Pro-Sevin
From: Chuck Abare
INTRODUCTION
Purple Martins are very adaptable creatures. If they hadn't been able to make the shift from nesting in trees to human prepared nest sites, they would not be nearly as numerous. Because we have attracted them, we have a responsibility to provide the best care that we can for them. We build housing that protects them from outside factors like weather, predators and nest competitors. We even supply calcium-rich eggshells or grit to supplement their diet. One area that is under debate is the prevention of pest infestation. Mites, lice, ants and blowflies can make the birds miserable at best and even manage to kill hatchlings. By having the birds in such close proximity to each other causes the pest problem to explode. In effect, we have caused the problem, so we must solve it. Nothing is nearly as effective as 5% Sevin Dust. Careful dusting at the onset of pest infestation effectively eliminates them. A one-time application solves the problem for the breeding season. Data from the EPA clearly shows that this pesticide is safe. Certainly, the risk of chick mortality is greater from pests than from Sevin. Research needs to be done to find the most efficient (minimum) dosage and application techniques so that we minimize the risks to the birds.
LEGALITIES
Landlords who use pesticides are concerned as to the legalities of their usage. Technically, it is illegal to use diatomaceous earth (DE) or anything else for that matter on a wild bird nest. Realistically, prosecution would not be likely as we are aiding the birds by our actions. The key is making sure that the smallest amount necessary is used in order to minimize the risk.
RISKS
The EPA's own data from their Integrated Risk Information System (IRIS) shows just how safe Carbaryl (Sevin) really is. In order for Carbaryl to even affect a human, 5.48 mg/day. It has a moderate to low mammalian toxicity. It is not considered to be an oncegen (tending to cause tumors). It is a weak mutagen (tending to cause mutations) and available data indicates that it has only low teratogenic potential (causes extreme malformations or monstrosities). Carbaryl is not expected to contaminate groundwater. While it is extremely toxic to aquatic invertebrates and honeybees, it has only low toxicity to birds. An important aspect of Carbaryl is how quickly it breaks down and is redered harmless. Its insecticidal properties are lost after 3-10 days. Most animals, including humans, readily break down carbaryl and rapidly excrete 75% of it in 24 hours. Data suggests that there is low to very low toxicity to birds.1
DOSAGE
Most landlords are using a teaspoon of 5% Sevin Dust applied under the nest at the first sign of nest mites. It would be worthwhile to try using a 2% dust in some gourds to see if a smaller dosage would be sufficient. Also, when to dust or spray may be important. Wet solutions have been applied to cavities before nesting will success. Could dusting also be done that early? These are questions that need to be answered.
CONCLUSIONS
The presence of pests on Purple Martins and in their nests is a serious health risk. A quick and serious solution must be found for these birds that need our help to survive. A 5% Sevin Dust seems to be a most effective and low risk method to solve the problem. Just as laws make it technically illegal to make nest replacements, return fall out hatchlings to their nests and, even to use DE, a sense of reason and common sense should allow us to properly care for this exceptional bird. As long as a minimum dose is effectively applied, it surely is in the best interest of the Purple Martin.
REFERENCES
1. Sevin: A Controversial Insecticide by Winand K. Hock http://pmep.cce.cornell.edu/facts-slides-self/facts/gen-pubre-sevin.html
