Northern California: Summer 2016

Summer 2016: June–July 31

Michael M. Rogers

Jeff N. Davis

Rob Fowler

Stephen C. Rottenborn

Recommended citation:

Rogers, M., J. Davis, R. Fowler & S. Rottenborn, 2021. Summer 2016: Northern California. <> North American Birds.

Highlights from this summer included the Region’s second Nazca Booby, Southeast Farallon Island’s first Least Storm-Petrel, an inland Magnificent Frigatebird, a healthy onshore Parakeet Auklet, and a cooperative Red-necked Stint. Breeding success at the Farallones was mixed, with cormorants and gulls having little success, but the smaller alcids doing fairly well.

Contributors (county and sub-regional compilers in boldface)

Many more observers are not specifically cited; all are appreciated. Ken Able (Lassen), David P. Arsenault, Dave A. Bengston, Murray Berner (Napa), William G. Bousman (Santa Clara), Lucas Brug, Ken Burton, Scott Carey, George E. Chaniot, Josiah Clark, Chris Conard (Sacramento), Rudy C. Darling (Nevada), Jeff N. Davis (Madera), Malia DeFelice, Al DeMartini, Bruce E. Deuel (n. C.V. counties), Scott Dietrich, Colin P. Dillingham (Plumas and Sierra), Cedric Duhalde, Todd Easterla, Amber D. Edwards, Scott Edwards, Elias Elias, Gil C. Ewing, Paul Fenwick, Brian Fitch, David Fix, Matthew Forster, Rob Fowler (Del Norte), Steve Gerow (Santa Cruz), Steve C. Hampton, John H. Harris (Stanislaus), Chris Hartzell, Garth Harwood, Cliff Hawley, Chris Hayward, Alan S. Hopkins, Eric Hopson, Debbie House, Lisa Hug, John E. Hunter (Trinity), Alvaro Jaramillo, Richard G. Jeffers, Logan Kahle (Contra Costa and San Francisco), Robert J. Keiffer (Mendocino), Dan Kopp, Alexandra Lamb (Humboldt), Paul E. Lehman, Robin L. C. Leong (Solano), John S. Luther, Michael J. Mammoser, Mark Martucci, Kevin McKereghan, Peter J. Metropulos (San Mateo), Dan J. Maxwell (Marin), Dominik Mosur, Kristie N. Nelson (Mono), Frances Oliver (San Joaquin), Ron & Nancy Overholtz, Ed Pandolfino (Placer), Linda Pittman, Jude Power (Humboldt), Robert C. Power (Alameda), Robert J. Richmond, Michael Rieser, Alex M. Rinkert, Don Roberson (Monterey), Michael M. Rogers, Stephen C. Rottenborn, Ruth A. Rudesill (Sonoma), Paul Saraceni, Ken Schneider, Christian Schwarz, Cooper Scollan, Jeff Seay (Kings), Shearwater Journeys, Daniel Singer, John C. Sterling (Modoc, Alpine, Calaveras, and Yolo), Emilie Strauss, Steve J. Stump, Brian L. Sullivan, Steven D. Summers (Tulare), Michele Swartout, Ronald S. Thorn, Jim Tietz (F.I.), John Trochet, Steve Tucker, Steve Umland (Tuolumne), Chuck E. Vaughn, Kent Van Vuren (Merced), Jerry R. White (Lake), David G. Yee, Bob & Carol Yutzy (Shasta).


C.B.R.C. (California B.R.C.); C.R.P. (Cosumnes River Preserve, Sacramento); C.V. (Central Valley); F.I. (Southeast Farallon Island, San Francisco); H.R.S. (Hayward R.S., Alameda); Point Blue (Point Blue Conservation Science); P.R.N.S. (Point Reyes National Seashore, Marin), S.F. (San Francisco, not State Forest). Reports of exceptional vagrants submitted without documentation are not published. Documentation of C.B.R.C. review species will be forwarded to Tom Benson, Secretary,


The lingering Greater White-fronted Goose flock at the Sacramento N.W.R., Glenn began the period with 58 birds on 9 Jun and dwindled to 25 by 31 Jul (LKh, m.ob.), considerably more than normally summer in the Region. The two Brant at Mono Lake, Mono remained through 6 Jun (m.ob.). A Trumpeter Swan sporting a neckband from a transplanted breeding population in eastern Oregon was found s. of Alturas, Modoc 12 Mar & 22 May (both ph. SCR) and 7 Jun (LPt).

