Observations (August 2016 through December 2019) and Photographs

Waterfowl through Doves

Colonization of s. BCS by Black-bellied Whistling-Ducks has proceeded more slowly than some may have predicted. The species was first recorded in 1991 and was confirmed nesting in 2004 (Erickson et al. 2013), and maximum counts in the La Paz area had reached 37 by 2 Dec 2004 (RoC, VOAP, DSa). Since then there has been only one record north of La Paz (La Purísima, 29 Feb 2016; NAB 70:235), and maximum counts have only reached 42 (18 Feb 2010; PH). The high count for this period was 32 at Lagunas de Chametla 21 Nov 2016 (NS), and one at Santiago 4 Jul 2018 (GMa) was the first to be reported from that relatively well-worked location.

Forty Snow Geese were together in the se. portion of the Mexicali Valley 12 Dec 2018 (JV et al.). Although the species is still regularly seen in large numbers in nearby portions of California and Sonora, this is the first double-digit report in the region since the early 1990s. Most notable among other reports were eight at Estero San José 16 Dec 2016 (ph. MEM); nine at Nopoló 3 Nov 2018–16 Feb 2019 (TH et al.); and 2 “Blue Geese” at Estero Punta Banda 6 Mar 2017 (ph. CIMC; Figure 3). The last represents the first report of this color morph in the region. The only Ross’s Geese of the period were at Lagunita El Ciprés 22 Dec 2017–28 Mar 2018 (EDZH et al.) and Presa Rodríguez 31 Mar 2019 (RAE). Other than Brant (and Canada Goose in the Mexicali Valley), Greater White-fronted Goose is now the most numerous and regularly reported goose in the region, by far. The only notable reports were of 21 on I. Cedros 12 Jan 2019 (ph. DRh; Table 1) and a possible “Tule Goose” (A. a. gambeli) among approximately 35 “typical” Greater White-fronted Geese (A. a. frontalis, smaller and paler than gambeli) frequenting Lagunita El Ciprés and the nearby Maneadero Plain 22 Dec 2017–17 Feb 2018 (bird located in photographs after the fact by SGM). Patten et al. (2003) expressed caution while discussing possible extralimital records of this subspecies.

The only interior Brant reported were 2 over Ejido El Choyal, BC 13 Mar 2019 (AL). Of the white-cheeked geese (Canada and Cackling Geese, formerly known collectively as Canada Goose), “Aleutian” Cackling Goose (B. h. leucopareia) is now the default subspecies throughout the region, except in the Mexicali Valley, where the “Great Basin” Canada Goose (B. c. moffitti) is more often reported. This period was typical with 56 Cackling Geese reported (out to I. Guadalupe and south to the Cape District, but with none in the Mexicali Valley) and 28 Canada Geese reported (all in the n. half of BC).

Most of the 13 Wood Ducks found together near San Felipe 9–10 Jul 2019 (ph. SNGH et al.) were juveniles and are believed to represent at least one local brood. The only previous regional nesting record was from Mexicali in 2004 (NAB 58:437–438). Another Wood Duck at Mulegé 21 Jan 2018 (FM) was in BCS, where it established only the third record. Eurasian Wigeons were at Estero Punta Banda 21–24 Dec 2019 (MJB et al.), Guerrero Negro 22 Jan–23 Feb 2018 (ph. FM, ph. KM; Figure 4), and Lagunas de Chametla 26 Oct 2019 (ph. JC). The last two were the fifth and sixth to be found in BCS. Six duck species that winter commonly in the region were found on unseasonal dates: Blue-winged Teal at Lagunita El Ciprés 22 Jun 2019 (JV et al.), Nopoló 12 Jun 2018 (TH), and Lagunas de Chametla 6 Jul 2019 (GMa); Northern Shoveler at Lagunita El Ciprés 9–15 Jun 2019 (ph. RP); American Wigeon at Colonia Zaragoza 9 Jul 2019 (RAE et al.); 2 Ring-necked Ducks at Estero San José 2–3 Aug 2016 (SGM); Lesser Scaup at Lagunita El Ciprés 12 Jun 2017 (ph. PL) and Guerrero Negro (6 on 5 Aug 2019, ph. MiHa); and Red-breasted Merganser at Estero Punta Banda 13 Jun–26 Aug 2017 (ph. WT et al.). Canvasbacks no longer winter commonly, and none were found south of Estero Punta Banda. Redheads nested again at Estero San José, with a female and ducklings seen 13 Jun 2017 (AS). The only Greater Scaup found away from Bahía San Quintín, where the species may still winter regularly in small numbers, were at Estero Punta Banda 24 Dec 2019 (JTS, NDe), San Felipe 8 Jan 2019 (AEM, JM), and Estero San José (up to two, 1–28 Jan 2018; ph. GMa et al.; Figure 5). White-winged and Black Scoters are very rare in the region. At least 2 White-winged Scoters were on the Pacific coast south to the Ensenada area, and three more were in the Gulf of California at Bahía de San Luis Gonzaga: two on 26 Nov 2016 (ph. RPO) and one on 2 Nov 2017 (ph. BS). At least 4 Black Scoters were on the Pacific coast south to the Ensenada area, and one in the Mexicali Valley near Colonia Batáquez 12 Dec 2018 (ph. JV et al.) represented the first regional record away from the Pacific Ocean.

The rarest of the ducks found were a first-winter Harlequin Duck at Bahía de los Ángeles 15–29 Jan 2019 (ph. GMe et al.; Figure 6; fourth BC record), Long-tailed Duck at Nopoló 24–28 Dec 2017 (ph. TH et al., Figure 7; third BCS record); female Barrow’s Goldeneye on the Canal Alimentador Central south of Algodones, BC 4 Feb 2017 (†NAL; the two previous regional records are from the same area); and Common Merganser at San Ignacio 16 Dec 2018–21 Mar 2019 (ph. GMa et al., Figure 8; first confirmed BCS record). Fifteen additional Common Mergansers were reported in n. BC during the period. Hooded Merganser showed well in BCS with one at the Guerrero Negro saltworks 30 Nov 2016 (ph. VOAP), three at three locations in ne. BCS during the winter of 2017–2018, and up to two at El Pescadero 12–27 Dec 2019 (ph. SM et al.).

