Noteworthy Bird Observations from Baja California, Mexico

NOTEWORTHY BIRD OBSERVATIONS FROM BAJA CALIFORNIA, MEXICO

STEVE N. G. HOWELL and SOPHIE WEBB, Point ReyesBird Observatory,4990 ShorelineHighway, Stinson Beach, California 94970

DespiteBaja California'sproximity to heavilybirded southern California, its avifauna remains surprisinglypoorly known. The paucity of data reqardingbirds in Baja Californiawas highlightedby Wilbur (1987). In particularit is apparentthat few ornithologistshave studied Baja California in summer,i.e., the periodbetween a species'spring and autumnmigration periods.For example,the occurrencein June 1991 of summeringCom- mon (Gavia iramet) and Pacific (G. pacifica) loons, Great Egrets (Casmerodiusalbus), Greater Yellowlegs(Tringa melanoleuca),Long- billed Curlews (Numenius americanus), Short-billedDowitchers (Limno- d rornus griseus), and CaliforniaGulls (La rus califo rn icus), all seenat Bahia San Quintin, would barely be worth noting had they been in southern California,yet there appear to be no previouspublished summer records for thesespecies in Baja California!ILlinas et al. (1989) and Escofetet al. (1988) did not specificallydistinguish oversummering individuals, and the former'sdefinition of •'summer"moreaccurately reflects autumn for shore- birds.] While muchof the increasedknowledge in recentyears can be attributed to improvedaccessibility, real changesin bird distributionare occurringin conjunctionwith man'simpact on the environment.For example,intensive cultivationof the Llano de Magdalenaaround Ciudad Constituci6nand CiudadInsurgentes, dating from the 1960s (AutomobileClub of Southern California 1990), has created habitat for White-tailed Kites and Western Meadowlarks,while the reservoirat EjidoH•roes de La Independenciahas allowedTricolored and Yellow-headedblackbirds to nest sideby side. This paper is basedmostly on our fieldwork in Baja Californiafrom 1 to 20 June 1991, whenwe twicedrove the entirelength of the peninsula.Our primaryobjective was to determinesummer and breedingdistributions of birds•particularly in the three mainsierras (Sierra de La Laguna,Sierra San Pedro Mfirtir, and Sierra Jufirez). We also include a few records from our trips to Baja California in December 1982, December 1983, Januaryand February1988, and October 1991, and someobservations contributed by other observers.Figures 1 and 2 locate placesmentioned in the species accounts. In total we detailnew informationconcerning 52 speciesin Baja Califor- nia. includingthree speciesnew to the peninsulaand four probablebreed- ing speciesunreported from Baja California (and Mexico as a whole) in summer.

SPECIES ACCOUNTS

LeastGrebe Tachybaptusdominicus. At Muleg•, on 5 June 1991, we saw a pair anda singleadult. and on 13 June 1991 a pair,an adultwith two full-grownjuveniles, and an adultwith two half-grownjuveniles. We estimateda maximumpopulation of Western Birds 23:153-163, 1992 153 BIRD OBSERVATIONS FROM BAJA CALIFORNIA

