San Diego Natural History Museum--Your Nature Connection[San Diego County Bird Atlas Project]

WRENDERINGS
Notable Observations
Summer 2002

Whether spring 2002 brought good birding or bad birding depends on whether you were looking for migrants or breeding birds. Migrant land birds were in our faces more than in any spring of the atlas period. But this may have been due, in part, to natural habitats' being so dry, so poor in insects, that migrants were forced to concentrate in fewer favored places. The record-breaking drought led to widespread nesting failure. Tricia Campbell and Pete Famolaro reported very low nest success at their long-term study sites at the Fallbrook Naval Weapons Station, Marine Corps Air Station Miramar, and Sweetwater Reservoir. In dry upland habitats the situation was even worse--see Michael Patten's article in this issue of Wrenderings.

Not quite in San Diego County but of great interest to us nonetheless is the story of the Brown Booby on Los Coronados Islands. Dick Erickson reported a pair incubating on Middle Rock on 18 May, but these were later found to have taken over the nest of a Western Gull! Gary Smith's report of a Masked Booby at Los Coronados on 6 April, in combination with other recent occurrences of this species, suggests the Brown may not be the last species of booby to colonize the islands. As exciting as the booby invasion is to birders, tropical ocean birds' pushing north carries a message of broad-scale climate change.

A Tricolored Heron found by Marjorie Hastings in the Tijuana River estuary (V10) 2-4 May was a surprise because none had been around in the winter, the species' usual season. Because of the lack of storms this spring, few Black Brant were reported on their overland crossing northwest from the Gulf of California. Nevertheless, John Martin saw 14 flying over the Borrego Springs Airport (F25) on 12 April, and Bob Thériault picked up one exhausted on the road at Yaqui Pass Road near Ram's Hill (H25) on 16 May.

Osprey illustration
Osprey

Ospreys attempted many new nests this spring, though some were aborted early in the season. They built near Seaforth Landing in Mission Bay (R8; broadcast on television channel 10!), on floodlights for ball fields at Mesa College (Q9) and San Diego State University (Q11), on some quarry equipment along Mission Gorge Road (Q11), and in a eucalyptus tree along the Tijuana River in Marron Valley (V16). Both established nests, at North Island (S9) and Scripps Ranch High School (N10), fledged young this year, and of the new nests, the ones in Marron Valley and at Mesa College were apparently successful. In the Anza-Borrego Desert, Paul Jorgensen saw 10 Swainson's Hawks at Ocotillo Wells (I29) on 6 March, Herb Stone saw 50 at Borrego Springs (F24). These were expected, being along this gregarious species' migration corridor, but more surprising were those at Palomar Airport Road and El Camino Real in Carlsbad (I7). John Martin first found three there on 3 April, and the number increased to 10 on 14 April when Paul Zucker and Edward Fox last reported them. Royce Riggan's sighting of an adult Zone-tailed Hawk in Matagual Valley (H18) on 30 March was near other recent records in the Lake Henshaw region. The one at Marjorie Hastings' home in Spring Valley (R12) on 11 April has less precedent.

Rare spring sightings of the Solitary Sandpiper were made at the Borrego Springs sewage ponds (H25) on 13 April by Al Eisner and on 20 April by Gjon Hazard. By far the most notable shorebird observation of the spring was by Mel Gabel, of a Surfbird at a golf-course pond at Ram's Hill, Borrego Springs (H25), from 28 to 31 March. Though this is the species' first inland record for San Diego County, the Surfbird has been seen repeatedly at the Salton Sea as a spring migrant between 18 March and 7 May and probably crosses overland by routes similar to those followed by the Black Brant. Single Black Oystercatchers were reported from Ocean Beach (R7) on 29 March by Brennan Mulrooney and on 28 May by John Martin, from Imperial Beach (V10) on 12 April by Todd Stands. Sue Smith's 14 Black-necked Stilts at Borrego Springs (G24) on 6 April were a large number for this rare migrant in the Anza-Borrego Desert, and Joe Barth's fledgling at the Ramona pond on 18 June added a new nesting species to the list for square K15.

