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Posted by Bill Pranty on 21:19:37 12/16/04
In Reply to: establishment of exotics - criteria? posted by David Scott
Hi David,
Determining the establishment of exotics in Florida falls to two committees in the U.S.: the Florida Ornithological Society Records Committee (FOSRC), and the American Birding Association Checklist Committee (ABA CLC).
The ABA CLC awaits local committee decisions regarding the addition or subtraction of exotics from states or provinces. Therefore, any decision to add a new exotic to the Florida bird list falls to the FOSRC. Following FOSRC acceptance of an exotic, the ABA CLC will then act.
Pasted below are the salient parts of the FOSRC Rules and Procedures, copied from their webpage:
http://www.fosbirds.org/RecordCommittee/RulesAndProcedures.htm
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APPENDIX A-JUDGING THE STATUS OF EXOTIC SPECIES IF FLORIDA
1. Philosophy: The Committee follows a philosophy about Exotic species similar to that of the AOU and most other ornithological organizations. Exotic birds are not really part of the avifauna and do not have a place on the State List until they are demonstrated to have or be part of an established, self-supporting population breeding freely in the wild. Information on the occurrence of unestablished Exotics has value, however, particularly for species whose ecological requirements are such that potentially they might become Established in Florida.
[snip]
3. Criteria for Establishment. The AOU Check-List, 6th ed. (1983,p. xx ), states, "Introduced species (deliberate or inadvertent) are deemed to be established if there are persistent records for at least 10 years and satisfactory evidence of maintaining a reasonably stable or increasing population through successful reproduction." This Committee follows those criteria but with several clarifications.
a. "Persistent records for at least 10 years" means satisfactory evidence of regular occurrence of a self-reproducing population within a defined geographic area continually throughout a 10 year period. It must be evident that the population within an area is maintained by a rate of natural reproduction that at least matches, preferably exceeds mortality, rather than by ongoing releases.
b. "Satisfactory evidence of maintaining a reasonably stable or increasing population" refers to evidence that the population has reached and is maintaining a size large enough that it is not in serious danger of collapse due to genetic deterioration through inbreeding. The minimum viable size differs among species depending on their mating systems, fecundity, and normal longevity. Populations with fewer than 30 actively breeding adults should be considered inadequate in any case, and populations of a few hundred breeding pairs generally are needed to provide reasonable assurance of genetic health. Satisfactory evidence" normally means that at least one detailed study of local population size and breeding biology has been published in a reputable scientific source such as a peer-reviewed journal or technical book. However, explosive population growth by widely evident natural reproduction may be considered "satisfactory evidence" if the population after 10 years can be shown to consist of several thousand freely breeding adults over a wide geographic area.
c. "Through successful reproduction" means that successful reproduction of free-living individuals has been clearly documented; that evidence is available that such reproduction is regular and routine; and that no evidence suggests that ongoing releases play a significant role in population maintenance.
d. Resilience may be a useful secondary criterion for judging Establishment. Species that have survived major perturbations such as hurricanes, habitat disruptions, etc., and subsequently nevertheless have increased in numbers, may have demonstrated a degree of natural viability - they are not critically dependent on fragile habitat conditions and they are able to reproduce at a rate greater than the minimum necessary for replacement of breeders.
e. Species that occur or have occurred in Florida as a result of unassisted vagrancy or dispersal from an Exotic population outside Florida which clearly meets all tests of Establishment within their exotic range, shall be evaluated as if they were Naturally Appearing even though they are Exotic. Thus, the placement of the House Finch on the State List, for example, does not require that it be evaluated for Establishment within Florida.
[snip]
5. Review procedures. The Committee shall review the status of any Exotic species if a credible scientific publication suggests that its status on the State List (present as Established, or absent) is incorrect, or if any 5 members of the Committee request a review. A review shall also be undertaken if a credible scientific publication suggests that the taxonomic treatment of an Established Exotic on the State List may be incorrect, notwithstanding present treatment by the AOU. The Committee shall follow the following special procedures in reviewing the status of an Exotic species in Florida in addition to the normal procedures for reviewing Reports which shall include using the deliberation progress log as appropriate to monitor review of these matters:
a. When reviewing an Exotic species for a new designation of Established as set forth above in paragraph 3.ff.; whether the population s identity and taxonomy is adequately known and Verifiable; and whether these subjects are adequately documented in a credible scientific publication. If adequate documentation does not exist, the Committee may not Vote until such documentation is published, but it should encourage the Society s members or others, including the Committee s own members, to undertake such research and to publish the results.
At the most recent FOSRC meeting, the "10-year" threshold was raised to 15 years, to better ensure establishment. )The webiste has not yet been updated to reflect this change).
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So in summary. Three events must take place before an exotic is added to the Florida list:
1) a species must be breeding and at least maintaining its numbers for 15 years;
2) verifiable evidence that confirms the identity of the species must exist; and
3) a paper that presents the data supporting proposed establishment must be published in a a peer-reviewed journal (or must be accpted for publication in the same).
In the case of the two exotics that you mentioned, Common Myna meets the first two criteria (present 15+ years, and documented by photographs) but not the third (peer-reviewed publication). Purple Swamphen meets the latter two (documented by photographs and specimens, and peer-reviewed publication) but not the first (present for 15 years). If swamphens are still found in Florida in 2012, it would be logical to review their status at that time.
Best regards,
Bill Pranty
Avon Park, Florida
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