32øN

30 ø

28 ø

1OO Km

/ 116øW 114ø

Figure1. NorthernBaja California, showing locations mentioned in the species accounts.Stippled areas represent sierras. A, SierraJfiarez; B, SierraSan Pedro M6rtir;C, RioColorado; D, RioHardy. l, IslasLos Coronados; 2, Tijuana;3, La Misi6n;4, Ensenada;5, Islas de Todos Santos; 6, Esterode Punta Banda; 7, Laguna Hanson;8, EjidoI-l•roes de la Independencia;9, Durango;10, Coahuila;•1, NationalObservatory (from the observatory, Vallecitos meadow is approximately 4 kmto thesouth-southeast, La Grulla meadow approximately 17 kmto thesouth); •2, SanFelipe; •3, Bahiade San Quinfin (La Pinta Pond is just south of the bay, see Palaciosand Alfaro•991); •4, San Fernando;•5, Catavifia;•6, Bahiade Los Angelesjunction; •7, GuerreroNegro; 18, EjidoVizcaino; 19, SanIgnacio. 154 BIRD OBSERVATIONS FROM BAJA CALIFORNIA about five pairs along the river at Muleg•, an area from which there are no historic records.Least Grebes were foundat Muleg• in 1987 (T. E. Wursterpers. comm.) and 1988 (D. Wimpfheimerpers. comm.), and it seemsthat they have been overlooked there(cf. Belding's Yellowthroat) rather than being recent arrivals. The lastpublished recordsof thisspecies in the peninsulaare from 1930 (Grinnell1928, Wilbur 1987). Clark•s Grebe Aechmophorusclarkii. As Wilbur (1987) pointed out, virtually nothingappears to be known,or at leastpublished, regarding the statusof Clark'svs. Western Grebe (A• occidentalis) in Baja California. We here put on record our observationsof Clark's Grebe (and numbersof Westernssimultaneously present): Bahia San Quintin, 14 June 1991• one Clark•s, three Western; Guerrero Negro, 1 December 1982, one Clark's, 12 Western; 9 December 1983, 12 Clark's, 20 Westerm San Ignacio, 9 December 1983, two Clark's, one Western; Bahia

• 26øN

=4 o

100 Km ,

/ 112øW 110ø

Figure2. SouthernBaja California,showing locations mentioned in the species accounts.A (stippled),Sierra de La Laguna.1, Muleg•;2, Loreto;3, Tripuiresort; 4, CiudadInsurgentes; 5, CiudadConstituci6n; 6, BahiaMagdalena; 7, La Laguna;8, Cabo San Lucas;9, San Jos• del Cabo.

155 BIRD OBSERVATIONS FROM BAJA CALIFORNIA

Magdalena,31 Januaryto 1 February1988, 12 Clark's,43 Western;San Jos• del Cabo, 4 February1988, one Clark's,two Western;26 February1988, one Clark's, one Western. Wedge-rumpedStorm-Petrel Ocear•odroma tet/•ys. In the companyof J. and K. Hortonwe sawtwo Wedge-rumpedStorm-Petrels, in looseassociation with numer- ous Least Storm-Petrels (O. microsoma), at 25ø50'N, 110ø00'W, about 40 krn southeastof Loreto, on 12 June 1991. While Wilbur (1987) reported only one previousrecord from the Gulf of California,J. and K. Horton (pers.comm.) have, since 1989, regularlyseen up to ten Wedge-rumpedStorm-Petrels off Loreto betweenMay and July.We haveseen thousands of Wedge-rumpedStorm-Petrels in the tropicalPacific Ocean and are very familiarwith the species.The