Status and Distribution of the Elf Owl in California

STATUS AND DISTRIBUTION OF THE ELF OWL IN CALIFORNIA

MARY D. HALTERMAN, Department of BiologicalSciences, California State University,Chico, California95929 STEPHEN A. LAYMON, Departmentof Forestryand ResourceManagement, 145 Mulford Hall, Universityof California, Berkeley, California94720 MARY J. WHITFIELD, Department of BiologicalSciences, California State University,Chico, California95929

In California,the Elf Owl (Micrathenewhitneyi) has been found only in riparianhabitats and scatteredstands of Saguaro(Carnegiea gigantea) along the lower Colorado River and at a few desert oases (Grinnell and Miller 1944). Although the specieshas never been numerousin California, there hasapparently been a populationdecline. Surveys in 1978 and 1979 located 11 and 6 pairsof Elf Owls, respectively,at two locationsalong the lower Col- orado River (Cardiff1978, 1979). Cardiff's(1978) completerecord of the 28 Elf Owl sightingsmade in California prior to 1978 identified eight locations where the specieshas been found. We gathered10 additionalrecords made since 1979 (Table 1). All recent records were for either Soto Ranch or near Water Wheel Camp. Since 1979, habitatdestruction has continued, resulting in the loss of much of the remainingcottonwood-willow and mesquite bosques(C. Hunter and B. Andersonpers. comm.). This lossis due to the proliferationof tamarisk (Tamarix chinensis),agricultural clearing, bank stabilizationprojects, urbanization, and recentsustained flooding (Laymon and Halterman1987). This lossand itspotential effect on Elf Owlsprompted thissurvey during the springof 1987. The objectivesof thisstudy were to (1) identifyand surveyareas where Elf Owls had been reportedduring and sincethe 1979 survey,(2) identifyand survey other areas of potential Elf Owl habitat, (3) determine the size and distributionof the breedingpopulation of Elf Owls in California,(4) describe the physiographicfeatures and vegetationof the sitessurveyed, (5) assess the conditionof the sites,including potential threats, and (6) developrecom- mendationsto halt and possiblyreverse the declineof Elf Owlsin California.

STUDY AREA AND METHODS

We selectedthe survey sitesby usingfour sourcesof information:sites identifiedby Cardiff (1978, 1980), sitesidentified by the CaliforniaDepart- ment of Fish and Game, sitesidentified by other field biologists,and sites identifiedby us during previousfield work along the Colorado River. We identifiedpotential Elf Owl habitat as patches of cottonwoods(Populus frernontii), Red Willow ($alix gooddingii), Honey Mesquite (Prosopis julifiora), ScrewbeanMesquite (Prosopis pubescens), palo verde (Cercidiurn floridurn), and Saguarosold enough to contain nest cavitiesand extensive enough to provideforaging areas. Also, the patchesmust experienceonly limitedhuman disturbance,e.g., little or no use by off-road vehicles(ORV). We conductedthe field surveysbetween 6 April and 8 May 1987 in all areas with suitablehabitat to which we had access.From historicalrecords, Western Birds 20: 71-80, 1989 71 Table 1 Sightingsof Elf Owls in California, 1903-1986

