[Tweeters] Truly special habitat - or just 'learned locations'?

[Steve Hampton]

Dennis et al,

You're probably right about climate change and Rough-legged Hawks (and
perhaps Northern Shrike as well).

A paper showed pronounced northward winter range retraction of Rough-legged
Hawks, pretty close to the rate of climate velocity (the rate at which
temperature avgs are shifting north).

Paprocki et al. 2014. Regional Distribution Shifts Help Explain Local
Changes in Wintering Raptor Abundance: Implications for Interpreting
Population Trends. *PLoS ONE 9*(1): e86814.


>From the abstract:  "We examined the latitudinal center of abundance for

the winter distributions of six western North America raptor species using
Christmas Bird Counts from 1975–2011. Also, we considered whether
population indices within western North America Bird Conservation Regions
(BCRs) were explained by distribution shifts. All six raptors had
significant poleward shifts in their wintering distributions over time.
Rough-legged Hawks (Buteo lagopus) and Golden Eagles (Aquila chrysaetos)
showed the fastest rate of change, with 8.41 km yr−1 and 7.74 km yr−1
shifts, respectively."

The eBird Trends maps for RLHA seem to support this as well.

good birding,



On Fri, Feb 16, 2024 at 1:37 PM Dennis Paulson <dennispaulson at comcast.net>
wrote:


> Jim, some years ago the entire roadside from East 90 to West 90 was in

> grasses and weeds and always had harriers and owls, but then they plowed

> most of the fields on the south side of the road.That got rid of the voles

> and their predators. The north side of the road still seems to have

> appropriate habitat, but perhaps it’s not. Also, there have been some

> floods that probably eliminated a lot of the voles (they were all over the

> road during one of them). It is impressive that whatever the vole

> population is, it’s large enough to support all those raptors. But voles

> multiply at a high rate.

>

> Rough-legged Hawks have all but disappeared from the Skagit County

> farmlands, and I don’t know how much of that is due to vole decline and how

> much to climate change. Northern Shrikes used to be fairly common in that

> area, but they too have disappeared, and perhaps neither of those species

> is wintering as far south as they used to. Same thing, of course, for Snowy

> Owls.

>

> Dennis Paulson

> Seattle

>

> > On Feb 16, 2024, at 12:44 PM, jimbetz at jimbetz.com wrote:

> >

> > Hi,

> >

> >  Have you been to the East 90?  There are Harriers, Short-eared Owls,

> Eagles, Kestrels, and

> > even the occasional Red-Tailed Hawk.  Not just a few but "concentrated"

> (common to see them

> > there this time of year and for the last 4 years that I've been going

> there.

> >

> >  However, not very far away (less than a mile or so as the owl flies) is

> the West 90 and

> > the road from there to Samish Island.  A lot of this seems, to this

> observer, to be

> > essentially the same habitat as the East 90 ... but there is no where

> near the concentration of

> > birds and very few to zero Short-eared Owls ... ???  I have seen

> harriers in the section

> > between the "wiggle in the road" and Samish Island.  And often an eagle

> or a hawk ... but

> > I've never seen a SEOW in that section.

> >  You would think that the concentration of just the harriers and SEOWs

> would deplete the

> > voles to the point that the birds would move on to different places.

> >

> >  Any ideas on why this is true?  Especially on why there are so many

> more birds at the

> > East 90.  Yes, I get it that it is all about the voles.  I just don't

> understand why

> > the area around the East 90 has so many more voles.  To my eye the

> habitat is the same -

> > the areas between the West 90 and Samish Island has been fallow for a

> similar amount of

> > time, has corn fields near by, has the same amount of water, etc.

> >

>  - Jim

> >

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-- 
​Steve Hampton​
Port Townsend, WA  (qatáy)
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