Loretobirds' smallsize (similarto the Least Storm-Petrel's),blackish plumage with a bold, very longwhite patchon the uppertail coverts,and flightmanner enabled us to identify them readily. American White Pelican Pelecarmser•tl•rorl•yr•cl•us. We saw five iramatures alongthe Rio Hardy on 20 June 1991, whichsuggests that somebirds oversummer in the Rio Coloradodelta. Reportedonly as a "wintervisitor in smallnumbers" to Baja Californiaby Wilbur (1987), althoughHowell and Pyle (1990) saw 450 at LagunaSalada on 15 May 1989. MagnificentFrigatebird Fregata magnificer•s.We saw one soaringwest over CiudadConstituci6n at 1920 on 11 June 1991, and 34 headingnorth at kilometer post45 betweenCiudad Insurgentes and Loreto, elevation300 m, at 0820 on 12 June 1991. AlthoughWilbur (1987) reportedonly one previousinland record from BajaCalifornia, Magnificent Frigatebirds commonly cross the peninsulavia the Santo DomingoValley (R. Rodriguez-Estrellaand E. Palaciospers. comm.). Least Bittern lxobr•cl•us exilis. Single males at San Ignacio, 5 June 1991, and near Durango,in the Rio Coloradodelta, 20 June 1991, suggestthe speciesis an overlookedbreeding resident in the peninsula. White-facedIbis Plegadiscl•il•i. One immatureat San Jos• del Cabo, 11 June 1991, is the firstof this speciesreported from BajaCalifornia in summer(cf. Wilbur 1987). Black-belliedWhistling-Duck Der•droc•grm au•umrmlis. Our sightingof a wary full-wingedadult at San Jos• del Cabo, 11 June 1991, representsthe firstrecord of this unmistakableneotropical duck for Baja California.Presumably the bird was a wandererfrom the Mexicanmainland where the speciesis common. Brant Branta bernicla. One at Estero de Punta Banda, 2 June 1991, and 18 at BahiaSan Quintin,15 June1991 appearto constitutethe firstsummer records from Baja California(cf. Wilbur 1987). A few Brant typicallyoversummer in southern California (Garrett and Dunn 1981). MallardAr•as plat•rl•r•cl•os. On 19 June 1991 we sawa femalewith nine small ducklingson the reservoirat kilometerpost 96 on Highway3, 8 km southof Ejido H•roes de la Independencia.There were also11 otherMallards (including four pairs) at the reservoir.Other breedingrecords for the peninsulawere in 1925 (Huey 1928) and May 1989, near La Misi6n(Howell and Pyle 1990). Northern PintailAr•as acura. In 1991 we saw 50 at GuerreroNegro on 4 June and three at the reservoir8 km southof Ejido H•roes de la Independenciaon 19 June.There is onlyone previoussummer record from BajaCalifornia, in June 1926 (Grinnell1928); Wilbur(1987) mistakenlyindicated that Grinnell(1928) citeda July record. Blue-wingedTeal Ar•as discors. A maleat the reservoir8 km southof EjidoH•roes de la lndependencia,19 June 1991, is the first reportedfor summerin Baja California (cf. Wilbur 1987). CinnamonTeal Armscyanoptera. We sawa femalewith nine ducklings,plus two courtingpairs and threesingle males, at the reservoir8 km southof EjidoH•roes de