Number of Date Site individuals Reference •

17 May 1903 Imperial Dam 2 Brown (1904) 23 April 1910 ImperialDam 1 Grinnell (1914) Apr 1915 Bard 2 Kimball (1922) 6 May 1946 CottonwoodSpring 2 Miller (1946) Apr 1959 Cottonwood Spring 2 AFN 13:401 7 May 1959 CottonwoodSpring 2 AFN 13:401 Summer 1959 Cottonwood Spring 2 AFN 13:456 11 May 1962 Cottonwood Spring 2 G. McCaskie (pers. comm.) 27 Apr 1963 CottonwoodSpring 2 G. McCaskie (pers. comm.) 11 May 1963 Cottonwood Spring 2 G. McCaskie (pets. comm.) 8 Jun 1963 Cottonwood Spring 2 G. McCaskie (pers. comm.) 25 Apr 1964 CottonwoodSpring 2 G. McCaskie (pers. comm.) Spring 1967 CottonwoodSpring 2 AFN 21:605 13 Apr 1969 Cottonwood Spring 1 AFN 23:626 31 May 1969 Soto Ranch 1 SBCM 4263 7 Apr 1970 Soto Ranch 4 AFN 24:625 18 Apr 1970 Cottonwood Spring 1 G. S. Suffel (pers. comm.) 18 Mar 1972 Corn Spring 1 AB 26:809 May 1972 Corn Spring 2 AB 26:809 23 Jun 1972 Soto Ranch 2 G. McCaskie (pers. comm.) 20 Apr 1973 DesertCenter 2 Small (1974) 25 Apr 1975 Corn Spring 1 AB 29:909 10 Apr 1976 Soto Ranch 2 & juveniles AB 30:892 23 Apr 1976 Corn Spring 1 AB 30:892 25 Apr 1976 Corn Spring 1 AB 30:892 6 Aug 1976 Wiley'sWell 2 BLM unpubl. data Aug 1976 Coon Hollow 2 R. McKernan (pers. comm.) 29 Apr- 12 Jun 1977 Soto Ranch 6 & juveniles AB 31:1190 Apr-Jun 1978 SotoRanch 10 pairs Cardiff(1978) 10 Jun 1978 Water Wheel Camp 1 Cardiff (1978) May-Jun 1979 Soto Ranch 5 pairs Cardiff (1979) May-Jun 1979 Water Wheel Camp 1 Cardiff (1979) 12 Apr 1980 Soto Ranch 2 AB 34:897 26 Jun 1982 Soto Ranch 2 & juveniles AB 36:1016 16 Apr 1983 Soto Ranch 6 AB 37:1028 21 Apr 1983 Water Wheel Camp 1 AB 37:1028 24 Apr 1984 SotoRanch 1 AB 38:1062 Summer 1985 Soto Ranch 4-6 AB 39:962

ø AB, American Birds; AFN, Audubon Field Notes; SBCM, San BernardinoCounty Museum; BLM, Bureau of Land Management. 72 ELF OWL IN CALIFORNIA we identifiedthis period as the optimum surveytime. We surveyedsites between sunsetand midnight. During the day we visitedthe sitesto describe and classifyhabitat quality and structure. Information gatheredfor all sitesincluded name, location, surveyresults, general comments, comments on health and vigor, extent (ha), dates surveyed,and habitattype. On the basisof this informationand previously publisheddata on the Elf Owl's habitatpreferences (Cardiff 1978, 1979), we ranked sitesinto four categoriesof predictedhabitat suitability: (I) excellent; (2) good; (3) marginal;and (4) poor (Table2). We ranked the siteson the basisof habitatdata collectedon the sitesbefore the Elf Owl surveyswere conducted. All areasexcept two were surveyedonce, and most areasof good or excellenthabitat were surveyedtwice, as were severalof the areasof marginal or poor habitat. We did not conductnocturnal surveys at two areas of ex- tremelypoor habitat.Repeat surveyswere conducted2-3 weeksafter the inital surveys. We conductedsurveys by automobile,foot, and boat. Nocturnalsurveys consistedof stoppingevery 50-100 m at the sitesand listeningfor Elf Owls. If few or no Elf Owlswere heard, we playeda tape of a male Elf Owl'sterritorial call to stimulatea response.The taped call was played 5-10 times with 1-minutepauses between calls at each station.We could hear the taped call 160 m away. We mapped the responses on U.S.G.S. 71/2-minute topographicmaps. At many sitestwo researchers"leap-frogged," working 100 m apart with one or both playingtape-recorded calls. Fifty-twosites were surveyedduring this study; 3I were checkedtwice. Siteswere numberedsequentially from north to south (Figure1).

RESULTS

We located 15 to 25 Elf Owls at 10 sites. The 42 sites at which Elf Owls were not found are listedin Appendix 1. The informationon the individual sitesis arrangedby sitename, location,survey results and discussion,habitat description,extent, dates surveyed,comments, and habitatquality rating. (5) Soto Ranch, 12 km N of Needles, One to three Elf Owls at 2 locations on the first visit and 2-4 Elf Owls at 3 new locations on the second visit. This representsa total of 5-7 Elf Owls at 5 sites,resulting in an estimatedpopula- tion of 5 pairs. Mature mesquitebosque with a few cottonwoodsnags; 64 ha; 13 and 29 April 1987; excellentquality. This populationhas apparently re- mained stable since I979. Soto Ranch contains the most extensive tract of mesquitebosque along the Colorado River in California.The removal in 1986 of 0.5 ha of bosquethat includedseveral large cottonwoodsnags in- dicatesthat the habitatis in dangeras the landownerclears additional farm- land. (11) Head of Clear Bay, 7 km N of HavasuLanding. One Elf Owl possibly heard on the firstvisit. Mixed-agetamarisk-mesquite-palo verde; 2 ha; I6 April and 2 May 1987; lightORV use;good quality.This small patch of high- quality habitatis relativelyundisturbed. It is probablytoo smallto support more than one breedingpair, and the bird possiblyheard there may have been a migrant.

