POPULATION STUDY

A surveyof Belding's SavannahSparrows in

Richard Zembal, Karla J. Kramer, Raymond J. Bransfield, and Nancy Gilbert

photographs by Bruce Peterson

rare is difficult. Although purposeof our investigationwas to pro- ( sandwichensis bel- breeding territories usually consistof vide an updateon the statusof Belding's Bdingi)ELDING'S is oneSAVANNAH of a few birdsSPARROW that re- very small patches of Pickleweed(Sal- SavannahSparrow in California, and side year round in the coastal salt icornia virginica), foraging occurs document the current condition of the marshes of southern California. The throughoutthe marsh,often well away habitat. race rangesfrom Goleta in Santa Bar- from the nesting sites (Bradley 1973; bara County, California, south to E! Massey 1977; Massey 1979). Moreover, Rosario, , the are relatively secretive. A CensusingTechnique (Grinnell and Miller 1944; van Rossem search for nests can lead to abandon- 1947; A.O.U. 1983). ment by the birds or to inadvertent me- Searchesfor territorial Belding'sSa- The relatively small numbers of in- chanicaldamage to nestsnever found. vannah Sparrowswere conductedat 30 dividualsdocumented in the recent past Two previousestimates of the Cali- different marshes in California. Counts and alarming lossesand degradationof fornia population have been made. were usually conducted in the early salt marsh habitat led to listing of this Bradley (1973) did not include several morning up to a maximum of three taxon as endangeredby the state. Beld- marshes in his census and estimated a hoursafter sunrise.This time was very ing's SavannahSparrow is also a Cate- total of about 1059 pairs.Massey (1977) rarely exceededand only when overcast gory 2 candidatefor federallisting. visited all of the known sites in the state conditionsappeared to be responsible Estimating population sizes of this and estimated about 1610 pairs. The for a prolongedperiod of morningsong.