156 BIRD OBSERVATIONS FROM BAJA CALIFORNIA

!a Independenciaon 19 June 1991, and a pair with one smallduckling on the Rio Hardy on 20 June 1991. Howell and Pyle (1990) reportedother recentsummer observationsin northernBaja California. GadwallAnas strepera. A pair at Ejido H•roes de la Independenciaand three malesat the reservoir8 km southof EjidoH•roes de !a Independencia,all on 19 June 1991, are the firstreported for summerin Baja California(cf. Wilbur 1987). RedheadAythya americana. A pair at Ejido H•roes de la Independenciaand another pair and singlemale at the reservoir8 km south of Ejido H•roes de la Independencia,all on 19 June 1991, are the first reportedin summerin Baja California (cf. Wilbur 1987). White-tailedKite Elanus leucurus.We observedfive birds (including one adultand twojuveniles) 11 km southof CiudadInsurgentes on 12 June 1991. In addition,two adultswere seennear CiudadInsurgentes in November1989 (R. Rodriguez-Estre!!a pers. comm.).Although the species'range has increasedgreatly in North America in recentyears, Wilbur (1987) reportedthat no rangeexpansion had been noted in Baja California.These observations represent a rangeextension of 400 km southfrom the nearestknown point of occurrenceon the peninsula.We followAreadon and Bull (1988) and Sibleyand Monroe(1990) in not consideringleucuru$ conspecific with the quitedifferent caeruleu$ of the Old World. LaughingGull Laru$ atticilia. On 20 June 1991, at San Felipe,we observed24 alternate-plumagedadults heading south offshore. These birds were probablydis- persingfrom the recentlydiscovered colony in the Rio Coloradodelta (Palacios and Me!link1992). Otherthan these records, the speciesis knownonly as a wintervisitor in BajaCalifornia, with one recordas earlyas September(Wilbur 1987). Franklin'sGull Larus pipixcan. One adult at GuerreroNegro, 1-2 December 1982, appearsto be onlythe sixthrecorded in BajaCalifornia (cf. Wilbur 1987); four of the records fall between late November and mid December. Heermann'sGull Larus heermanni. An adulton the reservoirat EjidoH•roes de la Independencia,elevation 1000 m, on 19 June 1991, is the first of this species reportedfor the interiorof BajaCalifornia (cf. Wilbur 1987), being105 km fromthe Gulf of California and 65 km from the Pacific Ocean. Gull-billedTern $terna nilotica. This speciesappears to be a common post- breedingvisitor to the Rio Coloradodelta and northeastcoast. We sawtwo groups, totaling37 alternate-plumagedadults (most apparently paired), at San Felipe,and 23 alternate-plumagedadults at the Rio Hardy, all on 20 June 1991. Wilbur (1987) reportedonly a few recordsand consideredthe species'status "uncertain." Forster'sTern $terna forsteri. Palaciosand Alfaro (1991) reportedthe recent discoveryof the firstknown breeding colonies of thisspecies in Baja California.The La Pinta Pond colonywas stillactive in 1991, with 30-35 birds(including 13 sitting on nests,a pair feedingtwo chicks,and three first-summerbirds) on 14 June. A second-summerbird at the reservoir8 km southof EjidoH•roes de !a Independencia, 19 June 1991, a first-summerbird at San Felipe, 20 June 1991, and nine first- summerbirds at the Rio Hardy, 20 June 1991, appearto constitutethe only other summerrecords for Baja California(cf. Wilbur 1987). BlackSkimmer Rynchops niger. On 20 June 1991 we sawone at San Felipeand an alternate-plumagedadult at the Rio Hardy. It is likelythat BlackSkimmers are regularpost-breeding visitors to theseareas as are LaughingGulls and Gull-billed Terns.Wilbur (1987) mentionedonly recordsfrom the northwestcoast in winter,but Palaciosand Alfaro (in press)reported skimmers in Baja Californiathroughout the year,at severallocations along the Pacificcoast south to LagunaOjo de Liebre,and alsoin the Bay of La Paz. Band-tailedPigeon Columba fasciata. One flew overVa!lecitos, in the SierraSan Pedro Mgrtir, on 16 June 1991. This representsthe first summerrecord from 157 BIRD OBSERVATIONS FROM BAJA CALIFORNIA northern Baja California, all other recordsthere being from Septemberto April (Grinnell 1928. Wilbur 1987). Spotted Dove Streptopelia chinensis. Although the A.O.U. (1983) included extreme northwesternBaja California in this species'range, the source for its inclusionis unclear(B. L. Monroe pets. comm.). and the specieswas not mentioned by Wilbur(1987). SpottedDoves may be residentin Tijuana, havingbeen established in San Diego sincethe 1950s (Unitt 1984), althoughin San Diego they are restricted mostlyto an area 10-12 km north of the internationalborder (P. Unitt pets. comm.). The only specificMexican recordswe are aware of are of up to three birdsat the Hospital del Carmen, Tijuana, from Augustto October 1990 (G. McCaskie pers. comm.) and one we saw on the southernedge of Tijuana, 1 June 1991. RuddyGround-Dove Columbina talpacoti. An adult male at San Jos• del Cabo, 11 June 1991. is the first recordedfor Baja California.The bird associatedloosely with Common Ground-Doves(C. passerina)and is a specieswith which we are very familiarfrom mainlandMexico. The RuddyGround-Dove has been reportedincreas- ingly in the southwesternU.S. in recent years,although mostly from autumn into winter (Dunn and Garrett 1990): thus its occurrencein Baja California is not unexpected. Groove-billedAni Crotophaga sulcirostris. On 10 November 1985, J. and K. Horton observedand photographeda Groove-billedAni at the Tripui resort, about 30 km south of Loreto (Figure 3). This isolatedrecord presumablyrepresents a vagrantfrom mainlandMexico and is the first of the speciesin Baja California this century;Groove-billed Anis formerlynested in the Cape District(Grinnell 1928).

