Family Reunions

Illinois birders held their annual Spring Bird Count today, so here's a couple of little jewels for the day:

Yellow Warbler (Setophaga petechia),
Wadsworth Prairie FP, Lake Co, IL 5/10/2014

This is a Yellow Warbler (Setophaga petechia). During migration, you can find them anywhere there's a few trees, but when nesting they're associated with riparian areas, particularly ones with willows.

Philadelphia Vireo (Vireo philadelphicus),
Waukegan Beach, Lake Co, IL 5/10/2014

This is a Philadelphia Vireo (Vireo philadelphicus). If you own an older field guide (say, early 1980's) these two species will be placed close together, with the vireos immediately before the warblers. Here's another shot that shows the similarities a bit more.

Tennessee Warbler, (Oreothlypis peregrinus),
Van Patten Woods FP, Lake Co, IL 9/25/2013

This is a Tennessee Warbler (Oreothlypis peregrinus). They can sometimes cause confusion with some of the plainer vireos, since they are all small, active insectivores with fairly small bills and little patterning on an olive-green body.

In South America, there are several birds in the Vireonidae that are named Peppershrikes, and a few more called Shrike-Vireos. These names came from the resemblance between these birds and shrikes like this one:

Northern Shrike (Lanius excubitor),
Salmon Lake, Nome, AK 8/10/2012

This is a young (and very cooperative) Northern Shrike (Lanius excubitor) from Alaska. At one time, the similarities between vireos and shrikes were considered to be an odd example of convergent evolution. Then ornithologists began to apply DNA technology to the question of relationships within the birds, and that completely revolutionized our view of the order Passeriformes. The oscine passerines (those with more complex voiceboxes and often more complex songs) are now thought to have split fairly early into a couple of infraorders, one including crows as well as shrikes and vireos, the other including most of the passerines we're familiar with here in the US. (In SE Asia and Australia there are quite a few of the Corvoidea families.) That last would include our Wood Warblers. These days, the vireos are now placed very close to the shrikes -- if you have a newer field guide, it will probably put vireos just after the shrikes. Those peppershrikes were rather presciently named, it seems, while the similarities between vireos and warblers are now thought to be due to convergent evolution. Both groups include small, insectivorous, foliage gleaners, so it's not surprising that they're fairly similar in shape and behavior.