73 ELF OWL IN CALIFORNIA

c• z ELF OWL IN CALIFORNIA

(13) Mouth of Chemehuevi Wash, 1 km S of Havasu Landing. One Elf Owl waspossibly heard on the firstvisit; we weretoo far from the responseto identifyit positively.Scattered mature mesquite-tamarisk-palo verde; 8 ha; 16 April and 1 May 1987; heavy ORV use; good quality. (15) DeslitWash, 2 km SW of Parker Dam. One Elf Owl may have been heard on the secondvisit; noisefrom DeslitCreek made positiveidentifica-

14-16/

22-26/ 2 27-3•\ I 32-35• 3 36/

43-45(x•R_IzONA 4• 49-5•J _----: _• ••--:_ •-o'---• --- -••-• Figure 1. Lower Colorado River study area, showingsites surveyed for Elf Owls in 1987. Numberscorrespond to thoseused in text and appendix.

75 ELF OWL IN CALIFORNIA

tion difficult. This impressivebut small stand of cottonwoodscould be cleared; mature patchesof cottonwood-willow;2-4 ha; 12 and 28 April 1987; good quality. (18) Headgate Rock Dam, 2.5 km ENE of Earp. Two Elf Owls seen and heard on the first visit. Patchy mature mesquite-tamarisk-cot•on- wood-willow; 3-4 ha; 12 and 28 April 1987; heavy human disturbance; good quality. There are severalpotential nest trees. While clearingis un- likely, useby man is inhibitingnatural regeneration in the area. Much of this habitat is in scatteredclumps and experiencesheavy human disturbance. Thesebirds may representa nestingpair even thoughthey did not respond on our second visit. (20) Wilson Road, 2 km E of Highway 95. One Elf Owl was heard on the first visit, and two responded on the second visit. Scattered patches of mature mesquite-paloverde; 15 ha; 11 and 26 April 1987; good quality. There appearsto be littleto distinguishthis site from many other similarareas where we did not detect Elf Owls. There is minimal human disturbance at this site, but there is a possibilitythat agricultureor ORV use may threaten the area. (26) South end of Water Wheel Camp, 21 km N of Blythe. Two to five Elf Owls on the firstvisit representing 2-3 pairs.Large, dense,and undisturbed patchesof mature tamarisk-mesquite,60% tamarisk; 130 ha; 11 and 25 April 1987; good quality.Several roads run throughthe area and they are probably used by ORVs and dove hunters. This area is surroundedby agricultureand could be clearedfor that purpose. (29) Aha Quin trailerpark, S end of Hall Island, 18 km N of Blythe. Two Elf Owls, representing1-2 pairs, respondedto the tape on the secondvisit; there are numerousnest sites.Scattered patches of dense, mature cottonwood-willow with tamarisk-willow-mesquiteunderstory; 8 ha; 10 and 24 April 1987; goodquality. Approximately 4 ha in the middlehas been cleared for an airstrip,and new ORV trailsare beingbulldozed. This patchof habitat is in need of protectionthrough either a managementagreement or pur- chase. (36) GooseFlats, backwater 3 km downstreamfrom 1-10freeway bridge. One Elf Owl heard on the firstvisit was probablya migrant;there are large cottonwoodsin this area, but they are widely scatteredand separatedby much open ground. Patchy cottonwood-willow;96 ha; 70% tamarisk, 3% cottonwood,2% willow; 8 and 22 April 1987; marginalquality. Most of the treeswere killedby firesand floodsin the early 1980s. We feel that the openessof the habitatmade it inadequatefor breeding. (41) Walter'sCamp, 0.5 km S of Three-fingerLake. Three Elf Owls were heardon the firstvisit. Mature mesquite-tamarisk-paloverde; 65 ha; 9 and 21 April 1987; heavy ORV use; good quality. This area has largetracts of mesquiteinterspersed with more open areas of palo verde. More habitat could be cleared for expansionof nearby trailer parks. There are many potentialnest trees. We believethat the site is adequate for breeding. We estimateda total population of 10-17 pairs from the resultsof the survey.Elf Owlswere probablybreeding at fivelocations and may havebeen breedingat four additionallocations. Three of the probableand four of the possiblebreeding sites were at locationswhere Elf Owls had not previously 76 ELF OWL IN CALIFORNIA