Figure 3. Groove-billedAni at the Tripui resort, 10 November 1985 Photo by Jim and l•aren Horton 158 BIRD OBSERVATIONS FROM BAJA CALIFORNIA

Whip-poor-willCaprimulgus vociferus. We clearlyheard sevenor eight Whip- poor-willsat La Laguna,the nightof 8 June1991, indicatingthe speciesto be a fairly commonsummer resident there. The birdsgave the relativelyslow, burry song typical of birdsin the southwesternU.S. and Mexico.Banks (1967) alsoheard Whip-poor- willsat La Lagunain May 1965 (not 1963 as citedby Wilbur 1987). Broad-billedHummingbird Cynanthus latirostris.J. and K. Horton observedand photographedan adultmale at their feederat E1Tripui resortfor four consecutive winters(mid-October to mid-January)from 1985/86 to 1988/89. The only prior report from Baja Californiais of severalat Cabo San Lucasin the late autumnof 1968 (Wilbur 1987). Anna'sHummingbird Calypte anna. J. and K. Horton observeda male at their feederat E1Tripuiresort, 12 October1985. This locationis about400 km southof the southernmostfrom which the specieshad been reportedpreviously, although Howell and P. Pyle saw up to four Anna's Hummingbirdsat GuerreroNegro on 11 and 12 October1991. Theseare the firstrecords of thisspecies for BajaCalifornia Sur (cf. Wilbur 1987). DuskyFlycatcher Empidonax oberholseri.We saw one or two birds,including a singingindividual, in an aspengrove at 2700 m elevationin the Sierra San Pedro Mfirtir, 17 June 1991. The specieswas alsofound at this site (about2 km southeast of the NationalObservatory) on 30 June 1984, when R. E. Webster(pers. comm.) notedat leasttwo pairs, and on 3 and 4 July 1987 (T. E. Wursterpers. comm.). Althoughthere are no breedingrecords for thisspecies in Mexico,these observations suggestnesting in the Sierra San Pedro Mfirtir. TropicalKingbird Tyrannus melancholicus. We saw one at the Nopolo tourist developmentjust south of Loreto, 13 June 1991. While the speciesis a regular autumnthrough winter visitorin the Cape District(Howell and Pyle 1988, Wilbur 1987, pers.obs.) there appear to be no previousspring or summerrecords from the peninsula. Thick-billedKingbird Tyrannus crassirostris. One at San Jos• del Cabo, 26 February1988, makesonly the fourthrecord for BajaCalifornia, the others,also in the Cape District,being in January1984 (R. Stallcuppers. comm.) and December 1986 and January1987 (Collinsand Atwood 1990). Hermit ThrushCatharus guttatus. On 17 June 1991 we heard,saw, and tape- recordedtwo or threeterritorial singing Hermit Thrushes in the sameaspen grove where we noted the DuskyFlycatchers (see above). R. E. Webster(pers. comm.) foundfive Hermit Thrushes in thesame area, 30 June1984, andT. E. Wurster(pers. comm.)noted three in the sameplace on 5 July 1985. This speciesis not knownto breedin Mexicobut these observations suggest that it doesso in the SierraSan Pedro Mfirtir. AmericanRobin Tu rdus m igratorius. Near LaõunaHanson, in the SierraJufirez, we saw a pair (the female sittinõon a nest)and heard three or four other birds sinõinõ,18-19 June1991. Thisconfirms the American Robin as a breedinõspecies in northernBaja California, followinõ the reportsof Howelland Pyle(1990), who discoveredthree or fourRobins (one sinõinõ) and an oldRobin nest at the samesite in May 1989. Nestinõby Robinsin the SierraJufirez may be fairlyrecent, as the specieshas colonized the mountains of SanDieõo County in thepast 50 years(Unitt 1984). American Pipit Antbus rubescerts.The early morninõ of 16 June 1991 an American Pipit made repeated sonõ fliõhts at Vallecitosmeadow, at 2450 m elevation in the Sierra San Pedro Mfirtir. This record and that of three at La Grulla meadow,3-5 Auõust1977 (Wilbur1987), suõõestthe possibilityof a smallbreedinõ populationin the boulder-strewnmeadows of the Sierra San Pedro Mfirtir. There is one recordof probablebreedinõ for southernCalifornia (Garrett and Dunn 1981).

