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

WRENDERINGS
Notable Observations
Fall 1999

With the rate of growth of our database continuing to accelerate, I can again offer only brief mention of some highlights in this column. Many more interesting discoveries require discussion in greater depth and may be better addressed in future Focus On articles.

Barbara Moore observed the Reddish Egret in south San Diego Bay (U10) again on 30 May, and Jim Peugh found an unexpected Tricolored Heron at Famosa Slough (R8) on 6 June; Ed Wallace noted it as late as 3 July. Both species are much less frequent in summer than in winter. Richard & Susan Breisch found at least two American Bitterns summering again at the mouth of Las Pulgas Creek in Camp Pendleton (E3), the site where they confirmed San Diego County's first breeding of the species last year. The only other report of a possibly breeding American Bittern this spring was Pete Ginsburg's of one at O'Neill Lake (E6) on 19 April.

The Turkey Vulture is one of the most difficult species to confirm breeding, so any definite information is worth recording. A Border Patrol agent told Dave Seals of smelling what he thought was a decomposing human body in square T17 northeast of Dulzura. Climbing the hill to investigate, he found instead a juvenile Turkey Vulture in a rock cave.

The Ross' Goose that has taken up year-round residence at the east end of Buena Vista Lagoon (H6) remained through the summer (Marj Freda). More or less domesticated Canada Geese are also summering and even nesting—Marj noted 7, including goslings, at the same location on 8 June. Likewise, Wood Ducks are spreading from their epicenters at Santee and Cuyamaca lakes. For example, Pete Famolaro had two males at the east end of Loveland Reservoir (Q17) on 10 June, and Sue Smith and David Au recorded five, including a fledgling, at Wynola (J19) on 8 May.

[Redhead chick]
Redhead chick
Robbie Fischer found 24 Redheads, including ducklings, in the sewage pond at the corner of Stuart Mesa Rd. and Vandegrift Blvd. in Camp Pendleton (G5) on 20 June, the first confirmation of Redhead breeding in our atlas database. Not breeding but unexpected in summer were two Ring-necked Ducks, one found by Robbie Fischer on a sewage pond near the Santa Margarita River (F5) on 26 June, the other by Kirsten Winter and Charles van Tassel on Miramar Reservoir (N10) on 23 June.

The nestlings at Scripps Ranch High School (N10) fledged successfully (the two young seen exercising their wings on 5 June by Paul Zepf) from the second known successful Osprey nest in San Diego County. A single Harris' Hawk was seen again around Borrego Springs (G24) from 20 to 26 May (Paulette Ache). Bill Haas noted an adult Zone-tailed Hawk near the San Luis Rey Picnic Area (G16) on 31 May, then Dan Bylin observed two immatures foraging near the Clevenger Canyon Trail (J14) on 26 June. It seems more and more likely that the Zone-tails have an unknown nest somewhere in central San Diego County.

Dave Seals encountered a Common Snipe, only the third for the county in summer, on 9 July at the upper end of El Capitan Reservoir, because of low water currently in square N17.

Four confirmations of the Spotted Owl this year were the first for the atlas period. Betty Siegel followed the pair near Cold Spring in Cuyamaca Rancho State Park, confirming that it fledged at least one young. Geoff Rogers found a family in William Heise County Park (K20), possibly the same as one seen later by Dave Seals along the Kelly Ditch Trail to the south (L20). He and Shannon Peters encountered yet another along Agua Dulce Creek in the Laguna Mts. (O23), a long-term Spotted Owl territory.

Long-eared Owls continue to show up in new places, perhaps the most surprising this year being Guajome Lake, where Shirley Grain found two fledglings near their nest on 13 April.

Following last year's first summer record for San Diego County of the Red-naped Sapsucker on Palomar Mountain, two more observations were made this summer. Joe Barth saw one at Doane Pond (E14), close to last year's location, while Ed Hall and Clark Mahrdt found another in the next square to the east. The Red-breasted Sapsucker is more expected, but even it reaches the southern limit of its breeding range in the Cuyamaca Mts., where it is very rare. Tom Dorman noted one carrying insects along the Azalea Glen Trail in Cuyamaca State Park (M20) on 19 June, and Betty Siegel and Diane Jadlowski observed another regularly near the Highway 79 bridge over the Sweetwater River (N20).

Bill Haas' intensive study of the Willow Flycatcher colony around the Forest Service's San Luis Rey Picnic Area (G16) revealed the birds suffering the highest rate of nest failure in 5 years of study. Bill located a new site for the species in the San Felipe Valley (I21); Mark Sogge, Willow Flycatcher expert with the USGS in Flagstaff, followed up, finding at least one pair with a probable nest, as well as two nests in the San Pasqual Valley (K11), at a place where John Lovio first located the species in 1992.

The Warbling Vireo, though fairly common in migration, is very rare in San Diego County as a breeding species, occurring mainly in riparian woodland near Fallbrook. So the discovery of one building a nest at Cibbets Flat (Q23) during a San Diego Audubon Society field trip is quite noteworthy, only the second confirmation of the species in our database and the first away from Fallbrook. Unfortunately, the nest was later abandoned and destroyed, presumably by a predator.

Cedar Waxwings lingered exceptionally late this year, even to 1 June, when Ken Weaver saw a flock of 50 in Fallbrook (D7).

Brian Mulrooney recorded the first summering Swainson's Thrush in southern San Diego County during the atlas period, with a singing male along the San Diego River in Santee (P12) from 17 to 23 June.