Joe Barth's Heermann's Gull flying upstream over Scissors Crossing (J22) on 3 July must have been dispersing north from the Gulf of California. Leif Myklebust reported a Laughing Gull, a rare visitor to San Diego County, at the San Diego River flood-control channel on 30 March. The Black Tern has become very rare in the county, especially in spring; Brennan Mulrooney saw one at the same location on 11 May.

Vaux's swift illustration
Vaux's Swift

Vaux's Swifts were far more abundant than usual this spring. The culminating report was Kevin Clark's of about 1000 in downtown San Diego (S9) on 4 May. The rare Black Swift showed up this year too. At Point Loma, Richard Webster noted two on 12 May, three on 13 May. Calliope Hummingbirds too were unusually numerous, with as many as 10 in a day (7 May) reported by Joe Worley at Point Loma. Acorn Woodpeckers showed up both east and west of their normal range with one in Earthquake Valley (K23) on 17 and 25 June (Joe Barth) and one on Point Loma on 12 May (Richard Webster).

There was almost no activity among invasive land birds from the north, but Gretchen Morse noted a Clark's Nutcracker along West Mesa Fire Road in Cuyamaca Rancho State Park (N20) on 10 March, and a Varied Thrush at Fort Rosecrans Cemetery (S7) remained until 10 May, when last reported by Richard Webster. The pace of the Western Bluebird's adaptation to city life is accelerating. Sue Smith reported there are now three pairs nesting at UCSD (O7). I found a nest with nestlings in Presidio Park (R8) 25 May, adding a new breeding species to the list for that square, and saw individuals occasionally through the summer in Balboa Park. Joe Worley noted an independent juvenile at Fort Rosecrans on 12 June.

The Gray Catbird appears to be on the increase as a vagrant to San Diego. Richard Webster noted one at Fort Rosecrans 27-28 May. The Sage Thrasher is a regular migrant through the desert but rare along the coast, where Maryanne Bache found one at San Elijo Lagoon 11-19 March. After only one observation of a spring migrant Bank Swallow in San Diego County the past five years, there were three this year: Pete Ginsburg had one at the sewage ponds near the Santa Margarita River mouth (G5) on 14 April, Gjon Hazard had one at the Dairy Mart pond in the Tijuana River valley (V11) on 4 May, and Craig Reiser had one in Santee (P13) on 5 May. After five years with only scattered pairs, Purple Martins mysteriously returned to Palomar Mountain in numbers. Paul Jorgensen saw 20 in Lower French Valley (D15) on 31 May, entering at least four cavities in three tall Jeffrey pines, and local resident Tony Jaramillo reported 60.

Two wintering White-throated Sparrows remained in Fort Rosecrans Cemetery until 30 April, one to 7 May (Joe Worley). Joe Barth's in the Fallbrook Naval Weapons Station (D7) on 9 May and Richard Webster's at Cabrillo National Monument (S7) on 10 May almost equaled the county's latest known dates for this rare winter visitor. Joe Worley reported a Clay-colored Sparrow, much less frequent in spring than in fall, at Point Loma on 5 May. Some Black-throated Sparrows may have been driven by the drought toward the coast. Sue Smith had one at Cabrillo National Monument on 13 April, and Steve Brad had one in Leucadia (K6) on 4 May. More intriguing were birds singing territorially in chaparral east of Buckman Springs (Q22/R22), where Matt Sadowski and Jim Wilson had a pair on 15 May and Mary Beth Stowe had one on 15 June; Neil Ferguson reported another on 8 July along Pine Creek Road.