Five Redheads at Huichica Creek W.A. 5 Jun (MBe) provided the second summer record for Napa. Thirteen Ring-necked Ducks at McCumber Reservoir 18 Jun (B&CY) included a female with 4 precocial young, providing a rare breeding record for Shasta. Summer White-winged Scoters were reported in greater numbers than usual, with three reports of one to two birds from Humboldt 17-23 Jun (Cheryl Kelly, AxL, Brad Elvert), one off Fort Mason, San Francisco 5 Jun (JsC), and one in Alviso, Santa Clara 20 Jun (Cole Jower). Black Scoters were likewise well represented, with the continuing male at the Pajaro River mouth Santa Cruz/Monterey through 16 Jun (m.ob.), one at San Pablo Bay N.W.R., Solano 12 Jun (Aidan Lende), a female at Pillar Point Harbor, San Mateo 26 Jun+ (ph. SCH, ph. m.ob.), a female at P.R.N.S. 10 Jul (ph. Matt Lau), and a male present for “a while” near Crescent City, Del Norte 29 Jul (LuB). The female Long-tailed Duck continued at the Pajaro River mouth Santa Cruz/Monterey through the period (m.ob.) and another was at Dillon Beach, Marin 21-24 Jun (CEV). Common Goldeneyes have historically been rare in summer, but this year they were reported widely and in higher than expected numbers. Two at the Tracy W.T.P. 16-19 Jun (Terry Ronneberg, DGY) were thought to provide the first summer record for San Joaquin and up to 8 were reported from five locations in Santa Clara (m.ob.).

Grebes through Pelicans

Summering Red-necked Grebes are annual, though in very low numbers. This season, singles were in S.F. at the Cliff House 7 Jun (ph. KnS, ph. David Assmann) and Crissy Field 20 Jul+ (ph. David Assmann, m.ob.), up to 4 were in Bodega Bay, Sonoma 27 Jun–28 Jul (ph. LHg, m.ob.), and one was at Drakes Beach, P.R.N.S. 29 Jul (DSg). A Laysan Albatross off Half Moon Bay, San Mateo 16 Jul, and a Wilson’s Storm-Petrel in the same area 16 and 23 Jul (both AJ, m.ob.), were not unexpected, though summer records of both are meager due to limited pelagic coverage at that time of year. Much less expected was F.I.’s first Least Storm-Petrel, captured during nighttime storm-petrel mist-netting 27 Jul (ph. Point Blue). At Point Pinos, Monterey, single Buller’s, Manx, and Black-vented Shearwaters 5 Jul (ph. BLS, †DR, CSc, PFw) were all quite early, as first arrivals of these species are more expected starting in mid- to late Jul.

An immature Magnificent Frigatebird at Crowley Lake, Mono 26 Jul (ph. Rick Ziegler, ph. R&NO) provided Mono’s fifth record and only the third Regional record in the last decade. Even more impressive was the Region’s second Nazca Booby, an adult on Monterey Bay over Soquel Canyon, Santa Cruz 16 Jul (ph. CSc, ph. DR, ph. Beth Hamel, ph. CHz, m.ob.). The first Regional record, a subadult at Point Pinos, Monterey 1 Feb 2016, was also accepted by the C.B.R.C. F.I. once again hosted our only Blue-footed Booby, 28-30 Jul (Point Blue). Numbers of Brown Boobies at F.I. dwindled from Feb through the spring and summer, with a high of 5 present 24 Jun–12 Jul (Point Blue). Other Brown Boobies included singles at the Cliff House, S.F. 10 Jun (BFi) and 2 Jul (PSar, KnS) and up to 2 at Point Pinos, Monterey 15 Jun–28 Jul (ph. BLS, ph. DR, ph. CSc). The continuing Northern Gannet was seen at F.I. on fewer than 20 percent of days during the period (Point Blue), suggesting that its favored roost was elsewhere; as in spring, it was occasionally seen at Half Moon Bay, San Mateo during the period (RAR, AJ, m.ob.). American White Pelicans are scarce in the city of S.F., occurring less than annually; this season, 1-4 were present in the Presidio/Crissy Field area 19 Jul+ (Joshua Jaeger, ASH, m.ob.). The Pajaro River Valley is typically the site of our highest coastal numbers, as evidenced by the high count of 230 at Struve Slough, Santa Cruz 31 Jul (AMR).

