Date: 11/12/18 6:40 am
From: Robert O'Brien <baro...>
Subject: [obol] Myrtle vs. Audubon's
A year or so I made a plea to report the current subspecies rather than
'Yellow-rumped'.
It didn't get very far, but counting these two, separately, among their
'hoards' can be a chore.

But it's quite simple at banding stations. In California, where I grew
up(?), Myrtles are relatively
uncommon to 'rare'. Here are some data reported by Bill Bousman in South
Bay Birds.
High time to unlump, I'd say.

Bob OBrien

PS I wonder if there are similar banding data from Oregon.

-------- Forwarded Message --------
Subject: Re: [southbaybirds] Palo Alto warblers
Date: Sun, 11 Nov 2018 21:32:32 -0800
From: Bill Bousman <barlowi...> <barlowi...>
To: <southbaybirds...>

Folks:

Other numbers concerning Yellow-rumped Warblers:

From banding data at the Coyote Creek Riparian Station in the 11 years from
1986 to 1996, the number of Myrtles was 794 and the number of Audubon's
were 2847, thus 22% were Myrtles.

From banding data at Wool Ranch from 1970 to 1972 (but only in spring and
fall), the number of Myrtles was 22 and the number of Audubon's were 151,
thus 12% were Myrtles.

Observers in Central California became interested in the proportion of the
two subspecies in the late 1960s and this culminated the following table
based on CBC data (count circles not described) for five major regions (*Am.
Birds* 27:660):
Region Yellow-rumped Warbler Percent Myrtles
Outer Coast 2089
42.0
Inner Coast 440
11.6
Inner Coast Range 625 3.8
Central Valley 2239
0.7
Sierra 11
0.0
[The printed table had 4.2 percent, but was corrected in a subsequent
volume.] They also commented that "an apparent difference in habitat
preferences exists between Myrtle and Audubon types. 'Myrtle' Warblers
basically prefer riparian growth, dense lowland oak woodland or residential
parks grown to dense stands of mature deciduous trees. 'Audubon's'
Warblers, on the other hand, prefer open or newly developed residential
areas with scattered small trees and shrubs."

Our Myrtles are probably all the subspecies *hooveri *that breeds in Alaska
and the Yukon and not *coronata *that nests in northwestern Canada across
to the east coast and winters in the southeastern U.S. The subspecies
*hooveri* was named for Theodore Hoover, the President's older brother, who
eventually became Dean of Engineering at Stanford. The older Hoover was an
active birder while enrolled at Stanford and became attracted to the valley
of Waddell Creek. Later, he purchased much of that land and his
granddaughter gave it to the state, now called Rancho del Oso.

Bill Bousman
Menlo Park

 
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