At least 6 Horned Grebes reached the mid-peninsula area, and one was all the way south at Cabo San Lucas 1 Feb 2018 (ph. TME). Far more notable was a Red-necked Grebe on the n. Gulf coast at Bahía Cristina 9 Nov 2018 (ph. RPO et al., Figure 9). The sole previous regional record was at Estero Punta Banda 31 Oct–9 Nov 2013 (NAB 68:153). The only BC reports of Band-tailed Pigeon were of one singing in the Sierra San Pedro Mártir 21 May 2019 (†RV, RB) and of an immature in the desert at Cataviña 19 Oct 2018 (ph. RAE, ph. SNGH). An Inca Dove at San Ignacio 14 Oct 2016 (†PC et al.) established the third confirmed BCS record.

Groove-billed Ani

Recolonization of the Cape District by Grove-billed Ani is proceeding slowly, if at all. Since the initial observation of at least 14 birds at Estero San José in Nov/Dec 2015, the species was recorded at four more locations north to La Paz, involving at least 9 individuals. The most notable observations from this period were of one at La Paz 15 Dec 2018 (†SLB; only previous record there was from 1 Jan 2016; contrast below) and two at Estero San José 13 May 2017; in the latter report, one was carrying nesting material (GMa). In 2019, reports were restricted to Estero San José and never involved more than 4 birds.

Cape District birds were originally described as a separate subspecies (C. s. pallidula; Bangs and Penard 1921), and Grinnell (1928) agreed that they “are easily distinguishable from any Mexican birds.” However, the species is now considered monotypic (Greenway 1967, Bowen 2020). The historical record is, of course, incomplete, but it now appears that the status of the species in BCS has always been irregular. Anis were found at Estero San José from 1882– 1890 with nesting confirmed in 1882 and 1887 (egg dates 29 Apr–3 Sep) and a maximum of 30 birds seen in 1887 (Brewster 1902, Grinnell 1928). A bird at Estero San José 5 Aug 1896 (SDNHM 22074) “appeared to have just arrived from the mainland” (Miller 1950:100). Anis were also noted at Santiago and near Todos Santos (Brewster 1902), but Ridgway’s (1916) report for La Paz (repeated by Grinnell 1928 and Wilbur 1987) is in error. He cited Belding (1883) for this, yet Belding (pp. 546–547) found the species only at Estero San José.

The species was not reported thereafter (Grinnell 1928, Bent 1940, Wilbur 1987) until 1985, when one was photographed at Tripuí (Howell and Webb 1992); it was the only one ever found north of La Paz. After that, and before Nov 2015, anis were seen in 2009, 2010, 2012, and 2013: always single birds in the far south, except for four at Los Frailes 18 Feb 2013 (†RL).

Goatsuckers through Shorebirds

Two Common Nighthawks found together in the foothills of the Sierra San Pedro Mártir 13 Jun 2018 (†AEM, JM, RG) established but the third regional record. The location, date, and number of birds involved all suggest the possibility of nesting. One was collected in the same mountain range 3 July 1893 (Erickson et al. 2013). Several Vaux’s Swifts were reported in the Cape District in migration and winter, as is normal, but none were reported from approximately the middle third of the peninsula. The number of Selasphorus hummingbirds, most presumably sedentarius Allen’s Hummingbirds, has risen in all seasons in nw. BC, but nesting still has not been confirmed beyond Real del Mar, just south of the California border. There have been few recent reports of Calliope Hummingbird in the region, so three this period were unexpected: one at Sierra San Pedro Mártir 30 Jun 2017, up to two in Ensenada 1–9 May 2018 (ph.), and one at Maneadero Plain 19 May 2018 (all observations JV et al.). Broad-billed Hummingbird is a very rare visitor to the region, so one at Miraflores 18 Nov 2016 (ph. VOAP) and five more at four locations in BCS Oct 2017–Jan 2018 made for a good showing.

Black Rail is so rarely encountered in the region that any report is cause for celebration; up to three were heard at Bahía San Quintín 2–15 Jun 2017 (JV et al.). The summer status of Sora in the region remains unclear. There has been no evidence or suggestion of nesting in BCS since 1928 (Bancroft 1930) nor in BC since 1997 (Wurster et al. 2001). Recent records extend from 10 Jul to 17 May at the extremes. Thus, one late May record (26 May 2017, Lagunita El Ciprés; RP, EB) and two June records—both 10 Jun 2018: Ciénega Redonda (AEM, JM, RG) and Campo Mosqueda (BH)were exceptional. An adult Purple Gallinule found in a yard in Ensenada 27 Aug 2018 was captured and released in a marsh nearby (CIMC, ph. MNMR, Figure 10). The only previous regional record was from the opposite end of the peninsula at Estero San José 14 Jan 2009 (Erickson et al. 2013). The mid-peninsula status of Common Gallinule is poorly known. This period, none were reported from the majority of the length of the peninsula, from the Ensenada area to San Javier. Perhaps lingering drought and its impact on freshwater habitats has taken a toll on the species, at least temporarily. An American Coot x Common Gallinule hybrid in Tijuana 9 Dec 2019–30 Jan 2020 was one of few observations of this combination reported anywhere (Erickson and Rottenborn 2020).

