Mid-May. Mid-morning. Onion Saddle near the top of the Chiricahuas. A relatively drab warbler looking like nothing so much as a washed out Grace’s is creeping along a Ponderosa bough feeding nothing like a warbler at all. Unexpectedly a second bird flips in and, though looking nothing like the first, presents what is obviously its mate with a large green caterpillar. The scene unfolds at eye level because we are on a ridge, the tree growing up from a canyon well below us. Shazam!
If your first Olive Warbler, Peucedramus taeniatus, was an adult male, you probably felt equal parts delight and confusiondelight at the bird’s beauty, confusion over why a orange, black, and gray bird would be labeled “olive.” But this is a sexually dimorphic (male and female have different plumages) species. If your initial sighting was a female, or even an immature male shown in the accompanying photograph, you probably weren’t as delighted nor as confused since these plumages lack the male’s stunningly rich head color but may show a yellow-green wash on the crown, nape, and upper back. Look carefully next time and you will notice that even breeding males show olive on wing primaries and secondaries and on the tail retrices.
One of Arizona’s special species, species found only here or more easily here than in any other state, Olive Warbler in any plumage has always confused the taxonomists, too, who can’t quite figure out where it belongs on the bird family tree. Initially thought to be closely related to our Wood Warblers, it was later shifted to a branch with Old World Warblers such as gnatcatchers and kinglets. Recent DNA studies suggest giving this species a family ranking all to itself.
A literal translation from Greek of Olive Warbler’s genus name is “pine runner,” so it should come as no surprise that this species should be looked for in conifers in the higher mountain ranges. Like many of our specialties, this species breeds from Central America through Mexico and reaches its northern apogee in our state. It can be found in southwest New Mexico and there are migration records from the Davis Mountains of Texas, but the most reliable and accessible sites are here in Arizona.
Olive Warbler in Arizona can be found in all the “Sky Islands” of the southeast, but also as far north as the Mogollon Rim, the Pinals of Gila County and the Mazatzals right here along the northeastern edge of Maricopa County. As expected, as it reaches its northern limits it becomes less common, more localized, and thus more difficult to find. Closest to Phoenix, we have seen Olive Warbler in the Bradshaws south of Prescott and reliably on the top of Mt. Ord north of Sunflower. Until the Beeline Highway improvements are completed in the spring of ’01, access to Ord is scary and Olive Warbler may be best looked for around Tucson and points south.
Rose Canyon on the Catalina Highway to the top of Mt. Lemmon is generally considered to be the easiest and best place for this species. Other good sites are Rustler Park in the Chiricahuas and the Huachuca Crest Trail accessed through Carr or Miller Canyons south of Sierra Vista. Most but not all Olive Warblers retreat south out of the state by the end of September, beginning their return in March. Overwintering individuals are typically found at somewhat lower elevations. We have seen them in mid-winter in the campgrounds at the top of Carr.
During breeding season this species should be looked for in pine and fir above 6000 feet where its favored tree is Ponderosa. Nests, usually with three to four eggs, are built near the tops of the tallest trees, often well concealed in mistletoe. It is little wonder that breeding behavior is little known and not well documented. Olive Warbler is an insect gleaner often found creeping along the highest branches or investigating needle clusters at the ends of pine boughs. The long, thin bill is an adaptation for crevice probing and clump poking.
Adding to the confusion regarding this unique species are its very distinctive but unwarbler like vocalizations. Its call has been verbalized as a downslurred “phew” and likened to that of a Western Bluebird. The song is a series of ringing, two syllable notes which may be accented on either syllable, most reminiscent of a titmouse. We once pointed out a singing Olive Warbler to a birder from West Virginia wearing a hearing aid who asked for help finding the “Carolina Wren.” Finding a tape and learning the song can be very helpful. Because of its lofty feeding venues and sluggish feeding habits the bird is often heard before it is seen.
Try looking for Olive Warbler in late summer when its mountaintop retreats will get you comfortably out of the desert heat. They may be easier to find this time of year, traveling in post-breeding family groups or mixed species flocks. Hike the ridgelines and watch for the burnt orange flash amongst the twittering frenzy of a “feed.” Keep an eye out for the electric yellow flash of lightning from the oncoming monsoon storm too.