159 BIRD OBSERVATIONS FROM BAJA CALIFORNIA

EuropeanStarling Sturnus uulgaris. On 14 June 1991 we notedadults feeding nestlingsat GuerreroNegro; the specieswas alsobreeding at Catavifia(adults with newlyfledged juveniles). We alsosaw one adultat the Bahiade losAngeles junction on Highway1 and two at RanchoCaracol, between Ejido Vizcaino and San Ignacio (about latitude 27ø30•N). This southwardexpansion has been mirrored on the Mexican mainlandopposite, where we saw singleStarlings 10 km north of Los Mochis and at the Rio Sinaloa crossingjust north of Culiacan,both on 24 June 1991. The previousfarthest south confirmed breeding in Baja Californiawas at San Fernando(30øN), with winter recordssouth to GuerreroNegro (Wilbur1987). SolitaryVireo Vireo solitarius.We notedeight birds, most singing but includingat leastone agitatedadult carrying food, at about2700 m elevationin the Sierra San PedroM•rtir, 16 June 1991. T. E. Wurster(pets. comm.) found a nestwith youngin the samearea, 3 July1987. Wilbur(1987) mentionedMay recordsof SolitaryVireos from this sierrabut statedthat they "almostcertainly do not nest there," although Grinnell(1928) consideredthe species"fairly common in summer"in the SierraSan Pedro M•rtir. Our observationssupport Grinnell's evaluation. WarblingVireo Vireogiluus. On 16 and 17 June 1991 WarblingVireos were fairly commonand presumedbreeding (singing, paired, and carryingfood) in the Sierra San PedroM•rtir, from at least1800 to 2700 m elevation.We find it hard to explain the lackof previoussummer records from the sierra(cf. Grinnell1928, Wilbur 1987). We alsosaw a migrantat Guerrero Negro on 5 June 1991. Red-eyedVireo Vireo oliuaceus.We observedone at Guerrero Negro, at times sideby sidewith the precedingspecies, on 5 June 1991. Red-eyedVireos are regular springvagrants to Californiaand that this is the first recordof the speciesin Baja Californiacan be readilyattributed to lack of observers. TennesseeWarbler Vermiuora peregrina. One at Cabo San Lucas, 6 February 1988. representsonly the sixthrecord for BajaCalifornia, the secondin winter(cf. Keith and Stejskal1987, Wilbur 1987). Orange-crownedWarbler Vermiuora celata. We saw one and heard another singingin woodedarroyos of the foothillsbetween La Misi6n and Ensenada,along Highway1, on 1 June 1991. The only other summerrecords from Baja California are from Islas Los Coronados, lslasde Todos Santos, and the "western Sierra San Pedro M•rtir" (Wilbur 1987). NashvilleWarbler Vermivora ruficapilla. One at Cabo San Lucas, 4 February 1988, is the firstrecorded in winter from Baja Californiaas well as the firstreported southof 26øN (cf. Wilbur 1987). BeldingrsYellowthroat Geothlypis beldingi. Belding'sYellowthroats were common along the river at Muleg•; we estimateda populationof at leastten pairsthere, with severaladults carrying food, on 5 and 13 June 1991. This populationappears to have been overlooked,as there are no historicreports from Muleg• (Grinnell 1928• Wilbur 1987), althoughD. Wimpfheimer(pers. comm.) noted the species there in 1988. Before hearing its song, we thoughtthat G. beldingi might simplybe a large allopatricform of the Common Yellowthroat(G. trichas),as consideredby some authors (cf. A.O.U. 1983). The song, however,which apparentlyhas not been described or previously recorded, is notably different from the Common Yellowthroat's.It is strikinglymore powerfuland richer;the sequencediffers from Common'stypical wi wich-uh-tein that the lastpart of the main phrasecomes first, i.e., wi te-wich-uh. SummerTanager Piranga rubra. Howell's sighting of a femaleat CaboSan Lucas, 15 December1983, supportsthe possibilityof a smallwintering population in the Cape District.Wilbur (1987) calledthis species"presumably only a rare migrant" away from the Rio Colorado,but at the sametime citeda Februaryrecord from San Jos• del Cabo.

