[obol] A Trip to NoCal, ideas about vagrant searching on the Oregon Coast

[DAVID IRONS]

Greetings All,

I just returned from a fabulous weekend of birding in Humboldt County, CA.  
Jennifer Brown and I spent the weekend with David Fix (former Oregonian) and 
Jude Power at their home in Arcata, CA.  We birded all day Sunday and the 
first half of today before heading home about 2:30.

This is my first trip to Humboldt during the prime fall vagrant season and I 
have always had a great curiosity about the sort of sites that host vagrant 
passerines and the most effective strategies for finding them.  I learned 
much and we had great success in actually finding a couple vagrant warblers.

The vagrants, semi-vagrants, and late migrants we found (no chased birds) 
included:

Black-throated Blue Warbler
Blackpoll Warbler
Palm Warbler
Orange-crowned Warbler (4-5 on Saturday)
Yellow Warbler (at least five on Saturday)
White-throated Sparrow
Say's Phoebe
Pacific-slope Flycatcher
Warbling Vireo


This morning we found a female Black-throated Blue Warbler in the "Entrance 
Patch" on the north spit of Humboldt Bay (Fairhaven area) and a 
White-throated Sparrow at the Cypress grove at the end of the spit.  The 
Entrance Patch is right at the entrance of the Coast Guard Station just 
before you get to the end of the spit.  On Saturday we helped David and Jude 
lead a Redwood Regional Audubon field trip to the South Humboldt Bay NWR in 
the morning.  We spent the remainder of the day birding the Ferndale Bottoms 
making many stops in the strings of willows and alders that bracket the Salt 
and Eel Rivers.  During the field trip we found a Say's Phoebe.  Then in 
mid-afternoon we found an immature Blackpoll Warbler along the Salt R. and 
later found a Palm Warbler along the Eel R.  On the way north today, Fix 
followed us up to the small town of Orick in n. Humboldt Co.  We birded the 
town's small refuse transfer station which sits back in the trees down a 
gated road just w. of town.  This is a great vagrant spot that is regularly 
covered by Ken Irwin.  Here we found a Pacific-slope Flycatcher and heard a 
persistent call that sounded like a N. Waterthrush, but we could never track 
it down.  There was an American Redstart at this site on Sunday.

There are some conventional "wisdoms" about vagrant searching that I left 
behind after my experience this weekend.

1.  It does not take some special set of weather circumstances to produce 
the likelihood of vagrants.  The weather (well there wasn't any) was almost 
summer-like with clear skies, light winds, and relatively warm temps (highs 
reaching about 70F).

2.  It doesn't necessarily take being in close proximity to ocean.  The 
Blackpoll and the Palm Warbler were seen at sites that were probably two 
miles inland and there were numerous groves and lines of trees between us 
and the ocean where the birds might have stopped had they chosen to do so.

3.  It doesn't take an isolated grove of trees at the end of a long 
tree-less penninsula.  As mentioned above, the sites where we found these 
vagrants were not the closest to the ocean or particularly isolated from 
other trees.

Here are some of the common elements in each of our discoveries.

1.  In each case the less expected birds were found in a fairly large mixed 
passerine flock that included; one or more species of chickadee (the more 
chickadees the better), kinglets, and other more expected warbler species 
(the presence of Townsend's or Orange-crowned seemed to be a particularly 
good indicator of flock potential).  In most cases we would walk along 
fairly briskly covering a large parcel of habitat until we located a feeding 
flock.  NO FLOCK, KEEP MOVING.

2. The unusual birds were most often found within the grove or line of trees 
and not on the outside edge which was the nearly exclusive domain of 
Yellow-rumped Warblers (we proabably saw 1000 in the past two days).  
Additionally, the vagrants tended to come in after the more common species.  
Chickadees and kinglets were invariably the first respondents to pishing and 
owl calls and then the warblers would start arriving.  If you find a flock 
keep pishing until you can no longer detect new birds coming in and the 
chickadees etc. start losing interest and moving off.

3. Size of the trees seems to make a difference.  We visited numerous 
favored vagrant sites around Humboldt (sadly we could not find a good bird 
in every one) and the most productive sites invariably had mature willows 
and alders or Monterey Cypress trees that were at least 30' tall.  The low 
windblown clumps out on the spit (15' tall or less) never held a significant 
sized flock and usually had only Yellow-rumped Warblers and Common 
Yellowthroats.  Small isolated clumps or low strings of willows and alders 
will on rare occasion produce an unusual passerine, as was the case with the 
Blue-gray Gnatcatcher Alan Contreras found at Florence this weekend.  
However, it is far more efficient to focus on first finding a sizeable 
feeding flock (more likely in bigger trees) and spending time working flocks 
rather than hitting lots of little patches and pishing your face off to pull 
out a single Common Yellowthroat or Lincoln's Sparrow.  In the Fairhaven 
area along the north spit of Humboldt there are several large patches of 
Willows and Alders.  The locals actively maintain pathways into these 
patches.  They normally walk into the middle of the patch where there is 
ususally an opening with good overhead clearance and visibility before they 
start pishing to bring in a flock.

In the coming days I intend to focus my energies on finding spots in the 
Florence area that meet some of the criteria listed above.  Hopefully, I 
will have some similar successes.

Dave Irons
Eugene, OR