Birds, Pesticides, and Flowering Gardens

Summary: Birds and pesticides do not mix! Join Kiersten and Cheryl as they talk about the history of birds and pesticides, the current status of birds and pesticides, and discuss what we can do in our own backyards.

 

For our hearing-impaired listeners, a transcript of this podcast follows the show notes on Podbean.

 

Show Notes:

“Huge decline in songbirds linked to common insecticide.” National Geographic, https://www.nationalgeographic.com

“A neonicotinoid insecticide reduces fueling and delays migration in songbirds,” by Margaret L. Eng, Bridget J. M. Stutchbury, and Christy A. Morrissey. Science, Vol 365, Issue 6458, pp. 1177-1180.

“Take Flight From Lawn Pesticides: Tips for Organic, Bird-Friendly Gardening,” by Hardy Kern, April 12, 2022. https://abcbirds.org

 

DIY Pesticides: Lawn Love, https://lawnlove.com

Natural Lawn Care Products: Jonathan Green, https://www.jonathangreen.com

For more information on rodenticides and birds please listen to our episode titled: Rodenticides: A Deadly Decision

 

Transcript:

Kiersten: Intro – Pesticides and birds do not mix. They have a long and devastating history ever since humans have begun using synthetic chemicals. In this episode we’re going to look at some of that history, current issues, and what we can do to help in our own backyard.

 

Cheryl: As Kiersten likes to do, we’re starting off with the definition of a pesticide.  A pesticide is anything that kills off something that humans have decided is a pest. They can be classified into insecticides that kill insects, rodenticides that kill rodents, herbicides that kill unwanted weeds, and fungicides that kill fungus. Every kind of pesticide affects birds. Usually in a detrimental way.  Since the 1940s, since the use of synthetic pesticides became more widely used, bird populations have continuously declined. Today around 1 billion pounds of pesticides are sprayed into the environment just in the United States.

 

Kiersten: Let’s take a look at what brought our attention to the fact that pesticides that we were using in the environment were killing off birds. Some of you may have heard of or read the book Silent Spring. Written by Rachel Carson this book brought attention to what pesticides such as organochlorines were doing to our environment. It focused on a specific pesticide known as DDT. It was used to kill off insects on crops and it was very effective. What we didn’t initially know was the long-lasting devastation that these chemicals could cause in the environment.

            All chemicals break down and when DDT breaks down it leaves behind DDE. DDE wreaked havoc on the lives of birds. Organochlorides are extremely persistent. They remain active for a long time and they are fat soluble which means they can accumulate in the fatty cells of organisms that are exposed to them and accumulate over time. I’m sure you see where I’m going with this. Birds that ingested insects sprayed with DDT didn’t just poop out the chemicals, they absorbed them into their system. Then when those birds were eaten by predators, the chemical was passed on to them. This is a process called biomagnification and with each step the contaminants become more concentrated.

            All birds were greatly impacted, but raptors were affected most of all because they were consistently eating contaminated food. DDT impacted their entire lifecycle. They died from ingesting the chemical, it was also passed onto the embryos in eggs causing them to never develop, but the most heart-wrenching side effect was the leaching of calcium from eggs shells. Birds were laying eggs with shells so thin that when females sat on the eggs to incubated them, they were crushing their own young.

            Because of DDT many species of birds were pushed to the brink of extinction, and we did learn our lesson. Organochlorides have been banned from use in the United States, but other pesticides have taken their place.

 

Cheryl: The effects of DDT were recognized almost sixty years ago, but today birds are facing threats from another pesticide. Chemicals known as “neonics” are now causing just as many problems as DDT. Neonics are a pesticide used mainly in the farming industry. It is sprayed extensively on crops. It is also used as a coating on seeds so that when the plant grows it will incorporate the neonic throughout the entire plant. It’s great for the plant but it has presented more hurdles for our birds.

            The neonics are especially devastating to our migrating songbirds. A research paper published in 2019 has shown that migrating birds that eat seeds covered in neonics lose wait drastically and delay their migr