[texbirds] (VERY LONG) Is the bar too high for adding an exotic to a state list?
- From: "Collins, Fred (Commissioner Pct. 3)" <Fred_Collins@xxxxxxxx>
- To: "1 Texbirds (texbirds@xxxxxxxxxxxxx)" <texbirds@xxxxxxxxxxxxx>
- Date: Tue, 16 Jul 2013 21:31:40 +0000
IS THE BAR TOO HIGH FOR ADDING AN EXOTIC TO A STATE LIST?
MY COMMENTS ARE IN UPPERCASE WHILE THE QUOTES FROM MARK LOCKWOOD, ABA AND AOU
ARE IN NORMAL TEXT.
On Texbirds on July 15th Mark Lockwood wrote:
-----Original Message-----
From: texbirds-bounce@xxxxxxxxxxxxx [mailto:texbirds-bounce@xxxxxxxxxxxxx] On
Behalf Of Mark Lockwood
Sent: Monday, July 15, 2013 2:15 PM
To: texbirds@xxxxxxxxxxxxx
Subject: [texbirds] Parrots and other exotics
In 2009 the TBRC adopted the criteria established by the ABA in 2007 for what
is required for a species to be considered established (and for those
interested, countable). The intention was that the TBRC would make some very
minor changes to better fill a state level need and placed on the TBRC
webpages. I think that fell through the cracks and may well be my fault that
it was not completed. In any case, the list of criteria can be found here:
http://aba.org/checklist/exotics.html
I BELIEVE THAT SEVERAL SPECIES SHOULD BE CONSIDERED FOR ADDITION TO THE TEXAS
LIST THAT CURRENTLY ARE NOT INCLUDED. THOSE ARE MUTE SWAN, EGYPTIAN GOOSE,
INDIAN PEACOCK, YELLOW-HEADED PARROT, LILAC-CROWNED PARROT, RED-VENTED BULBUL,
NUTMEG MANNIKIN (SCALEY-BREASTED MUNIA) AND ORANGE BISHOP.
THE AMERICAN ORNITHOLOGY UNION (AOU) HAS THE FOLLOWING CRITERIA FOR INCLUDING
EXOTIC SPECIES:
Species that have been introduced by humans, either deliberately or
accidentally, are considered to be established if there are persistent records
for at least ten years and satisfactory evidence that they are maintaining a
reasonably stable or increasing population through successful reproduction.
Ornithologists and birders are urged to pay close attention to species
introduced in their areas and to document constancy of occurrence and changes
in population size. Introduced species often are neglected although they
provide opportunity for fascinating research.
I BELIEVE ALL OF THE SPECIES CONSIDERED IN THIS DISCUSSION WOULD QUALIFY UNDER
THE AOU CRITERIA.
THE FOLLOWING IS THE AMERICAN BIRDING ASSOCIATION (ABA) CRITERIA WITH SOME
PERSONAL COMMENTS REGARDING SOME TEXAS SPECIES CURRENTLY NOT ACCEPTED TO THE
ABA LIST.
The ABA Checklist Committee considers an exotic bird to be established in one
or more regions of the ABA Area when the following eight criteria are met:
1) The species is recorded in the form of a published photograph or a specimen
archived in an ornithological collection. This criterion ensures that species
identification can be confirmed independently.
THIS IS CERTAINLY A GOOD CRITERIA. CAN DR. ARNOLD, DR. BROOKS OR SOMEONE TELL
US WHICH SPECIES ARE INCLUDED IN A COLLECTION IN TEXAS EITHER AS A SPECIMEN
RECORD OR A PHOTOGRAPHIC RECORD.
2) There is a more-or-less-contiguous population of interacting or potentially
interacting individuals, rather than a scattering of isolated individuals or
pairs. Most exotics present within the ABA Area are limited to metropolitan
areas. For persistence, it is vital that exotic birds in these areas are not
isolated from each other but rather occur in sufficient proximity to allow
interaction and therefore gene flow. Some exotics are found in the ABA Area as
a single interacting population, while others occur in several populations that
are isolated from each other.
