Snowy Egretpopulation on West Marin Islandincreased from 25 nests in 1965 to 325 in 1981. Comparingnest countswith the 1957 (Ralph and Ralph 1958) countof 400 individuals(adult and young)is risky, but assuming an averageof two young/nest, the 1979 and 1981 countswould represent 524 and 650 young respectivelyaugmented by an undeterminednumber of adultsattending nests. Thus it would appearthat Snowy Egretshave increas- ed on West Marin Island over the 1957 levels as well. The statewide count of Snowy Egret nestsincreased from 227 in 1969 to 3704 in 1978 primarily becausea new colonythat contained2500 nestswas discoveredat the north end of the Salton Sea in 1978 (Belluomini 1978). Black-crownedNight-Herons have probably decreasedin numbers on West Marin Islandsince 1957 when Ralph and Ralph (1958) estimated600 birds(adults and young). The CaliforniaFish and Game estimateof 100 nests in 1965 and my estimatesof 98 nestsin 1979 and 109 in 1981 suggesta recently stable population. The statewidesurvey of nests shows a small decrease from a maximum of 1225 in 1971 to 939 in 1978 (Belluomini 1978). Nestsin four of the Marin County coloniesare built in Eucalyptus,non- native trees introducedto Californiafrom Australiain the late 1800s. They growto heightsexceeding 100 m and occurin smallgroves where there are oftenno tallnative trees. They thus afford suitable nest sites for heronsin areas where nativetrees do not. One can only speculateabout how the introduction of Eucalyptusmay have affectedthe heronpopulation and distributionof col- onies. Perhapscolonies are more scattered,smaller and closerto certain estuarinefeeding grounds.Perhaps Eucalyptus trees provide alternatesites for coloniesthat were displacedby loggingin the past. The addition of. Eucalyptusto the Californiaflora seems unlikely to havebeen instrumental in increasingheron and egretpopulations. Note that only three of the coloniesactive in 1981 -- AudubonCanyon Ranch, Schooner Bay and Stafford Lake -- are on land protectedfrom development.The remainderincluding West Marin Island, the largestcolony and currentlythe only knownnesting site in Marin Countyfor SnowyEgrets and Black-crownedNight-Herons, are privatelyowned. That the colonieson privateland will remain undisturbed indefinitely cannot be assumed.Develop- mentis alreadyplanned for Da SilvaIsland, although the nesttrees will not be cut. Herons and egretsare limitedto nestsites that are near aquaticfeeding grounds,such as estuaries or lakes,and that are in inaccessiblelocations, such asislands, marshes or high in tall trees,where they are protectedfrom ground predators.When currentsites become unsuitable through destruction or ex- cessivedisturbance, the presence of alternativesites becomesimportant. Periodicregional surveys of heroncolonies should be continuedto determine the statusof populationsand to assessthe nestingand feedingresources for thesebirds as pressuresfrom developmentincrease.

180 MARIN COUNTY HERON COLONIES

ACKNOWLEDGMENTS

I thank the many people who helped during the nestingseasons at AudubonCanyon Ranch. Most have been acknowledgedelsewhere. I also thankElizabeth Meyers who helpedat SchoonerBay, PamelaWilliams who censusedat Nick's Cove and Karen Schwartz who helped at Audubon CanyonRanch. Philip Schaeffer, Jean Starkweather,Rosamund Day, Alan Ruppert,Meryl Sundove and DavidHolway assisted in the WestMarin Island counts. David Shuford, David DeSante and Laurence Binford made con- structivecomments on an earlier draft of the manuscript.William Thomson providedunpublished California Department of Fishand Game reports.Guy McCaskieprovided data on the LittleBlue Heron recordat WestMarin Island. Thisis PointReyes Bird ObservatoryContribution 241.

LITERATURE CITED Anonymous.1965. Untitled.Unpubl. rep. CaliforniaDep. Fish& Game, Sacramento. Belluomini,L.A. 1978. Statewide heron rookery inventory. CaliforniaDep. Fish & Game, Sacramento. Chase, T. & R.O. Paxton. 1966. The fall migration.Middle Pacificcoast region. Aud. Field Notes 20:87-88. Grinnell, J. & A.H. Miller. 1944. The distributionof the birds of California. Pac. Coast Avif. 27. Mason,J. & T.J. Barfield.1973. Laststage for Bolinas.North Shore Books, Inverness, CA. Moffitt, J. 1939. Notes on the distributionof herons in California. Condor 41:81-82. Pratt, H.M. 1970. Breedingbiology of Great Blue Heronsand Common Egretsin cen- tral California. Condor 72:407-416. 1972a. Nestingsuccess of Common Egretsand Great Blue Heronsin the San FranciscoBay region. Condor 74:447-453. 1972b. Nestingsuccess of Great Blue Heronsand Common Egretsat Audubon Canyon Ranch in 1971. Am. Birds26:699-702. 1974. Breedingof Great Blue Herons and Great Egretsat Audubon Canyon Ranch, California, 1972-1973. West. Birds 5:127-136. Ralph, C.J. & C.L. Ralph. 1958. Notes on the nestingof egretsnear San Rafael, California. Condor 60:70-71. Stoner, E.A. 1934. Recent occurrencesof the American Egret in the region. Condor 36:57-59. Tate, J., Jr. 1981. The Blue List for 1981. Am. Birds 35:3-10. Thompson, S.P. & C.D. Littlefield. 1980. Historicalreview and statusof colonially nestingbirds on Malheur National Wildlife Refuge, Oregon. Proc. 1979 Conf. Colonial Waterbird Group 3:156-164. Unitt, P. 1977. The Little Blue Heron in California. West. Birds 8:151-154.

181 MARIN COUNTY HERON COLONIES

ADDENDUM

The fire on 4 July 1981 on West Marin Islandapparently did not affect GreatEgret or SnowyEgret breeding there in 1982. The GreatEgret nests in- creasedto 187 and the Snowy Egretnests increased to 500 in 1982. The Black-crownedNight-Heron nests,however, decreasedto 80 in 1982 from 109 in 1981. It ispossible, though not proven, that the fire discouragedsome night-heronpairs from returningto the islandin 1982. In 1982 two previously unknown Great Blue Heron colonies were discoveredin Marin County (D. Shufordpers. comm.). One containingsix nestswas in a fir treeon the southshore of LakeNicasio. The othercontaining 11 nestswas in Eucalyptustrees on the eastside of Drake'sHead, a promon- toryreaching into LimantourEstero, the estuaryextending eastward from the mouthof Drake'sEstero. People rarely pass near these colonies and they have probablybeen activebut undetectedfor severalyears.

Accepted 25 March 1983

Great Egret Sketch by Narca Moore-Craig 182 MARIN COUNTY HERON COLONIES

Great Egretsduring pair formation Photo by Philip Greene

183 MARIN COUNTY HERON COLONIES

Great Blue Heron presenting a twig to its mate Photo by Philip Greene

184