Bitterns through Cranes

Least Bitterns were widely reported from nine counties, including confirmed successful breeding at Las Gallinas, Marin (m.ob.), the fourth modern Mono record at River Spring Lakes 17 Jun (ADeM), and the seventh Monterey record (and first in summer) at Zmudowski S.B. 12-28 Jun (CSc, ph. m.ob.). The Marin Black Vulture was seen again at P.R.N.S. 11 & 18 Jun (ph. LKh, Kathy Kaczynski). Sandhill Cranes bred successfully at two locations in Mono, with a pair and 2 young in the Antelope Valley 18-19 Jun (ph. DHo, CPD et al., ph. Micah Silver) and another pair with a single colt at Bridgeport Reservoir 18-29 Jul (ES, m.ob.).


Four Black Oystercatchers in Alviso 26 Jun (MMR, MJM, RGJ) provided the sixth record for Santa Clara, and the first pertaining to more than a single bird. A pair nested again at Ballena Bay, Alameda with small young seen 27 May (later predated; ph. Verne Nelson) and a nest with eggs 28 Jun (RJR). An American Golden-Plover in Sierra Valley 1-5 Jun (ph. FrO, ph. m.ob.) was the first for Plumas. The only Solitary Sandpiper reported was at the Chico W.T.P., Butte 16 Jul (MtF, ph. MSw), the same date one was found at this location in 2015! Five Wandering Tattlers at Point San Pablo 29 Jul (ph. Albert Linkowski) likely established the all-time high count for Contra Costa. A Whimbrel was far inland at Lee Vining, Mono 5 Jun (STu). Long-billed Curlews were again confirmed breeding near McArthur, Shasta, with 3 young seen 2 Jul (KAb). Three to four family groups with large chicks were also found at Crowley Lake, Mono in late Jul (Ken Wells, Karen Murphy, R&NO). Another Long-billed Curlew at the Ukiah W.T.P. 21 Jul (GEC) provided only the second inland record for Mendocino.

A Red Knot at Ocean Beach 3 Jun (ph. KnS, m.ob.) provided one of very few S.F. summer records. A Surfbird at Coyote Point, San Mateo 16 Jun (RSTh) was on an unexpected date halfway between the latest spring and earliest fall migrants. The only Stilt Sandpiper reported was an adult at the Anatolia Vernal Pool Reserve 22 Jul (ph. GEw, ClH, ph. Lily Douglas, m.ob.), providing one of few records for Sacramento. Alameda’s first Red-necked Stint was found at H.R.S. 10-17 Jul (ph. Vicki Robinson, ph. m.ob.) and again 26 Jul (Jeff Miller). Half of the Region’s eight records have occurred during Jul. A Semipalmated Sandpiper at Huichica Creek W.A. 23 Jul (ph. MBe) was only the fifth for Napa, with 4 of those coming in the past three years. Three Wilson’s Phalaropes at Lake Van Norden 26 Jun (David Hollie) provided a rare record for Nevada. A single Red-necked Phalarope at Pinecrest Lake 27 Jul (ph. Ellen Reintjes) was likewise unexpected for Tuolumne.