The number of Violet-green Swallows summering and nesting at rather low elevations has been one of the more unexpected revelations of our atlas effort. Now the species has been recorded in the breeding season even along the coast: Richard and Susan Breisch found two summering near the mouth of Las Pulgas Creek in Camp Pendleton (E3). The good news on the Purple Martin is that it has been confirmed nesting at three new sites this year, near Nate Harrison Grade on the southwest slope of Palomar Mountain (E13) by Conrad Sankpill, at Wynola (J19) by Sue Smith and David Au, and at Filaree Flat in the Laguna Mts. (N22) by Geoff Rogers. The bad news is that there were no more than two pairs of this frequently colonial species at any site.

Guy McCaskie saw a Pine Siskin, unprecedented at low elevations in summer, at the Dairy Mart pond in the Tijuana R. valley (V11) on 6 June. There are only a few breeding-season records even at high elevations, like Clark Mahrdt's and Ed Hall's for Palomar Mt. (E15) on 28 May.

Summering Purple Finches seem to be spreading at low elevations around Fallbrook, a totally unexpected event but following last summer's observations around Valley Center and Pala. This year Ken Weaver has had up to three in square B7 and six in C6; Marj Freda recorded two in D8, Ed Hall three in D9, and Pete Ginsburg found one near O'Neill Lake in Camp Pendleton in E6, so far the record nearest the coast.

Are Juncos extending their breeding range out of the mountains by colonizing avocado orchards? Joe Barth and Matt Sadowski found two in an orchard between Valley Center and Pauma Valley at elevation of only 1200 feet during our blockbuster weekend on 12 June. The birds continue to nest in their isolated lowland colony on and near the campus of UCSD (O8): Joni Ciarlatta observed one carrying nest material on 10 May, then Matt Sadowski saw another feeding a fledgling on 22 July.

Kirsten Winter discovered a major population of the Grasshopper Sparrow in native grassland around Willow Spring near the Riverside County line in square A5. She estimated 20 birds in only 20% of the suitable habitat on 25 May and 10 June. The colony is on Forest Service land, significant because much of the species' little remaining habitat in San Diego County is on private land subject to development. Other important populations located this year are in upper Piedra de Lumbre Canyon in Camp Pendleton (D4), where Bryan O'Leary, Jim Asmus, and I estimated 18 on 29 May, and around Wynola, where Sue Smith and David Au recorded 16 on 2 July.

Another unprecedented observation was Kirsten Winter's of a Black-throated Sparrow, singing territorially, in native grassland on the south slope of Poser Mt., northeast of Alpine (P18), on 18 June. She visited the site repeatedly but had the sparrow on one date only, suggesting it was a vagrant. Did the severe lack of winter rain in the desert drive this typically desert bird toward the coast?

The Black-throated Gray Warbler is rare as a breeding species in San Diego County, nesting normally only above 4000 feet elevation. Yet Bill Haas found a pair summering near the San Luis Rey Picnic Area (G16, 2600 feet), netting the female to verify that she had a brood patch.

Robbie Fischer recorded the first summering Wilson's Warblers for our atlas database along the Santa Margarita River in Camp Pendleton, with one bird in square G5 on 19 June, one in F5 on 27 June. I had a fledgling at the latter location in 1993, so it is good to see the species hanging on at the southern tip of its breeding range.

The Summer Tanager got a little closer to a first breeding record for San Diego County: on 8 June Bob Thériault found a pair in the Sentenac Ciénaga (J23), the same site where the species occurred last summer.

Joe Barth extended our knowledge of the sparse distribution of Scott's Oriole in south-central San Diego County, finding one bird at Diamond Jack's RV park in S16 on 15 June and two singing males on the east slope of Lyons Peak in S17 on 1 July.

The Tricolored Blackbird never ceases to surprise with its constant shifting of colony sites. It established new colonies this year behind the Viejas Casino (P18), where Kirsten Winter estimated 200 on 21 May and 4 June, and at Twin Lakes in Potrero (U20), where Richard & Susan Breisch estimated 100 on 26 June. Yet only a few nested at the pond on the northeast edge of Ramona (K15) that hosted such a large colony last year. The largest population of this seriously declining species found this year is in square C16 near Oak Grove, where Ken Weaver estimated 840 on 10 April.

Despite a gradual increase, the Bronzed Cowbird remains very rare in San Diego County, especially on the coastal slope. This spring's only record was Bill Haas' of a male at "Lake Emma," the huge borrow pit in the Sweetwater River near Dehesa (Q15), on 6 May.

Yet another introduced species to be aware of: the Nutmeg Mannikin, which is proliferating in the Los Angeles basin. Joe Worley noted up to five juveniles in Tecolote Canyon (Q8) on 8 July. A parrot being reported more and more frequently is the Red-masked Parakeet, known to aviculturists as the Cherry-headed Conure. Mary Beth Stowe reported six from Point Loma on 20 April.

Though migration of western land birds was magnificent this spring, the follow-up of eastern vagrants was pretty meager. There were two more Parula Warblers, one reported by Don Adams from Point Loma (S7) 22 May-2 June, another I encountered at Pio Pico Park along Otay Lakes Road on 8 June. Jemila Bennett and Ruby Hjorth reported a Black-and-white Warbler from La Mesita Park, La Mesa (Q12) on 16 May, Paul Jorgensen an American Redstart from Sheep Canyon in the Anza-Borrego Desert (D22) on 27 May, and Pete Ginsburg a Northern Waterthrush in lower Los Peñasquitos Canyon on 11 April. Rose-breasted Grosbeaks made a small splash. Deborah Jones had one in O8 in Rose Canyon (!) on 11 April, Ruby Hjorth had two at her home in Q11 on 4 June, and Bill Haas almost collided with two while driving through upper San Clemente Canyon in Marine Corps Air Station Miramar (O10) on 14 June.

--Philip Unitt

birdatlas@sdnhm.org

Redhead chick sketch by Nicole Perretta

Fall 1999 Wrenderings | Wrenderings Archive | Bird Atlas Introduction