I HAVE A PROBLEM WITH THIS FOR A VARIETY OF REASONS. WHILE THE PREMISE HAS SOME
VALIDITY THE FACT IS THAT MANY OF THE EXOTICS ARE ESTABLISHED IN URBAN AREAS.
EACH URBAN POPULATION IS INSULAR. THEY ARE POTENTIALLY INTERBREEDING YET
ISOLATED POPULATIONS. WILL WE NOT ADD A SPECIES TO THE STATE LIST UNTIL THE
ENTIRE TEXAS TRIANGLE BETWEEN SAN ANTONIO, AUSTIN AND HOUSTON IS NOTHING BUT
SUBDIVISIONS AND SHOPPING MALLS? UNFORTUNATELY EACH YEAR THE DISTANCE BETWEEN
URBAN CENTERS SHRINKS AND SMALLER ONES GROW TOWARD OTHERS. IF A SPECIES LIKE
NUTMEG MANIKIN IS FOUND IN ALL THE MAJOR METROPOLITAN AREAS BUT ONLY IN LARGE
NUMBERS IN HOUSTON IS IT SPREADING NATURALLY OR IS IT BEING RELEASED IN ALL
METRO AREAS? HOW COULD WE KNOW? THE RED-VENTED BULBUL HAS BEEN IN CENTRAL
HOUSTON FOR AS MUCH AS 60 YEARS. IT SEEMS TO BE SLOWLY SPREADING. TODAY IT IS
MUCH MORE PREVALENT WITHIN ITS HISTORICAL HOUSTON HABITAT THAN AT ANY TIME IN
THE PAST. THIS SPECIES DOES NOT VISIT BIRD FEEDERS AND CAN BE HARD TO DETECT.
BECAUSE IT IS NOT IN MOST FIELD GUIDES AND WAS IN NO NORTH AMERICAN GUIDE UNTIL
RECENTLY, IT LARGELY WENT UNIDENTIFIED OR MISS IDENTIFIED IN THE PAST. SO FAR
THIS SPECIES HAS EXHIBITED LITTLE DISPERSAL OR HAS GONE UNDETECTED. IS THE
HOUSTON METRO AREA SUFFICIENT FOR ESTABLISHMENT? THE AREA HOSTS MORE THAN 5
MILLION PEOPLE WHO I WOULD CONSIDER A VIABLE POPULATION. HOW MUCH HABITAT IS
ENOUGH TO DECIDE IF SOMETHING IS ESTABLISHED? CERTAINLY THE HOUSTON METRO AREA
IS LARGER THAN MANY ISLANDS IN THE WORLD WITH UNIQUE INSULAR POPULATIONS OR
ENTIRE SPECIES OF BIRDS.
3) The population is not currently, and is not likely to be, the subject of a
control program where eradication may be a management goal that is likely to
succeed. Some exotics (e.g., Mute Swan) present a clear danger to native
species or habitats, or to agriculture or commerce, in some areas, and listing
these species as established may create a conflict between some birders and
land management personnel.
THIS IS PURELY A SPECULATIVE JUDGMENT CALL. WILDLIFE AGENCIES HAVE BEEN UNABLE
TO LIMIT THE SPREAD OF MOST EXOTIC SPECIES. NOT BECAUSE IT IS NOT THEORETICALLY
POSSIBLE BUT BECAUSE JURISDICTION, PRIVATE PROPERTY RIGHTS AND POLITICS ENTER
THE PICTURE. INSPITE OF MONK PARAKEETS PRIMARILY LIVING IN ELECTRIC STRUCTURES
WHERE THE UTILITIES HAD A GREAT INCENTIVE AND LEGAL RIGHT TO EXTIRPATE THEM
THEY HAVE BEEN UNABLE TO DO SO AND HAVE GIVEN UP THE EFFORT BECAUSE OF PUBLIC
OPINION. FERAL CATS ARE AS ABUNDANT AS EVER LARGELY BECAUSE OF PUBLIC OPINION.
