Abstract
The issue of eradicating exotics was recently dealt with in an editorial by conservation biologist Stanley Temple in the June issue of the journal Conservation Biology (see: The Nasty Necessity: Eradicating Exotics, 1990, Stanley Temple, Conservation Biology 4: (2) 113-115). After reading the thought provoking editorial, I began to consider what the avicultural responsibility was in regards to the eradication of avian exotics. In deriving an answer to this perplexing situation, the first consideration must be upon on what grounds an exotic should be eradicated? Possible rationale for such an activity might include when the exotic species displaces native species or when agricultural losses are incurred. An example of the former situation is the introduction of the starling and mynah to Australia. Both species began using nests of some parrot species and, although not scientifically proven, may have negatively affected the parrots' populations. Scientific studies are needed, however, to determine the actual effect the exotic species is having on native bird populations. Such research would require several breeding seasons to complete and, therefore, may allow the expansion and establishment of the exotic to such an extent that eradication would not be possible. Eradication of species due to the harmful effects on agricultural crops is the most frequent justification.
In California, for example, parrots are considered class "B" pests. They are destroyed only when they are a threat to public health or become agricultural pests. Unfortunately, allowing citrus-loving psittacines to increase their numbers near orange and grapefruit orchards is analogous to discovering a cancerous growth, only to cover it up until it becomes a major problem.
I believe the overriding issue is not one of the possible negative effects of the birds but, rather, one of "ecosystem integrity'.' To a certain degree we are all "exotics;' having displaced the native Americans years ago when the first settlers colonized this country. Could it be that this is the reason for our lack of concern over maintaining this country in its natural state? While native plants are becoming popular for landscape purposes, the number of non-native (exotic) plants, trees and shrubs planted in the yards of Americans is astounding. Should we be surprised that a family that originated in Europe years ago, plants their yard with exotic trees, and vacations overseas, finds no harm in having an exotic bird in their yard? As long as people find and accept exotic birds flying about, they will continue to do so.
I believe, therefore, the answer lies with our own personal philosophy regarding the necessity for maintaining environmental integrity. The fact remains that a parrot from Bolivia has no place in a north temperate zone pine-oak forest. It is unfortunate enough that the simple presence of mankind has a negative effect upon wildlife populations, yet alone to consider that we often carelessly operate our recreational vehicles and landscape our yards with exotics. Disrespect for the environment has become epidemic. Justifying the eradication of exotic species due to their possible threat to agriculture fails to consider the fact that many gamebirds such as the Ring-necked Pheasant, an exotic established by our state and federal government, is frequently an agricultural pest itself!
There should be no doubt in anyone's mind that escaped cagebirds can and do become established. The lists extracted from Long's book, included with this editorial, show that this is not just a modem day phenomena. While the lists include only "established" species, nearly every major city contains a number of feral exotics, possibly not reproductively active sufficient to maintain themselves, but with obvious presence.
Assuming that aviculturists have an overall respect for their environment and do not wish to "pollute" their states' natural areas with exotic species, what can we do? Certainly I am not advocating eradication by means of killing anything. Unlike the unending unwanted dog and cat populations that must tragically be constantly kept in check, a home for each exotic bird could likely be found.
Additionally, methods such as using mists nets, coating seed with immobilizing agents, applying "sticky" adhesives to perches, and using noose traps do exist that could capture groups of escaped exotics. Remember, most of these birds were captured once prior to exportation. The fact remains, once a bird escapes from most aviaries, unless it is a pet, it does not often warrant the effort required to retrieve it. I believe the avicultural community must have a change of attitude, a shifting of priorities and enhancement of responsibilities. We must assume the responsibility for our birds whether they are in our confinement or flying around the neighborhood. When visiting an aviculturist, notice if there are double doors and a bird net nearby. If not, "tactfully" suggest that he/she make provisions for such. The literature documents 48 species of psittacines and 35 species of estrildid finches being introduced into areas where they are not native. In a number of these cases, it was escaped groups of cage birds that sourced the feral flock. Do we really want starlings and parrots at our outside feeders instead of grosbeaks and cardinals? Should we not be as committed to the survival of the colorful North American birds as we are to those species from tropical climes?
Jack Clinton-Eitniear Managing Editor
Note: The views expressed here are of the author and not that of the American Federation of Aviculture, its Board of Directors or magazine staff.