At least one Black Oystercatcher, often in association with an American Oystercatcher, continued to be seen through February 2020 in the s. Gulf of California in the La Ventana area, east as far as Punta Arena de la Ventana (GJS et al.). Two more were reported in the n. Gulf of California in 2019: Bahía de San Luis Gonzaga 20 Apr (HS) and Bahía de los Ángeles 21 Jul (GMe). In a pattern typical for the species, 6 Pacific Golden-Plovers were found along the Pacific coast south to Bahía Asunción between November and February. In contrast, the only American Golden-Plover, at Presa Rodríguez 2 Oct 2019 (ph. SNGH et al.; Figure 11), established just the second BC record (Erickson et al. 2001). The only Mountain Plovers found were at their last stronghold on Mesa de San Jacinto (35 on 20 Oct 2016; PAG, NAL) and far south at Villa Jesús María 12 Oct 2016 (MJB, ph. RAH et al.).

A Red Knot at the Cerro Prieto geothermal ponds 22 Aug 2019 (ESM) was at an inland location where the species has been found at least twice before in fall. The first for BC since Sep 2006, one Ruff was found over the period: Lagunita El Ciprés 29 Aug 2017 (ph. EDZH; Figure 12). Other rare and uncommon migratory shorebirds reported included 6 Stilt Sandpipers, 34 Baird’s Sandpipers, 39 Pectoral Sandpipers, and 11 Semipalmated Sandpipers. The birds were generally well distributed along the peninsula except for the last species; all of them were found in the La Paz area, which is normal. Nine Solitary Sandpipers in BC were all found in the fall but approximately 43 in BCS were about evenly split between fall and winter. A Wilson’s Snipe was in seemingly suitable nesting habitat at ~1000 m elevation near the California border at Ciénega Redonda 20 May–7 Jun 2018 (EDZH, IRG). Nesting by this species is undocumented in the region, though it was suspected at two locations in the Ojos Negros Valley in June 1927 (Huey 1928).

Jaegers through Waders

A Long-tailed Jaeger was near the mouth of Laguna San Ignacio 29 Mar 2018 (SLS). The species has been found in the s. Gulf of California in winter, but this bird was presumably a migrant and provided the earliest such record for the region. The only Common Murre found was just off Ensenada 8 Jul 2018 (ph. AH, ph. JV, JAFA); it established the first regional summer record. Unseasonal in winter in Pacific waters off BC, 6 Craveri’s Murrelets were photographed north to ~32.5° N, sw. of Punta Canoas 10 Feb 2017 (AEM, JM). As is now normal, Scripps’s Murrelet, Guadalupe Murrelet, and Rhinoceros Auklet were unreported in BCS waters (c.f. Erickson et al. 2018:28), although Guadalupe Murrelet nests at I. Asunción, BCS at least irregularly (Carter et al. 2005).

Two Black-legged Kittiwakes were found: one near I. San Martín 23 Apr 2018 (ph. Observadores de Aves del Valle de San Quintín) and one ~20 miles off Los Barriles 6 May 2019 (ph. CL); the latter was the first in BCS since 2009. Otherwise common gulls rare at inland locations included a Heermann’s Gull in the Ojos Negros Valley 8 Jun 2019 (ph. EDZH, IRG) and Sabine’s Gulls at Cerro Prieto geothermal ponds 24 Sep 2019 (ph. ESM) and Presa Rodríguez 2 Oct 2019 (ph. RAH et al.). Two Franklin’s Gulls were found in BC in April and October; 9 in BCS were present during April and November through January. Also in BCS, a Mew Gull at Cabo San Lucas 13 Feb 2019 (ph. RW; Figure 13) established the fifth state record. Unseasonal was a very worn “Thayer’s Gull” at Playa Punta Estero 14 Jun 2019 (ph. JV). Lesser Black-backed Gull numbers continue to increase in w. North America. Three in BC this period (San Felipe 9 Dec 2017, ph. AEM, JM; Ensenada 14 Mar 2018, ph. MJI, RAE; Cerro Prieto geothermal ponds 3 Dec 2018, ph. HC et al.) were overshadowed by one at El Centenario 18 Dec 2018–17 Jan 2019 (ph. KAR, ph. GMa; Figure 14), as it was the first for BCS.

Brown Noddy had been anticipated, but the region’s first, at La Paz 19 Dec 2017 (ph. LFM; Figure 15), was at neither the expected time nor place. Also somewhat anticipated was the region’s first winter Least Tern, at Punta Arena 30 Jan 2017 (†RCH et al.); there are a number of similar records for mainland w. Mexico. The only winter Common Tern reports we consider acceptable were also from the Cape District: eight seen during a boat trip from Cabo San Lucas to the Gorda Bank 29 Dec 2017 (†MLPR et al.) and one at La Paz 4 Jan 2018 (GMa). We considered acceptable reports of at least 12 winter Elegant Terns in BCS and one far north at Ensenada 17 Dec 2016 (RP et al.). As is now typical, Red-throated Loon was not reported south of Laguna San Ignacio. At Laguna Ojo de Liebre, the next lagoon system to the north, a Yellow-billed Loon 30 Mar 2018 (ph. MGH; Figure 16) established the first record for BCS and one of the southernmost anywhere in the world. Four previous BC records appear to be the only others for Mexico.

The Laysan Albatross population in the ne. Pacific Ocean is increasing. Away from its usual haunts there, the species was well represented in the Gulf of California this period with singles near I. Tortuga 12 Apr 2017 (MiG), I. San Ildefonso 9 Apr 2017 (MiG), I. Danzante 27 Feb 2018 (PA), and I. San José 1 Apr 2019 (CE). In contrast, no Black-footed Albatrosses were found there. The real albatross highlight was an imm. Short-tailed Albatross ~20 km nnw. of Cabo Colonet (~31.1400°N, 116.4100°W) 27 Mar 2017 (ph. DW, ph. NPD et al.; Figure 17). This now-recovering species had not been reported in Mexican waters since the 1880s (Loomis 1918, Grinnell 1928); however, two previous records have recently come to light: a sub-adult was off El Rosario (~29.898431°N, 115.995733°W) 20 Mar 2011 (†Tom Love), and a two-year-old male was west of I. Cedros 17–18 Feb 2012, tracked by a satellite transmitter deployed on the bird as a fledgling at Torishima Island, Japan in 2010 (Orben et al. 2018; R. A. Orben pers. comm.). That same bird visited the Bering Sea, the Aleutian Islands, the Gulf of Alaska, and the west coasts of Canada and the United States. We hope to report more of this species in coming years.