IN SPITE OF HAVING A LEGAL RIGHT TO DESTROY AN EXOTIC ANIMAL EVEN ONE WITH
POTENTIAL PUBLIC HEALTH THREATS PUBLIC OPINION OFTEN LEADS TO ANIMALS
CONTINUING TO ROAM FREE. PRIMARILY BECAUSE OF PUBLIC OPINION I DOUBT SERIOUSLY
IF ANY OF THE SPECIES CONSIDERED HERE COULD BE EXTIRPATED BY PUBLIC OR PRIVATE
EFFORTS. WHILE THE POTENTIAL TO REMOVE INDIAN PEACOCKS IS GREAT, SUCH EFFORTS
HAVE ALWAYS ENDED WITH THE PEACOCK FLOCK HAVING BETTER PUBLIC RELATIONS THAN
THOSE THAT WOULD REMOVE THEM. I DOUBT THERE WILL EVER BE A PUBLIC OR POLITICAL
WILL TO REMOVE THE LARGER BIRDS I AM CONSIDERING: MUTE SWAN, EGYPTIAN GOOSE OR
INDIAN PEACOCK.
4) The population is large enough to survive a routine amount of mortality or
nesting failure. We cannot provide a numerical threshold for determining when
an exotic species is established. The reason for this should be obvious: No
single number would be adequate for populations as varied as large, long-lived
parrots with low reproductive potential and small, short-lived finches with
high reproductive potential. Demographic characteristics such as habitat
preferences, lifespan, reproductive output, dispersal frequencies and
distances, and genetic viability will be considered separately for each
species. Members of the CLC will critically review each species based on the
documentation provided and will make a judgment based on the best available
evidence. Much attention will be given to factors such as population size,
distribution, and, particularly, evidence of successful breeding. However, we
recognize that some number of individuals is preferable as a baseline to judge
when a species may be established. The FOSRC prefers that populations ideally
contain at least "several hundred individuals," and the CLC agrees that in
almost all cases, populations numbering only dozens of individuals may be too
small to be considered established. Additionally, information should be
provided to indicate that there is little or no evidence that ongoing releases
play a substantial role in population maintenance. For gamebirds whose numbers
may be artificially supplemented from time to time, evidence should be provided
that these releases are not necessary to maintain population size or
persistence.
ALL OF THE LARGER SPECIES AS WELL AS THE PARROTS ARE VERY LONG-LIVED BIRDS.
FIFTY YEARS MAY NOT BE LONG ENOUGH TO KNOW IF A SPECIES WILL BE SUSTAINING INTO
THE NEXT 50-150 YEARS. HOWEVER, SINCE RECORDS FOR ALMOST ALL THE EXOTICS
CONSIDERED ESTABLISHED ONLY GO BACK ABOUT 120 YEARS OR LESS, WILL ANY SPECIES
EVER AGAIN BE ACCEPTED AS A VALID EXOTIC? WE COULD EASILY ARGUE THAT THE RECENT
DECLINE OF HOUSE SPARROW IS AN INDICATION THAT ITS ESTABLISHMENT IS FALTERING.
HAVE CATTLE EGRET BEEN HERE LONG ENOUGH TO MEET THIS STANDARD? CERTAINLY
EURASIAN COLLARED-DOVE HAS NOT. UNLESS A LONG TERM DETAILED STUDY IS UNDERTAKEN
OF EACH SPECIES WE CAN NEVER HOPE TO ANSWER THESE QUESTIONS. I DO NOT BELIEVE
THIS STANDARD WAS APPLIED TO ANY OF THE GRANDFATHERED SPECIES.
5) Sufficient offspring are being produced to maintain or increase the
population. Such criteria will vary from species to species, according to
factors affecting the population, both natural (competition from other species;
effects of hurricanes) and artificial (recapture for the pet trade; culling by
hunters). Certainly, a species whose numbers are increasing and whose range is
expanding is a better candidate for establishment than a species whose numbers
and range are stable. Species with declining numbers and/or contracting range
should have a much greater evidentiary threshold to meet before being
considered established.
I CONCUR WITH THIS STANDARD BUT THEN AGAIN HOUSE SPARROW IS SAID TO BE
DECLINING.
