MD/DC and the Possible Red Crossbill Split
Phil Davis (pdavis@ix.netcom.com)
Fri, 16 Jan 1998 23:10:13 -0500
Maryland / DC Birders -
The following message from Chair of the MD/DC Records Committee, Harvey
Mudd, asks for your help is support of the impending problem of splitting
Red Crossbills in multiple species (maybe even up to nine !). Please read
Harvey's message and be sure to check out the highly informative web site
on the various types of Red Crossbills. The web site (URL is at the end of
Harvey's message) gives samples of the calls of the various Red Crossbill
types, as well as other valuable information.
Thanks for your support on this initiative.
Phil Davis
MD/DCRC, Secretary
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The current irruption of Red Crossbills into Maryland presents area birders
with an opportunity to help unravel one of the more complex biological
situations in current North American ornithology.
As detailed by Paul DeBenedictis in his article "Red Crossbills, one
through eight" [Birding 27(#6), 494-501, 1995], crossbills have recently
been under intensive study by, among others, Jeffrey Groth who, in 1993,
published a monograph on them ("Evolutionary Differentiation in Morphology,
Vocalizations, and Allozymes among Nomadic Sibling Species in the North
American Red Crossbill": Univ. of California Publications in Zoology, 127,
1-143, 1993). Charles Sibley in his computerized "Birds of the World",
1996, mentions that, in a personal communication Groth had told him he
intended to propose splitting the North American forms of Red Crossbill
into 9 species.
At some time in the future, the AOU may accept some or all of these splits.
The policy of the Maryland/District of Columbia Records Committee
(MD/DCRC) is to follow AOU taxonomy. The question will then arise "Which
of these species has been recorded in Maryland and/or the District of
Columbia?" At present, Red Crossbill is not on the list of species that
MD/DCRC seeks to review.
However, rather than await the next crossbill invasion (scheduled for
roughly 20 years from now), MD/DCRC is attempting to get ahead of the curve
by soliciting tapes of the calls of the current invaders. We will
undertake to have sonograms prepared from the tapes in a centralized,
uniform manner, and deposit these sonograms in the MD/DCRC files for
possible future use.
The call types appear to be a major criterion for distinguishing the
Groth-proposed species, and according to DeBenedictis the races currently
recognized in specimens on morphological grounds cannot at the moment be
associated with certainty with call types. Thus, even study of museum
specimens might not permit resolution of the problem for MD and DC.
Since the opportunity to obtain such tapes may pass us by at any moment,
MD/DCRC urgently requests that observers who tape crossbill calls in
Maryland or DC send the tapes (or high quality copies of the originals) to
Phil Davis (2549 Vale Court, Davidsonville, MD 21035). If requested, after
sonograms have been prepared Phil will return the original material
submitted as well as copies of the sonograms themselves for the use of the
observer in sorting out the "species" he/she has recorded. If anyone
prefers to do the conversion to sonograms him/herself, he/she should please
send copies of the sonograms directly to Phil, with a notation as to what
program was used for the conversion. For all tapes or sonograms, it would
be most helpful if the observer were to note the exact locality, time,
flock size and even sex ratios, as well as the types of trees in which the
crossbills were feeding and the number (if any) of other species (i.e.
White-winged Crossbills) in the flocks.
To date, we are aware of type 3 and 4 calls having been identified in
Maryland. Tapes of other call types would certainly be of great interest.
However, our aim is to obtain a representative sampling of the calls from
various areas where crossbills are seen or heard in MD and DC. The help
and cooperation of all area birders will be most appreciated in
accomplishing this goal.
Thanks in advance to all who participate.
Harvey Mudd, Chair MDDCRC
P.S. Much additional information about the red crossbill situation is
available at the internet web site of the American Museum of Natural
History, "Crossbills: audiovisual guide", at:
http://research.amnh.org/ornithology/crossbills.
____________________________________
S. Harvey Mudd
NIMH/DIRP/LMB Building 36, Room 2D-15 36
CONVENT DR MSC 4070
BETHESDA MD 20892-4070
tel: 301-496-0681; fax 301-402-0245 email: shm@codon.nih.gov
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Phil Davis
home: PDavis@ix.netcom.com Davidsonville, Maryland, USA
work: PDavis@OAO.com Greenbelt, Maryland, USA
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