Birdernaturalist: Hilltopping at Pusch Peak

Not really a representative photo of our hike, this Crimson-bodied Lichen Moth, Lerina incarnata was simply the flashiest thing that Philip Kline and I saw on our hike yesterday up Pusch Peak, a prominent hilltop in the northwestern part of Tucson. I thought it would just make a good attention getter. Its host plant is Pineneedle Milkweed, Asclepias linaria, and it was seeking shelter near the base of one near the peak.

The view of Pusch Peak from my front yard, looking almost due north, exactly 6.5 miles away. Click on any photo for a larger version.

Our main reason for hiking to this peak was to determine if it was good for hilltopping butterflies. Not many people are familiar with this concept, but put briefly, many species of butterflies congregate on certain prominent peaks in order to find their mates. It's something of a singles bar, and if the conditions are good, it is quite a spectacle.

Here's a view of the hilltop itself. Good characteristics for the ideal hilltop is isolation, being the first peak above a large area, relatively flat top to allow access to walk around, and a variety of shrubs and trees for hilltopping insect to use as perches.

A view looking down to Oro Valley between Arizona Rosewood trees.

This is a Meridian Duskywing, widespread in oak woodlands and a well-known hilltopper. In fact, it's hard to find anywhere else other than on hilltops. It was hard to get photos of any of the butterflies here as they tended to not stop for long. There were also lots of Sleepy Duskywings and at least one Mournful Duskywing.

This is a Pahaska Skipper, the only one we saw.

A Gray Hairstreak on a Fendlerbush. This species may have been simply using this bush as a nectar source, rather than hilltopping. We ended up with about 20 species of butterflies at the top, numbering perhaps 100 individuals. Most numerous were the duskywings, Pipevine and Black Swallowtails, and Sara and Desert Orangetips.

A view looking up Pusch Ridge to Table Top, with Mt. Lemmon in the distance.

Butterflies aren't the only insects that hilltop. This rarely seen insect is a bot fly, probably Cuterebra austeni, which uses packrats as a typical host. There were probably nearly a dozen of them up here, each with a territory from which it chased others, either mates or territorial competitors.

This is another species of bot fly, but about 3 or 4 of these were using the top of the highest Arizona Rosewood tree as their hilltopping spot.

A bee fly, family Bombyliidae, either Anthrax irorratus or A. cintalpa (thanks to Joel Kits at Bugguide.net.)

This wasp is in the family Braconidae, a parasite. Probably a male, as it is lacking the long ovipositor.

This colorful jumping spider is Phidippus carneus, only coincidentally here on this hilltop.

Here are a couple views of the steep trail up to the top. It was a 2-mile hike each way, and was pretty unrelentingly up, up, up.

Of course, I did some botanizing on the way up and down. This is Senecio lemmonii, Lemmon's Ragwort.

Another composite but with flower heads completely different in structure is this delightful plant, Charphochaete bigelovii, Bigelow's Bristlehead.

One last composite (my favorite family), this is Trixis californica, American Threefold. The individual flowers are highly unusual, being two-lipped, rather than five-petaled and star-shaped or with one simple ray petal.

Sphaeralcea ambigua, Desert Globemallow.

Microsteris gracilis, Slender Phlox (a tiny annual).

Lotus rigidus, Shrubby Deervetch.

Lesquerella purpurea, Rose Bladderpod. The more familiar species of this genus have yellow flowers.

Hibiscus coulteri, Desert Rosemallow.

Fendlera rupicola, Cliff Fendlerbush.

Closeup of the Fendlerbush flowers.

Anemone tuberosa, Tuber Anemone

The lower parts of the trail. It starts in cactus-filled Sonoran Desert and the top is in a type of chaparral with scattered Arizona Rosewood and Scrub Oak.