[obol] Wrentit trajectories

[Braz]

Two more hypothetical reasons why Wrentits have not crossed the Columbia
River into Washington:

 - They are avoiding the exorbitant Washington sales tax.

- They have not yet learned to migrate on the backs of geese the way
hummingbirds have been rumored to do.



 - Mark Brazelton




On Feb 12, 2008 12:03 AM, Norgren Family <gnorgren at earthlink.net> wrote:

>      George Jobanek was working on the
> range expansion of Wrentits back in the
> mid-seventies. Did he ever publish some-
> thing, and where? He told me of a report
> of a Wrentit in a blackberry patch in the
> middle of an open field. I think it may have
> been in the fall and he attributed it to
> a dispersing juvenile. He hinted at multiple
> such out-of-habitat sightings. Herb Wisner
> provided my favorite moment at the 2007 Eugene
> CBC countdown when he reported a Wrentit in
> downtown Springfield "That had no business
> being there!" I am not familiar with the exact
> location, but have envisioned ever since some
> exotic shrubs in a traffic island.
>     This is not meant to contradict the breeding
> habitat preferences discussed in recent postings,
> rather point out that some dispersal activity
> does occur outside the nesting season, and Wrentits
> are capable of some boldness. The first Wrentits
> on record at Finley were at Gray Creek Swamp, which
> according to Fred Zeilemaker(then refuge biologist)
> was also the only location of Salal on the refuge.
> He assumed a causal relationship. I think today's
> postings show convincingly that while Salal contributes
> to a structure that Wrentits find congenial, it is
> far from obligate. On the 1975 Corvallis CBC I
> accompanied John Annear, Fred Zeilemaker's replacement,
> on Finley's west side. We spent a long time in
> and around Gray Creek Swamp while I made the bouncing
> ball sound over and over again. It proved the least
> productive hour and half of the whole day. Late in
> the day we parked by the gate on Bellfountain Rd
> due west of Bald Top's summit. After walking through
> private woods west of the road, where a commercial
> thinning was in progress, and going to the summit
> of Bald Top, we returned to the car and I heard
> the familiar ratchet call. Two Wrentits were in
> the fencerow right at the gate. It consisted of
> Poison-oak and lots of Trailing Blackberry(the
> only native blackberry in Oregon, aka "Wild
> Mountain Blackberry" and Dewberry"). This was
> a fairly isolated patch of cover. At the very
> least the birds had to cross Bellfountain Rd
> and its extensive, mowed shoulders.
>     In November of 1976 I was riding my bicycle
> on Bellfountain Rd and stopped at the jct of
> Airport Rd to catch my breath. The ratchet call
> caught my attention, and sure enough, there were
> two Wrentits in Armenian Blackberry next to the
> gate to the property on the ne corner of the jct.
> There was heavy Douglas-fir on the west side of the road
> and at the back of the lot on the east side, but
> the pair had undeniably crossed significant open
> ground to what struck me as no advantage. Having
> read Darrel's posting I'm beginning to wonder if
> in both these cases the Wrentits were attracted
> to any dessicated and now molding berries left
> on the canes. Or perhaps some invertebrate life
> was associated with the old berries.
>      Roy Gerig gives ample evidence for the Wrentit's
> ongoing spread in Polk County. I strongly suspect
> the Valsetz basin birds arrived up the Luckiamute
> or came north from the Yaquina watershed, rather
> than advancing east up the Siletz Basin. While
> many people have opined an eastward invasion from
> the coast, presumably at multiple spots, none of
> the evidence in this thread supports that theory.
> Why haven't Wrentits moved east from Astoria up
> the Columbia, an obvious corridor of continuous
> habitat? More compelling is their near absence
> from Yamhill County. This is the biggest corridor
> between the Willamette Valley and the Coast.
> The summits between the Yamhill Basin and rivers
> to the west are almost non-existent. The westernmost
> tributary of the Yamhill rises a mere 13 miles
> from the Pacific Ocean! The fog-zone and the
