Date: 5/31/26 5:22 pm From: Kimball Garrett via groups.io <cyanolyca818...> Subject: [LACoBirds] The glut of Hooded Warblers
Birders,
Andy Birch noted that his Hooded Warbler along the Los Angeles River in Frogtown yesterday was the fifth one for Los Angeles County this spring. Hooded Warblers, like some other species with which they share a breeding range mainly in the southeastern USA, vary year to year in their occurrence in California, and many of these southeastern species (also including Yellow-throated and White-eyed Vireos, Kentucky Warblers, and Northern Parulas) demonstrate a pattern of appearance here that is often correlated with Hoodeds.
I looked through eBird data for "spring" (April through June) records of Hooded Warblers in Los Angeles County and 2026 does indeed stand out. But first many caveats, e.g.: (1) the eBird database is far from a complete record of vagrant occurrences. Many records (especially prior to about 2005 and certainly prior to 2000) have not been entered. Any search of records beyond a "back of cocktail napkin" estimate must also look at North American Birds reports (and NAB progenitors, like Field Notes, American Birds and Audubon Field Notes), specimen databases, and numerous regional bird books and journals [as well as records committee reports, but Hooded Warbler records in California were not reviewed by the CBRC after 1978.] (2) Many older records lack publicly available details, so their acceptance must rely on confidence in whatever review they received from county/regional compilers, journal/newsletter editors, etc. at the time. (3) The eBird database is fairly informative about year to year variation, but analysis of longer term trends must somehow take into account two opposing factors -- the explosion of birders and birding effort (and the ease with which birders can now report sightings), and the declines in populations of many (though not all) migratory songbirds.
Required reading on the subject of annual variation in the occurrence of Hooded Warblers and their cohorts on the West Coast is "Implications of vagrant southeastern vireos and warblers in California" by Michael A. Patten and Curtis A. Marantz, published in The Auk 113(4):911-923. [available through various research archives, including SORA: https://digitalcommons.usf.edu/auk/ ] This paper analyzes the amazing spring/summer of 1992 when unprecedented numbers of many of these species occurred in California (including the first California breeding record of Hooded Warblers, at Descanso Gardens). The most likely explanations the authors suggested were westerly breeding range expansions of these species and anomalous winds and high pressure systems.
So how does 2026 stack up for Hooded Warblers in Los Angeles County? The five individuals recorded (and we still have the month of June to go) is the second highest total ever, exceeded only by the six individuals (not counting fledged young, but including two records not in eBird) in 1992. The only other years this century (2000-2026) with more than one Hooded Warbler in spring in the county were 2016, 2009, and 2006 (two birds each of those years). A single bird was recorded in eight years this century, and zero birds were found in 14 years.
As a rough measure of "co-occurrence" of Hooded Warbler and the other most numerous "southeastern" warbler, I note that 3.9 Northern Parulas were found in L. A. County in springs that also had records of Hooded Warbler, but only 2.1 Northern Parulas were found in springs with no Hooded Warblers. [Obviously there are more sophisticated ways of analyzing this.]
