Exotic and Hypothetical Species 593 Exotic and Hypothetical Species The following section addresses species that have main list. Observers for this atlas reported still more been observed in San Diego County since 1984 but escaped cage birds than are listed here, such as the are not native and do not (yet) have a well-established Golden-fronted Leafbird (Chloropsis aurifrons) and self-sustaining population in the wild. Probably or Rufous Treepie (Dendrocitta vagabunda); this sec- undoubtedly their occurrence in the county is based tion addresses only species seen repeatedly, species on escapees from captivity. They range from more or possibly establishing themselves elsewhere in North less domesticated birds with little chance of establish- America, and species given some consideration by ing themselves to others, such as the Black-throated the California Bird Records Committee as prospec- Magpie-Jay and Northern Cardinal, well on their tive natural vagrants. way to becoming naturalized. Eight introduced spe- Also in this section are species reported in North cies (Ring-necked Pheasant, Wild Turkey, Domestic American Birds or its predecessors that have been dis- Pigeon, Eurasian Collared Dove, Spotted Dove, Red- counted by the California Bird Records Committee. crowned Parrot, European Starling, House Sparrow) Hypothetical species addressed in my 1984 Birds of that have been considered established, at least in San Diego County are not repeated here. the past, are covered with the native species on the 594 Exotic and Hypothetical Species Black‑bellied Whistling‑Duck area by 2002 (Patten et al. 2003). Thus the Black-bellied Dendrocygna autumnalis Whistling-Duck could join the Painted Bunting as a spe- cies of which both vagrants and escapees are likely in San Two in the Tijuana River estuary (V10) 24 May 1986 were Diego County. probably escapees from captivity (R. T. Patton, Langham 1991). Nevertheless, the frequency of natural vagrants in the Salton Sink is increasing, with 19 records for that Mute Swan Cygnus olor Native to Eurasia, the Mute Swan has been intro- duced in North America as an ornamental water- fowl. Semidomesticated, the swan has increased in the suburban landscape and spread to the point where it is considered a nuisance in some states. In San Diego County the Mute Swan population is still Mercieca by Anthony Photo small, possibly not yet self sustaining. Breeding distribution: Mute Swans were released at the lake within the Del Mar racetrack (M7) sometime before 1997, where they have been fed by racetrack officials, nested repeatedly, and increased (A. Mauro). This source is presumably responsible for the swans seen in the adja- cent San Dieguito River estuary (two from 22 April to 10 June 2000, A. Dempsey, D. R. Grine) and at San Elijo Lagoon (L7; up to two on 8 July 1998, A. Mauro, and 22 April 2000, R. T. Patton). Mute Swans elsewhere in the county may be the result of independent introductions. The only site of more than three and of confirmed nest- ing is Lake San Marcos (I8/J8), with up to 12, including cygnets, 14 May and 8 June 1997 (J. O. Zimmer). Winter: In winter as in the breeding season, Lake San Marcos was our principal site for the Mute Swan, with up to 11 on 27 December 1997 and 9 on 2 February 1999 Photo by Anthony Mercieca (J. O. Zimmer). The least-expected site was a pond at the Roadrunner Club, Borrego Springs (F24), where there was one Mute Swan 28 February 1999 (P. D. Jorgensen). the last thing the Least Tern needs in San Diego County. Conservation: This account is the first published report of the Mute Swan’s occurrence and nesting in San Diego County. The species was not reported on any Christmas bird count in the county before 1997, though it may have been seen but dismissed as an escapee from captivity. Because of its history of establishing feral populations, the Mute Swan should not be ignored. Possible negative effects of the Mute Swan’s increase include its depleting the food supply for native waterfowl. In Maryland, Mute Swans have trampled eggs and chicks of the Least Tern (Ciaranca et al. 1997). Another threat is Exotic and Hypothetical Species 595 Ruddy Shelduck Tadorna ferruginea Native to Eurasia and north Africa, the Ruddy Shelduck is a popular ornamental waterfowl. Birds kept at the La Jolla Beach and Tennis Club (P7) are apparently responsible for repeated sightings around La Jolla, including the Torrey Pines golf course, Black’s Beach, and Southwest Fisheries Science Center (O7). One found near the La Jolla Beach and Tennis Club 23 January 2000 is preserved as SDNHM 50468. No more than two were reported during the atlas period 1997–2002, but eight flew by the Southwest Fisheries Science Center 20 April 2004 (S. E. Smith). In April 2003, an apparent pair were entering