A Tahiti Petrel was in the s. Gulf of California, off La Ribera, 22 Oct 2019 (ph. ZP, CG; Figure 18). The only previous regional records involved 3–4 birds off Cabo San Lucas 9 & 11 Oct 2013. A Northern Fulmar on the beach at Bahía Magdalena 22 Feb 2018 (ph. DGT) was the southernmost reported during the period; an apparently healthy bird flying over the bay on 3 Mar 2018 (ph. MLPR) was presumably different. Also beached was a Wedge-tailed Shearwater at La Paz 9 Sep 2017 (ph. GMa; specimen awaiting preparation at UABCS), establishing the first specimen record for the region. Buller’s Shearwaters were reported twice off extreme nw. BC: 6 Sep 2019 (JMM) and 23 Sep 2019 (RBM), about what is expected of this rare visitor. Short-tailed Shearwater went unrecorded altogether; this species was formerly considered an annual winter visitor off nw. BC. A Flesh-footed Shearwater 41 nmi. sw. of I. Natividad 26 Nov 2018 (ph. MPF; Figure 19) was the fourth reported from BCS and the first to be photo-documented. Townsend’s Shearwater was once a regular visitor to the s. waters of BCS, but the species’s entire nesting population on Is. Revillagigedos is now critically endangered, and it remains to be seen how rare the species has become in our area. One west of I. Catalina 15 Feb 2019 (ph. REW) was the only one reported this period.

Historically, Wood Stork was most numerous in the region as a summer/fall visitor to the Colorado Desert of ne. BC, but the species no longer occurs there or in s. California as it once did (last BC observation in 2010), presumably as a result of reduced numbers in the source population of w. Mexico. Thus, an adult on the nw. coast of BC at La Misión 10 Jul 2018 (ph. MaH) was exceptional. More typical of recent regional records was that of an adult first seen in the La Paz area 27 Sep 2017 (ph. AH) and still present at the end of the period, having made multiple visits during the interim to suitable wetland habitats, primarily at La Paz and Estero San José but also at Santiago and Presa de la Buena Mujer.

At least 2 Magnificent Frigatebirds at Estero Punta Banda 3 Sep 2017 (ph. JV et al.) and three at Playa La Misión 4 Sep 2017 (ph. RAE) may have represented as few as three birds. Nevertheless, this appears to represent the best showing on record for the nw. coast of BC and corresponded with a strong presence in San Diego County, California at the same time. An inland Magnificent Frigatebird at Cataviña 18 Oct 2018 (ph. RAE, ph. SNGH) was in the general area where the species has been known to cross the peninsula. Boobies, generally unexpected on the nw. coast of BC, were also well represented, especially in 2018: Masked/Nazca Boobies at Playa La Misión 2 Sep 2018 (imm. RAE) and Estero Punta Banda 20 Dec 2018 (ph. AHA et al.); 3 or 4 Nazca Boobies offshore 22 Sep–22 Nov 2018 (ph. RV, ph. MPF et al.); Blue-footed Boobies (one 17 Nov 2018, ph. TAB; two 23 Jun 2019, ph. JV et al.), and a maximum of 180 Brown Boobies 23 Jun 2019 (SNGH et al.) roosting and nesting at Is. Coronado; and at least 5 offshore Red-footed Boobies 8 Jul–8 Nov 2018 (ph. JV, ph. AG, ph. MPF et al.; Figure 20), another 3 Nov 2019 (ph. JTS, NDe), one in Ensenada harbor 8 Oct 2018 (MJB et al.; UABC 2149; Figure 21), and eight at offshore islands (Table 1). Meanwhile, Neotropic Cormorant was busy consolidating its gains in the Mexicali Valley. The state’s first confirmed nesting was at the Mexicali country club (200, 9 Jan 2019; LQK, SMT, ph. RAE; Figure 22) and Campo Mosqueda (200, 10 Jul 2019; SNGH et al.), and a record high of 262 was tallied along Laguna México, Mexicali 22 Dec 2019 (ph. ROA). American Bittern reports came only from Lagunita El Ciprés (Dec 2016, Dec 2017, Mar 2019), Bahía San Quintín (5, Jan 2019), and Laguna Ojo de Liebre (Dec 2017–Jan 2018). Reddish Egrets are rarely found away from the shore; one at the Cerro Prieto geothermal ponds 1 Oct 2018 (MJI, RAE) was the fourth to be found in the Mexicali Valley. Surprisingly, a Black-crowned Night-Heron at Is. Todos Santos 17 May 2017 (CF et al.) was the first to be reported from any of the region’s Pacific islands. Yellow-crowned Night-Herons have apparently nested in Ensenada since at least 2016. One or two nests were active there 15 Mar 2019 (ph. MJB). In the Tijuana area, White-faced Ibis were confirmed nesting at Presa Rodríguez in 2016 and 2018 (RAE, LRR) and at Parque de la Amistad in 2019 (RAE). These are the only locations in either state where the species is known to nest.

Nesting Magnificent Frigatebirds

Roberto Carmona and collaborators provided the following summary of work that will be published in more detail elsewhere.

The Magnificent Frigatebird nesting colony on I. Santa Margarita, BCS was known as perhaps the world’s largest (Diamond and Schreiber 2020), with 20,000 pairs reported by Moreno and Carmona (1988). The population was considered relatively stable for many years (Carmona pers. comm.), but surveys in 2015 and 2017 found fewer than 300 birds there and approximately 1500 nesting birds in the entire Bahía Magdalena lagoon complex, including two new nesting sites. In the meantime, approximately 700 nesting frigatebirds were found at a new colony in the s. Gulf of California at I. Espíritu Santo (Marrón et al. 2014). All told, these numbers suggest an approximate 90% decline in the BCS population, which could translate into a decrease of 26–32% for the entire species. Unfortunately, population declines and colony abandonment have been reported throughout the range of the species.