been found. A few more pairs may breed at some of the good or bettersites where we surveyedand did not find Elf Owls. Only one of the 42 siteswhere we did not detectElf Owls was in the excellent habitatsuitability category. This site, number 43, at the mouth of JulianWash, consisted of 65 ha of mesquite,tamarisk, ironwood, and palo verde closedto ORVs. There appearedto be sufficientnest sitesto accom- modate severalpairs of Elf Owls. Unfortunately,because of difficultaccess we were only able to surveythis site once, which may explainwhy no Elf Owls were detected. Seventeensites where we did not detectElf Owlswere in the good habitat suitabilitycategory. Many of thesesites were not extensiveenough or were too patchy to be consideredexcellent. The marginalhabitats are mostlysmall remnants of higher-gradehabitats. Many of theseareas have been degraded through habitat loss from flooding, clearingfor agriculture,and the establishmentof tamarisk. We found no Elf Owlsin poor habitats.These usually consisted of tamarisk patchesor areaswith only a few cottonwoodsin trailerparks. The proportionof sitesat which Elf Owls were found declinedwith habitat quality.Elf Owlswere found at 50% of the excellentsites, 32% of the good sites,8% of the marginalsites, and none of the poor sites(Table 3).

DISCUSSION

Why did we not find Elf Owlsin many areasof goodto excellenthabitat? Possiblyour criteriafor habitatranking are incorrector oversimplified.Fac- torsthat we did not recognizeor measuremay havebeen important in deter- miningoccupancy. Factors other than habitatsuitability may be limitingthe population:the populationof Elf Owls in Californiais so low and most sites are so smallthat stochasticevents may preventthe owlsfrom occupyingall suitablesites every year. This couldbe testedby multi-yearstudies to deter- mineoccupancy of sitesover a seriesof years.Elf Owlsmay ingestpersistent pesticides,such as DDT, on their winteringgrounds, resulting in eggshell thinningand reducedreproduction and keepingthe populationbelow the carryingcapacity of the habitat.Collection and measurementof eggshell fragmentscould help answerthis question.

Table 3 Site HabitatQuality and Elf Owl Occupancyalong the Lower Colorado River in 1987

Habitat quality Occupiedby Elf Owls No Elf Owls found

Excellent 1 1 Good 8 17 Marginal 1 11 Poor 0 11

Total 10 40 •

Two additionalsites of poor qualitywere not surveyedat nightbecause of poor access. 77 ELF OWL IN CALIFORNIA

Until the factors controlling the California Elf Owl population are understood,the firststep toward protectingthe speciesmust be habitatpro- tection. All nine siteswhere Elf Owls were located and may breed are in some danger of destructionfrom flooding, clearing for agricultureor development,or disturbanceby ORVs. Almostall of thesesites could be pro- tectedby managementagreements, conservation easements, or fee title pur- chaseby stateor federalagencies or conservationorganizations. Preservation of the fragmentsof existinghabitat probably will not be enoughto preventthe extirpationof the speciesfrom California;ultimately there mustbe effortsto restoresuitable habitats by removingtamarisk, reforesting with mesquite, cottonwoods,and willows,and excludingdisturbing activities. Many other en- dangeredspecies of this devastedriver systemwill also benefitfrom these measures.Only by such means will the numbersof Elf Owls currentlyin Californiaincrease. Without this managementit seemsunlikely that the Elf Owl, and many other speciesdependent on the Colorado River ecosystem, will be able to maintain their tenuous foothold in California.

ACKNOWLEDGMENTS

This studywas supported by the CaliforniaDepartment of Fishand Game Contract No. C-198I. BertinW. Anderson,William C. Hunter, and Brian Walton providedin- formationon potentialElf Owl habitat.Patty Young of CaliforniaDepartment of Fish and Game in Blytheprovided logistical support. Jeannie Anderson provided housing while we were in Blythe. Gordon Gould of the CaliforniaDepartment of Fish and Game provided informationon historicalElf Owl locationsand optimumtiming of surveysand supervisedthe contract.Thanks to SallieHejl, PhillipLefever, and Karen Seaman for assistance in the field.