Alcids Through Skimmers

Common Murres well inside S.F. Bay included 3 at Miller/Knox R.S., Contra Costa 24 Jun (Sheila Dickie) and one at H.R.S. 26 Jun (Bob Dunn). Pigeon Guillemots may be increasing and expanding as breeders inside S.F. Bay away from known nesting areas around Alcatraz Island and the Bay Bridge. This season, up to 3 were at Miller/Knox R.S. and around Brooks Island, Contra Costa from the start of the period to 24 Jun (ph. Michael Park, LKh, m.ob.), and one was at H.R.S. 26 Jun (RJR). Single pairs of Scripps’s Murrelets were off Half Moon Bay, San Mateo 16 Jul (AJ, m.ob.) and on Monterey Bay, Monterey 29 Jul (ph. CSz, ShJ, m.ob.), whereas Craveri’s Murrelets included a pair at Point Pinos, Monterey 11 Jul (†PFw) and two pairs on Monterey Bay, Monterey 16 Jul (DR, ph. CSc, m.ob.). An apparent Scripps’s Murrelet at the Cliff House 16 Jul (†PSa) provided the first onshore record for the city of S.F. of any Scripps’s, Craveri’s, or Guadalupe Murrelet. Cassin’s Auklets are extremely scarce inside S.F. Bay away from the Golden Gate, so one found dead in the Napa River across from Mare Island, Solano 25 Jun (ph. ScC, Carol Oaks) was unexpected. Healthy Parakeet Auklets are very rarely seen from shore in the Region, making one at Land’s End, S.F. 13 Jul (ph. Marty DeAngelo) an exceptional find. A Rhinoceros Auklet at the same location 13-16 Jul (ph. Marty DeAngelo, ph. m.ob.) was also noteworthy, as this species is infrequently seen from shore in the city of S.F., particularly for more than a few minutes. A Rhinoceros Auklet at H.R.S. 31 Jul (RJR) was as far south in S.F. Bay as the species has been recorded, though there are a surprising number of records from that location.

A count of 275 Sabine’s Gulls on Monterey Bay, Monterey 16 Jul (DR, m.ob.) was high for Jul, while 2 juveniles the same day off Half Moon Bay, San Mateo (AJ, m.ob.) may have been the earliest juveniles ever recorded in California. It is possible that Sabine’s Gulls bred early in Alaska and Siberia this year owing to a paucity of snow and ice this spring (fide PEL). Laughing Gulls are nearly annual in summer in recent decades; one at H.R.S. continued from spring to 19 Jun (RJR), and another was in Eureka, Humboldt 10 Jun–23 Jul (EE, m.ob.). Away from n. Siskiyou, where the species breeds, the only Franklin’s Gulls were singles at Mono Lake C.P., Mono 3 Jun (Santiago Escruceria), H.R.S. 4 Jun (RJR), Horseshoe Pond Beach at P.R.N.S. 9 Jun (Kate Carolan, Jane & Lee Swidler), and River Springs, Mono 16 Jun (LKh). We have become accustomed to seeing a few juvenile Mew Gulls appearing in Aug, a month or so before the species’ “normal” vanguard, but 3 juveniles at the San Lorenzo River mouth, Santa Cruz 22-28 Jul (ph. Jane Mio) were unusually early and provided an unexpected concentration of such pioneers. An older (non-juvenile) bird was in Humboldt at Arcata Marsh 14 Jul (DFx) and at nearby Humboldt Bay 27 Jul (Lizzie Feucht).

At F.I., Western Gulls suffered poor productivity, and the breeding population was the lowest on record (Point Blue). California Gulls once again tried to nest at F.I., but as usual their nests were destroyed by California sea lions hauling out in the nesting areas (Point Blue). California Gull numbers at Mono Lake, Mono were the lowest recorded in 34 years of monitoring, and drought conditions allowed coyotes to access one of the nesting islets (KNN). Although numbers of California Gulls breeding in S.F. Bay dropped for the third consecutive year, they still numbered nearly 40,000 (fide San Francisco Bay Bird Observatory). A Glaucous-winged Gull at Clifton Court Forebay, Contra Costa 2-29 Jun (LKh, m.ob.) was rare in the C.V. in summer. The pair of Least Terns at the Sacramento Regional W.T.P., Sacramento remained throughout the period, fledging 2 young (Randy Price, ph. CCo, Steve Scott). Efforts to attract Caspian Terns to newly constructed islands in a managed pond near Menlo Park resulted in the first San Mateo nesting colony since the 1980s, with 120 adults and 38 chicks counted 26 Jun (PJM). The only Black Skimmers away from S.F. Bay nesting areas and migratory stopover sites along Monterey Bay were 3 at Pillar Point Harbor, San Mateo 12 Jun (Robbie Fischer).