Despite western migrants' being so numerous this spring, eastern vagrants made a relatively minor show. Richard Webster reported three Tennessee Warblers from Point Loma, on 10, 28, and 30 May. At Fort Rosecrans, Brennan Mulrooney had a Virginia's on 11 May, Joe Worley a Parula 5-7 May, and Jim Coatsworth a Black-throated Green 4 May. Sue Smith last reported the wintering Grace's there on 20 April. Joe Barth had another Parula near Scissors Crossing (J23) on 5 July. Ginger Johnson and Bunny Jones netted, banded, and photographed a male Pine Warbler at Point Loma on 3 April. Black-and-white Warblers numbered seven, one in La Jolla (P8) on 31 March (Mary Mosher), one at San Elijo Lagoon (L7) on 28 April (Robert Patton), three on Point Loma 5-17 May (Joe Worley, Richard Webster), one at Canebrake (N7) 16 May (Chris Smith), and one at Scissors Crossing (J22) 23 June (Joe Barth). The genus Seiurus was represented by Richard Webster's Ovenbird at Point Loma 19-30 May and Jim Wilson's Northern Waterthrush at Agua Caliente County Park (M26) on 8 May. Jim Coatsworth's Hooded at Fort Rosecrans on 7 May rounds out the spring's roster of vagrant warblers.

Five or six Rose-breasted Grosbeaks were all near the coast except for Joe Barth's in Earthquake Valley (K23) on 17 June. Unexpected coastal reports of Scott's Oriole paralleled those of the Black-throated Sparrow: Richard Webster saw one at Fort Rosecrans on 19 May, one at Cabrillo National Monument on 28 May; Claude Edwards saw one in Serra Mesa (Q9) on 23 May.

Pioneers and recent colonists were the important news from the Anza-Borrego Desert. With the sponsorship of the state park, and the diligent work of Joe Barth, we are continuing to monitor these closely. Summer Tanagers returned to San Felipe Creek near Scissors Crossing (J22/J23) on 2 May, when Bob Thériault found the season's first. By July there were eight pairs in the area, of which seven nested successfully. Thanks to Bill Haas' ingenuity, we trapped and color-banded six birds, quite a challenge with this species that keeps to the canopy. With the birds in hand, we confirmed they were of the western subspecies cooperi. At least four males were at Lower Willows in Coyote Creek Canyon (D23), and at least one pair nested there. San Felipe Creek and Lower Willows each hosted one nesting pair of Brown-crested or Wied's Flycatchers, and another pair returned to the Roadrunner Club in Borrego Springs. Buntings comprised one mixed pair, the male an Indigo the female a Lazuli, that nested twice, and one pure pair of Indigos that nested unsuccessfully. Finally, Joe found a Lucy's Warbler at Vallecito (M24) on 5 May, but the bird couldn't be located again. Hopes of Lucy's Warbler colonizing a second location in San Diego County were dashed--for this year.

For better or worse, exotics continue to make news. Jim Morris' sighting of some species of the genus Anhinga flying north over San Carlos (Q12) on 7 April was probably of the same Old World Darter seen previously by Rich Breisch at Barrett Lake and Eric Mellink at Ensenada. "Wild" Turkeys continue to spread, pushing even to the edge of the Anza-Borrego Desert, with reports from Borrego Palm Canyon (F23) and Grapevine Canyon (I23). Guy McCaskie found a Eurasian Collared Dove, already established as a breeding species in Ventura County, at Marina View Park in Chula Vista (U10) on 29 May. John Martin's two Rose-ringed Parakeets in Ocean Beach (R7) on 28 May suggest that species is a step closer to establishing itself, as it has in Bakersfield. Pete Ginsburg saw a Green Jay at Point Loma on 17 April, and the Black-throated Magpie Jays persist in numbers in both Bonita and the Tijuana River valley. Bill Haas followed their nesting in Goat Canyon near Border Field for a third consecutive year. A couple of sightings of Painted Buntings reflect this species' being such a popular cage bird in Mexico. Phil Pryde reported an Orange Bishop, an African species colonizing Los Angeles and Phoenix, at Lake Murray (Q7) on 30 June.

--Philip Unitt

birdatlas@sdnhm.org

Summer 2002 Wrenderings | Wrenderings Archive | Bird Atlas Introduction