LITERATURE CITED

Brown, H. 1904. The Elf Owl in California. Condor 6:45-47. Cardiff, S. W. I978. Status of the Elf Owl in California. California Dept. Fish and Game. Job ProgressRep., ProjectW-54-R-10, Job III-10. Cardiff, S. W. I979. Statusand distributionof Elf Owls in California.State of Califor- nia, Dept. Fish and Game. Admin. Rep., ProjectE-W-3, Job IV-I.0 (January 1980). Grinnell, J. 1914. An account of the mammals and birds of the Lower Colorado River Valley. Univ. Calif. Publ. Zool. 12:129. Grinnell, J., and Miller, A. H. 1944. The distributionof the birds of California. Pac. Coast Avifauna 27. Kimball, H. H. 1922. Bird recordsfrom California,Arizona, and GuadalupeIsland. Condor 24:96. Laymon, S. A., and Halterman, M. D. 1987. Can the westernsubspecies of the Yellow-billed Cuckoo be saved from extinction? W. Birds 18:19-25. Miller, L. 1946. The Elf Owl moves west. Condor 48:284-285. Small, A. 1974. Westernbird photoõraphers.W. Birds 5:101-110.

Accepted5 duly 1989 78 ELF OWL IN CALIFORNIA

APPENDIX 1. Surveysites where Elf Owls were not detectedalong the Col- orado Riverduring 1987. Numbersrefer to localitiesnumbered in Figure1. (1) Cottonwoodand Cotton Springs,Joshua Tree NationalMonument; approx- imately10 maturecottonwoods; 0.2 ha; 5 April and 8 May 1987; poor quality. (2) Ironwood-palo verde area 5 kn N of Desert Center; scattered,mature ironwood-palo verde; 120 ha; 8 May 1987; poor quality. (3) Corn Springs,12 km SW of DesertCenter; palm oasis,approximately 100 fan palms(Washington filifera); 0.2 ha; BLM hasplaced nest boxes; 6 April 1987; poor quality. (4) Fort Piute Wash-PiuteSpring; scattered mature cottonwood-willow; 2 ha; a riparianstrip 15-50 m wide and 2.5 km long; 14 April 1987; goodquality. (6) Fort Mojave IndianReservation; a narrowstrip of habitatalong the Colorado Riverapproximately 9 km N of Needles;scattered mixed-age tamarisk-mesquite; 24 ha; 13 April 1987; poor quality. (7) Mouth of PiuteWash, 7 km N of Needles;scattered uneven-aged mesquite- tamarisk-paloverde; 24 ha; snagspresent; 13 and 30 April 1987; goodquality. (8) Needlessewage disposal site; scattered young willow-tamarisk with some mesquite; 16 ha; 15 and 30 April 1987; marginalquality. (9) Beal Lake in TopockMarsh; mixed, occasionally dense, tamarisk-willow-mesquite; 64 ha; 15 and 30 April 1987; good quality. (10) TopockGorge; uneven-aged tamarisk-mesquite-palo verde; 8 ha at 10 sites; 90% tamarisk;1 May 1987; not surveyedbecause of poor access;marginal quality. (12) CatfishBay, 3 km N of HavasuLanding; scattered uneven-aged tamarisk- mesquite-paloverde; 1.5 ha; 1 May 1987; marginalquality. (14) Saguarosin the Whipple Mountains, 7 km WNW of Parker Dam; 20 mature Saguarosalong 5 km of road, with one 2-ha clumpof 8 Saguaros;28 April 1987; someSaguaros have been damaged;poor quality. (16) CopperBasin Wash; mature patchy mesquite-palo verde-tamarisk; 3 ha; 12 and 28 April 1987; moderateORV use; marginalquality. (17) Mouth of BennettWash, alongParker strip; scattered mesquite-tamarisk; 1 ha; 12 and 27 April 1987; marginalquality. (19) Vidal Wash, 12 km S of Parker;dense, mixed-age mesquite-tamarisk; 6 ha; thereare a few cottonwoodsand willows;11 and 26 April 1987; goodquality. (21) Mesquitearea N of LostLake TrailerPark; dense, mixed-age mesquite-tamarisk; 16 ha; severalroads bisect site; 6 May 1987; good quality. (22) Lost Lake Resort,20 km S of Parker;trailer park with manyplanted cottonwoods;8 ha; 11 and 26 April 1987; marginalquality. (23) Burnedarea 2 km S of LostLake Resort, E of Highway95; extensivetamarisk with mesquiteand tamarisksnags; 125 ha; 11 and 26 April 1987; area burnedin 1985 in preparationfor agriculturalclearing; poor quality. (24) North end of Water Wheel Camp, 22 km N of Blythe;4 smallclumps of maturecottonwoods surrounded by agriculturalfields; minimal understory; 11 and 25 April 1987; poor quality. (25) Cottonwoodsat southend of Water Wheel Camp; 10 largecottonwoods; 6 May 1987; marginalquality. (27) ShaggyTree trailerpark, 19 km N of Blythe;several large cottonwoods and mesquites;11 April 1987; poor quality. (28) Red Roostertrailer park, 19 km N of Blythe; 20 maturecottonwoods; un- suitablefor owlsbecause of humandisturbance; 11 April 1987; poor quality. (30) Twin Palms Camp, 14 km N of Blythe; 20 mature cottonwoods,5 mature willows;10 April 1987; poor quality. (31) 3 km N of Blythe Boat Club; youngcottonwood-willow; 8 ha; and scattered patchesof tamarisk-mesquite-willow;26 ha; 10 and 24 April 1987; the habitatcould be cleared; good quality. 79 ELF OWL IN CALIFORNIA

