Hi Folks!
April is the month for the big push of Palm Warblers through Maryland. The
few that have over-wintered will be gone by the end of the month. Although
the current status has Palm Warbler consisting of two subspecies, in all
likelihood they are separate species.
The Western Palm Warbler [a.k.a. Brown Palm Warbler] (Setophaga palmarum
palmarum) breeds mostly in Canada west of Hudson Bay and winters along the
Coastal Plain from New Jersey to Mexico and on the Caribbean islands. The
Eastern Palm Warbler [a.k.a. Yellow Palm Warbler] (Setophaga palmarum
hypochrysea) breeds in Canada east of Hudson Bay and winters on the Coastal Plain
from New Jersey to Texas with most along the central Gulf Coast. There is a
poorly defined "intergrade" or "hybrid" zone where the breeding populations
meet.
In Spring, the bulk of Eastern Palm Warblers migrate through Maryland in
mid-April, before the push of Western Palm Warblers in late April and early
May. In Fall the pattern is reversed with Western Palms general moving
through before Eastern Palms [note: the Fall bar graphs in the 1996 Yellow Book
are reversed; the Spring bar graphs are correct]. Most of the breeding
population of Western Palm Warblers migrates west of the Appalachian Mountains
but plenty pass through Maryland in both migration seasons. Almost all
Yellow Palm Warblers migrate east of the Appalachian Mountains; there are few
records in Allegany County and Garrett County.
The subspecies are relatively easy to distinguish. Eastern Palm Warbers are
a continous even yellow from throat to the undertail coverts. Western Palm
Warblers have white in the belly that contrasts strongly with the yellow
undertail coverts. Males and females are similar and difficult to
differentiate even when in hand. Some Yellow Palm Warbler males sing in Spring
migration while passing through Maryland.
When You eBird, remember to have the "Show subspecies" box on the right
checked. This will enable You to enter directly what kind of Palm Warbler You
saw. Your data may help speed formal recognition of two species.
Good Birding!
Jim
Jim Stasz
North Beach MD
<_jlstasz...> (mailto:<jlstasz...>)
--
-- You received this message because you are subscribed to the Google Group 'Maryland & DC Birding'.
To view group guidelines or change email preferences, visit this group on the web at http://www.mdbirding.com
Posts can be sent to the group by sending an email to <mdbirding...>
|