Doves Through Falcons

Far less than annual in summer, a White-winged Dove was in Belmont, San Mateo 19 Jul (RSTh). Presumably the same bird was found less than 1 km northeast in Redwood Shores on 27 Jul (Susan Stratton). A transient Yellow-billed Cuckoo visited the Pajaro Dunes, Santa Cruz 28 Jun (ph. Norman Uyeda). A Western Screech-Owl calling in Lower Lee Vining Canyon 19 Jun (Bob Atwood) provided a rare record for Mono. Providing a fifth record for Stanislaus, a Northern Saw-whet Owl flew through an open window into a church in Ceres on 30 Jun (ph. Kara Claridge). Six Vaux’s Swifts over Blue Lakes 30 Jun (SJS) established the second summer record for Lake. Modoc’s first Broad-tailed Hummingbird since 1984, an adult male, visited a feeder in New Pine Creek 13-20 Jul (ph. KMcK). Closely studied and photographed, 2 Allen’s Hummingbirds, an adult male and adult female, at feeders in Lodi, San Joaquin 14-16 Jun (DGY, ph. LPt) provide further evidence that this species passes through the C.V. in small numbers during its southbound migration. Peregrine Falcons successfully fledged young from a nest near Tahoe City 6-8 Jul (Garrett Simpson); all other known Placer nest sites are in the lower North Fork American River canyon.

Flycatchers Through Thrushes

A Cassin’s Kingbird at C.R.P. 9 Jul (JTr) was one of very few ever reported in Sacramento. Two vagrant Eastern Kingbirds were found, one at Arcata Bottoms, Humboldt 7-9 Jun (LuB, m.ob.) and another along Payden Rd., Sacramento/El Dorado 5-10 Jun (CCo, DKo, ph. Bob Ellis, m.ob.). Two Scissor-tailed Flycatchers represented a good showing. One was at Big Lagoon C.P., Humboldt 3 Jul (ph. Illijana Asara), and another was at Usal Beach, Mendocino 11 Jun (TEa). A Willow Flycatcher at Burleigh-Murray S.P. 16-23 Jul (GrH, MDeF, CHy) established the first modern breeding-season record for San Mateo. A Least Flycatcher was along the Eel River near Fernbridge, Humboldt 9 Jul (Casey Ryan); we average less than one per summer. An Eastern Phoebe at Pillar Point Marsh 17 Jun (RSTh) provided the second summer record for San Mateo.

After an apparent three-year absence, a Least Bell’s Vireo was detected again at San Joaquin River N.W.R., Stanislaus, with a singing male there 14-27 Jun (Bobby Walsh, ErH). This endangered species nested at the refuge 2005-2007, was undetected 2008-2011, observed but without breeding confirmation in 2012, and again went undetected 2013-2015. Two Red-eyed Vireos were reported, one at the Presidio, S.F. 10 Jun (JsC, ph. m.ob.) and one at Blue Lake, Humboldt 24-29 Jul (RbF, m.ob.). Two juvenile Horned Larks at San Bruno Mountain S.P. 14 Jul (fide D. Pomeroy) provided the first breeding-season record for San Mateo in 20 years. The Bank Swallow colony at Año Nuevo S.P., San Mateo was larger than it has been in many years, with about 40 active nest cavities on 25 Jun (MDeF). A Pacific Wren in Old Mammoth 30 Jul (Brad Singer) established the first summer record for Mono. Providing one of few modern breeding records for S.F., a pair of Golden-crowned Kinglets nested at Golden Gate Park throughout the period (m.ob.).

Thrashers Through Warblers

Four Gray Catbirds were found this season, including one that established the first record with a date and location for Sacramento, 14 Jun at C.R.P. (JTr). Other Gray Catbirds were at Russian Gulch, Sonoma 20 Jun (DMo), Burleigh-Murray S.P., San Mateo 2 Jul (Bruce Mast), and Blue Lake, Humboldt 12-19 Jul (RbF, m.ob.). Northern Mockingbirds are rare in summer in Sierra and Humboldt, so reports from Sierra Valley 20 Jun (SEd, ADE) and Southern Humboldt Community Park 16 Jul (KBu, m.ob.) were notable.