6) The population has been present for at least 15 years. Previous CLC criteria
used a 10-year persistence threshold. As we have seen with several exotics, 10
years is an insufficient period to judge the likelihood that an exotic will
persist. Accordingly, we have increased the persistence criteria to 15 years.
The CLC readily acknowledges that 15 years may also be insufficient in some
cases to determine establishment; populations of many exotics follow a "boom
and bust" cycle over several decades-the population of Crested Mynas at
Vancouver became extirpated more than 100 years after its introduction. With
long-lived species (e.g., Amazona parrots) or when gamebird populations are
regularly subsidized, one could argue that persistence should be for 30 or more
years for genuine trends in the population to become obvious. Our point here is
that like numerical criteria, no simple formula of the number of years for
persistence can apply to all species. Flexible persistence criteria ("at least
15 years") and lack of numerical criteria will allow Committee members to
exercise their own judgment in potentially uncertain or controversial cases,
but only in the context of strong biological evidence and with the intention
that the final judgment be a conservative one.
MOST PEOPLE ONLY KNOW THE HISTORY THAT HAS OCCURRED IN THEIR LIFETIME. AS A
SOCIETY WE ARE SHORT SIGHTED. IN BIOGEOGRAPHY OUR HUMAN HISTORY IS BUT A
FLICKER OF A FLAME. LENGTH OF OCCURRENCE IS CRUCIAL TO DETERMINING WHEN
SOMETHING BECOMES ESTABLISHED BUT WE TEND TO WANT THAT TO BE WITHIN OUR
LIFETIME. WE KNOW LITTLE ABOUT THE AVIFAUNA OF TEXAS IN TERMS OF GEOLOGIC
BIOGEOGRAPHY. ANY TIME CRITERIA IS ARBITRARY AND EVEN 50 YEARS IS NO BETTER OR
WORSE THAN 15. CONSIDERING WE NOW HAVE SOME SEMBLANCE OF THE MAKE-UP OF THE
AVIFAUNA IN TEXAS FOR ABOUT THE PAST 150 YEARS, 50 YEARS SEEMS TO BE A GOOD
STANDARD, ABOUT A THIRD OF THE TOTAL RECORD PERIOD.
HOWEVER, IT IS IMPORTANT TO MAKE THE RECORDS AND MAINTAIN THEM. FROM THAT
PERSPECTIVE PERHAPS ALL THESE SPECIES AS WELL AS A FEW OTHERS SHOULD BECOME
PART OF THE OFFICIAL LIST WITH AN ASTERISK. THAT WOULD ENCOURAGE PEOPLE TO HELP
COLLECT THE INFORMATION THAT WILL HELP US LEARN THE STATUS OF THESE AND OTHER
INTRODUCTIONS.
7) The population is not directly dependent on human support. Although somewhat
subjective, this criterion is meant to exclude from consideration those exotics
that rely on direct human support for their ongoing survival and/or persistence
(reliance on bird feeders; periodic releases of additional individuals). For
instance, the Monk Parakeet population at Chicago, Illinois is wholly dependent
on bird seed provided by humans during the winter months, and this population
therefore is not recognized by the CLC as established, despite its size or
persistence.
