Great Basin Naturalist Volume 57 Number 2 Article 5 5-7-1997 Late fall and early spring bird observations for Mulegé, Baja California Sur, Mexico Robert C. Whitmore West Virginia University, Morgantown, West Virginia R. Craig Whitmore Mulege, Baja California Sur, Mexico Follow this and additional works at: https://scholarsarchive.byu.edu/gbn Recommended Citation Whitmore, Robert C. and Whitmore, R. Craig (1997) "Late fall and early spring bird observations for Mulegé, Baja California Sur, Mexico," Great Basin Naturalist: Vol. 57 : No. 2 , Article 5. Available at: https://scholarsarchive.byu.edu/gbn/vol57/iss2/5 This Article is brought to you for free and open access by the Western North American Naturalist Publications at BYU ScholarsArchive. It has been accepted for inclusion in Great Basin Naturalist by an authorized editor of BYU ScholarsArchive. For more information, please contact [email protected], [email protected]. Crt::at Basin NatumhJ'lt 57(2), tel 1997, pp. 131-141 LATE FALL AND EARLY SPRING BIRD OBSERVATIONS FOR MULEGE, BAJA CALIFORNIA SUB, MEXICO Robert C. Whitmore! and R. Craig Whitmore2 ABsrRAcr.-Observational data from spring and fall 1996 and ~..pring 1997 for the region near Mulege, Baja California Sur. Mexico, are summarized in tabular form. In addition, new or noteworthy data for 17 species are annotated to provide clarification ofpreviously published records. A umquely plumaKed bird, too far south for a female American Robin (TIR"­ dUoS migratnrltLf) in basic plumage and too far north for the endemic "San [Alue;" Rohin (.lUrdus migrutorius confinis) and intennediate in coloration between the two, was recorded. Range expansions are documented for several !l-pecies includ­ ing European Starling (Stumns t>ulgtnis), Anoa's Hummingbird (Colypte /'Will), Western MeadO\....lark {SturneUn negle.cta}, White-faced Ibi' (Pl<~adis chkhi). and White-fronted ('.oose (Anser ,dbijro"..). Least G,ebc, (Tachyhaj>Ws dominicus), a species ofconcern which i<; apparently declining in numbers, and Belding's Yellowthroat (Geothlypis bc~i), a spccie.'l endemic to Baja California Sur, were obselVcd in the fre.'lhwater marsh during all 3 study pcriOOs. Key words: Btya Culifomin. Stu; Mexico; Mw.egc. bird records, range expansion, desert naris. The avifauna of Baja Cali/oruia (hereafter Hotel Serinidad, approximately 2 km east ofthe BC), the second longest and most geographi­ town, supports small aircraft, while the nearest cally isolated peninsula in the world (Grismer commercial air service is to Loreto, approxi­ aJ1d McGuire 1993), is one of the most inter­ mately 132 km south. Its distance from both the esting, yet poorly studied, in North America nmthern and southern population centers makes (Wilbur 1987, Howell and Webb 1995). Late Mulege accessible only to hardy travelers. 19th and early 20th century natural history The area features both a brackish water tidal work in BC has been summarized by E. D. estuary, Rio Mulege, and a small, year-round Nelson (1921) and J. Grinnell (1928). Much of spring-fed freshwater lagoon. The former is the recent ornithological effort has been con­ small, <3 km long, runs primarily west to east, centrated in either the coast and mountains of and includes a poorly developed saltwater marsh n"'thern BC (Kiff et al. manuscript in prep­ ofcordgrass (Spartina folwsa, Gramineae), glass­ aration, Patten et al. 1993, Unitt et al. 1995), wort (Salicornia bigelovii, Chenopodiac-eae), and lagoons ofthe Pacific coast (Massey and Palacios saltworl (Batis maritima; plant names follow 1994), offshore islands (Anderson 1983, Cody Roberts [1989]). A narrow mangrove commu­ 1983), or southernmost regions from La Paz to nity, principally black mangrove (Avicennia the cape (Rodriquez-Estrella and Rivera-Rodri­ germinans, Avicenniaceae) and red mangruve quez 1992, Carmona et al. 1994, Guzman et aI. (Rhizophora mangle, Rhizophoraceae), occurs 1994). This report summarizes early spring irregularly along tbe estuary and on several 1996 and 1997 and late faIl 1996 observations small islands within its boundaries. Above tbe for the area near Mulege, Baja California Sur high tide zone are scattered stands of mangle (hereafter BCS). dulce (Mayte.ws phyllnnthaides, Celastraceae). MuJege is located on the east coast of BCS Lining the southeru edge of the estuary are north of Babia Concepcion and south of Santa several "retirement" communities consisting of Rosalia, straddling 26"53' ,111"58W (Fig. 1). permanent houses and semipermanent domi· Vehicular access is by means of Mexico High­ ciles formed by modifying various types of way 1, a reasonably maintained 2-lane asphalt motor homes and trailers. Many residents pro­ road passable during all but the wettest sea­ vide supplemental food for hirds in the fonn sons, approximately 800 Ian south of Tijuana, of typical "backyard" grain feeders and hum­ Baja California No,te (hereafter BCN), and mingbird feeders filled witb sugar water. Asso­ 500 km north ofthe cape. A landing sbip at the ciated with these communities are numerous IOivisioll ur R"\:.,,try, PO 8o.l6125, ~t V~aia University, MOI-gaJ",hlWll, wv 26&)().6U5. 