Kites through Owls

White-tailed Kite’s status in BCS is tenuous. Three birds were reported this period on single dates (Sep 2016–Dec 2018) at three widely scattered locations. Also widely dispersed in BCS were eight Golden Eagle reports, the most notable of which was of a juvenile on 26 Jan 2018 at I. Lobos in the s. Gulf of California (ph. MO’B et al.). Bald Eagles once nested locally in nw. BC and on both coasts of BCS. Individuals presumably from the small remaining breeding population around Bahía Magdalena generate infrequent observations throughout BCS. A nest found near El Dátil in 2018 (ph. JAA) was near Laguna San Ignacio and well north of the current known nesting grounds.

A most impressive kettle of raptors over Cerro de la Z at the tip of the peninsula 1 Jan 2018 included at least 1 Mississippi Kite, 1 Cooper’s Hawk, 3 Broad-winged Hawks (including 1 dark morph; Figure 23), 2 Swainson’s Hawks, and 12 Red-tailed Hawks (ph. NDo). Similar kettles have occasionally been reported from the Cape, but probably none have involved as many species as this. A kettle including 12 Broad-winged Hawks and a Swainson’s Hawk at Estero San José 5 Jan 2018 (ph. TW, PE) may well have involved some of the same individuals. Another Mississippi Kite was on the road to San Antonio de la Sierra 27 Jun 2017 (ph. DSh; Figure 24). The rarest hawks found were also in the Cape District: adult Gray Hawk at San Antonio de la Sierra 24 Feb 2017 (†MDC et al.; second regional record) and two adult Short-tailed Hawks together at La Laguna 14 Jul 2019 (ph. GMa; second regional record, Figure 25). Harris’s Hawk has made a real comeback in the California–Baja California border country in recent decades (Patten and Erickson 2000, CBRC 2007). This period, 2 or 3 were in the northwest (Chapultepec area, 13 Mar 2018, ph. MAMD; possibly escapees), one was in the high country (Rancho Japá, 14 Mar 2018, ICD), and one on the Río Hardy 10 Dec 2017 (AEM, JM) was the first reported from the Mexicali Valley in over 90 years (Patten et al. 2001, Hinojosa-Huerta et al. 2007). At least 5 BCS Red-shouldered Hawks extended south to the Cape District. In addition to the kettle birds mentioned above, 3 fall migrant Broad-winged Hawks were seen in the northwest, and approximately 19 were seen in BCS in winter—all but one in the Cape District.

The Swainson’s Hawk story is about far more than the few individuals mentioned above. As in California, the hawk’s status has changed in the last decade or two—perhaps more so than any other naturally-occurring bird species. In the region, Swainson’s Hawks are now regularly seen in spring and fall migration, can be especially numerous in winter, and are even establishing a nesting population. In the se. Mexicali Valley, high counts of 30, 69, and 23 were recorded between late November and mid-December in 2016, 2017, and 2018, respectively (AEM, JV et al.). Winter reports were widespread in the Cape District, and from 2–8 Dec 2018 at least 350 birds—and perhaps as many as 800, depending upon the number of birds double counted—were seen in the n. foothills of the Sierra de La Laguna (SLB, ph. GMa et al.). Most significant were the species’s continued efforts to colonize the Ojos Negros Valley. After the discovery of an apparently unused nest in 2016 (NAB 70:392), a copulating pair was observed 7 Apr 2017, and 6 birds seen 3 Apr 2018 were all believed by the observers to be “settled” (i.e., not migrants) (RAE, EDZH et al.). In addition, on 16 Jun 2017 one bird was seen in potentially suitable nesting habitat in another valley nearby, vic. Héroes del Desierto (ph. EDZH, IRG). Emphasizing the local nature of Swainson’s Hawk distribution is that there was only one bird reported from the vast majority of the Baja California Peninsula: specifically between Valle de San Jacinto in the north and La Paz in the south.

Ferruginous Hawk was unreported in BCS 2016–2018; 3 birds in 2019 (21–22 Jan, 15 Mar, 14 Oct) were widely scattered. Long-eared Owl is believed to be a rare resident in the n. part of the region, but there are few recent records. The only one during this period was of a bird near the Río Colorado at Laguna Grande 29 Oct 2018 (ph. NPi). Probably many fewer Short-eared Owls occur in the region, and only during the non-nesting period, but they are more conspicuous and are reported more frequently. Eighteen were reported this period from eight widely scattered locations from nw. and ne. BC to the tip of the peninsula. Another regionally rare owl, Northern Saw-whet Owl, is restricted to high elevations of the Sierra San Pedro Mártir, where it was found again in March–April 2018, and May–July and Nov 2019.

Kingfishers through Vireos

A Green Kingfisher at Loreto 31 Dec 2016 (ph. AJ; Figure 26) established the first regional record. This adds to the growing list of mainland w. Mexican species that have strayed across the Gulf of California. Lewis’s Woodpecker is a casual fall and winter visitor in n. BC. One was seen and photographed by many in the Valle de Guadalupe wine country 22 Nov 2017–25 Jan 2018 (PC et al.), two were at Laguna Hanson 4–5 Feb 2018 (ph. JV, ph. RP), and two were again at Laguna Hanson 21–22 Dec 2019 (SR, ph. RP). Acorn Woodpecker, a common resident at the north and south ends of the region, also generated one unusual record: a bird from the northern, pale-eyed population far into the Vizcaíno Desert at Santa Inés 19 Oct 2018 (ph. SNGH, ph. RAE). Williamson’s Sapsucker is well established in the Sierra San Pedro Mártir, but its status in the Sierra Juárez remains unclear; individuals were seen there (Laguna Hanson) 4 Feb 2018 and 28 Oct 2018 (JV, RP, ph. GMa). Other unusual woodpecker records include Yellow-bellied Sapsuckers on the lower Río Santo Tomás 5 Nov 2018 (†RAE) and at San Ignacio 16 Dec 2018 (ph. GMa); a Red-breasted Sapsucker at San Ignacio, BCS 2 Dec 2017 (RoC, ph. SA); Downy Woodpeckers at Tecate 14 May 2018 (JSw) and Valle de Médanos 31 Aug 2018 (†RAE); a phenotypically-pure “Yellow-shafted Flicker” at the Mexicali country club 9 Jan 2019 (†LQK); and a flight feather from a (purity-unknown) “Red-shafted Flicker” at Bahía Tortugas, BCS found 26 Oct 2017 (RAH). Crested Caracaras were seen again in extreme sw. BC and farther north at El Rosario 15 Oct 2016 (PC et al.) and Rancho El Descanso 3 Nov 2018 (ph. SNGH, ph. RAE).

