Monday, May 27, 2013

Warbler Guy, how do I ID western warbler songs from each other? Will sonograms of warbler songs help my effort?

Jasper (in Washington state), to help you, check out some western USA warbler sonograms:

Using them in combination with audio recording of each species’ song may be a good strategy to successfully “reading” corresponding sonogram for a given species.

Two sound-alike western species sonograms — the Hermit and Black-throated Gray Warbler — are shown here. Where their nesting ranges overlap (e.g., Mendocina County in northern California, among other places), you can sometimes hear them singing in the same forest.

In addition to these sonograms, my solution is to listen carefully when afield. Both species appear to possess dialects that may vary be region. But, for what it’s worth,  
my description of the Hermit’s song is that it’s more wheezy and less articulate/focused than the Black-throated Gray’s.

At, the author has his own description of how to distinguish each warbler’s song.

In addition: Donald E. Kroodsma’s book “The Singing Life of Birds” provides clues on how to “read” a sonogram as does his chapter “Vocal Behavior in the Cornell Lab of Ornithology produced “Home Study Course” that you can purchase (See:

Ultimately, it’s my humble opinion that getting out as often as possible during the breeding season and listening is the best remedy. Simply: What You Sow, Yee Shall Reap by listening carefully each time you’re afield where the warblers sing.

Saturday, May 18, 2013

Warbler Guy, which is the most common warbler to see in my suburban wooded backyard near Madison, WI after the peak of migration is over? In the Santa Cruz area where we have a winter home?

The answers for my peripatetic birder friend, Robert, (in Madison), are short and long.

Let’s stay with the brief ones so you can get back to birding outdoors (where I’d rather be now, truthfully (!) )

In Dane Co. where Madison lies, and depending on your yard’s habitat and its nearby vegetational makeup, you can often see Common Yellowthroat (in moist thickets and/or wetland areas where emergents occur), American Redstart (in forests), and Yellow Warbler (also most often in moist thickets and riparian areas).

As for the Santa Cruz area of California, the leading suspects during the non-breeding season (winter) include Townsend’s Warbler (a non-breeding season visitor only), Common Yellowthroat (a resident), and Yellow-rumped Warbler (non-breeding season only), with less likely visits from Hermit, Yellow-breasted Chat, Black-throated Gray, Wilson’s, and Orange-crowned, (with the latter often the most typical “winter” sighting among the final five listed above.

Hope this helps. Now back to our regularly scheduled program, meaning I’m outta here with my binos.

(male Common Yellowthroat,
below/right; photo by
Dan Pancamo)

Saturday, May 4, 2013

Warbler Guy, which warbler species are the most likely to mate together to produce hybrid (intergrade) individuals?

Whoa, Jennifer (in Houston): This is not an easy question.

And the answer requires me to put on my professor's cap.

So here goes: 

 Brewster's Warbler (right, above)

Lawrence's Warbler (right, above)

In general, Golden-winged X Blue-winged Warbler intergrades and Hermit X Townsend intergrades are two cases worth mentioning.

In the former, genetic shuffling may result in individuals called Brewster’s Warbler that express field marks from both the Golden-winged and Blue-winged. These hybrids show yellow underparts and a dark throat and head area behind the eye. In most cases, a Brewster’s results from the pairing of a “pure” Golden-winged and “pure” Blue-winged, though, in some cases, a Brewster’s is produced from the crossing of a Golden-winged and Brewster’s.

The Lawrence’s Warbler as a hybrid is less likely when a Golden-winged and Blue-winged mate. That’s because genetic traits involving an understanding of dominant and recessive traits come into play. 

For example, the white underparts of the Golden-winged are considered a dominant trait. So is the reduced head pattern of the Blue-winged. When these two dominant traits are seen in an individual, we call it a Brewster’s expressing the two dominant traits from its Golden-winged/Blue-winged parents.

Recessive traits include the yellow color of the Blue-winged’s underparts and the bold head pattern (throat and head area) of the Golden-winged. Newborns produced from these two types of warblers result in a Lawrence’s. Lawrence’s may also occur from the pairing of two Golden-wingeds expressing recessive genes as their underpart colors or, more rarely, the mating of two Brewster’s Warblers.

Got it? If you’re still with me and understand this explanation, then consider yourself a genius and an ardent warbler fan.

Other warbler species that often create hybrids are crosses between Hermit and Townsend’s Warblers, especially in Washington state. Here the breeding ranges of these two species overlap. In many cases, hybrids between Hermit and Townsend’s express the face pattern of Hermit and the underpart colors of Townsend’s, with the back of hybrid individuals more green than a pure Hermit. In addition, the black on the rear crown of male hybrids extends farther forward than on a pure Townsend’s.