2Aplu1ado 10, Q.uis nio Mu1o#. M"u:ge, Baja Qilifun';1L SUI:, Mc:dco. 131 132 GREAT BASIN NATURALIST' [Volume 57 west ofthe lagoon an arroyo meanders through " the center of a broad valley. The arroyo con­ tains water only during seasonally heavy rains. 4 Portions ofthe valley are heavily irrigated with ancestral water and support citrus orchards, 31 corn, garlic, onions, alfalfa, some truck crops, 6 and pasture. Annual rainfall averages < 12 em, the average computed from numerous years 29 without rain interspersed with an occasional heavy downpour. 11. Ornithologically, the Mulege region has re­ 12. ceived only anecdotal attention (Wilbur per­ 13. 27 14 15 • sonal communication, Howell and Webb 1992), •• even though the area is home to 3 species 1e • 17 endemic to BC, Xantus' Hummingbird (nomen­ clature follows the 1983 AOU Check-list with 25 appropriate supplements; see Appendix for scientific names), Belding's Yellowthroat, and Gray Thrasher. In addition, recent observations 23 indicate that a small colony of Least Grebes breed within the freshwater lagoon at Mulege (Howell and Webb 1992, personal observation) 114 112 110 and large concentrations of Hooded Oriole breed in the palmar. Fig. L Outline map of 2 states in Los Estados Unidas Field data were collected during February, de :Mexico, Baja California Norte and Baja California Sur, March, April, and November 1996 and Febru­ showing approximate position of prominent locations: 1, ary and March 1997. The data consist ofdirect Tijuana; 2, Ensenada; 3, Maneadero; 4, San Felipe; 5, Santo Domingo; 6, Bahia de San Quintin; 7, EI Rosario; 8, observation enhanced with playbacks of re­ Cataviiia; 9, Bahia de Los Angeles; 10, Guerrero Negro; corded songs/calls. Here we summarize new, 11, San Ignacio; 12, Santa Rosalia; 13, Mulege; 14, Bahia noteworthy or locale-specific information for Concepcion; 15, La Purfsima; 16, Comondu; 17, Loreto; 17 species, some of which may be considered 18, Ciudad Insurgentes; 19, Bahia Magdalena; 20, La Paz; common, but for which no Mulege records are 21, La Laguna; 22, San Jose del Cabo. provided in published sources (e.g., Nelson 1921, Grinnell 1928, Wilbur 1987, Howell and ornamental plantings and scattered palms in­ Webb 1992, 1995). In addition, we provide tab­ cluding native Mexican fan palm (Washingtonia ular summarization of our data for all species robusta, Arecaceae) and introduced date palm observed during the 3 time periods. Precise (Phoenix dactylifera, Arecaceae). Dense stands latitude/longitude locations were determined of these species are locally referred to as the using GPS (Gannin model #100), while approx­ "palmar." imate (hereafter approx.) locations were deter­ The freshwater lagoon, approximately 1.5 mined from an atlas of surface maps (Topo­ km long and 10-30 m wide depending on sea­ graphic International, Inc. 1986). son, is formed by damming the main spring, primarily to prevent tidal saltwater contamina­ ANNOTATED SPECIES ACCOUNTS tion. It supports a small community, a plantation of date palms, a dense stand of rush (JuncWJ Least Grebe. Observed at the freshwater sp., Juncacae), and limited citrus and mango oasis each day it was visited. In spring adults orchards. The lagoon is highly impacted by were attracted to tape recordings of their ad­ domestic cattle and pigs, which run freely and vertisement and distress calls. As many as 6 have trampled significant portions of the edge adults could be seen at 1 time within 50 m of habitat. Away from the water, habitat abruptly the tape player. All birds observed in March transforms into sarcocaulescent desert (Wig­ were in full adult breeding plumage (red eyes gins 1980) dominated by Cercidium, Bursera, and lack ofa white throat). Two juveniles were Pachycereus, and Opuntia (Wilbur 1987). To the observed on 26 April 1996. This species was J997] BAJA CALIFORNIA SUR, MEXICO, BIRD R£COnDs 133 not recorded in brackish water of tidal Rio from close range « 10 m) swimming in the Mulege. Based on playbacks, we estimate that freshwatc.- lagoon at Mulege. The furthest there were at least 8 pairs of Least Grebes in south for which Wilbur (1987:53) provides the oasis; we know ofat lea~t 1 successful nest­ documentation is Bahia San Quintin (approx. ing attempt. Howell and Webb (1992) also ob­ 300 27'N, 115°57'W) on the Pacific coast. The served them in the oasis and cited 2 other range map in Howell and Webb (1995:155) ohservations, from 1987 and 1988. This species shows the transient/winter range of tbis sp<...->cies was formerly common in the cape region but only on the Pacific coast side of the peninsula, has declined in that area because of habitat although the west coast ofmainland Mexico is degradation (Wilbur 1987:32-33). Since this included. oasis is highly impactcd by humans and appears Anna's IInmmingbird.