Date: 10/29/20 11:08 am
From: Bob Archer <rabican1...>
Subject: [obol] Re: Catharus thrush phenology: eBird Target List data
Target is on the Explore page. You can pick counties etc and see the
frequencies previously described. The Help area of eBird has a search
function as well to get you instructions.

Bob Archer
pdx

On Thu, Oct 29, 2020 at 9:04 AM Paul Sullivan <paultsullivan...>
wrote:

> Hi Wayne,
>
>
>
> Thanks for this information; it sheds good light on the question at hand.
>
>
>
> However, your explanation begs one question. Who knew there was something
> called “Target” feature in eBird? And how would one ever find it? Could
> you give a naïve, ordinary person directions to get to get to such a
> feature?
>
>
>
> Does one have to be signed up with eBird, have a large battery of eBird
> checklists on file, and a “wish list” of birds in location X to use the
> “Target” feature?
>
>
>
> Asking for a friend.
>
>
>
> Paul Sullivan
>
>
>
> *From:* Wayne Weber [mailto:<contopus...>]
> *Sent:* Wednesday, October 28, 2020 8:48 PM
> *To:* OBOL2 <obol...>
> *Cc:* PAUL SULLIVAN <paultsullivan...>
> *Subject:* Catharus thrush phenology: eBird Target List data
>
>
>
> Paul and Oregon Birders,
>
>
>
> In late October, Hermit Thrush is far more likely in your area than
> Swainson’s. Swainson’s is still possible, but highly unlikely at the late
> date of October 28.
>
>
>
> To quantify the likelihood of each species in October, I used the “Target”
> feature of eBird for nearby counties, which lists the percentage of lists
> containing each species for the whole month. Yamhill has a very small
> sample size for October (327 lists), so is not very useful. However,
> Multnomah has 8133 October lists, Washington has 5211, and Clackamas has
> 2137. Here are the results, in percentage of October checklists containing
> each species:
>
>
>
> MULTNOMAH
>
>
>
> Hermit Thrush 6.15%
>
> Swainson’s Thrush 0.87%
>
>
>
> WASHINGTON
>
>
>
> Hermit Thrush 1.34%
>
> Swainson’s Thrush 0.69%
>
>
>
> CLACKAMAS
>
>
>
> Hermit Thrush 3.37%
>
> Swainson’s Thrush 0.47%
>
>
>
>
>
> As you can see, Hermit Thrush is far more frequent than Swainson’s. I am
> surprised at the apparent scarcity of Hermit Thrushes in Washington County;
> the data for Multnomah and Clackamas are closer to what I would expect.
>
>
>
> Of course, these data are for the entire month of October. Most of the
> Swainson’s sightings were probably in the first week of October. In the
> last week, I would expect that Hermit is 10 to 20 times as likely as
> Swainson’s. However, as you know, Hermit Thrushes do spend the winter in
> your area in small numbers.
>
>
>
> In my area (Vancouver, BC), the peak fall migration for Hermit Thrushes is
> about mid-September to mid-October. I would expect that that they are not
> much later (maybe a week?) in northwestern Oregon. Thus, a date of October
> 28 is getting kind of late even for Hermit Thrush, unless your bird was
> preparing to spend the winter.
>
>
>
> I hope these data illustrate how useful “Target Lists” can be to quantify
> the likelihood of occurrence of any species in a particular month, at least
> for counties with large sample sizes. (The same could be done for an entire
> state, but this would be much less useful for a state as large as varied as
> Oregon.)
>
>
>
> All the best,
>
>
>
> Wayne Weber
>
> Delta, BC, Canada
>
> <contopus...>
>
>
>
>
>
> *From:* <obol-bounce...> [mailto:<obol-bounce...>
> <obol-bounce...>] *On Behalf Of *Paul Sullivan
> *Sent:* Wednesday, October 28, 2020 9:44 AM
> *To:* <obol...>; YamhillBirds
> *Subject:* [obol] Catharus thrush phenology
>
>
>
> It’s foggy here in McMinnville this morning. Just moments ago at 9 AM, I
> was scanning my backyard, counting the increasing number of juncos (up to
> 12 now), when a brown bird emerged from under a bush. I thought, “Oh good,
> a fox sparrow.”
>
>
>
> Then I realized, “No, it’s a THRUSH!” I locked on it with my binoculars
> as it hopped straight toward me, showing the thrush, not sparrow beak. Was
> it hermit or Swainson’s? My first thought was Swainson’s, but then I
> thought could it be hermit? I was waiting for it to turn and show me its
> tail, when it suddenly exploded sideways out of my field of view and was
> gone. I haven’t seen it again.
>
>
>
> I checked my copy of The Birds of Rummel Street that tallies 23 years of
> sightings in this backyard (1993-2016). The data displays presence or
> absence of a given species in each of 4 weeks in each month of each year.
>
> Swainson’s thrushes were recorded in 58 times, all between the first week
> of April and the first week of October.
>
> Hermit thrushes were recorded in 3 times between May and October, and 4
> times between the third week of November and the second week of February.
>
>
>
> What do folks who follow phenology say?
>
>
>
> Paul Sullivan
>
> McMinnville
>

 
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