Volume 42, Number 5 1233 The censusdates spannedthe period of E•ghtmarshes had populationsof 100 due •n part to generally•mproved eco- March 27 through July 17, 1986, but pmrs or more, collectivelymaking up logicalconditions. The 1977 censusfol- mostof our censusingwas conducted in 75 percentof the total. The population lowedseveral dry yearswhich was man- April and May 1986. at Point Mugu alone comprisedabout ifestin the poor conditionof the habitat, All known territorial individuals were 20 percent of the total, and about 35 or at leastpatches of habitat,at several counted at each marsh. Territoriality percentof the statepopulation was de- marshes(Massey 1977). The numerical was manifestthrough singing,scolding, tected in the marsheson land owned by difference between the 1977 total and extendedperching together of presumed the U.S. Navy, including Point Mugu, the presentone is aboutthe sameas the mates,nest-building, feeding young, and Anaheim Bay, and Camp Pendleton. total of the increasesdetected at just five aerial chases. In cases where aerial Adding in the population in Tijuana large marshes, Mugu Lagoon, Upper chaseswere circular, with the chasedin- Estuary, a portion of which is also Newport Bay,Los PenasquitosLagoon, d•vidual leavingthe area and the chaser ownedby the Navy, raisesthat percent- SweetwaterMarsh, and Tijuana Marsh returning to the vicinity of the original age to 45.2 percent or nearly half the The greatly improved conditions at perch site, a single territory was state's total. Point Mugu are probably attributable counted. In cases where the individual The increase in the number of Beld- to improved tidal circulation in the being chasedeventually held its ground ing'sSavannah Sparrows detected dur- western arm as a result of work done •n once removed from the original site of ing this investigationwas undoubtedly 1978. confrontation, two territories were counted. Single, perched, but nonsing- ing individualswere alsocounted aster- Table 1. Numbers of breeding pairs of Belding's Savannah Sparrows in California in 1986, ritory holders,where the spacingof sev- compared to two previous censuses. eral individuals in the marsh was quite Number of pairs uniform and most of the perchedbirds were singing.This latter manifestation Location 1973 t 19772 1986 of territoriality was usedconservatively to avoid over-countingby inadvertently Santa Barbara County •ncludingmates of singingindividuals. Goleta Slough 50 28 50 Carpinteria Marsh 100 34 74 With enoughobservation time in a given Ventura County patch of Pickleweed, it invariably be- McGrath Beach State Park -- 12 0 came clear which perched nonsinging Ormond Beach -- 17 20 •ndividuals should be counted. Such in- Mugu Lagoon 175 250 446 d•viduals were often joined eventually Los Angeles County by presumedmates or stronglyheld their Playa del Rey 25 37 32 Los Cerritos Marsh -- 5 2 ground over an extendedperiod, when Orange County much more obvious territoriality was Anaheim Bay 125 267 244 being manifested in adjoining territo- SunsetAquatic Park -- 6 0 ries. Our actual censusingtime at all 30 Bolsa Chica Wetlands 40 186 163 marshes totaled 151 hours. Newland Avenue Marsh -- -- 24 HuntingtonBeach Strip Marsh -- 34 47 Santa Ana River Mouth Marsh -- -- 0 Upper Newport Bay 130 83 245 State Census Results And Discussion San Diego County Aliso Creek Marsh -- -- 5 Santa Margarita River Estuary 125 106 107 The 1986 censusresulted in a pop- Buena Vista Lagoon 0 5 1 ulation estimateof about 2274 pairs of Agua Hedionda Lagoon 37 16 45 Belding's Savannah Sparrows in 27 BatiquitosLagoon 0 20 47 marshes(Table 1). This total is about San Elijo Lagoon 17 30 31 40 percent higher than the 1977 esti- San DieguitoLagoon 0 9 39 mate (Massey 1977). Two small popu- Los PenasquitosLagoon 160 52 156 Mission Bay: lations, those at the Newland Avenue Kendall-Frost Reserve -- 45 13 Marsh and at the Aliso Creek Marsh, San Diego River Flood Control Channel -- 70 28 were newly discovered,whereas three Beacon Island -- 4 0 othersapparently have been extirpated, San Diego Bay: those at McGrath Beach State Park, Paradise Marsh -- 16 19 Sunset Aquatic Park, and Beacon Is- Sweetwater Marsh -- 40 118 E Street Marsh -- 18 8 land. Numbers were appreciably (50 WesternSalt Company Dikes 3 -- 100 70 percent or more) larger than the 1977 South Bay Marine Reserve -- 25 15 estimates at nine marshes and appre- Tijuana Marsh 100 95 225 ciably smaller at eight marshes.Three Totals 1,084 1,610 2,274 of the increases,however, those at Go- leta Slough,Carpinteria Marsh, and Los Bradh,y, 1973. PenasquitosLagoon, approachedor re- 2Massey,1977. turned to 1973 population levels. Thetotal for the WesternSalt CompanyDikes includes 8 territoriesat the "J" StreetMarsh.