(32) MayflowerCounty Park, 9 km N of Blythe;mature Honey Mesquite; 6 ha; no understory(campground), all dead branchesremoved; 11 and 23 April 1987; marginalquality. (33) 200 m S of 6th AvenueTrailer Park; young,dense tamarisk-mesquite, 75% mesquite;4 ha; 7 and 23 April, 1987; marginalquality. (34) 2 km W of 6th Avenue Trailer Park; dense,old Honey Mesquite-Bacchari$; 16 ha; 7 and 23 April, 1987; good quality. (35) Big Hole, 5 km NE of Blythe; scattered,mature cottonwood-willow-mesquite, 40 ha; cottonwoodsin narrow strips;young cottonwood-mesquite;40 ha; marshy;7 and 23 April, 1987; marginalquality. (37) 1 km N of MclntireCounty Park; maturecottonwood-willow; 60 cottonwoods in a 1-kin strip;8 and 22 April, 1987; marginalquality. (38) H. Miller County Park, 18 km S of Blythe; scatteredtamarisk-cottonwood- willow; 0.5 ha; 9 April, 1987; poor quality. (39) ArizonaState Universityrevegetation site, 11 km S of Palo Verde; plantedin 1979, park-likecottonwood-willow; 16 ha; 9 and 21 April, 1987; good quality. (40) 2 km W of Walter's Camp, Cibola National Wildlife Refuge; scatteredpalo verde-mesquite-smoketree; 190 ha; 21 April, 1987; good quality. (42) Acrossfrom LighthouseRock; dense,patchy tamarisk-mesquite-palo verde; 4 ha; 5 May 1987; not surveyedat nightbecause of poor access;poor quality. (43) Mouth of Julian Wash; open ironwood-paloverde; 65 ha; mature, scattered mesquite-tamarisk;65 ha; 5 May 1987; area closedto ORV use;excellent quality. (44) Unnamed washes between Julian and Para Washes; scattered mesquite-tamarisk-paloverde; 8 ha; scatteredpalo verde-ironwood;8 ha; 5 May 1987; good quality. (45) Mouth of Para Wash, 5 km N of Picacho State RecreationArea; scattered denseclumps mesquite-tamarisk-palo verde; 8 ha; open ironwood-paloverde-mesquite; 4 ha; 19 April and 3 May 1987; good quality. (46) Taylor Lake and White Washand PicachoState Recreation Area; densetama- risk-palo verde-mesquite;4 ha; 19 April and 3 May 1987; good quality. (47) Main campground,Picacho State Recreation Area; open with clumpsof paloverde-mesquite-tamarisk;4 ha; 19 April and 3 May 1987; good quality. (48) BetweenImperial and Lagunadams; occasionally dense tamarisk-mesquite- palo verde;230 ha; mostlytamarisk, there is alsoone 2-ha patchof maturewillow- cottonwood-tamarisk;18 April and 2 May 1987; good quality. (49) Along the All-AmericanCanal; 11 km NE of Yuma; patchy tamarisk-mesquite-paloverde; 24 ha; interspersedwith roadsand agriculturalpatches; 17 April and 4 May 1987; good quality. (50) Along the All-American Canal; 12 km NE of Yuma; mature cottonwood- willow-tamarisk;2 ha; 17 April, 2 and 4 May 1987; good quality. (51) Alongthe All-AmericanCanal, 2 km N of PicachoState Recreation Area turn- off; occasionallydense palo verde-mesquite-tamarisk;64 ha; tamarisk-paloverde- mesquite;64 ha; 20 April 1987; area not revisited;good quality. (52) Araz Wash,5 km W of Winterhaven;young palo verde-mesquite-tamarisk;2 ha; densemesquite-palo verde; 1 ha; 20 April, 1987; marginalquality.