and exiting a cave in the cliff face above Black’s Beach, suggesting a possible nest site (S. E. Smith). Six were at Crown Point, Mission Bay (Q8), 2 November 2002 (M. A. Faulkner), and one was at a pond just north of Imperial Beach (V10) Photo by Anthony Mercieca 31 March 2003 (R. Bledsoe). Mandarin Duck Aix galericulata As one of the world’s most exquisite and popular waterfowl, the Mandarin Duck is kept commonly in captivity. Thus reports from seven locations during the atlas period were not a surprise. All were of single individuals, except at a pond along Buena Creek 2.7 miles southeast of downtown Vista (H8). Here J. O. Zimmer noted a pair on 13 May 1999 and up to eight on 3 January 2000. The Mandarin Duck is not established as a feral bird in California, but such establishment becomes ever more likely with the spreading provision of nest boxes for Wood Ducks. In Fallbrook (D8) in 2003, rehabilitator Terri Halverson reported at least three breeding pairs and a brood of six chicks found when their nest tree was chopped down. Photo by Anthony Mercieca Band‑rumped or Harcourt’s Storm‑Petrel Oceanodroma castro The California Bird Records Committee once accepted a later reversed itself (Garrett and Singer 1998). There are sighting of this difficult-to-identify species 25 miles west no well-supported records near California. of San Diego 12 September 1970 (McCaskie 1990), but it Red‑tailed Tropicbird Phaethon rubricauda The California Bird Records Committee has accepted a 16 August 1980 (Roberson 1993), but this location is sighting 145 nautical miles west-southwest of San Diego closer to Mexico than to San Diego. Nazca Booby Sula granti One came aboard a boat 50 nautical miles west of Punta species to the list of California birds (Garrett and Wilson Banda, Baja California, 27 May 2001, and rode the boat 2003). A sibling species of the Masked Booby, the Nazca as it came into San Diego Bay. Therefore, the bird’s Booby nests largely on the Galapagos and Malpelo islands, occurrence in San Diego was clearly not natural, and with only a few nesting on Mexico’s San Benedicto Island, the California Bird Records Committee did not add the possibly on the Alijos Rocks (Pitman and Jehl 1998). Darter Anhinga melanogaster Darters in the Western Hemisphere are undoubtedly The seemingly simple identification of the Anhinga has escapees from captivity; the species is raised at the San now been complicated by local sightings of that species’ Diego Wild Animal Park and San Diego Zoo. In south- counterpart in the Old World, the Darter. Free-flying ern California and Baja California at least two Darters 596 Exotic and Hypothetical Species have been reported from the Imperial Valley, one near J. Hannan) and one, probably a Darter rather than an Ensenada. In San Diego County one was at Barrett Lake Anhinga, flew over the San Carlos area of San Diego (S18) 2 February and 7 April 2001 (R. and S. L. Breisch, (Q12) 7 April 2002 (J. Morris). Crested Caracara Caracara cheriway The Crested Caracara is resident as far northwest as central Baja California and southern Arizona, where its numbers are declining. But the status of at least 10 reports of caracaras in California is clouded by the question of whether the birds were escapees from captivity. One was photographed in San Diego County near the edge of the Sweetwater River estuary (U10) 9 February 1995 (R. Christie, B. C. Moore; Garrett and Singer 1998). Photo by Anthony Mercieca Red‑necked Stint or Rufous‑necked Sandpiper Calidris ruficollis The record of a juvenile photographed in the Tijuana (Roberson 1986). All nine of the species’ well-supported River valley 10 August 1980 (AB 35:226, 1981) was not occurrences elsewhere in California are of birds in the accepted by the California Bird Records Committee more easily identified adult breeding plumage. Black‑headed Gull Larus ridibundus The report of one at Point Loma (S7) 23 January 1990 (AB 44:329, 1990) was not accepted by the California Bird Records Committee. Nevertheless, there are 20 well-sup- ported winter records elsewhere in California, south to Huntington Beach, Orange County. Photo by Anthony Mercieca Ringed Turtle‑Dove Streptopelia risoria The Ringed Turtle-Dove, the domesticated form of the African Collared Dove (S. roseogrisea), was one of the first birds to be domesticated. It remains one of the most popular cage birds. Escapees are seen in San Diego County from time to time (two reported by atlas observers), but no nesting in the wild has been confirmed here, and no feral population has established itself anywhere in California. Photo by Anthony Mercieca Cockatiel Nymphicus hollandicus The Cockatiel is native to Australia and very popular as Psittaciformes, the Cockatiel shows no evidence of estab- a cage bird in San Diego County.