The annual occurrence of selected vagrant flycatchers and other passerines is shown in Table 2. There are few regional records of Dusky-capped Flycatcher. At a coastal site in winter, one bird at Valle de Médanos 18 Dec 2016 (†RAE, LRR) was at a time and place consistent with the vast majority of >100 California records (https://californiabirds.org/rarebirds.asp). In contrast, a bird in potentially suitable nesting habitat near Laguna Hanson in the Sierra Juárez 27 May 2018 (ph. JV; Figure 27) was unlike any accepted California record to date. A Brown-crested Flycatcher near La Laguna 12 Aug 2019 (†GMa) was also in potentially suitable nesting habitat but was only the third to be found in the region. There were numerous records of Tropical Kingbird, as is normal. Most notable was one at the Mexicali zoo 27 Dec 2016 (ph. MJI et al.; Couch’s Kingbird [T. couchii] not excluded conclusively); possibly the same individual was present at the same location a year before. Western Kingbird is rare in BC in winter; singles were in the Ensenada area 17 Dec 2016 (ph. RAH et al.) and 27 Jan 2018 (†RP et al.). Rare at any time in the region were Eastern Kingbirds at El Descanso 2 Sep 2016 (ph. AEM, JM) and San Quintín Plain 3 Oct 2018 (ph. MJI, ph. RAE), and Scissor-tailed Flycatchers at Bahía de los Ángeles 1 Nov 2016 (ph. GF, MF), San Juanico 29 Apr 2019 (ph. GJS), Todos Santos 7 Nov 2017 (NC), and vic. Santa Anita 13 Jan 2018 (ph. JH) and 25 Jan 2018 (†CT). Willow Flycatcher is a rare migrant in BCS; one at Rancho Santa Mónica 28 Sep 2019 (RAH et al.) was the only one found this period. A Least Flycatcher in the foothills east of Todos Santos 24 Nov 2018 (†GMa, DG) was only the second for the Cape District. Dusky Flycatcher is rarely reported away from its breeding grounds in the Sierra San Pedro Mártir—and actually, it’s rarely reported there (Figure 28). This period two were found in the Vizcaíno Desert: at Rancho El Descanso 10 Oct 2016 (ph. RAE et al.) and Cataviña 20–22 Jan 2019 (ph. SNGH, ph. RAE). Two Eastern Phoebes were found: Estero La Misión 17 Nov 2016 (ph. JSt) and Presa Santa Inés, near Todos Santos, 1 Dec 2019–12 Jan 2020 (ph. SM, ph. RiC).

Bell’s Vireo has been found a surprising number of times in the Ensenada area in winter; two more were seen, together, 1–22 Dec 2018 (JV et al.). Similarly, Gray Vireo is widespread but local in winter in BCS (almost exclusively on the east side); in BC individuals were at Ejido El Choyal 9 Dec 2017 and 8 Jan 2019 (AEM, JM) and Bahía de los Ángeles 24–28 Jan 2018 (GF, MF). Remarkable were three Yellow-throated Vireos in the Cape District, as there are no previous regional records: Sierra Las Pirras 9 June 2017 (VOAP, ph. JEAS et al.; Figure 29), and San Antonio de la Sierra 20 Jun 2017 (MDC, ph. DF; Figure 30) and 26 May 2018 (†GMa et al.). It seems plausible that the last two observations may have involved the same individual. A Warbling Vireo at the Mexicali country club 27 Dec 2016 (ph. MJI et al.) was the first to be found in BC in winter.

“Solitary Vireos”

Sight records of “Solitary Vireos” (Vireo solitarius complex) are problematic throughout North America, but we have our own unique issues in BCS. The endemic “San Lucas Vireo” (V. cassini lucasanus), resident in the Cape District, is typically brightly colored and is often misidentified as Blue-headed Vireo. We would be hard pressed to accept a sight record of Blue-headed Vireo within the range of lucasanus. Average differences in the clarity of their songs may yet prove useful in distinguishing these species. Likewise, we are hesitant to accept sight records of migratory nominate Cassin’s Vireos (V. c. cassinii) within the range of lucasanus, for fear of dull individuals of the latter. Erickson et al. (2001), without acknowledging the existence of lucasanus, considered 8 Cassin’s Vireos in the mountains of n. BCS (Sierras de San Francisco and Guadalupe) in October 1997 to probably be wintering nominate cassinii. There is no other evidence or suggestion of wintering birds of this sort in BCS (although the occasional vagrant is expected), and we now consider those birds most likely to have been lucasanus. A singing bird in the Sierra de San Francisco 22 Jan 2019 (ph. SNGH, ph. RAE; Figure 31) appeared typical of lucasanus. The reported specimen of nominate cassinii from BCS (Erickson et al. 2013) should be reexamined.

The problem of distinguishing “intermediate-plumaged” Blue-headed Vireos and nominate Cassin’s Vireos exists throughout much of the continent. Exemplary was a “Solitary Vireo” at Cataviña 3 Nov 2018 (ph. SNGH, ph. RAE; Figure 32) believed to have probably been Blue-headed but perhaps best left unidentified.