I WOULD AGREE WITH THIS BUT TOO REALIZE THAT THE URBAN ENVIRONMENT IS PART OF
OUR OVERALL ECOSYSTEM AND AN ABUNDANT AND PERSISTENT HABITAT TYPE IN TEXAS THAT
IS AND WILL EXPAND INTO THE FORESEEABLE FUTURE. ANIMALS THAT ADAPT TO THIS
ECOSYSTEM WILL SURELY BE THE WINNERS IN THE ARMS RACE OF EVOLUTION. WHEN I WAS
A STUDENT AT TAMU IN THE LATE 60S AND EARLY 70S THE LEADING BIOLOGISTS IN THE
STATE, INCLUDING CLARENCE COTTAM, THOUGHT THE WHITE-WINGED DOVE WOULD GO THE
WAY OF THE PASSENGER PIGEON. WHITE-WINGS ADOPTED THE URBAN ENVIRONMENT. THEY
ARE NOT LIKLEY TO GO EXTINCT. ARE THEY DEPENDENT ON A MULTI-BILLION BIRD
FEEDING INDUSTRY? EDGAR KINCAID LIKEWISE THOUGHT RED-CROWNED PARROTS MIGHT
ALSO GO EXTINCT. THEY STILL MAY IN MEXICO BUT THEY APPEAR TO HAVE ADAPTED TO
URBAN ENVIRONMENTS IN THE UNITED STATES SO ARE NOW SAFE FROM EXTINCTION IT
WOULD SEEM. THE RED-VENTED BULBUL DOES NOT USE BIRD FEEDERS. HOWEVER, ITS
DISTRIBUTION SEEMS FOCUSED ON EXOTIC PLANTS IN URBAN LANDSCAPES. IS IT MORE OR
LESS HUMAN DEPENDENT THAN THE WHITE WINGED DOVE? HOW MUCH OF THE SPREAD OF THE
WHITE-WINGED AND EURASIAN COLLARED-DOVE ARE DEPENDENT ON BIRD FEEDERS AND
CHINESE TALL-TREES? I THINK WE MUST ACCEPT URBAN ENVIRONMENTS INCLUDING THEIR
BIRD FEEDERS AND EXOTIC VEGETATION ARE PARTS OF TEXAS' LANDSCAPE. THE FACT
THAT A SPECIES IS DEPENDENT ON THIS LANDSCAPE IS NO DIFFERENT THAN ONE
DEPENDENT ON TALL-GRASS PRAIRIE OR LONG-LEAF PINE FORESTS, WHICH ONLY NOW EXIST
BECAUSE THEY ARE MAINTAINED BY HUMANS. CERTAINLY THE ATTWATER PRAIRIE CHICKEN
IS FAR MORE DEPENDENT ON HUMAN SUPPORT THAN NETMEG MANNIKINS.
8) A publication, ideally in a peer-reviewed journal or book, describes, how,
when, and where the above seven criteria have been met. A publication will
streamline the voting process by clearly presenting evidence of establishment.
In the absence of a publication, the CLC may still vote on a motion to add an
exotic to the ABA Checklist if such evidence has been gathered by a Committee
member or other interested individual. In the latter two instances, a detailed
analysis of the issue must be published in a suitable scientific source if the
species has been determined to be established.
THE INTERNET AND EBIRD HAVE DRASTICALLY CHANGED THE ABILITY TO GATHER DATA FROM
FAR MORE PEOPLE THAT EVER THOUGHT POSSIBLE JUST A FEW YEARS AGO. DIGITAL
PICTURES HAVE ALLOWED THE DOCUMENTATION OF BIRD RECORDS WHICH WOULD OTHERWISE
CAUSE QUESTIONS ABOUT PROPER IDENTIFICATION. THIS IS ESPECIALLY TRUE FOR
EXOTICS SINCE THEY FREQUENTLY ARE NOT IN FIELD GUIDES. WE NOW HAVE THE ABILITY
TO TRACK EACH SPECIES FROM ACCIDENTAL OCCURRENCE AS IN THE CASE OF CLAY-COLORED
THRUSH TO COMMON RESIDENT WITH DATA REPORTED TO EBIRD. THE TOOL CAN BE
INCREDIBLY BENEFICIAL IN DOCUMENTING THE OCCURRENCE AND SPREAD OF EXOTIC
SPECIES. DAN BROOKS HAS USED BIRD WATCHER DATA TO PUBLISH SOME PEER-REVIEWED
JOURNAL ARTICLES ON SOME OF THE SPECIES MENTIONED IN THIS DISCUSSION. HOPEFULLY
MORE RESEARCHERS WILL LOOK AT HIS EXAMPLES AND BEGIN TO STUDY HOW THESE SPECIES
AS WELL AS SOME NATIVE SPECIES THAT HAVE ADAPTED TO URBAN ENVIRONMENTS ARE
ESTABLISHING THEMSELVES IN THE NOVEL ENVIRONMENTS.