1234 American Birds, Winter 1988 For sheer numbers of birds, Point Mugu is unrivaled, with 19.6 percent of the total population and just over 200 more pairsof Belding'sdetected than in the next largestpopulation. In terms of overall habitat suitability for the larger populations, Upper Newport Bay ap- pearsto be the most highly productive. With only about 5.2 percent of the salt marsh acreage inhabited by Belding's occurringat Upper Newport Bay,about 10.8 percent of the birds detectedin the state were found there in 1986. Sweet- water Marsh, with just 2.4 percent of the total marsh area considered, hostsa density of about 2.3 pairs per hectare and 5.2 percent of the state's total of Belding's. Extirpations were noted at three marshes,Buena Vista Lagooncontained only one territorial individual, essen- tially a fourth extirpation. These marsheshad contained very few indi- viduals during the earlier censusperi- ods. Presently,nine sitescontain fewer than 50 individuals (25 pairs). Mathe- matical models have shown that with an effective population size of 50 indi- viduals,genetic material is lost in every generation. However, smaller popula- tions can be saved if their numbers are rapidly increased (Frankle and Soule 1981). The 27 salt marshescurrently occu- pied by Belding's Savannah Sparrows total approximately 2,150 hectares of salt marsh vegetation, salt flats, and small tidal channels. Excluded from this total were very large channels,ponds, and lagoonsusually coveredby water where the separationof acreagescould be made. Only a small fraction of this totalarea is nestinghabitat for Belding's. culverts or other constrictions. Yet, six The upper marsh habitat is rare in sincethe habitatis likelyto be inundated of the eight largestpopulations occur in southern California, since it was the at a time when many eggswould be vul- easiest to fill and claim for other land marsheswith full or nearly full tidal re- nerable. For some pairs, the reproduc- gimes.Such marshesgenerally also ac- tive potential for an entire seasoncould uses. In such dynamic habitat over a commodatethe largestwealth of other be lost and the local populations swell relativelysmall total area in relatively speciesand organismsas well. or declinedramatically depending upon few places,dramatic changesin local Belding's has done well at a few lo- the weather. populationsare not entirelyunexpected. calities where tidal influence is minimal The long-term security of the habitat The healthiest situation for the Beld- or lacking, but in someof thesecases at for Belding'sSavannah Sparrows is in- ing's appearsto be one that includesa least,the long-termstability of the hab- timately tied with ownershipand use of full tidal regimeand ampleupper-marsh itat is in question. If the health of the the land. About 63 percent of the elevations. Thirteen of the 27 marshes, habitat is primarily dependenton rain- marshes,containing 40.6 percent of the comprisingabout 59 percentof the total fall,dry yearsand particularlyprolonged Belding'sdetected in 1986, is mostly in acreageand occupiedby 70.1 percent drought will periodicallytake a toll on private ownership. The most secure of of the Belding'sdetected, are subjectto the habitat and numbersof Belding's. the currently occupiedmarshes are per- regular unobstructedor nearly unob- Much of Los PenasquitosLagoon, for haps those on land owned by the U.S. structedtidal flushing.In at leasttwo of example, was cracked, parched. and Navy. The greatest of the few success the 13 marshes,however, lush pickle- unsuitablefor Belding'sin 1977(Massey storiesfor Belding'ssince 1977, for ex- weed has become established in small 1977). Wet yearsat placeslike Los Pen- ample, has occurredat Point Mugu. As areasthat are subjectto tidesmuted by asquitos Lagoon may even be worse, a result of a habitat enhancementproj-

Volume 42, Number 5 1235 cox and Dan Yparraguirre for their ob- servations.The staff biologists of the U.S. Navy's Western Division Office at San Bruno, Steve Kovach, Michael Stroud, and Patty Worthing, provided invaluable support. Slader Buck and Clark Winchell arranged access and provided support on Camp Pendleton. Ihis work was funded in a major way by the U.S. Navy.