Jays through Finches

California Scrub-Jay is generally absent from the middle of BC; two at El Rosario 3 Oct 2018 (MJI, RAE) appear to have been the first found at that relatively well-worked location. Winter swallow numbers were modest in the Cape District, with no reports of Tree, Northern Rough-winged, or Barn Swallow exceeding 100 at the two most favored areas: La Paz and Estero San José. Lingering late at Estero San José were 2 Northern Rough-winged Swallows, 10 Barn Swallows, and 2 Cliff Swallows 12 Jun 2017 (SC). Red-breasted Nuthatches were recorded in the California District in two of the period’s four fall/winter seasons: 4 Oct 2017–20 Feb 2018 and 16 Sep–23 Oct 2019. A Golden-crowned Kinglet at Estero La Misión 22 Oct 2018 (SNGH, RAE) was the only one found. A singing Ruby-crowned Kinglet on the late date of 18 May 2019 high in the Sierra San Pedro Mártir (aud. JTS et al.) was in potentially suitable breeding habitat and suggested the possibility of summering there.

In a typical pattern, Townsend’s Solitaires were found in fall and winter down the spine of the peninsula in the Sierra Juárez, in the Sierra San Pedro Mártir, and at Cataviña/Santa Inés, but one in the Sierra de San Francisco 22 Jan 2019 (ph. RAE, ph. SNGH) established only the seventh BCS record. Varied Thrush was recorded only in n. BC: Rancho El Descanso 30 Oct (ph. KLG), Ensenada 3 Nov (LO, ESP, ph. RP), and Sierra San Pedro Mártir 13 Oct 2019 (ph. KTTC). More Gray Catbirds than expected were found. In addition to the four fall birds summarized in Table 2, winter birds were at Cabo Pulmo 2–3 Dec 2016 (ph. SI) and Ensenada 17–24 Dec 2016 (ph. RAH et al.), and a spring vagrant was at Guerrero Negro 4 May 2017 (ph. AGA). One of the most exciting finds of the period was a Bendire’s Thrasher in Ensenada 13–16 Feb 2018 (ph. AH et al.; Figure 33), which established only the fourth regional record. Reports of 28 Sage Thrashers were more than have become customary in recent years; this species was once considered locally common (Wilbur 1987). All but four birds were in BC, and 21 were during the prime period of northward migration: January–March. An Olive-backed Pipit at Real del Mar 27 Oct 2019 (ph., aud. RAE; Figure 34) was the best of the Siberian vagrants found this period. The only previous Mexican record involved a bird at Cataviña 18–19 Oct 1996 (Hamilton et al. 2000). Routine in comparison is the occurrence of Red-throated Pipit, with October totals of seven in 2016, two in 2018, and one in 2019. More interesting was one seen at sea 2 nmi. north of I. Coronado Norte 3 Nov 2018 (MPF). None were recorded in the Cape District, where the species was found almost annually in winter from Feb 2005–Feb 2012.

Purple Finch is now a very rare visitor in the region; three on the nw. coast of BC Oct/Nov 2017 were the only ones reported. A male Cassin’s Finch at Rancho San José de Castro 25 Oct 2017 (†RAH, EDZH) established the second record for BCS, where Purple Finch remains unrecorded. The only Pine Siskins reported south of Bahía de los Ángeles were at La Laguna 8 Jan 2018 (†TF, GK) and El Pescadero 19 Dec 2019 (GMa). Lawrence’s Goldfinches moved south in good numbers in the fall of 2018. The most notable observations were of 400 at Rancho El Águila II 3 Nov (SNGH, RAE), at least 13 at Bahía de los Ángeles 18–31 Oct (ph. GF, MF), and singles at two locations on the Vizcaíno Peninsula 2 Nov (ph. RAE, SNGH, GMa).

Longspurs through Buntings

Longspurs were poorly represented, with no Lapland Longspurs found and only two Chestnut-collared Longspurs: Valle de Médanos 17 Oct 2017 (RAE) and El Socorro 14 Dec 2018 (SR). Most welcome was the report of an onboard Cassin’s Sparrow at 31.164°N, 117.767°W (59 nmi. wsw. of Punta Santo Tomás) 30 Oct 2018 (ph. MPF; Figure 35), as the single previous records for BC and BCS were not photo-documented. There were few reports of Grasshopper Sparrow: three from the breeding grounds in nw. BC, two of fall migrants in northern and central BC, and two from the Cape District wintering grounds. Contrast this with >30 seen in the Cape District in the winter of 2015–2016. Lark Bunting was well represented compared to recent years, with two at Ensenada 17 Apr 2019 (ph. ASJ) the most notable reported. At the southern limits of their winter/dispersal ranges were three “Slate-colored Juncos” at three locations in far nw. BC in Oct 2018 and Nov 2019, “Oregon Juncos” at El Rosarito 24 Oct 2017 (RAH et al.) and I. Natividad 2 Nov 2018 (ph. SNGH et al.), and a “Gray-headed Junco at Bahía de los Ángeles 12 Nov 2016 (ph. GF, MF). “Gambel’s” White-crowned Sparrow and “Mountain” White-crowned Sparrow winter commonly in the region, the latter primarily in BCS. “Mountain” White-crowned Sparrows migrate later in spring. Thirty White-crowned Sparrows were reported in May of 2017, 2018, and 2019; six were identified as “Mountain” and one as “Gambel’s.” Golden-crowned Sparrows at Cataviña 10 Nov 2017 (2, ph. AH) and 19 Oct 2018 (ph. RAE, ph. SNGH), Punta Prieta 21 Oct 2018 (ph. SNGH, ph. RAE), and in BCS at Loreto 10 Mar 2018 (†JK) were south of their usual haunts in the California District and mountains of BC. Seven White-throated Sparrows were found in nw. BC. All regional records are restricted to the n. half of BC. Five Swamp Sparrows were found in nw. BC and one at San Ignacio 16 Dec 2018 (ph. GMa; Figure 36) was the first to be photo-documented in BCS.