> attendant Sitka Spruce described by Darrel are
> smeared and blurred across the landscape to an
> extent I have not seen in any of the corridors
> north or south of here. Yet Wrentits are represented
> by a single pair at Linda Fink's farm. If they
> really were moving inland I would expect them
> to show up there before Benton County.
>      The clincher is Jamie Simmons' data. That's
> right, data, where the rest of us have provided
> anecdotes. Breeding Bird Surveys consist of 50
> stops along a prescribed route, each half a mile
> apart. The observer looks and listens for exactly
> three minutes at each point. The route is begun
> at exactly the same time, based on date, latitude,
> and longitude. I must confess I was surprised
> by the numbers Jamie gives us. Less than one Wrentit
> for the whole route per year for the first three
> decades of the Salado BBS. If the Benton County
> birds came directly from the west, surely a fair
> number would have showed up on the Salado BBS back
> in the 70s. Observer error is certainly not a factor.
> Don MacDonald did it every year( except for 1972
> when Fred Zeilemaker was his substitute) until Jamie
> took over. I actually put Wrentit on my lifelist
> at Don's elbow, while doing a survey at Takenitch
> Creek in the Oregon Dunes.
>     The astounding jump to almost 10 Wrentits per
> survey in the past decade parallels the increase
> in Polk County described by Roy Gerig. We don't
> have a control for observer effort there, unlike
> the Salado BBS. And one can ponder the logging
> history of the Salado Route. Large areas of timber
> go untouched on private land, then harvest spikes
> when stumpage prices rise. I recall gazing across
> the Valsetz basin in 1980--hundreds of square miles
> without a clearcut. Today it is the opposite. But
> as Darrel has indicated, Wrentits frequent tall
> timber on his property. Surely Don would have recorded
> more than .58 birds per year if they were there.
>      If memory serves me right, the Eugene Wrentits
> were first consistently detected on the Lane Community
> College campus. I presume this was the first place
> they were recorded on the Eugene CBC, and for several
> years the only place. At that time my family moored
> a sailboat at Orchard Point and spent a lot of time
> on parts of Fern Ridge Reservoir's western shore,
> many spots inaccessible by road. I never heard a
> Wrentit there. In 1976 I was on the team that
> covered Zumwalt Peninsula and we found a pair
> of Wrentits. They were in closed canopy, middle-aged
> Douglas-fir with light underbrush. As far as I know,
> that was the first occurence in that part of the count
> circle. Three years ago I was back there with
> Alan Contreras and we found Wrentits at three
> widely separate locations. At times it was hard
> to tell how many there were. While some were
> associated with dense stands of Doug-fir, there
> were others on the south side of Zumwalt Park
> where only Armenian Blackberry grew, dry marsh
> to the south, lawn to the north. I believe
> one can expect to find Wrentits all along the
> western and southern edge of the Eugene CBC
> circle these days. It seems if this population
> had arrived from the direction of Florence,
> Wrentits would have showed up west of Eugene
> before they were detected on the LCC campus.
>     Then there are the Wrentits on the eastside
> of the Willamette Valley. They have been lagging
> slightly behind the birds in Polk County, but
> spreading none-the-less. No one is going to
> suggest they arrived there(Lebanon, Crawfordsville,
> Brownsville) from the west. I'm fairly confident
> the Coast Range is being colonized from the south
> and EAST. To be sure, much of the impetus is
> clearcutting and commercial regeneration, but
> it has not been luring fog-zone birds eastward.
> The founding population probably started in the
> Coquille or Umpqua Basin and has been spreading
> northward since the mid-twentieth century. A
> contributing factor there would have been not just
> temporary deforestation, but aforestation and
> reforestion.  Savannas were passively and actively
> turned to woodland, stump ranches were returned
> to forest. Lars Norgren
>
>
>
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