Museums Cited

CUMV: Cornell University Museum of Vertebrates, Ithaca, NY
MLZ: Moore Laboratory of Zoology, Occidental College, Los Angeles, CA
MVZ: Museum of Vertebrate Zoology, University of California, Berkeley, CA
SDNHM: San Diego Natural History Museum, San Diego, CA
UABC: Colección Ornitológica del Laboratorio de Vertebrados de la Facultad de Ciencias, Universidad Autónoma de Baja California, Ensenada, BC
UABCS: Universidad Autónoma de Baja California Sur, La Paz, BCS
UMMZ: University of Michigan Museum of Zoology, Ann Arbor, MI
USNM: National Museum of Natural History, Smithsonian Institution, Washington, DC
WFVZ: Western Foundation of Vertebrate Zoology, Camarillo, CA

ABSTRACT: In this summary of notable recent observations, we discuss 529 naturally-occurring species with records that we find acceptable for the two states combined (480 and 449 for Baja California and Baja California Sur, respectively). Included are five species not previously reported from the area: Brown Noddy, Green Kingfisher, Yellow-throated Vireo, Red-faced Warbler, and Flame-colored Tanager. Another five species are newly reported for one state or the other: Purple Gallinule in Baja California and Common Merganser, Lesser Black-backed Gull, Yellow-billed Loon, and Hepatic Tanager in Baja California Sur. Three reports of Short-tailed Albatross, the first from Mexican waters since the late 1800s, are discussed. Other issues discussed in detail include Hurricane Rosa, Pacific island birds, Gulf island landbirds, montane birds of Baja California, and taxa and populations recorded only before 2000. We also present an update of state lists for Baja California and Baja California Sur.

Figure 1

RESUMEN: En esta síntesis de observaciones recientes y destacadas documentamos 529 especies que ocurren naturalmente para ambos estados combinados, con registros que consideramos aceptables (480 y 449 para Baja California y Baja California Sur, respectivamente). Se incluyen cinco especies no reportadas previamente en el área: Anous stolidus, Chloroceryle americana, Vireo flavifrons, Cardellina rubrifrons y Piranga bidentata. Otras cinco especies se reportan por vez primera para uno u otro Estado: Porphyrio martinicus en Baja California y Mergus merganser, Larus fuscus, Gavia adamsii y Piranga flava en Baja California Sur. Presentamos tres reportes de Phoebastria albatrus, los primeros en aguas mexicanas desde finales de los 1800s. Otros aspectos tratados son el huracán “Rosa,” aves de las islas del Pacífico, aves terrestres de las islas del Golfo, aves de montaña de Baja California, y especies y poblaciones registradas solamente antes del año 2000. Incluimos también una actualización de los listados estatales para Baja California y Baja California Sur.

Treatment of the avifauna of the Baja California Peninsula (i.e., the Mexican states of Baja California and Baja California Sur) and associated islands was unique for most of the 20th century. The American Ornithologists’ Union Check-list of North American Birds included the peninsula within its coverage area from the first edition (AOU 1886) through the fifth (AOU 1957), unlike any other region of Mexico. Not until the 6th edition (AOU 1983) was coverage expanded to include all of Mexico and the rest of Middle America. Coverage was, of course, also afforded in the Mexican checklists by Friedmann et al. (1950) and Miller et al. (1957). Since Grinnell’s (1928) detailed account of the peninsula’s avifauna, periodic summaries have become less thorough (Wilbur 1987), if not more richly illustrated (Erickson and Howell 2001, Erickson et al. 2013).

Meanwhile, quarterly summaries of noteworthy bird observations in North American Birds began in 2000 and continued apace through about 2015, at which time the journal began to falter. Coverage of the rest of Mexico was less consistent. During the same period, eBird came into its own and is now the dominant force in the submission and reporting of bird observations throughout much of the world.

We prepared this 3+ year summary of observations, based primarily on eBird submissions, to maintain uninterrupted coverage while North American Birds regional reports begin again online (Floyd 2020, Leukering 2020). We also took this opportunity to update the checklists of the states’ birds previously written by Howell et al. (2001) and Erickson et al. (2013).

Figure 2

Highlights of this 2016–2019 summary include reports of four species new to the area, all from Baja California Sur: Brown Noddy, Green Kingfisher, Yellow-throated Vireo, and Flame-colored Tanager. Additional first state records include Purple Gallinule in Baja California and Common Merganser, Lesser Black-backed Gull, Yellow-billed Loon, and Hepatic Tanager in Baja California Sur. Other exceptional rarities reported were primarily of North American origin (Barrow’s Goldeneye, Red-necked Grebe, Common Nighthawk, Gray Hawk, Brown-crested Flycatcher, Bendire’s Thrasher, Cassin’s Sparrow) but also included Tahiti Petrel from the South Pacific and Olive-backed Pipit from Asia. In Baja California, boobies made an impressive appearance off the northwest coast, and nesting Neotropic Cormorants burst upon the scene. In a league of its own, however, and our choice for the highlight of this entire report, was the reappearance of Short-tailed Albatross to Mexican waters after going unreported since the late 1800s, even if “spoiled” by the revelation that two had been found earlier in the decade. On a somber note, Tricolored Blackbird seems on the verge of extirpation in Mexico. Other issues touched upon include Hurricane Rosa (2018), Pacific island birds, Gulf island landbirds, and the montane avifauna of Baja California.

Updated state checklists are included. Accepted are 529 naturally-occurring species for the two states combined: 480 and 449 for Baja California and Baja California Sur, respectively. Ten of the most-often-reported non-native species are also included. We revisit a number of old records, present evidence for the region’s first Red-faced Warbler, and discuss taxonomic issues resulting from recent decisions of the North American Classification and Nomenclature Committee of the American Ornithological Society (often formerly referred to as the “AOU Checklist Committee”). We end with a discussion of taxa and populations recorded only before 2000, and some of the reasons why this may be so.

Study area, abbreviations, and other explanations. Our region of study comprises the states of Baja California, Baja California Sur, and offshore waters to 200 nautical miles (370 km) from the nearest point of land, including islands, but excluding waters closer to the Mexican mainland or other islands outside of our boundaries (map shown by Erickson et al. 2013). In the ornithological literature, the land area involved has typically been referred to simply as Baja California (Lower California in the older literature) or “the peninsula” for short. But Baja California now correctly refers to only the northern half of our region and the extreme northern, and especially northeastern, portions of Baja California cannot properly be referred to as “peninsular.” Nevertheless, we use the words peninsula and peninsular when appropriate, but we more often use the words region and area, which herein refer specifically to our study area. Specific localities mentioned in the text, tables, and checklist are shown in Figures 1 and 2.

BC the state of Baja California and offshore waters

BCS the state of Baja California Sur and offshore waters

NAB North American Birds (journal)

I., Is. Isla, Islas

n., s., e., w. and combinations for compass directions

ph. recognizable photo on file with us or available online

aud. audio recording archived at the Macaulay Library of Natural Sounds, Cornell Lab of Ornithology, Ithaca, NY

† description on file with us or available online

Unless otherwise noted, further details (and often photographs) of most of the recent observations included here can be found in individual eBird submissions available online. When NAB is cited for older records, further details (and sometimes photographs) can be found there and are available online for the years 2000–2007 (https://sora.unm.edu/node/209) and March 2012–July 2016 (available to American Birding Association members at https://www.aba.org/nab-pdf-archives/).

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