Hailing originally from the UK, where there are many offshore island legendary for find rare vagrants, the (California) Channel Islands off the coast of Santa Barbara exert a magnetic attraction for me. Unfortunately, the most accessible islands are very large and tend not to have the same concentrating effect on migrants as the small islands off the UK. In addition, the two most westerly islands – Santa Rosa and San Miguel – are extremely exposed to the dominant NW air flow along the outer coast. This flow is a death knell for landbird migrants reaching the islands. The ideal conditions are calm with a “marine layer” (a fairly low layer of cloud typically several hundred feet off the water) or an offshore wind. For this reason, and the fact it is a shorter and cheaper boat ride, I concentrate my efforts on Santa Cruz Island.
Santa Cruz has two locations that you can easily visit
during the day – Scorpion Anchorage and Prisoners Harbor. Initially, I used to
visit Prisoners more regularly. This is the traditional location where visiting
birds go to see the endemic Island Scrub Jay and has a stream that enters the
ocean with some nice riparian areas. I have a good record of pretty much always
finding something of interest here. My best find was a Connecticut Warbler, but
other good birds have included Black-throated Blue Warbler, Nelson’s Sparrow
and Painted Bunting.
However, in recent years, I have tended to visit Scorpion more
often. Although Scorpion lacks the water and riparian attractions of Prisoners,
there are other such areas close to Prisoners that probably dilute how concentrated
migrants can get there. In contrast, Scorpion lies towards the eastern tip of
the island, which due to extensive overgrazing for many years, is much more
barren. As a result, the valley there with its eucalyptus groves seems likely
to concentrate birds that have arrived elsewhere on the eastern tip. In
addition to the eucalyptus groves, Scorpion also had a couple of patches of
fruiting fig trees that can attract birds, although these are not used as much
by migrants as I would expect.
My fellow Brit birder, Hugh Ranson, has had regular success
visiting there and has experienced four days with good fallouts of numerous
rarities including some very high-quality birds. Frustratingly for me, I have never
had a good fallout and instead have had a lot of duff trips with just one or
two “common rarities” such as Palm Warbler or Clay-colored Sparrow seen. We
haven’t been able to work out any particular weather conditions that differentiate
good days from so-so days. As a result, I am just trying the brute force the
situation by making repeated visits in the hope my luck will change. At least
in the last year or two, I have been doing a bit better and am hoping the trend
continues.
Due to potential commitments that were likely to consume
most of October, I decided to make an effort to visit Scorpion on September
23. We have had some atypical weather lately with a marine layer combined with a lot
of high cloud and monsoonal humidity and even a few showers. With such low
numbers of migrants on the mainland coast, I harbored no illusion that Scorpion
would be hopping with birds but felt there could be a few vagrants around. In
fact, a Dickcissel had just been reported out there.
Upon arrival, it was quickly apparent that there were not
too many migrants, particularly warblers, around. However, I had seen this
movie before and hoped that persistence would pay off. In particular, the first
couple of hours after the boat arrives are busy with campers hauling gear to
and from the jetty and rangers cruising around on vehicles, which creates a lot
of disturbance that dies down later on. The Dickcissel proved easy to locate
along side a couple of Lazuli Buntings, so at least I had that, although it was
bird I had seen several times previously on the island and had in fact found
the first island record at Prisoners some years back.
The first part of the campground was pretty birdless from a
migrant perspective so I headed up to the little valley that connects through
to the group campground further on. This valley is a reliable spot for migrants
and I scrounged up a few Western Tanagers, a Black-headed Grosbeak and couple
of Western Wood-Pewees. The group campground proved quiet bird wise so I
decided to retrace my steps back through the campground to the Dickcissel spot.
Near to there, the work area for revegetation efforts meant there were some plastic
trays with water, an attractive resource on such a dry island.
I just had just reached the last tree before leaving the
campground when I noticed some movement up in the eucalyptus – a gray and
yellow warbler. For a moment, I thought it was a Parula but with slightly
better looks I could see it was a Magnolia. The tree contained a mini-flock of
the Magnolia, a Yellow Warbler and 4 Bushtits. I don’t see Magnolias annually
in the county, but have found at least eight over the years, with the last one
also at Scorpion.
I then rechecked the Dickcissel area and found the flock had
increased to now include an Indigo Bunting, five Lazuli Buntings and a Brewer’s
Sparrow. Heading down towards the beach I found a small Spizella flock in the dry
creek bed that was mostly Chippings with a single Brewer’s, as well as yet more
Lazuli Buntings.
I hiked back all the way to the group campground, which was
as I anticipated less disturbed than earlier. I found a number of new migrants,
but they were all common ones. However, playing some mobbing calls at the start
of the canyon connecting back to first campground pulled in a Chestnut-sided
Warbler and gave excellent looks at a Swainson’s Thrush. As I headed back to
the dock for the return trip, I noticed my ebird list was on 49 – could I get
to 50 species? I decided to check the Spizella flock near the beach in the hope a Clay-colored Sparrow, which is fairly regular out here, might have joined them.
And voila, there were two! Excepting a ‘chase trip’ where I visited Scorpion
after a massive fall-out of rarities, this was probably my most productive trip
to date. Let’s hope the upward trend continues as I have scheduled another
visit in a couple of days.
Comments
Post a Comment