LITERATURE CITED

AMER1CAN ORNITHOLOGISTS' UNION. 1983. Check-list of North American Birds. 6th edition. Allen Press, Lawrence, Kansas. BRADLEY, R. A. 1973. A population census of the Belding'ssavannah sparrow, Pas- serculussandwichensis bddingi. Western Bander 48(3):40-43. FERREN, W. R., JR. 1985. Carpinteria saltmarsh:environment, history,and bo- ect there, tidal inundation was dramat- Pickleweedin suchmarshes is probably tanical resources of a southern California ically increased in a large section of establishedat artificially low elevations estuary.U.C. Santa Barbara Herbarium, marsh, and the number of Belding'sde- and a quickly imposed full tidal regime Publ. No. 4. tectednearly doubled. Point Mugu, with might ruin the habitat for Belding'sin FRANKLE, I. R., and M. E. SOULE. 198 I. Conservationand . Cambridge about 19 percent of the existinghabitat some situations. However, with proper Univ. Press.Cambridge, Mass. for Belding's,houses approximately 20 project planning and a better under- GRINNELL, J., and A. H. M1LLER. 1944. percentof the birds detectedin the state. standingof the autecologyof shrubby The distribution of the birds of California. Hopefully, the planned restoration ac- Salicornia, lush Pickleweed might be Pacific Coast Avifauna No. 27. tivities at the mouth of the Santa Mar- grown at proper elevationsprior to the MASSEY, B. W. 1977. A census of the garita River on Camp Pendleton will inundation of existingstands. breedingpopulation of the Belding'sSa- vannah Sparrow in California, 1977. havesimilar resultson Belding'shabitat Bringing the tides back and letting Nongame Wildlife Investigation Final and numbers in the near future. Other nature take its coursemay not result in Report E-l-l, Study IV, Job 1.2, to Cal- relatively secure sites include those the quick development of good habitat ifornia Department of Fish and Game, owned and managed by the California in some instances, even given proper Sacramento. Department of Fish and Game and by elevations. At the Seal Beach National __. 1979. Belding's Savannah Sparrow. the University of California. Develop- Wildlife Refuge, for example, an un- Contract Report, Contract No. ment proposals exist at several of the planted restoration area of about 41 DACW09-78-C-0008, U.S. Army Corps of Engineers,Los AngelesDistrict. hectares was taken down to suitable ele- marshesin private hands.Public acqui- ONUF, C. P. 1984. The biologicaland veg- sitionof privateholdings would increase vation in 1980. Salicornia cover in 1986 etationmonitoring programs for the Car- the degreeof protectionfor this sparrow. wasfairly uniform and growingbut was pinteria Estero Enhancement Project. There are problems associatedwith far from dense or tall enough to form ProgressReport No. 3. Marine Sci. Inst., trespassingby people and pets at most good Belding'shabitat except quite lo- Univ. of California, Santa Barbara. of the marshescensused, and eachcould cally. In contrast, about half of the SALATA, L. R. 1981. Santa Margarita River estuary resourcevalues and management Newland Avenue Marsh was disced and benefit,and somegreatly, from habitat recommendations. U.S. Fish and Wildlife restorationprojects. Re-establishing and destroyedin 1982, but had recovered Service,Washington. maintaining a strongocean influence at and was functional lessthan two years VAN ROSSEM, A. J. 1947. A synopsisof several localities would benefit many later without any other treatment. the savannah sparrows of northwestern other species as well. If the needs of Careful examination of such examples Mexico. Condor 49:97-107. Belding'sSavannah Sparrow are to be shouldlead to a better understandingof ZEDLER, J. B. 1982. The ecologyof south- ern California coastal saltmarshes: a addressedadequately during restoration the characteristicsof good habitat and community profile. FWS/OBS-81/54, projects,however, the existingelevations allow us to facilitate its development. U.S. Fish and Wildlife Service,Washing- of lush Pickleweed stands and their use ton. shouldbe considered.About 26 percent ZEMBAL, R. L. 1986. A surveyof Belding's of the marshesnow occupied by Beld- SavannahSparrows on the Marine Corps ing's containing7.7 percent of the total ACKNOWLEDGMENTS Base,Camp Pendleton,California, 1984- population, are subjectto little or no 1985. U.S. Fish and Wildlife Service, La- guna Niguel, California. tidal influence and another 7.7 percent We thank Elizabeth Copper,Shannon now house22.1 percentof the Belding's Cunniff, Mary Jo Elpers,Jack Fancher, --US. Fish and Wildlife Service, and are subjectto muted or periodically Sharon Lockhart, Barbara Massey, 24000 Avila Road, Laguna Niguel, reducedtides. A goodpercentage of the DenyseRacine, David Smith, Carl Wil- California 92656.

1236 American Birds,Winter 1988