160 BIRD OBSERVATIONS FROM BAJA CALIFORNIA

WesternTanager Piranga ludoviciana.Wilbur (1987) indicatedthat "a few may winter in the southernCape District."Grinnell (1928), however,reported several winterrecords from the Cape District.We, likeother observers (R. Rodriguez-Estrella and P. Unitt pers.comm.), have found Western Tanagers to be fairlycommon in the Cape Districtin winter: Wilbur'sstatement was obviouslyan error. Green-tailedTowhee Pipilo chlorurus. On 16 June 1991, at 2700 m elevationin the SierraSan PedroM•rtir, we observedan agitatedpair of Green-tailedTowhees behavingas if they had a nest.We alsosaw and tape-recordedtwo differentsinging birds. These are the first reported summer recordsof this speciesfrom Baja Californiaand suggestthat Green-tailedTowhees breed there; this is not particularly surprisingsince they breed commonly at suitableelevations in the mountainsof southernCalifornia (Garrett and Dunn 1981). Chipping Sparrow Spizella passerina. Around Laguna Hanson, 18-19 June 1991, we found Chipping Sparrowsto be fairly common. We saw four juveniles (apparentlyfrom three broods)being attended by adultsand three singingadults. Neither Grinnell (1928) nor Wilbur (1987) reported any summerrecords from the Sierra Ju•rez, althoughHowell and Pyle (1990) found the speciescommon and singingthere in May 1989. We spentmost of 19 Junesearching, without success, for Brewer'sSparrows (S. breweri), suspectedto breed at Laguna Hanson by Wilbur (1987). Song Sparrow Melospiza melodia. At Catavifiawe noted four or five pairs, with adultsfeeding recently fledged juveniles, on 2, 3, and 14 June 1991, indicatingthe persistenceof the populationdiscovered at this oasisin 1989 (Howell and Pyle 1990). Thesebirds had blackish-streakedunderparts like M. m. cooperito the north rather than the reddish-streakedunderparts of •. m. rivularisto the south. TricoloredBlackbird Agelaius tricolor. It was a surpriseto find a colonyof 30 to 50 pairs (adultscarrying food into a dense tule marsh)at Ejido H•roes de ia Independenciaon 19 June 1991, away from previouslyreported sites. The marsh also held 10 to 20 pairsof Red-wingedBlackbirds (A. phoeniceus).There are few recentrecords of TricoloredBlackbirds from Baja California,particularly in summer, and the last reported breeding in the peninsulaappears to have been in 1885 (Grinnell 1928, Wilbur 1987). Western Meadowlark Sturnella neglecta. One seen 2 km south of Ciudad Insurgenteson 12 June 1991 was 700 km southof any other mainlandbreeding seasonrecord (cf. Wilbur1987, pers.obs.). We did not searchthe area intensively, but it seemslikely that WesternMeadowlarks will colonize(or have colonized?)this relativelynew agriculturalregion. Yellow-headedBlackbird Xanthocephalus xanthocephalus. On 19 June 1991 we saw three pairs, at leasttwo of which were attendingbegging juveniles, at Ejido H•roes de la Independencia,a new nestinglocation for this species.In the Rio Coloradodelta we saw12-15 pairsfeeding fledglings, and apparently also nestlings, in an irrigationditch 3 km west of Durango. Howell and Pyle (1990) had found territorialYellow-headed Blackbirds at both placesin May 1989. We alsosaw three or four other malesin the Rio Coloradodelta between Durango and Coahuila,19 June 1991. Brewer'sBlackbird Euphagus cyanocephalus. A maleat Catavifiaon 2, 3, and 14 June1991 constitutesthe southernmostbreeding season report for the peninsula(cf. Wilbur 1987). Brown-headed Cowbird NIolothrus ater. In June 1991 we noted several Brown- headedCowbirds between Palo Verde(21 km northof Muleg•)and San Jos• dei Cabo:Palo Verde, one femaleon 13 June;Muleg•, one maleon 5 June,two or three heardon 13 June:Tripui resort, one maleand one femaleon 12 June(present there sincethe early 1980s, J. and K. Horton pers.comm.); kilometer post 37, between Ciudad Insurgentesand Loreto, one male and one female on 12 June; between

161 BIRD OBSERVATIONS FROM BAJA CALIFORNIA

Ciudad Constituci6nand Ciudad Insurgentes,one male on 12 June; Ciudad Constituci6n,one male and two femaleson 12 June;San Jos• del Cabo, one male on 11 June. The farthestsouth this specieshad been reportedpreviously in Baja California in summer was San Fernando (Wilbur 1987).

