Plumbeous Vireo CAUTION, the imm Neotropic, Y-h Blackbird
First off, on Monday there's a Yellow-headed Blackbird along the west-facing fenceline of the Naval Outlying (helicopter) Field in Imperial Beach (accessed from the end of 5th). This species seems to turn up at this spot a few times almost every spring.
The unusually pale immature Neotropic Cormorant at Lake Cuyamaca does indeed appear to be just that: a very pale (presumably worn) immature Neotropic. Terry H. obtained much better photos of the bird over the weekend, showing the correct facial pattern, and Stan W. was able to track down at least one photo on the web which matches the appearance of this bird (although always beware of countless misidentified photos of virtually any species posted at a myriad of websites and that turn up with just the average google search).
There has been a rash of Plumbeous Vireo reports in San Diego County during the past 10 days or so (as well as to a somewhat lesser degree in Orange County). Several of these birds are known wintering stakeouts that are still present; and indeed, this species regularly remains into mid-April, with the latest known wintering birds during the past 15 years staying until ca. 21 April (fide GMcC). So, even "new" birds found during the first half of April are likely wintering birds that weren't discovered previously and may have wintered within just a mile or two, but moved with changing feeding conditions. In contrast to these April wintering birds, TRUE SPRING MIGRANT PLUMBEOUS VIREOS IN THE COUNTY AND PRESUMABLY ANYWHERE IN CALIFORNIA WEST OF THE NORTHERN DESERTS AND AWAY FROM LIKELY BREEDING SITES ARE STRICTLY CASUAL, and Guy has ZERO documented records of such spring vagrant Plumbeous in his database for the past 15 years anywhere in San Diego County. Not even any from Anza Borrego. Most of the very few valid records of spring vagrants over the years in southern CA are from May, including a photographed bird in Imperial County in mid-May some 10 years ago. The problem with a slug of spring reports of this species is confusion with DULL Cassin's Vireos, which are not unusual. Recent eBird reports in the county of Plumbeous include at least one photo'd bird that's a Cassin's, and two tape recorded singing birds, of which one sounds good for Plumbeous (but which wintered locally) but the other sounds like a Cassin's. The San Diego Atlas appears to paint too rosey a picture of the spring status of Plumbeous, in our opinion, and it is uncertain which of the "dozen" spring records cited during the atlas period were well documented. Some of those records were undoubtedly from the first two-thirds of April, when wintering birds were likely involved. Anyway, the status of this species as a true spring migrant (vagrant) needs to be carefully re-assessed, and all such reports should be carefully documented with an extensive series of photos and/or tape recorded.
–Paul Lehman, San Diego
Source: SanDiegoRegionBirding Latest Reports