As the month has progressed, spring migration has been gradually winding down here at the Audubon Starr Ranch Sanctuary in Orange County. The last migrant warblers I've seen were over a week ago, and in the last few days, it's mostly consisted of a trickle of Warbling Vireos coming through this week, and an occasional Western Tanager or Black-headed Grosbeak. Despite that, there's still been a few interesting sightings of uncommon visitors. Last week, for example, while exploring Fox Canyon, I observed an Olive-sided Flycatcher on a prominent sycamore perch.
Though our recent weather has felt more like something from February, breeding activity chugs along, with plenty of nesting all around us. Among the nests I recently found was an Anna's Hummingbird nest along Bell Creek, and I was also thrilled today to find two freshly-hatched chicks in our bluebird box near the visitor parking area! I have also observed increasing numbers of fledglings out and about; in the past week this has included quite a few young House Wrens and Oak Titmice shadowing their parents. I even encountered some adorable Mallard ducklings with their mother while conducting aquatic vertebrate surveys in the southern stretch of Bell Creek last week.
There are also some notable raptor updates: last Wednesday I saw a White-tailed Kite soaring above the grassland area of lower Bell Canyon! This species used to be more common here, with up to 5-6 pairs historically breeding on Starr Ranch. While White-tailed Kites are believed to be nomadic, with populations shifting in response to cyclical prey abundances, they have experienced a steep population decline throughout Southern California in recent decades. Causes of this decline include habitat loss, as their favored grassland and scrub hunting grounds have been replaced by development, and has perhaps been exacerbated by prolonged drought over the years. It's been over two years since the last documented kite sighting on the sanctuary, so it's encouraging to see that they're not yet totally gone.
Additionally, I noticed a pair of noisy Peregrine Falcons soaring above the upper reaches of Bell Creek in the very northern corner of Starr Ranch a few days ago. In recent months, I've seen a falcon perhaps once a month at different areas of the property, but this week's observation is very exciting as it strongly suggests nesting activity! Peregrine Falcons have seen something of the opposite trend as White-tailed Kites, as their populations have recovered strongly since the 1970s, when the species was endangered in North America from effects of DDT contamination. In Orange County, Peregrines were absent for nearly 4 decades, but now may be more abundant than they were historically. However, in over 40 years of sanctuary history, Peregrines have never nested on Starr Ranch property! The steep, rocky cliff faces in upper Bell Canyon, where I saw the pair, certainly make for prime Peregrine Falcon nesting habitat, and I'll be hoping to peruse the area for more sings of breeding this season.
And with that, here's a list of all species observed at Starr Ranch since May 11th:
Great Horned Owl
Robert Snowden is the seasonal ornithologist at the Audubon Starr Ranch Sanctuary.