Friday, June 24, 2005

Canada Goose Population Control

The ever-increasing numbers of Canada geese have led local governments to look for ways to halt their growth in population. Some have tried various means of scaring off the geese, such as dogs or pyrotechnics. (During a Christmas Bird Count this past January, a pyrotechnics contractor skewed my team's numbers by mixing up the flocks that we had counted with those we had not reached yet.) Others have oiled eggs during the breeding season, a practice that is done here in D.C. Last year, Oregon ran a pilot program of lacing bait with contraceptives and feeding it to the local Canada geese. As a population control method this appears to have been successful, as eggs were 51 percent less likely to hatch.

Large flocks of geese certainly have undesirable effects upon parks and local ecosystems. Excrement left on lawns and playing fields gets the most attention, but the geese can also wreak havoc on worthy goals like marsh or meadow restoration. The question, then, is what to do about it.

Contraceptives (or oiling of eggs) is probably preferable to the more "explosive" options. Dogs may disturb other nesting birds, and pyrotechnics affect all animals, not just the geese. Officials in Oregon claim that their program controls only geese:

The active ingredient Nicarbazin does not build up in the bodily tissue of birds, dropping to undetectable levels five days after consumption, according to the Food and Drug Administration's Web site.

Since Canada geese breed earlier than most other birds, other species who eat treated bait should not be affected, developers say....

A previous avian birth-control compound, Ornitrol, was pulled from the market in 1994 because it had adverse effects on non-target species, Wolf said.

The failure of the previous contraceptive should be cause for worry. Other birds will eat the bait provided. The newly-separated cackling goose seems particularly vulnerable to harm from this contraceptive program. The EPA ought to take the effects upon the various subspecies of Canada and cackling geese into account while weighing whether to approve the contraceptive program for widespread use.

Whatever the merits of the contraceptive program, as well as more disruptive programs, in the final analysis the surge in goose population is the problem brought on by human manipulation. Parks, lawns, and artifical ponds provide geese with attractive resting and breeding grounds. No amount of tinkering with reproductive systems will change this, so it appears to me that the population of Canada geese is likely to see a major change anytime soon.

 
{"cc_re__cc_re__cc_by_sa_3_0_us": ["reblognetwork.com/button.php?u=dendroica\" /></a>\n<br />\n\n<!-- <a href=\"http://www.bird-networks.com/\"><img src=\"http://lh4.ggpht.com/_2ssiTDreG4Y/SXaFEgHbNNI/AAAAAAAACgk/WfH1l1qra1o/s144/bsn_logo_88.jpg\" /></a>\n--> <br />\n\n<a href=\"http://www.blogoversary.com\"><img border=\"0\" alt=\"Get your own free Blogoversary button!\" src=\"http://www.blogoversary.com/button.php?born_date=2005-06-18\" /></a>\n\n<br />\n<script src=\"http://technorati.com/embed/ptyxbgc66.js\" type=\"text/javascript\"> </script> <br />\n\n<a href=\"http://creativecommons.org/licenses/by-sa/3.0/us/\" rel=\"license\"><img alt=\"Creative Commons License\" style=\"border-width:0\" src=\"http://i.creativecommons.org/l/by-sa/3.0/us/88x31.png\" /></a><br />\n</div>\n<div class='clear'></div>\n<span class='widget-item-control'>\n<span class='item-control blog-admin'>\n<a class='quickedit' href='//www.blogger.com/rearrange?blogID=13764021&widgetType=HTML&widgetId=HTML1&action=editWidget&sectionId=sidebar' onclick='return _WidgetManager._PopupConfig(document.getElementById(\"HTML1\"));' target='configHTML1' title='Edit'>\n<img al"]}