Note that the CLC has not mentioned any threshold for geographic range occupied
in the ABA Area. Again, this will vary considerably between species, and the
CLC will vote on each species on a case-by-case basis. As an example, during
2006, the CLC considered adding the Black-hooded Parakeet (Nandayus nenday) to
the ABA Checklist based on a large and increasing population along the central
Gulf coast of Florida. This species met all eight of the above criteria as an
established exotic, but was nonetheless rejected because two CLC members were
concerned that its geographic range (perhaps 150 square miles) was not
sufficiently large to confirm establishment.
THIS MAY BE A VALID POINT BUT SHOULDN'T A LOWER STANDARD BE APPLIED TO THE
INDIVIDUAL STATES? FYI, HARRIS COUNTY IS 1778 SQUARE MILES, TRAVIS COUNTY 1022,
AND TARRANT COUNTY 897 SQUARE MILES FOR POINTS OF REFERENCE.
The CLC has chosen to "grandfather in" the 17 species presently found on the
ABA Checklist that exist in the ABA Area wholly as exotic populations (species
with both native and exotic populations, such as the Canada Goose or House
Finch, are considered natives). The 17 exotics species presently on the ABA
Checklist are the Mute Swan, Chukar, Himalayan Snowcock, Gray Partridge,
Ring-necked Pheasant, Rock Pigeon, Eurasian Collared-Dove, Spotted Dove,
Budgerigar, Monk Parakeet, Green Parakeet, White-winged Parakeet, Red-crowned
Parrot, Red-whiskered Bulbul, Spot-breasted Oriole, House Sparrow, and Eurasian
Tree Sparrow. (The European Starling is a native vagrant based on a specimen
from Shemya Island, Alaska). If a CLC member or any other birder believes that
one or more of these "grandfathered" species should be removed from the main
part of the Checklist, then data should be gathered and published so that the
Committee can vote on a motion for removal. The CLC readily acknowledges that
some exotics currently on the ABA Checklist do not meet one or more of the
above criteria, and that these species likely would be rejected as established
species should the new criteria be applied to them.
The CLC hopes to eventually determine the states or provinces in which
establishment has been attained for each of the 17 exotics that are on the main
list of the ABA Checklist (we cannot determine establishment of a species on a
more local level). The criteria-or more accurately, the lack of criteria!-used
to determine establishment varies among the local records committees so
substantially that the CLC feels it is necessary to produce its own list based
on the above eight criteria.
Exotic species that become extirpated will be moved from the main list of the
ABA Checklist to Appendix: 1, Extirpated Exotics, a list that currently
contains four species. For species with greatly declining populations (e.g.,
the Budgerigar in Florida), we choose to wait until the population is
completely extirpated before we vote on removing the species from the main part
of the Checklist in the (unlikely) case that the population rebounds. The ABA
Recording Standards & Ethics Committee has ruled that extirpated exotics cannot
be "counted" on lists submitted to the ABA.
In addition to the 17 exotics currently on the ABA Checklist, literally dozens
of other species have been observed within the ABA Area. In Florida more than
100 exotic birds have been documented by photographic or specimen evidence. At
some future point, the ABA CLC intends to compile a list of all exotic species
or species of uncertain provenance that have been recorded within the ABA Area.
11/19/2007
(c) Copyright 2013 American Birding Association, Inc. No material displayed on
the ABA website
A FINAL THOUGHT. WHAT IS THE PURPOSE OF THE OFFICIAL STATE LIST? DOES IT
REFLECT THE BIRDS THAT OCCUR AND HAVE OCCURRED IN THE STATE WITH THEIR
DISTRIBUTION? DO WE RECOGNIZE THOSE BIRDS THAT HAVE POPULATIONS IN THE STATE
REGARDLESS OF ORIGIN? OR IS IT A SET OF RULES FOR THE LISTING GAME?
Fred Collins
(281) 357-5324
Director: Kleb Woods Nature Center
Cypress Top Historical Park
Commissioner Steve Radack
Harris County Precinct 3
www.pct3.hctx.net<http://www.pct3.hctx.net>
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