Millard Canyon Studies Yield Nature’s Secrets

Young Humboldt lily in Millard CanyonThe following was written by Mickey Long, AFC advisor and field biologist in support of AFC's mission to preserve Millard Canyon.

Surveys revealed a rich site with interesting natural history. Birders from Pasadena Audubon conducted weekly bird surveys in the canyon in 2012, walking the trail and identifying and counting every bird seen.   Fourteen individual, experienced observers (including AFC Board member Laura Garrett) completed about a dozen surveys through June, and they note the start and ending times, recording any nesting birds as well as migrants that depend on the water, insects and other foods provided by the canyon. The first survey tallied a whopping 25 Black-throated Gray Warblers in the oaks, along with many other migrants. Surveys thus far are recording about 150-180 individual birds of 32 to 38 species per survey, and to date at least 56 bird species total have been recorded.

Pellets formed by Great Horned Owl, found in Millard Canyon

During an April visit to the canyon, I picked up two pellets from a Great Horned Owl lying along the trail under the oaks.  Owl pellets are formed from the undigested fur and bones of food items and are regurgitated by the birds nightly shortly after a meal. They are a great source of information on nocturnal animals living in an area, and careful cleaning and analysis of these yielded three medium-sized rodent skulls in the two pellets. Expecting they were from the common native wood rats of our canyons, I was a bit surprised to find, based on skull and tooth features, they were Roof Rat (Rattus rattus), two adults and one young. Roof rats are an undesirable inhabitant of attics and sometimes in Rodent remains found in Millard Canyonwild canyons as in this case. Are the owls hunting in the adjacent housing tracts each night, helping control these introduced rodents? Along with these mammals, small parts of Jerusalem crickets (“Potato Bugs”) were also found in both pellets, indicating that these large local owls are also dining on these rather large (2”) insects at night.

AFC biologist Thomas Juhasz conducted specialized surveys for the possible presence of the Endangered Arroyo Toad (Anaxyrus californicus) and other amphibians. In addition to birds, the plants of Millard are also under scrutiny. From surveys conducted by Juhasz and by me, we know the property and vicinity supports at least 107 plant species, both native and introduced. One of the most interesting is the beautiful, orange-flowered Humboldt lily (Lilium humboldtii var. ocellatum), a California Native Plant Society “Limited Distribution”species, found in two small populations on the property.

All this information further validates the outstanding biological values of the Millard Canyon property and supports the application for grants with the State and Federal Agencies.

- Mickey Long, AFC advisor and field biologist
April 26, 2012