ACKNOWLEDGMENTS

We thank Jim and Karen Horton, Guy McCaskie,Eduardo Palacios, Ricardo Rodriguez-Estrella,Rich Stallcup, Philip Unitt, Richard E. Webster, David Wimpfheimer,and ThomasE. Wursterfor sharingtheir unpublishedobservations. We also thank Eric Mellink, EduardoPalacios, and RicardoRodriguez-Estrella for their helpfulcomments on the manuscriptand for drawingour attentionto certain references.This is PointReyes Bird Observatorycontribution number 512.

LITERATURE CITED

Amadon, D., and J. Bull. 1988. Hawks and owls of the world: A distributionaland taxonomic list. Proc. West. Foundation Vert. Zool. 3(4):295-357. AmericanOrnithologists' Union. 1983. Check-listof North AmericanBirds, 6th ed. Am. Ornithol. Union, Washington,D.C. AutomoBileClub of SouthernCalifornia. 1990. BajaCalifornia. Automobile Club of S. Calif., Los Angeles. Banks,R. C. 1967. Birdsand mammalsof La Laguna,Baja California.Trans. San Diego Soc. Nat. Hist. 14:205-232. Collins,C. T., and Atwood,J. L. 1990. Firstrecords of the Thick-billedKingbird in Baja California,Mexico. W. Birds21:75-76. Dunn, J. L., and Garrett, K. L. 1990. The identificationof Ruddyand Common ground-cloves.Birding 22:138-145. Escofet,A., Loya-Salinas,D. H., and Arredondo,J. I. 1988. El esterode Punta Banda(Baja California, M•xico) como habitat de la avifauna.Ciencias Marinas, pp. 73-100. Garrett, K. L., and Dunn, J. L. 1981. Birdsof SouthernCalifornia. Los Angeles AudubonSoc., Los Angeles. Grinnell,J. 1928. A distributionalsummation of the ornithologyof LowerCalifornia. Univ. Calif. Publ. Zool. 32:1-300. Howell, S. N. G., and Pyle, P. 1988. Additionalnotes on birdsin Baja California. Aves Mexicanas1(88-1):2-3. Howell,S. N. G. andPyle, P. 1990. Additionalnotes on birdsin BajaCalifornia, May 1989. Aves Mexicanas 2(90-1):6-7. Huey, L. M. 1928. Some bird recordsfrom northern Lower California. Condor 30:158-159. Keith, A. R., and Stejskal,D. 1987. Two outstandingsites for vagrantsin Baja California.Mexican Birding Association "Bulletin Board" 1(87-3):3. LlinasG., J., Amador S., E., and MendozaS., R. 1989. Avifaunacostera de dos esterosde la Bahiade La Paz, Baja CaliforniaSur, Mexico.Inv. Mar. CICIMAR 4(1):93-104. Palacios,E., and Alfaro, L. 1991. Breedingbirds of LagunaFigueroa and La Pinta Pond,Baja California, Mexico. W. Birds22:27-32. 162 BIRD OBSERVATIONS FROM BAJA CALIFORNIA

Palacios,E., and Alfaro, L. 1992. Occurrenceof BlackSkimmers in Baja California. W. Birds 23:173-176. Palacios,E., and Mellink,E. 1992. Breedingbird recordsfrom MontagueIsland, northern Gulf of California. W. Birds 23:41-44. Sibley,C. G., and Monroe,B. L., Jr. 1990. Distributionand Taxonomyof Birdsof the World. Yale Univ. Press, New Haven, CT. Unitt, P. 1984. The birdsof San Diego County.San Diego Soc. Nat. Hist. Memoir 13. Wilbur,S. R. 1987. Birdsof BajaCalifornia. Univ. of Calif.Press, Berkeley.

Accepted 19 Deceml•er1991

Belding'sYellowthroat Sketch by Tim Manoils

163