The only Ovenbird for the season was heard singing in Rancho Cordova, Sacramento 15 Jun (ClH). The Lake Almanor, Plumas Northern Waterthrush from spring continued to 8 Jun (DPA). Four Black-and-white Warblers were reported, about average for summer. F.I. had its fourth record of Prothonotary Warbler 13 Jun (Point Blue). There are no known breeding records of Common Yellowthroat for Sierra (fide CPD), so a singing male near Webber Lake 30 Jun (ScD) was notable. Six Hooded Warblers (all males) were found. The most significant was a singing male at Beale A.F.B. 1 Jul (Michelle Ocken), the first for Yuba. Other Hoodeds were found at Redwood Creek, Marin 3 Jun (Mark Dettling), P.R.N.S. 5 Jun (Noah Arthur), Klamath Glen, Del Norte 8 Jun (LuB), Redwood R.P., Contra Costa (ph. LKh, m.ob.; eighth county record), and Don Davee Park, Monterey 8-11 Jul (ph. MiR, ph. DR, v.r. BLS, m. ob.). A total of 16 American Redstarts was the highest in the Region since 17 were reported in 2007; all were coastal except for one at Convict Lake, Mono 2 Jun (Larry & Carol Nahm) and one at Citrus Heights, Sacramento 3 Jun (MkM). Four Northern Parulas were found, including one at Arcata Marsh, Humboldt 24 Jul (AxL) that was probably a post-breeding visitor. Five Chestnut-sided Warblers was a slightly above-average total, with the most interesting being Plumas’s first at Chester 28 Jul+ (Elliot Casper, Jonathan Dachenhaus). The only Canada Warbler of the season, always very rare in summer, provided F.I.’s 59th record 12-13 Jun (Point Blue).

Sparrows through Finches

The only wayward Green-tailed Towhee of the season was on F.I. 1 Jul (Point Blue). Black-chinned Sparrows were confirmed breeding again along Summit Ridge, Santa Cruz with recently fledged begging young seen 18 Jun (AMR). Another Black-chinned was seen along Cherry Lake Rd., Tuolomne 29 Jun (Blaine Carnes), where a small local population has been known since 2009 (eBird data).  A singing Lark Sparrow near Chittenden 12 Jun (AMR) was in an area where nesting, a rare event in Santa Cruz, is possible. The first Sagebrush Sparrow for Sierra was along Dog Valley Rd. 17-20 Jun (JSL, Alison Sheehey, JCS, FrO). A Golden-crowned Sparrow at Chitactac-Adams C.P. 26 Jul (Gary Martindale) was only the second Jul record for Santa Clara. Juvenile Dark-eyed Juncos were seen at Babel Slough, Yolo 13 Jun and Reichmuth Park, Sacramento 16 Jun (both ph. Mark Sawyer). A few pairs of Dark-eyed Junco are known to nest at C.R.P. but they are exceedingly rare anywhere else in the C.V. (fide CC). Nine Summer Tanagers were found, including 4 in S.F. A total of 19 Rose-breasted Grosbeaks was below the average of 25. One female Rose-breasted in Ukiah, Mendocino 27 Jul (ph. DAB) was possibly a hybrid with Black-headed Grosbeak.

Notable Blue Grosbeak reports included one of an adult and a juvenile at Spenceville W.A. 15 Jun (CDu), a probable first breeding record for Nevada. A family group with 2 adults seen feeding 2 young along the Pajaro River 3 Jul provided the first breeding confirmation for Santa Cruz (AMR). A Blue Grosbeak along Dog Valley Rd. 17 Jun (JSL) was a first for Sierra. Eight Indigo Buntings was a slightly below-average total. Two Bobolinks at Eagleville, Modoc 7 Jun (LPt) were at the state’s only traditional breeding location.  The only Scott’s Oriole of the season was at Chidago Canyon, Mono 18 Jun (LKh), where this species is occasionally reported.

Report processed by Byron Swift, 28 Mar 2021.

Photos–Northern California: Summer 2016

Pelagic birders on Monterey Bay were thrilled to find the second Nazca Booby for Northern California over Soquel Canyon, Santa Cruz County, 16 Jul 2016. Photo © Beth Hamel.