A Yellow-headed Blackbird was far at sea approximately 50 km wnw. of Cabo San Lázaro (24.9440°N, 112.8510°W) 4 Oct 2016 (BM). Continuing a recent trend, >20 Orchard Orioles were found in the Cape District in winter 2016–2018, but only two were reported there in 2019. Much rarer in winter is Baltimore Oriole; three were found in BC and one in BCS. Equally rare in BCS at any season is Bullock’s Oriole, with only four found there during the period. As usual, there were few Red-winged Blackbirds seen on the middle third of the peninsula. Five at Nopoló in the winters of 2017–2018, 2018–2019, and 2019–2020 (ph. TH et al.) were north of the usual wintering area. The species’ status remains unclear on the Magdalena Plain, where nesting was confirmed in 2006, and up to six birds in the La Paz area in June 2017 and 2018 (ph. GMa et al.) suggests the possibility of eventual nesting there as well. Tricolored Blackbird seems destined for extirpation from Mexico, resulting primarily from the species’ continuing range contraction in s. California. Nesting in 2017 and 2018 involved only a few hundred birds and was restricted to three sites along the California border. The numbers were down to 150 birds at one site in 2019. Even with this underway, a male in a large blackbird flock sw. of Ejido Durango 27 Dec 2016 (ph. MJI et al.) established the first record for the Mexicali Valley. Although Bronzed Cowbird is regular in the Mexicali Valley, a juvenile being fed by a female Bullock’s Oriole near Cerro Prieto 11 Jul 2019 (ph. SNGH, ph. LQK; Figure 37) established the cowbird’s first confirmed nesting record for the region. A Great-tailed Grackle at Is. San Benito 28 Mar 2017 (NPD) was likely the same individual seen at the same location exactly one year earlier.

All four fall seasons were poor in terms of the numbers of vagrant warblers recorded, with most species failing to reach their previous ten-year average (Table 2). Each year did produce one stand-out record: Bay-breasted Warbler at San Ignacio 21 Oct 2018 (†GMa; third BCS record), Pine Warblers at Rancho San José de Castro 25 Oct 2017 (ph. RAE, ph. RAH, EDZH; Figure 38; second BCS record) and Maneadero Plain 5 Nov 2019 (KAR, ph. GHR), and Grace’s Warbler at El Rosario 21 Oct 2016 (ph. PAG, NAL; third BC record). Many vagrant warblers winter in BCS, at least irregularly. The tally for this period included 1 Louisiana Waterthrush (La Laguna 4 Jan 2019, ph. GMa et al.), 4 Lucy’s Warblers, 1 Cape May Warbler (Miraflores 27 Feb 2018, ph. RAE; Figure 39), 2 Northern Parulas, 1 Blackburnian Warbler (San Antonio de la Sierra 9 Dec 2018, †GMa), 1 Chestnut-sided Warbler, 1 Black-throated Blue Warbler (vic. San Dionisio 10 Nov 2019, ph. GMa), 3 Hermit Warblers, and ~25 Palm Warblers. In BC there was a winter Magnolia Warbler at Ensenada 20–23 Dec 2018 (ph. RP et al.) and only 4 Palm Warblers. Rare “southwestern” species in winter were represented by a Grace’s Warbler near La Laguna 2 Mar 2019 (ph. GMa et al.; Figure 40) and Painted Redstarts in Tijuana 8 Dec 2018 (†SR), near San Antonio de la Sierra 25 Nov 2017–21 Feb 2018 (ph. VOAP et al.), and near La Laguna 10 Nov 2019 (ph. GMa; Figure 41). Last among the rare warblers was a single spring vagrant, a Northern Parula in Ensenada 5–13 May 2018 (ph. RP et al.).

Among the best of the Sierra de La Laguna discoveries this period was a male Hepatic Tanager 3 Apr 2019 (JC, ph. GMa; Figure 42). The single previously documented record for BCS only recently came to our attention: a male at La Laguna 26 Jun 2016 (ph. OF, iNaturalist; Figure 43). Surpassing those, though, was the region’s first Flame-colored Tanager, at Todos Santos 24 May 2017 (ph. SB; Figure 44). Rose-breasted Grosbeak was not just found in fall (Table 2); two were at Ensenada 12–31 Jan 2018 (ph. EDZH et al.). Nearby, a Black-headed Grosbeak on the Maneadero Plain 21 Dec 2019 (ph. JV, RPM) established the first confirmed winter record for BC; the species winters commonly in BCS. The only Indigo Bunting found outside the fall migration period (Table 2) was at Rancho Japá 11 Jun 2017 (RAE). A Varied Bunting at Rancho Santa Mónica 25–26 Oct 2017 (ph. RAE, RAH, EDZH) was the third to be found in extreme nw. BCS; the record of one photographed at Guerrero Negro 19 Oct 2010 (NAB 65:169) is now considered inconclusive (SNGH pers. comm.). There remains only one BC record.

Exotic Species

Monk Parakeet appears to be well established in Mexicali, Tijuana, Ensenada, Guerrero Negro, Loreto, and La Paz. Scattered individuals were seen elsewhere. Meanwhile Black-throated Magpie-Jay reports were restricted to nw. BC and se. BCS. Scaly-breasted Munia now occurs regularly in fall in nw. BC, but nesting has not been detected. All reports to date have been from the period of 21 Sep–12 Jan. Cinnamon-rumped Seedeaters were found only in the Cape District: at La Paz, Todos Santos, San José del Cabo, and Cabo San Lucas. An 18 Oct 2010 report far from there, on the Vizcaíno Peninsula (NAB 65:169), is now questioned (SNGH pers. comm.).

Photos–Baja California Peninsula: August 2016–December 2019 and Discussion
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